# Spitfire Combat Radius (range) evolution, limitations? (1 Viewer)



## IdahoRenegade (Dec 28, 2019)

I understand the Spitfire was more limited in range than some other fighters. I'm curious, year by year, what was the combat radius that could be achieved (with a combat-suitable, drop tank (not a fixed ferry tank)). How much did this harm it's usefulness once past the BOB, when the fighting turned towards offensive war, rather than as a point defense fighter? And how much did the Griffin engine drop the range (I'm assuming the larger, more powerful engine returned poorer fuel efficiency). Wikipedia shows a 470 mile combat radius, but doesn't tell what variant or aux tanks it would be equipped with. I haven't found much else definitive. Specifically, fighter variants, not recon versions.


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## tomo pauk (Dec 28, 2019)

Combat radius depends/depended on many factors - how much of the time the engine was pushed to the max power, ratio between internal and 'droppable' fuel, altitude and speed of cruise and/or combat. So unless those things are specified, we will not be able to arrive at a strict figure.


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## MIflyer (Dec 28, 2019)

An article I read a few years back said the Spit IX, used a fighter bomber after the Normandy invasion, with two 500 lb bombs, had a combat radius of 90 miles.

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## Shortround6 (Dec 28, 2019)

If we could find the aircraft data sheets for many of the marks it would be a start. 
like http://www.spitfireperformance.com/spit21ads.jpg 

However some are incomplete.

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## PAT303 (Dec 28, 2019)

I think this one would go a long way http://www.spitfireperformance.com/spitfire9-fuelsystem-lr.jpg

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## drgondog (Dec 28, 2019)

IdahoRenegade said:


> I understand the Spitfire was more limited in range than some other fighters. I'm curious, year by year, what was the combat radius that could be achieved (with a combat-suitable, drop tank (not a fixed ferry tank)). How much did this harm it's usefulness once past the BOB, when the fighting turned towards offensive war, rather than as a point defense fighter? And how much did the Griffin engine drop the range (I'm assuming the larger, more powerful engine returned poorer fuel efficiency). Wikipedia shows a 470 mile combat radius, but doesn't tell what variant or aux tanks it would be equipped with. I haven't found much else definitive. Specifically, fighter variants, not recon versions.


Planned Combat radius is limited to a.) internal fuel available after dropping external tanks, and b.) military/combat power time.
Maximizing combat radius included minimum use of internal fuel to warm up, take off and form up before switching to externals for climb and cruise.

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## PAT303 (Dec 28, 2019)

MIflyer said:


> An article I read a few years back said the Spit IX, used a fighter bomber after the Normandy invasion, with two 500 lb bombs, had a combat radius of 90 miles.



The biggest problem dive bombing with the Spit was speed, during training they practiced with smoke bombs but when they started operations over Normandy with real 500 pounders they found they would hit 400+ mph within seconds giving the pilots very little time to adjust, also the bombs fuses wouldn't work effectively, they were designed to arm after being dropped horizontally from a bomber not vertically in a dive.


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## pbehn (Dec 28, 2019)

Until the introduction of the Mk IX the issue wasn't range at all but performance. Even with the introduction of the MkIX there was the question of what missions you could perform because there were not really many suitable bombers to escort.


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## pbehn (Dec 28, 2019)

The internal and external fuel carried on the Spitfire was gradually increased throughout its life, but the consumption of the Merlin and later Griffon also increased. I don't think combat with wing tanks is realistic but I have read that a Spitfire Mk XIV with a slipper tank (30gal as I remember) was on par with a Spitfire Mk IX.

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## PAT303 (Dec 28, 2019)

pbehn said:


> Until the introduction of the Mk IX the issue wasn't range at all but performance. Even with the introduction of the MkIX there was the question of what missions you could perform because there were not really many suitable bombers to escort.



You need a Merlin 60 to maintain a decent level of performance once you start adding fuel, the British also seemed to be dead against doing anything that upset the handling of the Spit, they even wired up the aft fuselage tanks on their Mustangs because of it. The Spitfire could have done more if they simply gave the thing more fuel.

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## PAT303 (Dec 28, 2019)

pbehn said:


> I don't think combat with wing tanks is realistic but I have read that a Spitfire Mk XIV with a slipper tank (30gal as I remember) was on par with a Spitfire Mk IX.



It could beat both the Me109G and FW190A with the 90G tank fitted.


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## pbehn (Dec 28, 2019)

PAT303 said:


> You need a Merlin 60 to maintain a decent level of performance once you start adding fuel, the British also seemed to be dead against doing anything that upset the handling of the Spit, they even wired up the aft fuselage tanks on their Mustangs because of it. The Spitfire could have done more if they simply gave the thing more fuel.


Which aft fuel tanks in which Mustangs? The P-51B/C and D are unstable with fuel in an aft tank as are the equivalent Mustang II and III aren't they? Where would you put more fuel in which Spitfire? What more would you have done, where and when?


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## tomo pauk (Dec 28, 2019)

There is certainly no need to wait until second half of 1944 to increase fuel tankage on the Spitfire IX (picture kindly provide by Glider years ago):

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## pbehn (Dec 28, 2019)

tomo pauk said:


> There is certainly no need to wait until second half of 1944 to increase fuel tankage on the Spitfire IX (picture kindly provide by Glider years ago):


 But as with the Mustang, the rear tank made it unstable and so should be used first, with a large external fuel load it could travel into a place it wouldnt have fuel to return from.


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## tomo pauk (Dec 28, 2019)

pbehn said:


> But as with the Mustang, the rear tank made it unstable and so should be used first, with a large external fuel load it could travel into a place it wouldnt have fuel to return from.



Not the rear tank, but fuel in that tank (or tanks) was what made the Spitfire and Mustang with unstable. Mustang was stable enough once half of it's fuel from the rear tank was used up.

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## pbehn (Dec 28, 2019)

tomo pauk said:


> Not the rear tank, but fuel in that tank (or tanks) was what made the Spitfire and Mustang with unstable. Mustang was stable enough once half of it's fuel from the rear tank was used up.


 Stable enough for normal flight or combat? Not only was the Mustang faster it was more economical. At cruise settings it would go 30miles further per hour. There is no way to make the Spitfire anything like the Mustang in range, it needs much more fuel to do the same job to start with.


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## tomo pauk (Dec 28, 2019)

pbehn said:


> Stable enough for normal flight or combat? Not only was the Mustang faster it was more economical. At cruise settings it would go 30miles further per hour. There is no way to make the Spitfire anything like the Mustang in range, it needs much more fuel to do the same job to start with.



Stable enough for combat - the SOP was to use up half of fuel from rear tank and then switch to drop tanks. 
My reasoning is that people here want more range/radius on Spitfire. That does not neccesarily means that it must be good as a Mustang with rear tank. Let's recall that Mustang without rear tank (150 imp gals + 120 imp gals in drop tanks) was good for 470 miles of radius per the demanding USAAF conditions - enough for escort bombers to Magdeburg, Kiel or Stuttgart (where I fly today/tomorrow).
BTW - the Spitfire VII and VIII should be even better than Spitfire IX, they already have front fuel tankage increased to 95 imp gals, and leading edge tanks (25 imp gals total).


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## PAT303 (Dec 28, 2019)

pbehn said:


> Which aft fuel tanks in which Mustangs? The P-51B/C and D are unstable with fuel in an aft tank as are the equivalent Mustang II and III aren't they? Where would you put more fuel in which Spitfire? What more would you have done, where and when?



Both the MkIX and Mustang/P51 were unstable with full rear tanks, both required 35-40G to be burnt off before any maneuvers could be performed and both RAE Farnborough and Jeffery Quill of Supermarine asked for 30G rear tanks to be fitted to Spitfires from the MkII to no avail. The MkIII had the larger 96G main tank in 1940, PR Spitfires had the 20G under seat tank, 30G rear seat tank and the enlarged leading edge D tanks from the PR MkVI onwards in 1940, the MkV had a 29G rear tank and 45 G D/T in 1941. The MkVIII and MkIX could have come from the factory with any combination of internal auxiliary and D/T's from 1942, plus the MkIX got 66 and 75G rear tanks plus 45-50 and 90G D/T's. There was options galore in regards to increasing the Spitfires range, but like I said earlier it really needed the two speed/two stage Merlin to be truly effective, as did the Mustang/P51.


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## PAT303 (Dec 28, 2019)

pbehn said:


> Stable enough for normal flight or combat? Not only was the Mustang faster it was more economical. At cruise settings it would go 30miles further per hour. There is no way to make the Spitfire anything like the Mustang in range, it needs much more fuel to do the same job to start with.



The difference is the Spitfire could have been going to the Ruhr in 1942, the P51 didn't reach Berlin until 1944.


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## pbehn (Dec 29, 2019)

PAT303 said:


> The difference is the Spitfire could have been going to the Ruhr in 1942, the P51 didn't reach Berlin until 1944.


To do what with what?

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## drgondog (Dec 29, 2019)

There were no maneuver restrictions on the P-51B/C/D with tank at 60 gallons. In summer 1944, however SOP was 65 gallons in fuse tank unless mission combat radius exceeded 600 miles. Otherwise the practice was to burn 20+ gallons during climb to altitude before switching to externals.

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## pbehn (Dec 29, 2019)

tomo pauk said:


> Stable enough for combat - the SOP was to use up half of fuel from rear tank and then switch to drop tanks.
> My reasoning is that people here want more range/radius on Spitfire. That does not neccesarily means that it must be good as a Mustang with rear tank. Let's recall that Mustang without rear tank (150 imp gals + 120 imp gals in drop tanks) was good for 470 miles of radius per the demanding USAAF conditions - enough for escort bombers to Magdeburg, Kiel or Stuttgart (where I fly today/tomorrow).
> BTW - the Spitfire VII and VIII should be even better than Spitfire IX, they already have front fuel tankage increased to 95 imp gals, and leading edge tanks (25 imp gals total).


I don't disagree, if you take all the possible internal fuel and put it in a Mk VIII then you have maybe 140-150 gallons. The Merlin uses about 150 G/hr at maximum and 50 G/hr on cruise. So you have 20 minutes on combat power and enough for 2 hrs cruise home, but the Spitfire doesn't cruise as far as a Mustang on the same settings so they are 60 miles shorter than a Mustang with the same internal fuel. Then there are the other issues, the British made Mk VII and VIII and sent them to Malta and the far east. What aircraft would they escort? Neither the British nor the USA had suitable bombers for daylight raids until 1943. To have an escort force on a long range mission you need at least three waves, very quickly you need 1000 planes and pilots to mount the campaign. The British had invested massively in night bombing and bombed Cologne with 1000 bombers in May 1942, how do you make a case for more investment in day bombers and fighters to do the same job?

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## Admiral Beez (Dec 30, 2019)

The FAA got the combat range extended with slipper tanks, see bottom of Armoured Aircraft Carriers


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## Zipper730 (Dec 30, 2019)

Regarding fuel capacity, if I recall (I should know this but don't), the baseline fuel load was 85 (imp) gallons in the forward fuselage; then for reconnaissance variants: A tank (uncertain as to volume) was added in the rear fuselage (a ballast, which was added to correct for the weight of the constant-speed propeller, was removed for this), then an additional rear tank (unsure as to size), and one under the pilot's seat (which I'm uncertain of what its capacity was, or why it was later removed), of which, at least one of the rear-tanks were carried over onto some of the Mk.V's; The wings would see, on the PR variants: 66 (imperial) gallons in each leading edge, ahead of each of the wing's main-spars; on the VII, VIII, IX: 13 or 14 (imperial) gallons to each leading edge ahead fo the spar.

Anybody have anything more?


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## Kevin J (Dec 31, 2019)

Zipper730 said:


> Regarding fuel capacity, if I recall (I should know this but don't), the baseline fuel load was 85 (imp) gallons in the forward fuselage; then for reconnaissance variants: A tank (uncertain as to volume) was added in the rear fuselage (a ballast, which was added to correct for the weight of the constant-speed propeller, was removed for this), then an additional rear tank (unsure as to size), and one under the pilot's seat (which I'm uncertain of what its capacity was, or why it was later removed), of which, at least one of the rear-tanks were carried over onto some of the Mk.V's; The wings would see, on the PR variants: 66 (imperial) gallons in each leading edge, ahead of each of the wing's main-spars; on the VII, VIII, IX: 13 or 14 (imperial) gallons to each leading edge ahead fo the spar.
> 
> Anybody have anything more?



AFAIK the maximum fuel load of a Merlin engined Spitfire was 286/296 IG, 266 IG for a Griffon engined one. The maximum external fuel load was 90 IG, about 28 IG was needed for take off. So if there's no wing tanks then your maximum fuel load in this scenario is 85/96 IG front fuselage and 28 IG rear plus 90 IG slipper. So max combat radius should be about 270 miles. If you added wing tanks of 28 IG and another rear fuselage tank of 28 IG then you should get a combat radius of about 360 miles.
The base line Spitfire had a combat radius of 100 miles, add a 60 IG P-40 drop tank under the fuselage and you should get about 180 miles.
You're not going to get to Berlin and back in a Spitfire fighter.


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## Peter Gunn (Dec 31, 2019)

I don't know why you guys are having such a hard time figuring range, on my way back from Michigan last week I just hit the "Range" button on the touch screen in my XT4 and it gave me the number of miles/km I could go at my current speed with what was in the fuel tank.

I mean, c'mon guys, it ain't rocket science...

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## pbehn (Dec 31, 2019)

Peter Gunn said:


> I don't know why you guys are having such a hard time figuring range, on my way back from Michigan last week I just hit the "Range" button on the touch screen in my XT4 and it gave me the number of miles/km I could go at my current speed with what was in the fuel tank.
> 
> I mean, c'mon guys, it ain't rocket science...


Thats OK as long as no pesky bandits make you put your foot down.

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## Shortround6 (Dec 31, 2019)

Peter Gunn said:


> I don't know why you guys are having such a hard time figuring range, on my way back from Michigan last week I just hit the "Range" button on the touch screen in my XT4 and it gave me the number of miles/km I could go at my current speed with what was in the fuel tank.
> 
> I mean, c'mon guys, it ain't rocket science...


Yep, it is much more complicated than that 





How many turns on what size rubber band will give how many seconds into the head wind we have today?

Or what is the airspeed of an unladen swallow?

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## soulezoo (Dec 31, 2019)

Is that an African or European swallow? (and where's the coconut?)

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## BiffF15 (Dec 31, 2019)

And what's your favorite color?


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## Peter Gunn (Dec 31, 2019)

BiffF15 said:


> And what's your favorite color?



GREEN! NO... PURPLE... WAIT!!! Bwaaaaaaaaaaaaaaaaaaaaaaa...

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## Zipper730 (Dec 31, 2019)

Kevin J said:


> AFAIK the maximum fuel load of a Merlin engined Spitfire was 286/296 IG, 266 IG for a Griffon engined one.


The Griffon engined variants had LESS internal fuel?


S
 Shortround6

W
 wuzak
do you have any figures for the rear tanks used on the Spitfire and the tank used on early PR variants under the pilot's chair?


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## pbehn (Dec 31, 2019)

Zipper730 said:


> The Griffon engined variants had LESS internal fuel?
> 
> 
> S
> ...


Its easy enough to find on the net. The Griffon took up more space and needed a bigger oil tank.


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## PAT303 (Dec 31, 2019)

Kevin J said:


> So max combat radius should be about 270 miles.



610 Squadron flew a fighter sweet from Tangmere to Isselburg, almost 400 miles with 90G D/T's and landed with 50-60G of fuel still on board. http://www.wwiiaircraftperformance.org/610-ORB-1sept44.jpg

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## BiffF15 (Jan 1, 2020)

PAT303 said:


> 610 Squadron flew a fighter sweet from Tangmere to Isselburg, almost 400 miles with 90G D/T's and landed with 50-60G of fuel still on board. http://www.wwiiaircraftperformance.org/610-ORB-1sept44.jpg



Any combat action on that sweep?


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## Kevin J (Jan 1, 2020)

PAT303 said:


> 610 Squadron flew a fighter sweet from Tangmere to Isselburg, almost 400 miles with 90G D/T's and landed with 50-60G of fuel still on board. http://www.wwiiaircraftperformance.org/610-ORB-1sept44.jpg


Yes, an interesting route. I've just looked it up, you go via the Channel Tunnel. Now me, I'd have flown by air from Rochford airport just outside Southend on Sea to Isselburg.


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## PAT303 (Jan 1, 2020)

BiffF15 said:


> Any combat action on that sweep?



No, likely explains returning with so much fuel remaining.

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## Kevin J (Jan 1, 2020)

PAT303 said:


> No, likely explains returning with so much fuel remaining.


The longest flights were England to La Pallice, France and Darwin, Australia to Timor, Indonesia, both over water so you can do them using econ cruise.


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## IdahoRenegade (Jan 13, 2020)

tomo pauk said:


> Combat radius depends/depended on many factors - how much of the time the engine was pushed to the max power, ratio between internal and 'droppable' fuel, altitude and speed of cruise and/or combat. So unless those things are specified, we will not be able to arrive at a strict figure.



What criteria did the AAC use for establishing the combat radius of escort fighters? Time to form up, fuel efficient cruise to enemy territory, high speed (defensive) cruise, XX minutes of combat, return, reserve? Had to be some standard to establish the radii defined for the P-47, P-38 and P-51. What would the various Spitfire configurations do under the same criteria?


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## tomo pauk (Jan 13, 2020)

IdahoRenegade said:


> What criteria did the AAC use for establishing the combat radius of escort fighters?



Warm up + take off (all equivalent of 5 min normal power), climb to 25000 ft using normal power (the distance covered is NOT included in range/radius), cruise at 210 indicated air speed, 5 min combat at WER, 15 min combat at military power, return to base at 25000 ft and 210 mph IAS, 30 minutes allowance at min power. No allowances for evasive maneuvers apart that 20 min worth of combat. No 'bonus' accounted for the lightened aircraft returning to base.
As for how Spitfire will do under these conditions - you could take a look at aircraft's manuals (some can be found on this forum) and data sheets (like one here) and do the back-of-the-envelope math.


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## blau (Feb 28, 2022)

IdahoRenegade said:


> I understand the Spitfire was more limited in range than some other fighters. I'm curious, year by year, what was the combat radius that could be achieved (with a combat-suitable, drop tank (not a fixed ferry tank)). How much did this harm it's usefulness once past the BOB, when the fighting turned towards offensive war, rather than as a point defense fighter? And how much did the Griffin engine drop the range (I'm assuming the larger, more powerful engine returned poorer fuel efficiency). Wikipedia shows a 470 mile combat radius, but doesn't tell what variant or aux tanks it would be equipped with. I haven't found much else definitive. Specifically, fighter variants, not recon versions.



A bit late in a thread, sorry. Actually, it's not an answer, I do share your feelings about lack of data. It seems that the question of range or fuel consumption was not considered as very important. For example, on a premium site about Spitfire (WWII Aircraft Performance), there is a big article about direct comparison between Spitfire and Me109* - Spitfire Mk. I versus Me 109 E (Spitfire Mk I versus Me 109 E)

At the very end, there are just few rows under **Miscellaneous Particulars*


*Fuel Consumption:-*



Spitfire I​Me 109 E​


Capacity85 gallons88 gallonsAll-out level89 gal/hr at 17,000'5 minute Kurzleistung69 gal/hr at 14,763'Climbing81 gal/hr at 12,000'30 minute erhöhte Dauerleistung66 gal/hr at 16,404'Cruising Rich68 gal/hr at 14,500'Dauerleistung (Continuous)59 gal/hr at 16,076'Cruising Weak49 gal/hr at 18,500'  Most economical cruising25 gal/hr at 14,000'Sparsamer Dauerflug (Most economical)55 gal/hr 

On the other hand, the same report stated maximum power of Merlin III as 1310 HP at 9,000 ft, while DB 601 A was rated as 1036 HP at 5,250 ft... So, basically 25% more power, and 20 % more fuel consumed.....

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## Vincenzo (Feb 28, 2022)

1310/1036 1,26 so 26% more power ~25%
89/69 1,29 so 29% more fuel ≠ 20%

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## GregP (Mar 7, 2022)

Looking at the Spitfire pilot manual for the IX, XI, ands XVI, we find that all of these Spitfires had a 48-gallon upper tank in the nose. The manual is British, so the "gallons" are naturally Imperial gallons. Normal Spitfires had an additional 37 gallons under the top tank. Fuselages considered "rear view," had 47 gallons. So, depending on "rear view," they had either 85 or 95 gallons. This translates into 92.4 and 104.4 U.S. gallons, if the added extra tanks are not used, as they normally weren't.

Later Mk. IX and all XVI Spitfires also had two additional tanks behind the pilot that were normally wired shut and were normally unused. On regular Spitfires, these added up to an extra 75 gallons. In "rear view" fuselages, it was another 66 gallons. These were used only for "Special Ops." In U.S. gallons, these added 90 or 79.2 U.S. gallons each.

That makes for a total of 192 or 193.2 U.S. gallons for regular and "rear view" fuselages.

The Merlin burns 130 gph at 3,000 rpm and +15 psi boost for combat. These are Imperial gallons. In U.S. gallons, that is 156.6 gph. At a 2,400 rpm cruise at +4 psi boost, it burns 54.78 U.S. gph.

Assume we have 85 Imp gallons or 92.4 U.S. gallons of fuel to start with and we allow for 5 minutes of combat. That burns 13.05 U.S. gallons. If we cruise for the rest of the time at 2,400 rpm and +4 psi boost, we have about 78 minutes of fuel remaining. Assume we want 20 minutes of reserve, so that leaves about 58 minutes of cruise at 170 – 200 mph. Assume 200 mph cruise. We can cruise outward for 29 minutes and back for 29 minutes. That means the cruise range is 96.7 miles exclusive of combat. If we start with the 95 Imp gallons, that range, or actually radius of action, becomes a whopping 115.0 miles exclusive of combat. If we are at 170 mph, the ranges for 85 and 95 Imp gallons become 82.2 and 97.8 miles.

For special ops, let's assume we have the two normally unused rear tanks full and we have 160 Imp gallons (192 U.S. gallons). Assume the same power settings, fuel consumption, and 20 minutes of reserve. The range at 170 mph suddenly become 249.3 miles and, at 200 mph, we have a range of 293.3 miles.

Recall, these ranges are really radii, not one-way ranges, and DO NOT take into account for startup, taxi, takeoff, and climb to altitude. Real radii will be less.

I have placed these ranges on a WWII map of Europe below, centered over London (have to be centered SOMEWHERE).







The small inner circles are without the "extra" tanks that were not normally used. The large outer circles are with the normally-unused extra tanks. WITHOUT the "extra" tanks, they barely make the continent. WITH the "extra" tanks, they barely make Germany, much less Berlin.

Now, later in the war, when based inside continental Europe, that might be another story. If you take off from Western Germany without extra tanks, you STILL can't make Berlin and back. With the extra tanks, you can.

The manual really doesn't SAY if a Spitfire with fuel in the extra tanks is combat-ready or not. I am assuming mostly not, but it might be they are.

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## PAT303 (Mar 9, 2022)

You forgot to add a drop tank, the Spit could carry up to 100G in a torpedo tank which gets you to Berlin, the fighter bases were right on the coast, even the Mustangs were as close to the channel as possible. I doubt any aircraft could make it to Berlin and back on internal fuel only.


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## BlackSheep (Mar 9, 2022)

PAT303 said:


> The biggest problem dive bombing with the Spit was speed, during training they practiced with smoke bombs but when they started operations over Normandy with real 500 pounders they found they would hit 400+ mph within seconds giving the pilots very little time to adjust, also the bombs fuses wouldn't work effectively, they were designed to arm after being dropped horizontally from a bomber not vertically in a dive.


I wonder what had a bigger effect, the extra 1000lbs or a lack of dive brakes in the increased dive speed? I wonder if the Brits tried adding drag with the gear down and the old tried and true pilot sticking his cupped (more efficient than a flat hand because you are literally catching air in the cup of the hand) hand out the canopy?


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## GregP (Mar 9, 2022)

I didn't forget to add a drop tank. I posted the basic radius on internal fuel. Drop tanks are another calculation problem that I'll leave to anyone who is interested.

But, just eyeballing it quickly, at cruise the Merlin burns only about 55 gph, so a 100-gallon (Imperial gallons) drop tank is really 120 U.S. gallons and the Spitfire will go very slightly more than another 2 hours. Call it two hours.

So, at 200 mph, the radius is another 200 miles (1 hour out at 200 mph and 1 hour back), which STILL doesn't get it to Berlin and back from London, even with the "extra tanks" full. What is worse is that if the 5 minutes of combat comes at the extreme radius, meaning the drop tanks are dropped, it might not make it back to England, either. So, I'd say long-range escort is not exactly the forte of the Spitfire and, in real life, it wasn't EVER going to be.

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## PAT303 (Mar 9, 2022)

London to Berlin is about 580 miles, East Anglia to Berlin is about 510 miles, warm up taxi take off and climb to 25,000ft on the top rear 33G tank, that fixes the handling problem, cruise on the DT as far as you can go which is most of Germany leaving you 42G in the rear, 96G in the main and 26G in the leading edge tanks, if the leading edge tanks are extended inwards to rib 1 like the PR versions you have 50G. Read my post #34, the Spit could have roamed all over Germany from 1943 onwards.

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## GregP (Mar 9, 2022)

If that is so, I wonder why they mostly didn't? 

Surly the people flying them might have been interested. Yes, they participated in a few "Rhubarbs," but most of the strafing was done by long-range escorts returning at low altitude from escort duty when the Luftwaffe was mostly not an issue.

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## pbehn (Mar 9, 2022)

GregP said:


> If that is so, I wonder why they mostly didn't?
> 
> Surly the people flying them might have been interested. Yes, they participated in a few "Rhubarbs," but most of the strafing was done by long-range escorts returning at low altitude from escort duty when the Luftwaffe was mostly not an issue.


Did anyone ask in 1943?


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## GregP (Mar 9, 2022)

There was an actual war on at the time. Had it been a decent bet, they would have flown those missions, don't you think?

It's easy. The fuel they had is the fuel they had to go out and back. Adding a drop tank only gets you outbound for half the drop tank. Then, you'd best be headed home.

So, he flies for 2 hours at 200 mph and drops the drop tanks. He is 400 miles away and he has no fuel in the normally-unused "extra tanks. The internal fuel he has left will get him 2 * 96.7 or 2 * 115 miles back, which will fall well short of home base. If he HAS the extra tanks full, then he has about 2 * 250 or 2 * 293 miles to fly. So, he can go another 50 miles, fly 5 minutes of combat and make it home with 20 minutes reserve OR another almost 100 miles before doing the same.

The normally-unused ":extra" tanks are unused for a reason and, if he doesn't use them, the drop tanks can get him into a LOT of trouble OR they can allow him to fly combat patrol well within the return-home range on internal fuel, which is what they actually did.

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## wuzak (Mar 10, 2022)

PAT303 said:


> London to Berlin is about 580 miles, East Anglia to Berlin is about 510 miles, warm up taxi take off and climb to 25,000ft on the top rear 33G tank, that fixes the handling problem, cruise on the DT as far as you can go which is most of Germany leaving you 42G in the rear, 96G in the main and 26G in the leading edge tanks, if the leading edge tanks are extended inwards to rib 1 like the PR versions you have 50G. Read my post #34, the Spit could have roamed all over Germany from 1943 onwards.



PR Spitfire leading edge tanks were not sealed.

The total fuel that could be fit inside a PR leading edge tank was 66 UKG (each wing), the wing fuel bags for the VIII/XIV was 13,5 UKG (IIRC). 

Is 50 UKG the total you expect for wing tanks extended inward? Double (Ish) what was in the VIII.XIV wings?


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## PAT303 (Mar 10, 2022)

GregP said:


> He is 400 miles away


With 42G in the rear tank, 96G in the main tank and 26G in the leading edge tanks, should get him home shouldn't it?


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## PAT303 (Mar 10, 2022)

wuzak said:


> Is 50 UKG the total you expect for wing tanks extended inward? Double (Ish) what was in the VIII.XIV wings?





https://images.squarespace-cdn.com/content/v1/531fdb48e4b0e8fbe6259952/1416114379008-4V3OH4A5TBUCCHD80S7S/image-asset.jpeg


Extend the tank inwards to rib one or two using the available space, that would give you 25-6G per side, 50-2G total.


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## PAT303 (Mar 10, 2022)

wuzak said:


> the wing fuel bags for the VIII/XIV was 13,5 UKG (IIRC).


The MkXIV could take on all the current models of the 109 and 190 with the 90G slipper fitted giving even more range.


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## wuzak (Mar 10, 2022)

GregP said:


> But, just eyeballing it quickly, at cruise the Merlin burns only about 55 gph, so a 100-gallon (Imperial gallons) drop tank is really 120 U.S. gallons and the Spitfire will go very slightly more than another 2 hours.



I thought you had erred in your calculations, but reading an earlier post you have converted UKG to USG to get the 55 gph figure.

Then you converted 100 UKG to 120 USG to calculate your extra flight time.

Seems like a lot of converting.


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## wuzak (Mar 10, 2022)

PAT303 said:


> https://images.squarespace-cdn.com/content/v1/531fdb48e4b0e8fbe6259952/1416114379008-4V3OH4A5TBUCCHD80S7S/image-asset.jpeg
> 
> 
> Extend the tank inwards to rib one or two using the available space, that would give you 25-6G per side, 50-2G total.



I understand now.

Looking at that picture, it wouldn't be so much an extension, but additional tanks.


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## Geoffrey Sinclair (Mar 10, 2022)

Repeating from "Wasn't the P-51 the best escort fighter of the war?" Page 32, message 623, 6 February. As of January 1944 external tanks for Spitfires being made were 30 gallon (Metal, wood, fibre) and 45, 90 and 170 gallon metal. "relevant Spitfire VIII figures from the original sources quoting maximum weak-mixture power setting as 320 mph at 20,000 ft, consuming about 1.1 gallon per minute. This corresponds with an engine setting of 2,400 rpm, +4 lbs boost (66 gallons per hour). So this seems similar. From the same source, the RAF were allocating 23 gallons for take-off and climb to 20,000 ft, and 36 gallons for 15 minutes of combat, leaving 63 gallons for cruise. This gives an endurance of 57 minutes, or a range of 304 miles, for an escort radius of 152 miles." (no reserves) 

Now using 122 versus 124 gallons above

The mark VIII was 47+49 = 96 in front of the pilot, a 14 gallon tank in each wing = 124, the early IX 48+37 = 85. Under RAF rules the early mark IX range was 434 miles versus the VIII at 660 miles, or an additional 39 gallons for 226 miles, 5.8 miles per gallon. Interestingly the mark VIII.pilot's notes talk about a 26 gallon rear fuselage tank. Morgan and Shacklady talk about an 18 gallon Mareng bag in each wing for later mark IX. A late model IX with 95 in front of and 33 gallons behind the pilot has 128 gallons, versus the mark VIII with 124. If the IX also had the wing Mareng bags its fuel load would be another 36 gallons.

The third edition of the Spitfire mark IX, XI and XVI pilot's notes has the pair of rear fuselage tanks with 75 gallons (66 for "rear view" fuselages), permission from the Area Commander is needed to fill the 75 gallon tanks for special operations, while the 66 gallon tanks for "rear view" fuselages "they must not be used in any circumstances". One reason for a pair of rear fuselage tanks was to reduce fuel movement, my understanding for the 66 gallon option = 2x33 is it was safe to enter combat after one tank was emptied but the improved elevators designed by Westland were needed to carry the rear fuselage fuel.

If we have a mark VIII using 36+22 gallons combat and reserve it leaves 66 gallons of internal fuel, 1 hour, 320 miles, add some distance for economic cruise outside hostile airspace and gains during descent, subtract an allowance for formation flying.

Off the shelf in 1943 is mark VIII with 90 gallon drop tank, 23 gallons lost to warm up and climb, leaving 67 external, add the distance covered in the climb puts the Spitfire around 300 miles from base when the tank is emptied so a radius of around 300 miles. Cumulative mark VIII production to end June 1943 was 252, halve that to account for reserves, training and losses and you have 125, around 6 or 7 squadrons, 2 wings, of Spitfires able to reach 300 miles radius under European conditions in a force able to sustain operations.

Turning to what if territory, adding a 33 gallon tank to the read fuselage of the mark VIII adds 160 miles to the range, that would require 140 to 150 gallons of external fuel to reach the new maximum possible radius. Rule of thumb seems to be 1 pound of self sealing fuel tank for 1 imperial gallon of capacity, external metal tanks maybe half of that. So 33+75 pounds of tanks, 183 gallons of 100 octane, over 1,400 pounds with around 270 pounds internal, Spitfires were cleared to carry 1,000 pounds of bombs. Use the lighter paper tanks and cut the external load to 140 gallons and save around 100 pounds.

According to the maps I have Friston England to Isselburg Germany is around 255 miles. (The road trip people say 286 miles but you need to drive to Harwich for a ferry), 610 squadron were using the Griffon engine mark XIV, which the pilots notes say had 111 gallons internal fuel plus the 90 gallon tank and the round trip is said to have used 130 to 140 gallons, allocate 40 gallons for combat and 20 for reserve and that is the fuel load.


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## Peter Gunn (Mar 10, 2022)

Ya'll have to excuse my ignorance here but, I'm using 
G
 Geoffrey Sinclair
post, but have seen reference elsewhere re:

"while the 66 gallon tanks for "rear view" fuselages "they must not be used in any circumstances"."

OK, if the Spit had fuselage tanks that were never supposed to be used, wth were they there for? Looks?

I'll assume it's a weight/balance issue then? Or did they just say screw it, we got some room back here let's just slide some unusable fuel tanks in here for giggles?


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## pbehn (Mar 10, 2022)

Peter Gunn said:


> Ya'll have to excuse my ignorance here but, I'm using
> G
> Geoffrey Sinclair
> post, but have seen reference elsewhere re:
> ...


I think they were there because they were fitted without really being tested, they had severe effects on stability.

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## tomo pauk (Mar 10, 2022)

GregP said:


> If that is so, I wonder why they mostly didn't?



Official doctrine was not allowing. Charles Portal's opinon (he was the Marshal of the Royal Air Force back then) was that escort fighters don't work.


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## Geoffrey Sinclair (Mar 10, 2022)

Peter Gunn said:


> Ya'll have to excuse my ignorance here but, I'm using
> G
> Geoffrey Sinclair
> post, but have seen reference elsewhere re:
> "while the 66 gallon tanks for "rear view" fuselages "they must not be used in any circumstances"."


I would start with the probability the pilot's notes are a post war edition, with increased safety margins, rather like the way post war Mosquitoes never flew at the weights routinely used in wartime. The P-47 and P-51 needed extra tail area to compensate for the cutting down of the fuselage, so it is logical the Spitfire would as well, but that modification did not happen to the mark IX and XVI. Leading to post war the old style fuselages were considered safe enough to use the rear fuselage tanks if the mission was considered worth it, the cut down fuselages were not.

Fuel management, the notes say take off was using the main tank, then at 2,000 feet 
a) no drop tank but rear tanks filled, switch to the rear fuselage tanks until empty.
b) drop tank, no rear tanks, switch to the drop tank until empty
c) drop and rear fuselage tanks filled, change to rear tanks until only 30 gallons left in them, then switch to drop tank until empty then back to rear tanks.

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## Milosh (Mar 10, 2022)

Geoffrey Sinclair said:


> The P-47 and P-51 needed extra tail area to compensate for the cutting down of the fuselage, so it is logical the Spitfire would as well, but that modification did not happen to the mark IX and XVI.


Spitfires got larger rudders on those MKs.


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## GregP (Mar 10, 2022)

PAT303 said:


> With 42G in the rear tank, 96G in the main tank and 26G in the leading edge tanks, should get him home shouldn't it?



I was talking about Spitfire fighters, not about PR Spitfires taking pictures. PR aircraft didn't win the skirmish, the battle, or the war. They took useful pictures that helped other people win the war. A bomber escort of PR Spitfires would be mostly useless. Yes, SOME PR Spitfires retained some guns, but they weren't exactly optimized for fighter duty and weren't used for it.

Out of 20,367 Spitfires built, the PR variety accounted for a whopping 241 or 1.2%. So they weren't exactly plentiful.

You can do the math as well as I can, I'm sure.

Cheers.


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## Shortround6 (Mar 10, 2022)

Geoffrey Sinclair said:


> c) drop and rear fuselage tanks filled, change to rear tanks until only 30 gallons left in them, then switch to drop tank until empty then back to rear tanks.


So basically the _pair_ of rear tanks was a codge (get around) of not having an appropriate sized drop tank? 
The 170 gal was too big and the 90 gal tank too small to reach the "drop point" without using more internal fuel than wanted? 

A bit like the Mustang not really having 269 gal (US) of use to use from internal tanks (and taking out the warm up-takeoff) 

So the Spitfire really was using about 30-40imp gallons plus the 90 imp gallon drop tank on the way out and the 30-35imp gallons plus forward fuselage tank/s plus wing tanks for combat and the trip back. ?


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## Geoffrey Sinclair (Mar 10, 2022)

GregP said:


> I was talking about Spitfire fighters, not about PR Spitfires taking pictures. PR aircraft didn't win the skirmish, the battle, or the war. They took useful pictures that helped other people win the war. A bomber escort of PR Spitfires would be mostly useless. Yes, SOME PR Spitfires retained some guns, but they weren't exactly optimized for fighter duty and weren't used for it.
> 
> Out of 20,367 Spitfires built, variety accounted for a whopping 241 or 1.2%. So they weren't exactly plentiful.


The total Spitfires from the British production reports is 20,349 including the following PR types, 32 III, 229 IV, 16 X (with guns), 471 XI, 200 XIX, total 973 PR types, 4.8% of production. Then there were the conversions.


Shortround6 said:


> So basically the _pair_ of rear tanks was a codge (get around) of not having an appropriate sized drop tank?


No, the pair was to minimise the problems when fuel shifted in the tank as the Spitfire flew. Like the P-51 the rear fuel caused stability problems, so again like the P-51 some of the capacity was used before switching to the drop tanks.


Shortround6 said:


> The 170 gal was too big and the 90 gal tank too small to reach the "drop point" without using more internal fuel than wanted?


How does drop tank capacity affect internal fuel usage? For most of the fuel tank arrangements on the IX the 90 gallon tank was too big. The RAF did not see the point of a 170 gallon combat tank, given internal fuel loads of 124 gallons in the VIII and 85 in the IX and from all accounts the tank had a lot of drag. So the biggest combat tank was the 90 gallon one. Add 75 gallons of rear fuselage fuel to the IX but drop that to 30 gallons on the way out leaves 85+30 = 115 gallons, less 55 gallons or so combat and reserves, leaves 60 gallons which becomes the range limit, by burning 40 or so gallons of internal fuel outbound you would be turning back with a still partly filled 90 gallon external tank, even after the deductions for warm up and climb. To take full advantage of the 90 gallon tank capacity the 36 gallons of wing tanks would need to be added, joining the rear fuselage tanks. Or else you can go the other way, reduce the external fuel so the tank is empty around maximum radius, in a hand waving approximation, the 45 gallons internal used outbound means the external fuel load drops to 45 or so gallons from 90. 


Shortround6 said:


> So the Spitfire really was using about 30-40imp gallons plus the 90 imp gallon drop tank on the way out and the 30-35imp gallons plus forward fuselage tank/s plus wing tanks for combat and the trip back. ?


If the rear tanks were fitted then yes, burn off around half of more of the fuel from the rear tanks, then switch to the drop tank, then drop the tank if entering combat, and unless there was enough internal tankage, use a smaller external tank or even a partially filled 90 gallon one.


Milosh said:


> Spitfires got larger rudders on those MKs.


(VIII and IX) Yes, but that already had them before the cut down fuselages versions were built. Using the pilot's notes the broad chord rudder was judged to be not enough for the cut down fuselage aircraft to safely use the rear fuselage fuel tanks, probably in peace time anyway.

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## GregP (Mar 10, 2022)

My production numbers for PR types don' match yours, Geoffrey, but the point is still that there weren't very many and they weren't all that useful for fighter vs. fighter combat. 

So, any missions of the type contemplated above would be in Spitfires that did NOT have leading edge tanks. Therefore, that fuel will not be there in a Spitfire on a combat mission.

And that was the point. Finding a few airframes with extra fuel doesn't make your mission really practical, even on paper, in a Spitfire and it also didn't in the real world of WWII aerial games. Spitfires were among the world's BEST at what they did, but they didn't fly ALL mission and really couldn't as a general rule.

Sure, you could cobble together a "Speed Spitfire," but you were not going to cobble together 500 of them and then go destroy Berlin. It wasn't exactly realistic approach to the end of the war.

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## Zipper730 (Mar 10, 2022)

Geoffrey Sinclair said:


> Repeating from "Wasn't the P-51 the best escort fighter of the war?" Page 32, message 623, 6 February. As of January 1944 external tanks for Spitfires being made were 30 gallon (Metal, wood, fibre) and 45, 90 and 170 gallon metal. "relevant Spitfire VIII figures from the original sources quoting maximum weak-mixture power setting as 320 mph at 20,000 ft, consuming about 1.1 gallon per minute. This corresponds with an engine setting of 2,400 rpm, +4 lbs boost (66 gallons per hour). So this seems similar. From the same source, the RAF were allocating 23 gallons for take-off and climb to 20,000 ft, and 36 gallons for 15 minutes of combat, leaving 63 gallons for cruise. This gives an endurance of 57 minutes, or a range of 304 miles, for an escort radius of 152 miles." (no reserves)


What cruise speed was needed for escort missions? Typically the P-51's flew around 300-305 mph and it's turning radius was wider than the Spitfire (a function of having a higher stall speed)...

I remember the USAAF had modified a Spitfire IXc, is this the internal fuel figures they are talking about, or was that another arrangement?


> The third edition of the Spitfire mark IX, XI and XVI pilot's notes has the pair of rear fuselage tanks with 75 gallons (66 for "rear view" fuselages), permission from the Area Commander is needed to fill the 75 gallon tanks for special operations, while the 66 gallon tanks for "rear view" fuselages "they must not be used in any circumstances". One reason for a pair of rear fuselage tanks was to reduce fuel movement, my understanding for the 66 gallon option = 2x33 is it was safe to enter combat after one tank was emptied but the improved elevators designed by Westland were needed to carry the rear fuselage fuel.


What's a "rear view" fuselage? Is that a design with a Malcolm hood?

I assume the "rear-view" fuselage designs didn't have the redesigned elevator?


> Off the shelf in 1943 is mark VIII with 90 gallon drop tank, 23 gallons lost to warm up and climb, leaving 67 external, add the distance covered in the climb puts the Spitfire around 300 miles from base when the tank is emptied so a radius of around 300 miles.


The more fuel you stuff in the plane, you'll take longer to climb, so that will have to be factored in.

I would also assume that if you were going to use the aft-tanks you'd want to burn those down first to cover at least part of the climb to adjust the CG to within tolerable limits for combat; then switch to drop-tanks for the rest of the climb and flight until combat starts.

BTW: I remember some of the early PR variants had a tank under the pilot that was added: I don't know why that was removed from later aircraft, if there was a good reason.



tomo pauk said:


> Official doctrine was not allowing. Charles Portal's opinon (he was the Marshal of the Royal Air Force back then) was that escort fighters don't work.


Ironically, night-fighters were often used to cover bomber-formations.


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## GregP (Mar 10, 2022)

Zipper730 said:


> What cruise speed was needed for escort missions? Typically the P-51's flew around 300-305 mph and it's turning radius was wider than the Spitfire (a function of having a higher stall speed)...
> The Mareng bag was in lieu of the normal wing-tanks, so it would add 8 gallons versus 36 gallons for a grand total (internal) of 150 gallons for the Mk.VIII and 158 gallons for the Mk.IX.
> 
> I remember the USAAF had modified a Spitfire IXc, is this the internal fuel figures they are talking about, or was that another arrangement?
> ...


The 1-g stall speed doesn't have a lot to do with turning radius. A Spitfire in a level turn at 200 knots (or any OTHER speed) pulling 3-g has exactly the same turn radius as any OTHER airplane at 200 knots pulling 3-g. A lower stall speed simply means that the Spitfire can get just a bit slower before stalling. The thing is, NOBODY who flew a fighter wanted to be in aerial combat anywhere NEAR the 1-g stall speed. What they wanted in a fight was to be near the stall speed for your current g-load, so their turn rate was at its best. It's all in the maneuvering envelope.

All these folks wanting to stuff more fuel into Spitfire are thinking like WWII mission planners. But in the war, they had real Spitfires to plan with, so the long-range missions went to the airplanes that could handle long-range missions. Except for a few times after some fuel managed to get stuffed in (rather late in the war), those missions just didn't involve Spitfires. Spits were reserved for what they did best, be a dogfighter.

Long range was generally the purview of the P-38 with drop tanks, the P-47 with two P-38 drop tanks (PTO, 368th FG), and the P-51 Mustang we all know about. Spitfires were tasked with short to medium-range defense and fighter attack / patrol, usually attacking enemy fighters and bombers, but sometimes getting other tasking. The PR units flew high, fast, and took great pics, but weren't used much on fighter sweeps. No use in risking them when dedicated fighter Spits were available. Also, the PR birds were mostly all assigned to PR units, not fighter units.

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## wuzak (Mar 10, 2022)

Zipper730 said:


> What's a "rear view" fuselage? Is that a design with a Malcolm hood?



It's a bubble canopy with cut down rear fuselage.

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## Zipper730 (Mar 11, 2022)

GregP said:


> The 1-g stall speed doesn't have a lot to do with turning radius. A Spitfire in a level turn at 200 knots (or any OTEHER speed) pulling 3-g has exactly the same turn radius as any OTHER airplane at 200 knots pulling 3-g. A lower stall speed simply means that the Spitfire can get just a bit slower before stalling.


Generally an airplane's corner velocity is the square root of the g-load x stall speed. The stall speed of the Spitfire was lower than the P-51 so it would be able to pull its rated g-load down to lower speeds than the P-51 would.

The P-51 also had a higher g-load so even if they were the same, the P-51 would technically be higher.


> The thing is, NOBODY who flew a fighter wanted to be in aerial combat anywhere NEAR the 1-g stall speed. What they wanted in a fight was to be near the stall speed for your current g-load, so their turn rate was at its best.


And the tightest turn rate happened to be where the rated load-factor hit the minimum speed to do it at. The turn rate would tighten down to that point; then widen out below that since you don't have enough speed to produce the lift to pull the load-factor needed.

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## PAT303 (Mar 11, 2022)

GregP said:


> I was talking about Spitfire fighters, not about PR Spitfires taking pictures. PR aircraft didn't win the skirmish, the battle, or the war. They took useful pictures that helped other people win the war. A bomber escort of PR Spitfires would be mostly useless. Yes, SOME PR Spitfires retained some guns, but they weren't exactly optimized for fighter duty and weren't used for it.








I'm not talking about PR Spitfires


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## PAT303 (Mar 11, 2022)

Why does the Spitfire have to do the Mustangs role?. Spits could have been ranging out to 400 miles over the Med, Europe the Pacific contributing far more than what they did if the RAF had the same thinking as the USAF who where at that time fitting ferry tanks to P47's to at least try and get into the fight. Spitfire VIII's and IX's flying escort to the German border from early '43 would have achieved far more than the pointless sweeps they did actually do over the channel because the RAF refused to fit aux tanks.


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## PAT303 (Mar 11, 2022)

Geoffrey Sinclair said:


> drop and rear fuselage tanks filled, change to rear tanks until only 30 gallons left in them, then switch to drop tank until empty then back to rear tanks.


Same as the 'stang, it was forbidden for pilots to do any maneuvers with drop tanks fitted or with more than 30-40G of fuel still in the rear tanks, the only exception was the MkXIV, it could fight with the 90G combat tank fitted.

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## GregP (Mar 11, 2022)

Zipper730 said:


> Generally an airplane's corner velocity is the square root of the g-load x stall speed. The stall speed of the Spitfire was lower than the P-51 so it would be able to pull its rated g-load down to lower speeds than the P-51 would.
> 
> The P-51 also had a higher g-load so even if they were the same, the P-51 would technically be higher.
> And the tightest turn rate happened to be where the rated load-factor hit the minimum speed to do it at. The turn rate would tighten down to that point; then widen out below that since you don't have enough speed to produce the lift to pull the load-factor needed.



I agree about the corner velocity, which was not a thing in WWII.

But, you didn't SAY corner velocity. You said turning radius, which has nothing to do with the corner velocity. The turning radius is only related to the velocity squared and the g-fore / bank angle. Recall the level turn g-force is 1/ cos (bank angle). I don't care if you are in a Spitfire, a Bf 109, or a Boei8ng 727, if you are at 300 mph and pulling 3-gs, the turning radius is 2,127 feet. Minimum turn radius will intersect the stall speed, for sure. But nobody in WWII or any other war was trying to engage in aerial combat as slowly as possible. If they get that slow, they are in some trouble and are likely losing the fight or at LEAST are very afraid. There isn't a lot of excess power in a WWII fighter for sustained hard turning. They were in fights that ended rather quickly and, if they WERE turning hard, the fight was descending all the time.

R = V^2 / g * tan (bank angle).

So, which one are you interested in, Zipper, corner velocity which was not once used in WWII or turning radius? Or maybe some other variable? Had you led off with corner velocity, I would have agreed, though it was NOT a number used in WWII. That came after jets, with their higher speeds, made finding the minimum turning radius in a fight a thing to be investigated. The corner velocity of an F-16 is about 450 knots, but it has an afterburner to keep the energy up to that speed. No WWII fighter will sustain much of a turn at 450 knots. Not enough power to stay level in much of a turn at that speed.

It's all good. Cheers.

Hi Pat303.

I didn't suggest the Spitfire perform the Mustang's role, IIRC, it was suggested that the Spitfire would have been a decent long-range fighter. The Mustang WAS a long-range fighter and the Spitfire wasn't, though it got better near the end of the war. It was a superb dogfighter, just not very good at doing it a long way from home.

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## GregP (Mar 11, 2022)

PAT303 said:


> Why does the Spitfire have to do the Mustangs role?. Spits could have been ranging out to 400 miles over the Med, Europe the Pacific contributing far more than what they did if the RAF had the same thinking as the USAF who where at that time fitting ferry tanks to P47's to at least try and get into the fight. Spitfire VIII's and IX's flying escort to the German border from early '43 would have achieved far more than the pointless sweeps they did actually do over the channel because the RAF refused to fit aux tanks.



Yes, perhaps. The thing is, they weren't doing that.


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## Zipper730 (Mar 12, 2022)

GregP said:


> I agree about the corner velocity, which was not a thing in WWII.


There were charts that talked about turning radius vs g-load which effectively produce the same concept, even if the term wasn't used. Airplanes generally flew at a speed that was tactically usable.

For escort that might be slower than for interception, where the goal is to get out there and destroy the bomber before he can drop bombs on target (which very well might be a city). For escort, the idea would be to be going fast enough that, if jumped by fighters, you were either going fast enough that, in the event of combat, you could either start maneuvering right away, or get up to an optimum speed quickly enough to do you good.

I'm not sure if the 320 mph speed cited for the spitfire was based on escort, general fighter sweeps, or intercept. I do recall that the P-51 usually flew a little slower on escorts, and it seemed to give a good account of itself. I'm not sure how the acceleration rate of the P-51 compared with the Spitfire at 300 or 320 mph (level flight), but I remember hearing it'd dive faster.


> The corner velocity of an F-16 is about 450 knots


I didn't know the F-16's was that high to be honest. I believe you however, since I know little about the capabilities of the F-16, but I'm surprised the number was so high.


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## BiffF15 (Mar 12, 2022)

Zipper730 said:


> There were charts that talked about turning radius vs g-load which effectively produce the same concept, even if the term wasn't used. Airplanes generally flew at a speed that was tactically usable.
> 
> For escort that might be slower than for interception, where the goal is to get out there and destroy the bomber before he can drop bombs on target (which very well might be a city). For escort, the idea would be to be going fast enough that, if jumped by fighters, you were either going fast enough that, in the event of combat, you could either start maneuvering right away, or get up to an optimum speed quickly enough to do you good.
> 
> ...


Zipper / Greg,

The number isn't far off, but it's not a hard window due to its FBW. It's more of a band and, "that's all I'm going to say about that."

Cheers,
Biff

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## GregP (Mar 12, 2022)

Below is a v-n diagram.






The so-called "corner velocity" is located where the 1-g stall speed meets the positive limit load, right where it shows "maneuvering speed" or "corner speed" above. Each v-n diagram is different for different altitudes and weights. The 1-g stall speed changes with weight: Vs new = Vs known * square root (New Weight / Known Weight). It changes with g-load as the square root of the g-load, that is: Vx new = Vs known * square root (g-load). You can calculate the max g-load at any airspeed as: n = (airspeed / stall speed)^2. If your 1-g stall speed is 95 mph and you want to pull 8g's, then the airplane will stall at 268.7 mph, or 95 * sqrt(8).

While this is all known and is built into FBW systems today, it was NOT in WWII and they didn't train WWII fighter pilots in "energy maneuvering'. WWII fighter pilots were not performing high yo-yo and low yo-yo maneuvers, unless it was by accident. They trained by flying against combat veterans who had a decent grasp of what a WWII fighter would do, but didn't exactly understand the v-n diagram above.

The turning radius question is answered by the positive load limit line, and the radius is as I described above. R = (V^2) / (g tan (bank angle)). The minimum radius is where the load limit is reached right at stall speed. Most WWII fighter pilots didn't want the minimum turn radius and didn't even know how to find it. They just wanted to beat the guy behind them right now without stalling. So, they'd pull until the airplane gave a stall warning or got to the g-limit (usually +8) and then back off a bit.


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## PAT303 (Mar 13, 2022)

Milosh said:


> Spitfires got larger rudders on those MKs.


They also got reprofiled ailerons, different bob weights and the aileron hinges were redesigned and moved to give better high speed authority from the MkII through to the MkVIII and IX, testing done on a MkIX showed it was suitable for combat with the bottom 33G tank full.

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## Geoffrey Sinclair (Mar 13, 2022)

Imperial gallons for British types, US gallons for US types. I am sure others can refine the dates, fuel loads and ranges. What would be good to see is an 8th Air Force P-51 fuel load planning document compared to the official fuel consumption performance figures. This is of course all assuming despite every theatre insisting on some Spitfire VIII and/or IX and official doctrine at the time the decision is taken to retain the mark VIII in Britain as then long range escorts, that is assuming the western German fighter defences will be strengthened and be very effective against unescorted heavy bombers, in part by withdrawing fighters from the southern front, making the tasks of the allied Mediterranean units easier, before the events actually happen.

Starting with the imaginary longest range Spitfire fighter version, 96 Gallons in front of the pilot, 36 in the wings, 75 behind the pilot internal. Burn 45 gallons of the rear fuselage fuel outbound. That leaves 96+36+30 = 162 gallons on board entering combat at maximum radius, allowing 35 gallons for combat and 22 gallons for reserves leaves 105 gallons, enough for 509 miles at 320 mph at 20,000 feet, the outbound fuel is 90 gallons external + 45 gallons rear fuselage = 135 gallons, less 23 for warm up and climb leaving 112 gallons. Call it 500 miles radius to allow for 10% more fuel consumption outbound due to the extra drag, assume 320 mph cruise all the way back to base then going vertical to the runway to account for the formation flying fuel penalty of the junior pilots at the rear of the formation.

The 2 points I take from the above is with the historical Spitfire fuel arrangements there is no point in going beyond 90 gallons external and if you were to drop the radius to 400 miles, so around 40 gallons less carried, the weight savings come to around 325 pounds (fuel and smaller self sealing tanks), which is small compared to the overall weights.

The first mark VIII to be fitted with a 75 gallon rear fuselage tank was MT818 (built in June 1944, no date for fuel trials), tests showed 37 gallons needed to be burnt off to make the aircraft properly stable. It would appear the extra weight of the mark VIII forward fuel tanks helped the stability situation.

Meantime the US modified Spitfire IX MK210 to have 43 gallons of fuel in the rear fuselage (more an under cockpit tank), 33 gallons in the wings (2x16.5) in addition to the usual 85 gallons, so 161 gallons internally, plus a pair of 62.5 gallon drop tanks. It was flown from Maine to Newfoundland to Iceland to Britain in July 1944. Weight was 10,150 pounds, still air range 1,600 miles. MK317 was similarly modified and crossed the Atlantic in September 1944. The RAF decided the wings had lost too much strength as a result of the changes. Anyway look at the dates.

The brief I assume is a Spitfire escort fighter for the 8th Air Force from mid 1943 to at the latest May 1944, after that the acute need for longer range high altitude fighters goes, while the RAF then had Mustangs with longer ranges even without a rear fuselage tank, the USAAF had many more fighters and from September the continental airfields are open. The advantage for the Spitfire changes then is any extra weight carrying ability improves the effectiveness at other operations, like fighter bomber.

The P-47 saw plenty of air combat July 1943 to May 1944 so the idea is to keep the Spitfire radius comparable to the P-47, the medium range escort by P-51 standards. The off the shelf Spitfire VIII with a 90 gallon external tank radius was about 300 miles. Add the ahistorical assumption a 33 rear fuselage tank is added sometime later and the radius becomes 380 miles.

Some limitations on 8th Air Force operations. Roger Freeman states the early B-17F, 55,000 pounds, 1,760 gallons of fuel, had a combat radius of 320 miles under 8th Air Force operational conditions, climb high quickly, fly in large, tight formations. To go further meant carrying fuel in the bomb bay. The long range "Tokyo" tanks made that radius 700 miles. 

B-17 with extra tanks, first loss, plus the last combat loss of the previous, non Tokyo tank, block.
B-17F-55-BO, production from December 1942, first 8th Air Force loss 7 May 1943, last B-17F-50-BO combat loss 30 January 1944.
B-17F-25-DL, production from January 1943, first 8th Air Force loss 14 May 1943, last B-17F-20-DL combat loss 21 February 1944.
B-17F-30-VE, production from February 1943, first 8th Air Force loss 21 May 1943, last B-17F-25-VE combat loss 22 February 1944.

The 6 September 1943 raids saw 22 B-17 officially lost to lack of fuel, though only 8 were the shorter range variants.

Due to the detachments to the Mediterranean the 8th Air Force flew no B-24 operations late June to early September 1943 while as of end October 1943 the 8th had 16 B-17 and 4 B-24 groups operational, by end December it was 18 and 7. So in mid 1943 the 8th was primarily a short range B-17 force. In addition to the early B-17 range issue in mid 1943 the USAAF was waiting to build the numbers to being able to send 300 sorties on a raid. The self defending bomber required a degree of herd immunity to saturate the defences. For example on 6 March 1944 the 8th lost or wrote off to all causes 81 B-17 and B-24, but that was from 730 sorties, compared to 69 B-17 from 320 sorties on 14 October 1943.

Also remembering 1943 escort tactics were to remain in sight of the bombers, so either the fighters are slowing down to around 240 mph, or they are weaving.

The idea is then as of mid 1943 the RAF puts together 2 wings of Spitfire VIII, rising to 3 or 4 by end of year, for escorting 8th Air Force heavy bombers, each wing the equivalent of an under strength US fighter group. This is quite possible given the historical mark VIII production. These are replaced by Mustangs in the first half of 1944 and/or the USAAF has enough fighters available the RAF can stop doing the missions.

According to Roger Freeman P-47 radius with relevant external fuel, nominal tank capacity / actual capacity
75/84 280 miles. In use August 1943
200/205 275 miles. (part filled) In use July 1943.
108/108 325 miles. In use September 1943.
150/165 375 miles. In use March 1944
2x150/165 550 miles. This arrangement "made handling difficult"
200/215 480 miles. In use November? 1944, project initiated in October, took 34 days to deliver the first tanks.

Number of 8th Air force fighter groups flying combat sorties as of end of month 3 in July 1943, 4 in August, 6 in September, 8 in October, 11 in December. The 9th Air Force had one fighter group operational in December. An extra 3 groups of P-47 equivalents would be useful until end 1943 at least.


GregP said:


> My production numbers for PR types don' match yours, Geoffrey, but the point is still that there weren't very many and they weren't all that useful for fighter vs. fighter combat.


While the PR types were not that useful as escorts it would be good to know which web site has the very wrong Spitfire production numbers, managing to report only a quarter of the actual PR versions. Also the figures I posted are not mine, they come from the Vickers company archives, Ministry of Aircraft Production, Ministry of Supply, Air Ministry and RAF and cross checked.


GregP said:


> So, any missions of the type contemplated above would be in Spitfires that did NOT have leading edge tanks. Therefore, that fuel will not be there in a Spitfire on a combat mission.


Technically the mark VIII wing tanks were leading edge as far as I know. The 66.5 gallon leading edge tank in the PR versions I understand was not self sealing. The VIII already had 14 gallons in the wing, you would need to go to a pair of 20mm cannons or fit the E wing to free up the outer wing leading edge and the extra wing tanks would start somewhere outboard of the armament, not sure how much volume is there forward of the spar, also the fuel lines have to be threaded through the armament area and while good for CoG purposes, when filled the tanks would not help the roll rate.


GregP said:


> Sure, you could cobble together a "Speed Spitfire," but you were not going to cobble together 500 of them and then go destroy Berlin.


No fighter was going to destroy Berlin. Is it possible to redo the radius map with the different cruise speeds and combat allowance?


Zipper730 said:


> What cruise speed was needed for escort missions? Typically the P-51's flew around 300-305 mph
> What's a "rear view" fuselage? Is that a design with a Malcolm hood?
> I assume the "rear-view" fuselage designs didn't have the redesigned elevator?
> The more fuel you stuff in the plane, you'll take longer to climb, so that will have to be factored in.
> BTW: I remember some of the early PR variants had a tank under the pilot that was added: I don't know why that was removed from later aircraft, if there was a good reason.


Cruise speed is one of those it depends, whether the tactic is to stay with the bomber or to be moving faster for self protection and better ability to intercept. The rear view fuselage was the "bubble" canopy and being a late production type it tended to have the bigger tail/elevator. Agreed the extra fuel weight will add to consumption, particularly on climb. Not sure about an under the pilot tank, but the early PR types had all sorts of camera and fuel combinations.


Zipper730 said:


> I'm not sure if the 320 mph speed cited for the spitfire was based on escort, general fighter sweeps, or intercept.


The 320 mph speed was based on Spitfire VIII operations in the Mediterranean. The reason for the 320 mph cruise is speed = safety, it made it much harder to bounce the formation, based on things like the Fw190 evaluation. As well it gave better opportunities to set up an attack. As is well known few normally flew at economic cruise in European contested airspace, while the units in the Pacific knew the chances for combat were minimal except near the target, so economic cruise almost all the way, in a loose association of aircraft that only tightened up near the target.


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## Zipper730 (Mar 13, 2022)

Geoffrey Sinclair said:


> The 320 mph speed was based on Spitfire VIII operations in the Mediterranean. The reason for the 320 mph cruise is speed = safety, it made it much harder to bounce the formation, based on things like the Fw190 evaluation. As well it gave better opportunities to set up an attack.


Understood: Was the P-51 better in acceleration from 300-350 mph?


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## pbehn (Mar 13, 2022)

When did the US decide that bombers needed escorting at all times? Initial British reservations about the B-17 were dismissed because there werent enough of them for mutual defence. It became increasingly obvious to some, not all, that even the heavy defence of the B-17 was not sufficient, so when was the decision made by the USA and why would the British develop the Spitfire as an escort before that date. They had a long range fighter that they ordered in 1940 called a "Mustang". It is a rhetorical question because I have a book on the development of the P-51B.

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## Juha3 (Mar 13, 2022)

As said the longest Spit escort missions were to La Pallice. 12 Spit VIIs from No. 131 escorted Lancasters there thrice in August 1944 (9, 11 and 12 August) operating from RAF Culmhead, straight line one way distance 550 km /340 mls, over water route, around Brittany/Bretagne, 750 km / 465 mls. Flight times were 3.45, 3.50 and 3.35 hours. Number of Lancs were according to the 131 Sqn F540 about 30, 14 and a force of.

Ps. I forgot one word, in *Europe*, RAAF Spit VIIIs made at least one longer in South West Pacific Area, escorting 4 B-25s against a Japanese radar station on Timor in Nov 1944.

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## PAT303 (Mar 13, 2022)

Looking at this image a MkVIII with rear tanks plus a 90G drop tank could have flown out between the P47 and P38, that would have made a great contribution to the war instead of flying pointless sorties over Belgium.


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## tomo pauk (Mar 13, 2022)

PAT303 said:


> Looking at this image a MkVIII with rear tanks plus a 90G drop tank could have flown out between the P47 and P38, that would have made a great contribution to the war instead of flying pointless sorties over Belgium.



Mk VIII was mostly used away from the G. Britain...

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## PAT303 (Mar 13, 2022)

There is no reason the hundreds of MkIX's and XIV's sitting on RAF fields couldn't have aux tanks fitted, the MkIX had larger 17G leading edge tanks designed for them so had another 10G over the MkVIII.


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## tomo pauk (Mar 13, 2022)

PAT303 said:


> There is no reason the hundreds of MkIX's and XIV's sitting on RAF fields couldn't have aux tanks fitted,



Agreed 100%.



PAT303 said:


> the MkIX had larger 17G leading edge tanks designed for them so had another 10G over the MkVIII.



Please elaborate about the larger 17G L.E. tans for the Mk.IX, this is the 1st time I hear about that.


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## GregP (Mar 13, 2022)

PAT303 said:


> View attachment 661233
> Looking at this image a MkVIII with rear tanks plus a 90G drop tank could have flown out between the P47 and P38, that would have made a great contribution to the war instead of flying pointless sorties over Belgium.



But that is not what they DID with them in real life, is it? Spitfires were used as short-medium-range fighters, regardless of what WE might think to use them for. You're playing at a big "what-if," and it's fun to do. I'll say this for you Pat, you have a real desire to rewrite history.

What if we captured all the Fw 190D's intact and used them against Germany? It might have had a decent effect, but we didn't do it, so any arguments about what might happen if we had done so are 100% pure conjecture ... a big what-if. There are no correct or incorrect thoughts in a what-if because there is no possibility to prove or disprove the supposition.

So, yes, they COULD have used the Spitfires for different missions than they were actually used for, but the effect of NOT FLYING the missions that were actually flown has to looked at when you postulate any changes to the war outcome. And you can't go back a choose from missions that did not result in enemy contact because they had no way of knowing which missions those were until they had already been flown. Re-tasking any mission would have to be done before you knew how it would actually turn out.

A textbook "what-if" in the case of re-tasking Spitfires that were never going to be really released for re-tasking in any event.

It's like going back in time and trying to convince anyone that Pearl Harbor was going to happen, like in the movie, "The Final Countdown." History didn't record it that way, so it never happened, despite Hollywood's best attempt at it. I enjoyed the movie a lot when I first saw it. It shows you really can't fight an F-14 at 210 mph even if you wanted to. Now we don't even have F-14s to fly about. They be gone, except for maybe a few in Iran that likely need some maintenance and some new parts.

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## PAT303 (Mar 14, 2022)

GregP said:


> But that is not what they DID with them in real life, is it?


They didn't use P47's P51's or P38's for long range missions either until they decided to fit aux and drop tanks too them, I'm not trying to rewrite history, the single biggest negative against the Spitfire was it's lack of range, it could have easily been given longer legs but it wasn't and that was the difference between the British and the Americans, the British said it's too hard, the Yanks said get out of the way we are making it happen.


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## PAT303 (Mar 14, 2022)

GregP said:


> What if we captured all the Fw 190D's intact and used them against Germany?


????, I'm taking about fitting aux tanks to Spitfires such as the 33+33G rear aux tanks fitted to all MkXVI's from the factory, what has that got to do with flying captured 190 Dora's?.


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## PAT303 (Mar 14, 2022)

tomo pauk said:


> Please elaborate about the larger 17G L.E. tans for the Mk.IX, this is the 1st time I hear about that.


A 17G fuel bladder was developed for the MkIX to go where the MkVIII 13G metal tank was fitted, like all good idea's it was squashed very quickly by the RAF.


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## tomo pauk (Mar 14, 2022)

PAT303 said:


> A 17G fuel bladder was developed for the MkIX to go where the MkVIII 13G metal tank was fitted, like all good idea's it was squashed very quickly by the RAF.



Thank you. 
Do you have a source?


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## Zipper730 (Mar 14, 2022)

PAT303 said:


> A 17G fuel bladder was developed for the MkIX to go where the MkVIII 13G metal tank was fitted, like all good idea's it was squashed very quickly by the RAF.


That is pretty strange, what benefit would that have over the 13G tank?


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## Shortround6 (Mar 14, 2022)

Without knowing the construction of the tanks it gets hard to judge. 
Fuel bladders had different degrees of self sealing but so did "tanks". 
Bare metal tank or external coating/ covering or internal tank liner?
Fuel bladders had different thicknesses and numbers of layers depending on the size of the bladder and the support from surrounding structure and the degree of protection desired. 

One 7.9mm hit or multiple 7.9mm hits/ single 13mm hit ?
Although very few tanks offered full protection from a 12.7-13mm hit. 

What is the weight of the bare tank or bladders and what is the cost ?
The US and British did not have unlimited amounts of rubber or rubber compounds even though they had a much better supply than the Germans.

Basically the Spitfire needs the larger fuselage tank, the two 13 gallon wing tanks and about 30 gallons in the tail to equal a P-51 with just internal wing tanks. 
P-51 with a pair of 75 US gallon drop tanks has about 120 imp gallons outside. Spit is limited to 90 imp gallons outside?
P-51 cruises 20-30mph faster at the same fuel burn per hour as the Spitfire (?).

The P-47`is criticized for it's short range but it holds about 254 Imp gallons inside so even if it needs twice the fuel per hour as the Spitfire VIII it has a range just getting into the rear tank territory. 
Actually the P-47 can do pretty well cruising on 105-110 Imp gallons an hour, about 210-215 ISA at 25,000ft.

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## GregP (Mar 14, 2022)

Well Pat,

You are correct that, near the end of the war, they figured out how to get at least SOME decent range from Spitfires. Since they did that, I'm pretty sure you are correct that they COULD have done it earlier than they did in real life. The U.K. was never never really flush with Spitfires and pilots at the same time and, had they found this range earlier, then yes, some Spitfires COULD have been re-tasked with different missions.

I am just pointing out that, had they done so, you would have to factor in the Spitfire missions that didn't get flown due to the retasking. It makes for an interesting "what if," except for the fact that they HAD longer-range fighters that DID fly those missions, and we'd have to speculate whether or not the Spitfires would add some dimension that was lacking in the missions flown by other fighters.

Suppose some missions flown by Mustangs or Lightnings, et al, were to be retasked with Spitfires. Would they get better results than were achieved or did the Mustangs, Lightnings ,et al, accomplish the mission? If they DID accomplish the mission, what would the Spitfires add that was missing in the original mission? If they didn't accomplish the mission, why do we think Spitfires would have done so when the mission failed in the event when flown by other aircraft?

I'm trying to understand what adding range to the Spitfire earlier than they did in real life would change, and I'm having a hard time flushing out the benefit that would accrue over and above what was actually accomplished by other aircraft. If you replace 300 P-51s with 300 Spitfires on an escort mission, would they do it better? By the time we were flying 300-plane escort missions, the Luftwaffe wasn't exactly in a position of air superiority, and the losses were pretty low. Some of the losses we HAD were due to Me 262 kills, and I'm not really sure Spitfires could have done any better than P-51s did against Me 262s. Maybe, maybe not.

I AM sure the Spitfire pilots would all have felt better with some extra fuel aboard and I AM sure they would have found a way to take advantage of the extra range afforded by the extra fuel. So, your point is taken that, yes, more fuel in Spitfires earlier than happened in real life would have been better for the Allies.

We could have had a huge impact had we started flying Douglas Skyraiders in 1943 escorted by your longer-range Spitfires. But, that's another thread ...

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## PAT303 (Mar 14, 2022)

GregP said:


> You are correct that, near the end of the war, they figured out how to get at least SOME decent range from Spitfires. Since they did that, I'm pretty sure you are correct that they COULD have done it earlier than they did in real life. The U.K. was never never really flush with Spitfires and pilots at the same time and, had they found this range earlier, then yes, some Spitfires COULD have been re-tasked with different missions.


There was never a shortage of Spitfires, the RAF had hundreds sitting around the country side ready to defend against the Luftwaffe when they themselves were being constantly pushed back towards Germany. As far as how difficult fitting extra tanks where, Sydney Cotton had no issue fitting a 20G tank under the seat of the MkII in 1940 and the MkV had a rear 29G tank designed for it in 1941, drop tanks were used pre war. If you look at the FAA they fitted 89G drop tanks from RAAF Kittyhawk's and flew them off carriers when RAF MkIX's were achieving nothing patrolling the channel with standard 85G main tanks in 1944.


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## PAT303 (Mar 14, 2022)

Zipper730 said:


> That is pretty strange, what benefit would that have over the 13G tank?


Have a look at the photo in my earlier post, there is a lot of room in the inner leading edge of the Spitfires wing, I think it was designed to be easily fitted and conform to the shape easily, can't prove it but it makes sense to use a material that when filled stretches out to fill the space efficiently.


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## GregP (Mar 14, 2022)

PAT303 said:


> There was never a shortage of Spitfires, the RAF had hundreds sitting around the country side ready to defend against the Luftwaffe when they themselves were being constantly pushed back towards Germany. As far as how difficult fitting extra tanks where, Sydney Cotton had no issue fitting a 20G tank under the seat of the MkII in 1940 and the MkV had a rear 29G tank designed for it in 1941, drop tanks were used pre war. If you look at the FAA they fitted 89G drop tanks from RAAF Kittyhawk's and flew them off carriers when RAF MkIX's were achieving nothing patrolling the channel with standard 85G main tanks in 1944.



There were way fewer Spitfires than Hurricanes in the BOB and they never DID have a lot of the "sitting around."


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## GregP (Mar 14, 2022)

PAT303 said:


> Have a look at the photo in my earlier post, there is a lot of room in the inner leading edge of the Spitfires wing, I think it was designed to be easily fitted and conform to the shape easily, can't prove it but it makes sense to use a material that when filled stretches out to fill the space efficiently.



I don't think I need to look more at your post. Spitfires had the gas they had, didn't get more until they did, and it was always less than long-range until late in the war. So, they were used for the missions they flew. Anything else is conjecture. Conjecture is fun, but what the heck are you trying to do, Pat? Rewrite history so it conforms to your pet theory? Why are you still going with this?

They did what they did and, yes, they COULD have done other missions. To what end? The war was won in the real world and almost certainly would not have been much, if any shorter had another 500 miles been added to the Spitfire's flying range. The U.K. built some 20,367 Spitfires. They were well used in WWII.

So, again, what are you trying to change and why? What is your end aim? To replace all U.S.-furnished fighters with British fighters? Or what? There weren't enough Spitfires to replace 15,000+ P-51s and 15,000+ P-47s with Spitfires.

I'm not really arguing. I'm trying to understand what you want everyone to see, and what it would change during WWII in your eyes.


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## wuzak (Mar 14, 2022)

GregP said:


> There were way fewer Spitfires than Hurricanes in the BOB and they never DID have a lot of the "sitting around."



20,000+ Spitfires were built, most of them during the war.

How many Spitfires were available in the BoB is irrelevant to how many were available in 1943-1945.

The clue to the availability of Spitfires is when they were released for overseas service. Which was in 1942, if I am not mistaken.


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## GregP (Mar 14, 2022)

Yes, Wayne, and they WERE released and DID fly missions. If you read my post, I already SAID there more than 20,000 Spitfires built.

What does he want to change, and what would it accomplish that wasn't otherwise accomplished during the war? How would putting in the absolute MOST fuel into Spitfires a bit earlier affect the war's timeline? If all it does is to add reserve fuel, then nothing would change. They HAD long-range fighters that flew long-range missions.

What would Spitfires with extra fuel that didn't EVER get as long-range as Mustangs and Lightnings accomplish that would change the war? Why is this worthy of discussion if it doesn't change what happened for the better?

I'm sure Pat has something in mind. I'm just trying to find out what it is.


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## wuzak (Mar 14, 2022)

I'm sure that longer range Spitfire IXs would have been handy in escort relays with P-47s, P-38s and P-51s. 

Certainly it would have allowed more flexibility in their operation.

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## PAT303 (Mar 15, 2022)

GregP said:


> There were way fewer Spitfires than Hurricanes in the BOB and they never DID have a lot of the "sitting around."


The BoB ended in 1940, the war ended in 1945.


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## PAT303 (Mar 15, 2022)

GregP said:


> I'm not really arguing. I'm trying to understand what you want everyone to see, and what it would change during WWII in your eyes.


I'm not trying to change anything other than doing to the Spitfire what the American's did to their fighters, add more fuel.


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## pbehn (Mar 15, 2022)

wuzak said:


> 20,000+ Spitfires were built, most of them during the war.
> 
> How many Spitfires were available in the BoB is irrelevant to how many were available in 1943-1945.
> 
> The clue to the availability of Spitfires is when they were released for overseas service. Which was in 1942, if I am not mistaken.


Those figures also give a clue as to how quickly an airforce of circa 1,000 fighter planes wears out new planes.


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## wuzak (Mar 15, 2022)

Question for 

 drgondog
:

In a relay escorting system, does the operating radius of the first leg affect the operating radius of the second leg, and so forth?

My thought is that if you have Spitfires as your first leg and they have only a 100 mile radius, the second leg will have to escort from that point, or earlier. 

Making its way to the rendezvous, the second leg can use a more economical cruise setting. But when they get near the rendezvous, where potential for enemy action is greater, they will need to be at higher speeds with worse economy.

If the Spitfire extends its radius to 150 miles then the second leg can spend more time at the economical cruise settings. Which may allow them a greater escort radius.


Or this could be just reaching at straws on my part, with the reality that once over the continent all the escort will have to use a higher cruise speed with lower economy.

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## Vincenzo (Mar 15, 2022)

what could happening if Spitfire, this WI long ranged, escort are engaged over the Belgium?


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## drgondog (Mar 15, 2022)

wuzak said:


> Question for
> 
> drgondog
> :
> ...


Simple answer Yes. More complicated is that the Wing Fighter Command Ops officers 65th, 66th and 67th worked with 8th AF Ops and Bomb Division Ops to plan dispositions for every mission. The first breakdown was the Target selections to gain perspective for longest range target group.

Use Spring 1944 when Mustang and Lightning force level was nearly equal to the task of assigning 3 Long Range Escort FG per Bomb Division. In mid April there were 4 8th AF, 2 9th AF Mustang FGs and 3 8th AF Lightning FGs. Nearly always they would be assigned Target escort. The next level of complexity was encountered if one or more targets were of Berlin or greater radius (Stettin, Posnan, Brux. Munich.

If single thread attack, like April 29 Berlin, the plan (which was screwed up when one BD did a walkabout way south of the penetration route) then the Penetration escort of P-47 FGs were going as far as Celle before R/V with either a P-38 or P-51 FG combination assigned to a.) first TF, b.) second TF and c.) third task force. In this example, one Mustang FG might arrive early near the RV, then sweep along the planned route in front of the 1st TF seeking LW formations. A second and 3rd FG arriving near the same RV - but later - actually picked up the 1st Task Force boxes. Sometime later as the 2nd TF was passing through the same space, perhaps two Mustang FGs would arrive to escort the boxes of the 2nd TF, and finally the third escort force of two P-38 Fgs would pick up trail TF.

The RV in this example is where (approximately) the P-47s were relieved, one by one as they escorted the 1st, 2nd and 3rd TF inbound.

The Sweeping FG was able to use fuel more efficiently because they were not tethered to the bomber stream, but each of the target escort FGs were so tethered and generally split within FG to cover high center, high trail and lead level in separate squadrons or even sections - Essing.

The reverse process also depended on the combat radius of the Withdrawal P-47 (or RAF Mustang III in several instances) to relieve the target escort as they rounded the target and set course for home - still with their assigned bomb groups - until relieved by Penetration escorts.

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## PAT303 (Mar 15, 2022)

wuzak said:


> Or this could be just reaching at straws on my part, with the reality that once over the continent all the escort will have to use a higher cruise speed with lower economy.


Good point, this is one of the many reasons I believe the A6M wouldn't have succeeded over Europe because it relied on a slow cruising speed with a weak mixture to get it's range. It was proven right back in 1941 when MkV's did raids over France that speed is life but it could be safe cruising at a lower speed ''if'' the flight in front of you has cleared the airspace, likewise the returning flight is flying past the next so they could also cruise at a slower speed. Either way MkIX's with a 400 mile combat radius in 1943 would have been a handy plane to have.

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## tomo pauk (Mar 15, 2022)

PAT303 said:


> Good point, this is one of the many reasons I believe the A6M wouldn't have succeeded over Europe because it relied on a slow cruising speed with a weak mixture to get it's range.



A6M relied on more than 850 liters of fuel, made possible via the 330L drop tank. Or, more than double vs. Bf 109E-3/E-4, Hurricane I or Spitfire I/II.

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## GregP (Mar 15, 2022)

PAT303 said:


> The BoB ended in 1940, the war ended in 1945.



You think?

So, no real plan, just add more Spitfire fuel. Well. they didn't until later in the war when they did, but it still wasn't enough to make the Spitfire a long-range airplane.

But, that's OK. They never made the Bf 109 anything but a short-range airplane and it was the most prolific aircraft in enemy shoot-downs, so maybe it isn't all bad.

Cheers.


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## wuzak (Mar 15, 2022)

drgondog said:


> Simple answer Yes. More complicated is that the Wing Fighter Command Ops officers 65th, 66th and 67th worked with 8th AF Ops and Bomb Division Ops to plan dispositions for every mission. The first breakdown was the Target selections to gain perspective for longest range target group.
> 
> Use Spring 1944 when Mustang and Lightning force level was nearly equal to the task of assigning 3 Long Range Escort FG per Bomb Division. In mid April there were 4 8th AF, 2 9th AF Mustang FGs and 3 8th AF Lightning FGs. Nearly always they would be assigned Target escort. The next level of complexity was encountered if one or more targets were of Berlin or greater radius (Stettin, Posnan, Brux. Munich.
> 
> ...



So, basically, it depends on the specific escort role?

Fighters in close escort will have their range extended when fighters in earlier stages of the relay have theirs extended, while fighters performing sweeps ahead of the bomber formation will gain little, or no, benefit?


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## 33k in the air (Mar 15, 2022)

Why would the RAF pursue extended range for its Spitfires given that Bomber Command had long since switched to nighttime bombing? It had no impetus to extend the range since it didn't need it. The USAAF was responsible for its own operations. The USAAF had to painfully learn for itself that daylight bombing without fighter escort was too costly no matter how dense the formations and well-armed the bombers.


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## Shortround6 (Mar 15, 2022)

PAT303 said:


> I'm not trying to change anything other than doing to the Spitfire what the American's did to their fighters, add more fuel.


Added how much fuel when ?

The long nose P-40s held 180 US gallons down to 135 US gallons depending on type of fuel tank protection. 
However they weren't really supposed to carry that much in combat. The tank behind the seat was supposed to used for ferrying/deployment. The P-40C got the drop tank but the 52 gallons just about equaled the fuel lost to the self sealing tanks. 
Also notice that the Mustang originally held the same amount of fuel as the Early Tomahawk did. They did get protected tanks in the Mustang though. 
P-39s didn't hold much more fuel than British planes did. 
P-38s didn't get drop tanks until the F model starting in March of 1942 and the D & E models had 300 US gallons for two engines. 

US fighters often had to make long range deployments in the 1930s and early 40s. Their extra fuel capacity was more towards such deployments than it was escorting bombers.


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## GregP (Mar 15, 2022)

I'm pretty sure the Brits weren't going to leave home defense to imported U.S. fighters after they added the extra fuel to the Spitfires. They were going to fly the missions they flew, no matter what fuel got added. The Spits just might have been able to go a bit farther or stay up longer, but they would not be transferred to other places leaving the bases where they were assigned undefended.

Still, Pat has a point, a bit more fuel would have been welcome on many occasions. The only time they ever had too much fuel was when they were on fire.


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## wuzak (Mar 15, 2022)

33k in the air said:


> Why would the RAF pursue extended range for its Spitfires given that Bomber Command had long since switched to nighttime bombing? It had no impetus to extend the range since it didn't need it. The USAAF was responsible for its own operations. The USAAF had to painfully learn for itself that daylight bombing without fighter escort was too costly no matter how dense the formations and well-armed the bombers.



Very few, if any, 8th AF bombing raids were flown that were completely unescorted. They used partial escorts, or at least planned to, on missions until true long range escorts were available that could escort all the way to the target.

RAF Spitfires were involved with escorting 8th AF bombers in conjunction with P-47s. Certainly for raids in 1942 and 1943. Not sure about later - the USAAF probably had enough fighters in Britain by that stage to not need RAF help.


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## 33k in the air (Mar 15, 2022)

wuzak said:


> Very few, if any, 8th AF bombing raids were flown that were completely unescorted. They used partial escorts, or at least planned to, on missions until true long range escorts were available that could escort all the way to the target.



Yes, but in this context it means long-range missions, i.e. beyond the existing range of the fighters.


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## ThomasP (Mar 16, 2022)

I suspect the reason the Spit Mk VIII and such were assigned to the Med & CBI theaters was that the increased fuel load had more value there. Maybe?


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## EwenS (Mar 16, 2022)

ThomasP said:


> I suspect the reason the Spit Mk VIII and such were assigned to the Med & CBI theaters was that the increased fuel load had more value there. Maybe?


Spitfire VIII and IX were flown alongside each other in the Mediterranean, sometimes simultaneously in the same squadrons. Initial deliveries to India came from Spitfire VIII stocks originally shipped to MUs in North Africa and then flown to India eg 81 squadron from Dec 1943. Spitfire VIII started arriving in Australia in Oct 1943.


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## drgondog (Mar 16, 2022)

PAT303 said:


> View attachment 661233
> Looking at this image a MkVIII with rear tanks plus a 90G drop tank could have flown out between the P47 and P38, that would have made a great contribution to the war instead of flying pointless sorties over Belgium.


This map incorrectly states combat radius (actual flight tested, agreed, and published by Service Command)


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## drgondog (Mar 16, 2022)

pbehn said:


> When did the US decide that bombers needed escorting at all times? Initial British reservations about the B-17 were dismissed because there werent enough of them for mutual defence. It became increasingly obvious to some, not all, that even the heavy defence of the B-17 was not sufficient, so when was the decision made by the USA and why would the British develop the Spitfire as an escort before that date. They had a long range fighter that they ordered in 1940 called a "Mustang". It is a rhetorical question because I have a book on the development of the P-51B.


The Blitz Week followed by Scheinfurt-Regensburg two weeks later made it crystal clear that LW would inflict politically unsustainable losses. After Eaker and Asst Scy War Lovett appealed to Arnold, all summer planned P-38H and J deployments were re-directed to ETO, and all P-51B deployments were directed to ETO.

The AAC/AAF did not 'order' Mustangs until A-36 ordered in April 1942. In the next several months, the XP-78 (XP-51B) was approved, the NA-99 (P-51A with contract conversion to NA-104 P-51B-5), the P-51B-1 and C-1 were ordered. The priority for combat tanks were placed in even higher priority but MC was very delinquent in delivering until summer 1943.

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## drgondog (Mar 16, 2022)

wuzak said:


> So, basically, it depends on the specific escort role?
> 
> Fighters in close escort will have their range extended when fighters in earlier stages of the relay have theirs extended, while fighters performing sweeps ahead of the bomber formation will gain little, or no, benefit?


If I understand your question, yes - it depends. If the target radius was within Combat Radius of the P-47D then the planners hd far more flexibility (Very Rare after March 1944 until Transportation Plan of May 1944 when many more tactical range rail and infrastructure and airfield targets were selected.

P-51 and P-38 combat radius were maximized when RV was relatively near the assigned targets - cruise in a straight line at 300mph TAS at 25K w/75gal combat tanks - 270mph TAS with 110gal combat tanks. Sweep efficiency even better as there was no need to Ess over bombers while keeping fuel efficiency and tactical speed in the optimal performance envelope.

The key technical improvements were 85gal fuse tank (P-51B Dec 1943), 55gal Leading Edge tanks (P-38J Dec 1943) and 65gal extension to main fuse tank (P-51D-25 June 1944).

The key attributes of P-51B/C and P-38J were the increase to internal fuel (47% P-51B), (36% P-37J), and finally 21% P-47D.

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## Zipper730 (Mar 16, 2022)

Just as an item of confusion: Wasn't a Spitfire Mk.IX a modified Mk.V revised to standards similar to the Mk.VII/VIII?


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## GregP (Mar 16, 2022)

Correct, the Spitfire IX was basically a Spitfire V with a 2-stage Merlin (60-series) instead of a single-stage engine (XX or 40-series). Other changes were relatively minor and sometime included a larger fin and rudder ... sometime not. Like most other aircraft that got a power increase, they didn't add the extra tail volume at first, but did later. In the P-51D and P-47D, they added a dorsal fin. In the Spitfire, they made the fin and rudder taller.

Early Spitfire IX drawing:





It was converted from a MK. V airframe.

Later Spitfire IX:





Note the extra fin and rudder height, almost always needed when power was added. They ALSO added a 4-bladed prop to they IX instead of a 3-bladed unit on the Mk.V, so they added area forward of the CL that would require more tail authority.

The Mk. XVI had the same airplane and tail with a cut-down read fuselage and a bubble canopy. Spitfire XVI:





You might find this interesting:

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## wuzak (Mar 16, 2022)

GregP said:


> The Mk. XVI had the same airplane and tail with a cut-down read fuselage and a bubble canopy. Spitfire XVI:



The Mk XVI was the Mk IX with a Packard engine, the Merlin 266.

No all Mk XVIs had the cut down fuselage/bubble canopy. And we can see that the Spitfire XIV was built in both standard canopy and bubble canopy versions without change of designation.




GregP said:


> Correct, the Spitfire IX was basically a Spitfire V with a 2-stage Merlin (60-series) instead of a single-stage engine (XX or 40-series). Other changes were relatively minor and sometime included a larger fin and rudder ... sometime not. Like most other aircraft that got a power increase, they didn't add the extra tail volume at first, but did later. In the P-51D and P-47D, they added a dorsal fin. In the Spitfire, they made the fin and rudder taller.



The Mk V had 40-series engines in production. No production V had a XX-series engine.

Remembering, also, that the Mk V was a Mk I/II fitted with the Merlin 45. That was chosen because it would bolt in as nearly a direct swap, whereas the Merlin XX would have required fuselage changes.

A V with Merlin XX would have been more competitive with the Fw 190A and Bf 109F-4 than the actual Mk V was.


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## tomo pauk (Mar 16, 2022)

wuzak said:


> A V with Merlin XX would have been more competitive with the Fw 190A and Bf 109F-4 than the actual Mk V was.



Would you please elaborate on this?


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## wuzak (Mar 16, 2022)

tomo pauk said:


> Would you please elaborate on this?



The second gear would have allowed much better performance at lower altitudes, with similar, or better, performance at higher altitude.

The 45 had the same supercharger as the XX. The XX's high gear was slightly higher than the 45's only gear, which meant a slightly higher FTH than the 45.

The V/45 would have had a small advantage at and just before FTH, and, perhaps, at the gear change point of the XX. Basically the V/XX would have been superior, except for a small altitude band.


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## tomo pauk (Mar 16, 2022)

wuzak said:


> The second gear would have allowed much better performance at lower altitudes, with similar, or better, performance at higher altitude.
> 
> The 45 had the same supercharger as the XX. The XX's high gear was slightly higher than the 45's only gear, which meant a slightly higher FTH than the 45.



In theory - yes, the Mk.XX should've provided better high-alt performance, but in reality both were giving about the same power when operating in the FS gear (obviously the only S/C gear available for the Mk.45). Reason probably being that S/C of the Mk.XX was using up more HP there, due to the higher gearing (9.45:1 vs. 9.09:1)?
Yes, the presence of the MS gear on the Mk.XX would've added some performance at very low altitudes.



wuzak said:


> The V/45 would have had a small advantage at and just before FTH, and, perhaps, at the gear change point of the XX. Basically the V/XX would have been superior, except for a small altitude band.



Mk. XX was also slightly heavier, 1450 lbs vs. 1385. 
I reckon that Mk.V/XX would've been superior at really low altitudes, comparable vs. historical Mk.V at medium altitudes, and climbing a tad worse at higher altitudes, with about same speed. 
Best thing with Mk.V/XX is that it would've been available already in 1940 - basically a 'MK.III minus'?


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## 33k in the air (Mar 16, 2022)

drgondog said:


> The Blitz Week followed by Scheinfurt-Regensburg two weeks later made it crystal clear that LW would inflict politically unsustainable losses.



Not just politically, but operationally. Even a 5% loss rate is substantial if sustained over a period of time: a starting force of 100 bombers, suffering a constant 5% loss rate per mission, would be down to 63 aircraft after just 9 missions.

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## Zipper730 (Mar 16, 2022)

Okay, it seems the issues that have been covered so far are...

*Variants & Fuel Loads*
With the Spitfire IX/XVI being modified Mk.Vs, why did they become more popular than the Mk.VII and Mk.VIII's? Also, why would the IX have features (i.e. reprofiled elevators) the VII & VIII didn't (unless I'm wrong)?

Regarding internal fuel-loads, I have the following for the Spitfire variants

*Mk. I thru II*
Upper:......./..48
Lower:......./..37
*Total:*............*85

Early PR Variants*
Forward:......*85*
..Upper:.......48
..Lower:.......37
Underseat:.-*80*
..Under:.......30
..Aft:.........../50
Wing:...........Unknown
*Total:*...........*165 Minimum

Mk. V*
Forward:.........85
..Upper:........./48
..Lower:........./37
Aft:................-29 (w/ 170 gal slipper tank)
*Total:*....../...../*114

Mk. IX *
.......................(Mod 1335)....(Mod 1377)....(Mod 1414)
Forward:...........85....................96...............-96
..Upper:............48...................-48..............-.48
..Lower:............37...................-48................48
Aft:................../74.................../74.................66
..Upper:............41.................../41...............-33
..Lower:............33....................33.................33
*Total:*..............*159*............../--*170*............._*162*

While I think this was covered, but with rear-tankage being used on the Spitfire IX/XVI only with orders from the Squadron commander on the razorback models, and under no circumstance on the cut-back models: This was post-war, correct?

As for what drop tanks were available and when, I'm not sure what was available at what time, though I have a feeling the 170 gallon slipper was available when the 29 gallon tank was available on the Mk.V since the 29 gallon tank couldn't be used without the 170 gallon slipper. It seems that by 1942, the 90 gallon slipper was available as the FAA was using it. I'm not sure when the 89 gallon tank used on the P-40 first became available for use (was this 89 US or Imperial?).

There were also torpedo-tanks, which were just regular drop-tanks most ordinary aircraft used, I'm not sure what was available when, as well.

*Procedures & Tactics*
I remember reconnaissance variants of the P-38 used a ferry-climb power-setting, which apparently gave superior range over combat climb (I'd have figured it'd work the other way, but almost all my knowledge on aircraft is based on jets). If this is correct, could that have been used on Spitfires for escort to increase range?

*Other*


 GregP
pilots had v-n diagrams back in WWII times. I remember looking at a number of pilots handbooks on avialogs (F4U and A-26) and they had the v-n diagram within them. I don't know if the RAF had the same stuff in their documentation, but it stands to reason that they probably would.

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## wuzak (Mar 16, 2022)

I don't recall the elevators being reprofiles specifically for the IX, or any late model Spitfires.

There were changes to them, but I thought that was relatively early in production. Maybe even Mk II.

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## PAT303 (Mar 17, 2022)

GregP said:


> but it still wasn't enough to make the Spitfire a long-range airplane.


So a Spit with a 96G main, 75G rear aux, twin 13G leading edge and a 90G drop tank is not a long range fighter?.


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## PAT303 (Mar 17, 2022)

Shortround6 said:


> Added how much fuel when ?


Once the 60 series Merlins came into production, from the MkVIII-IX.


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## PAT303 (Mar 17, 2022)

wuzak said:


> The Mk XVI was the Mk IX with a Packard engine, the Merlin 266.


And from what I have read all of them had 33+33G rear aux tanks from the factory


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## PAT303 (Mar 17, 2022)

tomo pauk said:


> Best thing with Mk.V/XX is that it would've been available already in 1940 - basically a 'MK.III minus'?


The MkIII was an improved aircraft in every way over the MkV, it just did everything better.


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## drgondog (Mar 17, 2022)

PAT303 said:


> So a Spit with a 96G main, 75G rear aux, twin 13G leading edge and a 90G drop tank is not a long range fighter?.


Fuel capacity is not the only issue, but clearly without the 90gal drop tank it has more internal fuel than P-51B without 85 gal fuselage tank. The combat radius of Spit powered by 1650-3 or -7 equivalent, and using same set of assumptions AAF set for CR, it should be able to go ~ 300 miles and fight for 20 minutes. Better than P-47 with 108gal combat tank.

The 90 gal external tank was a ferry tank IIRC and would not be permitted in AAF for combat ops. The two week desperation trial of the 205gal ferry tank was limited (high drag, unpressurized). 

Was the 90gal tank pressurized?


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## PAT303 (Mar 17, 2022)

wuzak said:


> Maybe even Mk II.


That's correct, reprofiling them totally transformed the handling above 350mph as per Winkle Browns writing.


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## GregP (Mar 17, 2022)

wuzak said:


> I don't recall the elevators being reprofiles specifically for the IX, or any late model Spitfires.
> 
> There were changes to them, but I thought that was relatively early in production. Maybe even Mk II.



Check this out, Wayne:





Note the difference between the early, rounded fin and rudder (mostly converted Mk.V airframes with a 2-stage Merlin (61 or 66) and the Late Mk VII / IX fin and rudder. Center bottom is the stab and elevator change for late Mk. IX. The counterbalance area had been increased to make the pitch forces a bit lighter.

And a Merlin 266 is just a Merlin 66 made by Packard. It fits in the same engine mounts and sheet metal as a Roll-Royce Merlin 66. But, I'm sure you knew that.


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## GregP (Mar 17, 2022)

PAT303 said:


> So a Spit with a 96G main, 75G rear aux, twin 13G leading edge and a 90G drop tank is not a long range fighter?.



No.

It's a photographic airplane and had best not get tangled up with ANY fighter with that much fuel as it would be meat on the table. But, it could go fast and take pictures quite well, which is what it did in real life. With the drop tanks gone, unless approved by the commander, you will be missing the 75-gal rear aux volume and you are down to 122 gallons, which is enough for cruising for maybe 2 hours give or take a bit depending on cruise speed, with a bit of reserve. That is not long-range in anybody's book, likely even yours if you think about 8-hours missions a P-51 flew routinely.


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## wuzak (Mar 17, 2022)

GregP said:


> Note the difference between the early, rounded fin and rudder (mostly converted Mk.V airframes with a 2-stage Merlin (61 or 66) and the Late Mk VII / IX fin and rudder. Center bottom is the stab and elevator change for late Mk. IX. The counterbalance area had been increased to make the pitch forces a bit lighter.



I did not know that the elevator was upgraded that late.

But it was not actually a required modification to make the IX, as had been claimed. It was more of a general improvement.

The fin is the same in the I, II, V, IX, VIII and XIV. It was the rudder that was changed. Obviously for directional stability.

Late model Spitfires (20-series) got the fin and rudder from the Spiteful, which was larger and had a different shape.





GregP said:


> And a Merlin 266 is just a Merlin 66 made by Packard. It fits in the same engine mounts and sheet metal as a Roll-Royce Merlin 66. But, I'm sure you knew that.



Of this I was aware.

Was pointing out that the difference between the IX and the XVI was that the former had a Rolls-Royce engine and the latter had a Packard engine. Some XVIs had the cut down rear fuselage, just as some XIVs had the cut down rear fuselage.

Here is a XVI without the bubble canopy









VH-XVI | Supermarine Spitfire Mk.XVI | Private | Thimo van Dijk | JetPhotos


VH-XVI. Supermarine Spitfire Mk.XVI. JetPhotos.com is the biggest database of aviation photographs with over 4 million screened photos online!




www.jetphotos.com


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## wuzak (Mar 17, 2022)

GregP said:


> No.
> 
> It's a photographic airplane and had best not get tangled up with ANY fighter with that much fuel as it would be meat on the table. But, it could go fast and take pictures quite well, which is what it did in real life. With the drop tanks gone, unless approved by the commander, you will be missing the 75-gal rear aux volume and you are down to 122 gallons, which is enough for cruising for maybe 2 hours give or take a bit depending on cruise speed, with a bit of reserve. That is not long-range in anybody's book, likely even yours if you think about 8-hours missions a P-51 flew routinely.



The combination of fuel tanks Pat listed were possible in late production Spitfires. Which had guns and ammo.

VIIIs and XIVs had the 96 gallon main tank, plus 2 x 13.5 gallon tanks in the wing leading edge (inboard of the guns).

Some later aircraft also had rear fuel tanks fitted.

Note that, like the P-51, the Spitfire couldn't fight with the rear tanks full. But could with a partial load.

2 hours cruising is going to be ~500-600 miles. Which is a substantial improvement for combat radius over the standard Spitfire.

Sure it isn't as long as P-51s, but it would have been a useful gain.


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## GregP (Mar 17, 2022)

2 hours cruising is about 360 - 390 miles if you are flying escort since the escorts stayed with the bombers who were on economy cruise at 185 - 190 mph or so. It might be 500 - 600 miles if the mission didn't involve escort but, since we're talking about long-range airplanes, most of the long-range missions WERE escort. Certainly not all. As I understand it, Spitfires were not very often involved in anything close to long-range operations, so what we have here is a bit of wishful retasking that really never amounted to much in actual operations.

You can certainly do it in your invented wish-world, but it didn't happen very often really. Not saying if couldn't have happened. I'm saying it didn't very often in actual WWII, so I'm still having trouble trying to figure out what the end purpose is for retasking one of the world's best fighters to something other than what it was actually used for, taking it away from helping to actually WIN the real war.

Want to win the war sooner? Leaving everything the same except for the bombing targets. 

Bomb food production / shipping and the industrial electrical grid and the war ends MUCH sooner, with or without longer-range Spitfires.


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## wuzak (Mar 17, 2022)

GregP said:


> 2 hours cruising is about 360 - 390 miles if you are flying escort since the escorts stayed with the bombers who were on economy cruise at 185 - 190 mph or so. It might be 500 - 600 miles if the mission didn't involve escort but, since we're talking about long-range airplanes, most of the long-range missions WERE escort.



With the relay system, the fighters did not escort the bombers all the way to target and all the way back.

Even so, 360-390 miles is still an improvement on the Spitfire's combat radius.




GregP said:


> As I understand it, Spitfires were not very often involved in anything close to long-range operations, so what we have here is a bit of wishful retasking that really never amounted to much in actual operations.



The RAF did not have the need. The USAAF had the need, but did not know it yet. And when the USAAF did realise their need, they had better options.

Which meant that it wasn't a priority.

The Spitfire would never have had P-51 range, but its range could have been extended allowing for more flexible operation.


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## Milosh (Mar 18, 2022)

Didn't the Spitfires allow more US a/c to escort further? Every Spitfire squadron that did the initial escort freed up a USAAF squadron for the longer escort missions.


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## GregP (Mar 18, 2022)

wuzak said:


> With the relay system, the fighters did not escort the bombers all the way to target and all the way back.
> 
> Even so, 360-390 miles is still an improvement on the Spitfire's combat radius.
> 
> ...



Agree, especially the "could have" part. Makes me wonder if they increased the Merlin or Griffon's oil supply when they added extra fuel .... something to look into anyway.


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## GregP (Mar 18, 2022)

Milosh said:


> Didn't the Spitfires allow more US a/c to escort further? Every Spitfire squadron that did the initial escort freed up a USAAF squadron for the longer escort missions.



Likely true ... seems very likely, anyway.


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## wuzak (Mar 18, 2022)

GregP said:


> Agree, especially the "could have" part. Makes me wonder if they increased the Merlin or Griffon's oil supply when they added extra fuel .... something to look into anyway.



They certainly did for Merlin PR Spitfires, 

A Mk IX


https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Supermarine_Spitfire_Mk_IX_%2840929727970%29.jpg/800px-Supermarine_Spitfire_Mk_IX_%2840929727970%29.jpg



A Mk XI


https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Spitfire_PRXI_PL893_%2827871192617%29.jpg/800px-Spitfire_PRXI_PL893_%2827871192617%29.jpg



You can see the deeper fuselage just below the spinner where the oil tank was located.

The oil tank was relocated for Griffon Spitfires, so it may not have been visible if the tank volume was increased.

PR Spitfires did a lot longer range than an extended range IX would be able to do, so the exiting tank may be sufficient.


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## ThomasP (Mar 18, 2022)

Merlin_____________ Fuel / Oil
Spitfire Mk I_________ 85 / 5.8 Impgal
Spitfire Mk II_________85 / 5.8 Impgal
Spitfire Mk V________ 85 / 5.8 Impgal
____________________85+90 DT / 8.5 Impgal
____________________85+29+170 DT / 14.5 Impgal
Spitfire Mk VIII______122 / 7.5 Impgal (early)
___________________122 / 8.5 Impgal (late)
Spitfire Mk IX________85 / 8.5 Impgal
Spitfire Mk XVI______ 85 or 95 / 7.5 Impgal

Griffon
Spitfire Mk XII_______ 85 / 6.0 Impgal (early)
____________________85 / 7.0 Impgal (late)
Spitfire Mk XIV_____ 111 / 9.0 Impgal
Spitfire FR Mk XIV__ 142 / 9.0 Impgal
Spitfire PR Mk XIX__ 217 / 9.0 Impgal
Spitfire Mk XVIII____ 173 / 9.0 Impgal

All of the above is from the AM Pilot's Notes.

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## GregP (Mar 18, 2022)

Nice list, ThomasP.

Your post seems simple enough, but we all know it takes awhile to get these things together, especially combing through manuals.

Thanks.

So, we're kind of back to the Spitfire definitely NOT being long range with the above list. The PR XIX had a Griffon. At low cruise, it was 90 Imp gal/hr and, at full rattle, it was 225 Imp gal/hr. So, the 217 Imp gallons shown above would give you about 2 hours at low cruise with a 20 minute reserve. You had a useful radius for pics, but you weren't going all that far.

With the Mk.V, you had 114 Imp gallons without the drop tanks, so you really didn't want to fly more than about 2.5 hours away from friendly territory because, if you dropped the tanks, you wouldn't get back, even at economy cruise. That's with no reserve. To HAVE a reserve, subtract 20 - 30 minutes. With the British weather, you'd NEED reserve. Still, it lets you run a decent patrol about an hour or so from base.

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## Wild_Bill_Kelso (Mar 18, 2022)

Interesting discussion.

To some extent it seems to be a bit US and UK national perspectives talking past each other a bit.

Bomber escort does not just mean strategic bombing, and better range does not _just_ mean bomber escort. Better range means better endurance, which is useful for air defense, and also for all kinds of tactical roles (such as when used as fighter-bombers, which people tend to forget Spitfires actually were).

It seems to me like the P-51 was the best escort fighter in wide use during the war, but it wasn't the only option. The Spitfire had the reputation, fair or not, as the most effective Allied fighter in air combat against German fighters, at least among the Anglo-Americans. It was just limited by it's comparatively short range so it was mainly (though certainly not exclusively) used for defense. 

The British did have a lot of Spitfire Mk Vs sitting in the UK at one point during the mid-war which weren't doing much except acting as a deterrent to daylight raids against the home island. When they were released for deployment to Theaters in the Pacific and Mediterranean they were somewhat limited in their tactical role due largely to range.

I believe the Spitfire Mk VIII, which had somewhat enhanced range over the Mk V, seemed to have been more widely used in a broader range of roles, and was generally considered much more effective despite just having moderately better performance. Even in the defensive role, enhanced flight endurance means more time to get up to altitude and form up, more time to find and chase down targets, more time to fight once combat begins. More time to fly back to base after you chased an enemy aircraft.

So it seems to me that improving the range of the Spitfire could have paid substantial dividends even if the P-51 still ended up dominating the strategic escort role. I don't know enough about the technical aspects to say how feasible it was. I know the Spitfire had a pretty slim wing and was generally a fairly small aircraft compared to some of the later war designs, but they certainly improved the range of the Mk VIII over the V. The Bf 109 had the same issues in this regard and the Germans never seem to have really solved the problem either.

Even the longer-legged VIII was still a bit too short ranged for the Pacific. If they could have enhanced it say 50% more it would have been very helpful I think. And if they had something like the Mk VIII just a few months earlier that might have saved lives in the Mediterranean.


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## GregP (Mar 18, 2022)

If you look at ThomasP's fuel tankage list above, they DID improve the Spitfire's range. They didn't make it a long-range fighter, but it got better, which is what I think you were saying.

I'm not too sure why, but very many British airplanes have almost no fuel. The Spitfire started out that way, the Bristol 188 didn't have enough fuel to get to top speed, it needed to throttle back and land before running out. I talked with former English Electric Lightning pilot and asked him if it really was a Mach 2+ fighter. He scratched his beard and said, and I quote, "Toward the fuel you could get going Mach 2 or a bit more. If you ever got going Mach 2 headed away from the fuel, you were never going to get back to the fuel."

His words, not mine.

Try flying a Folland Gnat without extra tanks. You won't get very far!

Likely, the lack of fuel in British planes is exaggerated but, in general, they weren't known for long range *unless that was the mission*. Then, they flew are far as any other nation's aircraft. You never see the Short Empire or Sunderland being denigrated for short range, do you? The Comet had to have enough fuel to be intercontinental, so likely it's just a few airplanes that give rise to the notion ... Spitfire being one of them.

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## pbehn (Mar 18, 2022)

The need for a top class short ranged interceptor didn't disappear until well after D-Day. Until 1943 when Stalingrad and El Alamein decided the course of the war things could have turned for the worse as viewed at the time. But even after that, the possibility of sneak tip and run raids wreaking havoc on UK and USA assets in UK existed and keeping the D-Day build up secret as far as a landing in Normandy not Calais meant German recon had to be confronted and stopped, which it was.

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## Wild_Bill_Kelso (Mar 18, 2022)

Yeah I think low fuel capacity was part of what made a good interceptor and dogfighter, especially against tactical bombers. In the Philippines and Malaysia etc., during the early war, the Allies sometimes sent up F2As and P-40s with half their fuel in order to perform better against the Japanese fighters.

The Bf 109 and Spitfire were both optimized for combat either right over a battlefield or defending against bombers. They were both quite good at it. The odd thing (to me) is that they never figured out a way to give them substantially longer range. I think Spit VIII had about 40% better range than the Spit V (I'm sure somebody will correct me, but this site says 680 vs. 470, which works out to much less than that in terms of combat radius) but that is about the same range that a lot of other fighters in the war had at the beginning (1940-41) and considerably less than what was considered normal for say, a naval fighter.

The Soviet fighters for the most part stayed short legged and they also, with a couple of one-off exceptions, never really worked out longer ranged versions. But their emphasis was almost entirely on air superiority over the battlefield. And they had a lot of strategic limitations on materials and supplies.

If you are trying to get the ultimate level of performance, the least possible amount of weight is what you want.... but the relatively low fuel capacity is also quite limiting. Like so many design problems in WW2, it's a bit damned if you do, damned if you don't. The trick in threading the needle was making an aircraft which could be configured either 'light' or 'heavy', but that wasn't easy.


I think something like a Spit VIII, had it been more widely available and in greater numbers, could have made quite a difference in the Pacific and Burma, particularly if you could have had something in quantity in say 1942 or early 1943. And in the Med as well.


As for Jets flying Mach 2, i think what you described can be said for a lot of jets, especially in the 60s but even today. I spoke to an F-18 pilot once who told me pretty much the same thing.


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## GregP (Mar 18, 2022)

Yeah, using afterburner / reheat makes even a big fuel tank get small quickly, doesn't it?

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## Wild_Bill_Kelso (Mar 18, 2022)

Getting back to the fighter / fuel capacity thing, I guess the difference is, once you have more than ~1,000 - 1,200 hp engines, you start to have the power to move heavier aircraft around the sky. Then it's time to go back to the drawing board and give yourself a bit more fuel, guns, armor, and other things. The Fw 190 was much heavier than a Bf 109 but by no means less capable. The P-51 was also a heavy aircraft, as was the F4U, F6F, P-47, P-38, Typhoon, Tempest etc.

What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...

And once we have afterburners, it's zoom time but you are getting there by basically sticking a fire hose full of fuel out the back of your aircraft. Hard to carry enough to make that last.


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## pbehn (Mar 18, 2022)

Wild_Bill_Kelso said:


> Getting back to the fighter / fuel capacity thing, I guess the difference is, once you have more than ~1,000 - 1,200 hp engines, you start to have the power to move heavier aircraft around the sky. Then it's time to go back to the drawing board and give yourself a bit more fuel, guns, armor, and other things. The Fw 190 was much heavier than a Bf 109 but by no means less capable. The P-51 was also a heavy aircraft, as was the F4U, F6F, P-47, P-38, Typhoon, Tempest etc.
> 
> What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...
> 
> And once we have afterburners, it's zoom time but you are getting there by basically sticking a fire hose full of fuel out the back of your aircraft. Hard to carry enough to make that last.


Range is great if you have it and you need it. Within days of the Normandy landings airfields were being constructed in Normandy to save the trip of 100 miles across the channel. The guys in combat on the ground would not be impressed to hear that their fighter cover was off to Berlin, because they could.

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## Wild_Bill_Kelso (Mar 18, 2022)

Well if you have the extra range capacity, and have sufficient power to haul your aircraft around the sky in spite of a larger gas tank, (sufficient so that you are still competitive with enemy aircraft) it helps for _everything_. Including supporting ground troops right over the battlefield. A lot of the problems that the Aussies had defending Darwin was due to the limited flight endurance of the Spit Vs they were flying. If they had Spit VIII, or say, Corsairs, it would have gone a lot better I think.

Similarly, Spitfires were not as heavily engaged as they could have been during battles like El Alamein because they lacked range and flight endurance.

More fuel capacity _can_ mean range to fly to Berlin (or maybe Rotterdam), but it can also mean flight endurance to climb to altitude, form up, fly around and find enemy aircraft, engage them at high boost for longer periods, and still be able to fly back to base if you happened to chase them a bit.

In 1940 or 41, it probably makes sense to build aircraft with very small fuel capacity, since your ~1,000 engine isn't going to be good at hauling 180 gallons of fuel around the sky and the priority is defending the homeland and controlling the sky directly over the battlefield. Once you have a 1,500 hp engine (or a 2,000 hp radial) then it's time to look at carrying more, IMO.


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## tomo pauk (Mar 18, 2022)

Wild_Bill_Kelso said:


> Even the longer-legged VIII was still a bit too short ranged for the Pacific. If they could have enhanced it say 50% more it would have been very helpful I think. And if they had something like the Mk VIII just a few months earlier that might have saved lives in the Mediterranean.



They could, and they did. In late 1944, that is, when there was such a thing like rear-fuselage tankage for Spitfire IX for example, by what time Allies were firmly in France.
There was no 'long range escort fighter' doctrine at the RAF, just like at other air forces/services (bar Luftwaffe and what Japanese had). Thus no long range escort fighters.



Wild_Bill_Kelso said:


> So it seems to me that improving the range of the Spitfire could have paid substantial dividends even if the P-51 still ended up dominating the strategic escort role. I don't know enough about the technical aspects to say how feasible it was. I know the Spitfire had a pretty slim wing and was generally a fairly small aircraft compared to some of the later war designs, but they certainly improved the range of the Mk VIII over the V. The Bf 109 had the same issues in this regard and the Germans never seem to have really solved the problem either.



Spitfire was one of the biggest 1-engined fighters when introduced. Similar size like the P-40 or P-51. Thus the ability to carry a lot of firepower, fuel and to receive much bigger and more powerful engines as war progressed, without paying the penalty in handling after the upgrades.
Bf 109 was indeed small.



pbehn said:


> The need for a top class short ranged interceptor didn't disappear until well after D-Day. Until 1943 when Stalingrad and El Alamein decided the course of the war things could have turned for the worse as viewed at the time. But even after that, the possibility of sneak tip and run raids wreaking havoc on UK and USA assets in UK existed and keeping the D-Day build up secret as far as a landing in Normandy not Calais meant German recon had to be confronted and stopped, which it was.



D-Day was 18 months after the German disasters at Stalingrad and in North Africa. Let's not make an elephant out of a mouse, like terror the 'tip and run' attacks were sometimes described. 
Hawker Hurricane was not a 'top class short range interceptor', yet it was happily made in more than 2700 copies in 1943, and almost 690 pcs in 1944. 
D-Day was made possible via the aerial offensive WAllies mounted through 1943 and 1st half of 1944 (plus the earlier efforts, often futile), it would not have been possible if the WAllies were twiddling their fingers above the UK airspace.



pbehn said:


> Range is great if you have it and you need it. Within days of the Normandy landings airfields were being constructed in Normandy to save the trip of 100 miles across the channel. The guys in combat on the ground would not be impressed to hear that their fighter cover was off to Berlin, because they could.



The guys on the ground were there because Luftwaffe was trashed by the time the guys were actually there. Air cover was never in question, with RAF and USAAF displaying the many:1 superiority in numbers vs. LW, while also having the qualitative edge.
WAllies not having an all-LR force in the ETO between June of 1943 and July of 1944 at was the thing that supplied some oxygen to the Luftwaffe in 1944, lest they suffocate.


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## pbehn (Mar 18, 2022)

Wild_Bill_Kelso said:


> In 1940 or 41, it probably makes sense to build aircraft with very small fuel capacity, since your ~1,000 engine isn't going to be good at hauling 180 gallons of fuel around the sky and the priority is defending the homeland and controlling the sky directly over the battlefield. Once you have a 1,500 hp engine (or a 2,000 hp radial) then it's time to look at carrying more, IMO.


The Spitfire first flew in 1936, with a fixed pitch twin blade prop it had about 660BHP available on take off. The early Bf 109s had Jumo 210 engines that only produced around 600-700 BHP. The British were looking to have more range, that is why they got heavily involved with NAA and the Mustang with its 180 gallons of internal fuel ordered in 1940, it was known as a P-51 when the USA eventually started using it.


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## tomo pauk (Mar 18, 2022)

Wild_Bill_Kelso said:


> What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...



Why would everyone want something like a Bearcat, bar as a carrier-vessel bird?


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## pbehn (Mar 18, 2022)

tomo pauk said:


> *D-Day was 18 months after the German disasters at Stalingrad and in North Africa. Let's not make an elephant out of a mouse, like terror the 'tip and run' attacks were sometimes described.*
> Hawker Hurricane was not a 'top class short range interceptor', yet it was happily made in more than 2700 copies in 1943, and almost 690 pcs in 1944.
> D-Day was made possible via the aerial offensive WAllies mounted through 1943 and 1st half of 1944 (plus the earlier efforts, often futile), it would not have been possible if the WAllies were twiddling their fingers above the UK airspace.
> 
> ...


I wasnt, that is why I posted "But even after that, the possibility ". We now know what Germany had and what it could do or have done, that was not the case for people responsible for UK air defence in WW2. They had to assume that there could be another generation of planes, to improve on the Fw190, maybe a jet, in fact what happened was the V1 and V2 and Me 262s and Arado 234s. The Hurricane was not considered a top class interceptor after 1940, it was produced but not for the air defence of UK.

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## PAT303 (Mar 18, 2022)

GregP said:


> No.
> 
> It's a photographic airplane and had best not get tangled up with ANY fighter with that much fuel as it would be meat on the table.


Greg, fighter variants of the Spitfire had all manor of aux and drop tanks fitted, you seem to think only PR Spits did, I'll post this photo again




This is NOT a PR Spitfire, ALL production MkXVI spits had this tankage arrangement, as has already been posted the MkXVI is just a Packard engined MkIX, which is nothing more than a modified re-engined MkV, which are nothing more than modified re-engined 1940 era MkII's, Spits could have had aux tanks as soon as the engine power allowed the increase in weight.

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## pbehn (Mar 18, 2022)

tomo pauk said:


> The guys on the ground were there because Luftwaffe was trashed by the time the guys were actually there. Air cover was never in question, with RAF and USAAF displaying the many:1 superiority in numbers vs. LW, while also having the qualitative edge.
> WAllies not having an all-LR force in the ETO between June of 1943 and July of 1944 at was the thing that supplied some oxygen to the Luftwaffe in 1944, lest they suffocate.


That is what happened, it wasnt certain that that would happen in 1942 to 43 when decisions had to be made. If long range and single engined fighters escorting bombers was so important why didnt the USA take it seriously until mid 1943?


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## Wild_Bill_Kelso (Mar 18, 2022)

tomo pauk said:


> Why would everyone want something like a Bearcat, bar as a carrier-vessel bird?



I'd say the Bearcat was pretty close to a sweet spot in terms of range, performance, armament, agility, and so on. A good balance of traits.


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## Wild_Bill_Kelso (Mar 18, 2022)

pbehn said:


> That is what happened, it wasnt certain that that would happen in 1942 to 43 when decisions had to be made. If long range and single engined fighters escorting bombers was so important why didnt the USA take it seriously until mid 1943?



Well the US had longer ranged fighters than a Spitfire, with the exception maybe of the P-39 and the F2A, the main US Pursuit types like P-40 and F4F, had ~700 - 800 mile range (equivalent of a Spitfire Mk VIII or a bit better). They needed longer still particularly for China and the Pacific, and they kept pushing the boundaries, but the P-51 wasn't the only long-ranged US fighter. The (twin engined) P-38 eventually had a range of 1,000-1,300 miles, the P-47, F6F and F4U each managed ~800 -1,000 miles or (depending on various conditions and configurations). 

Arguably the main reason the US were in fact pushing for longer ranged aircraft was the necessity or possibility to have to fight over the Pacific. But the extra range was helpful in many Theaters.

Seeing as Spitfires were being used in North Africa from mid-1942 (actually 145 squadron was there in February) and in the South Pacific by early 1943, they certainly could have used better range. By the time of second El Alamein, the DAF was limited in the use of their Spitfire Mk Vs which flew sorties only half of the days in October. Kittyhawks were having to escort the medium bombers. Toward the end of the battle, P-38s became available in the Theater.

I've already mentioned the range / endurance related issues over Darwin though I could get into more detail.

Seeing as some of the PR Spitfires from the Mk X and XI actually had quite good range, it seems like there should have been some way to make a long range fighter version, maybe a two gun variant would have been possible?

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## Wild_Bill_Kelso (Mar 18, 2022)

tomo pauk said:


> They could, and they did. In late 1944, that is, when there was such a thing like rear-fuselage tankage for Spitfire IX for example, by what time Allies were firmly in France.
> There was no 'long range escort fighter' doctrine at the RAF, just like at other air forces/services (bar Luftwaffe and what Japanese had). Thus no long range escort fighters.



Initially I'd agree with you, but by the time the British Army was engaged in North Africa and the ANZAC forces were engaged with the IJA in the Pacific, the need for a fighter that could fly to Axis bases in Tunisia say, or across the Owen Stanley range in New Guinea, was certainly noted. They had time to come up with something. Some Spitfires were in Theater in the Pacific but had little effect on the war due to range.



tomo pauk said:


> Spitfire was one of the biggest 1-engined fighters when introduced. Similar size like the P-40 or P-51. Thus the ability to carry a lot of firepower, fuel and to receive much bigger and more powerful engines as war progressed, without paying the penalty in handling after the upgrades.
> Bf 109 was indeed small.



Spitfire was big for 1936, but by say, 1941 it's fairly small. The fuselage is comparable to the Bf-109 IMO, though it has larger wings. It's a slender, slim aircraft. It certainly looks small next to say a P-38, an F4U, or a BF 110. Not that small was bad.


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## tomo pauk (Mar 19, 2022)

pbehn said:


> I wasnt, that is why I posted "But even after that, the possibility ". We now know what Germany had and what it could do or have done, that was not the case for people responsible for UK air defence in WW2. They had to assume that there could be another generation of planes, to improve on the Fw190, maybe a jet, in fact what happened was the V1 and V2 and Me 262s and Arado 234s. The Hurricane was not considered a top class interceptor after 1940, it was produced but not for the air defence of UK.



WAllies have historically taken care for the possibility of the new-gen German fighters, by making Tempest, Spitfire XIV, Merlin Mustang and P-47.



pbehn said:


> That is what happened, it wasnt certain that that would happen in 1942 to 43 when decisions had to be made. If long range and single engined fighters escorting bombers was so important why didnt the USA take it seriously until mid 1943?



LR SE fighters were important. That USAAF took a long time to make them shows that the monopoly on institutional inertia does not exist.



Wild_Bill_Kelso said:


> I'd say the Bearcat was pretty close to a sweet spot in terms of range, performance, armament, agility, and so on. A good balance of traits.



Bearcat was a short-range fighter, armed with .50 HMGs when it entered the service. That is despite being a post-war machine.
Performance was great for 1943, but there was a lot of - especially Allied - fighters that were faster, particularly above 25000 ft.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> Initially I'd agree with you, but by the time the British Army was engaged in North Africa and the ANZAC forces were engaged with the IJA in the Pacific, the need for a fighter that could fly to Axis bases in Tunisia say, or across the Owen Stanley range in New Guinea, was certainly noted. They had time to come up with something. Some Spitfires were in Theater in the Pacific but had little effect on the war due to range.



Same thing of 'institutional inertia' - everyone has it, some institutions being with smaller, other with greater inertia. The smaller inertia, the faster the changes to answer the operational needs.



Wild_Bill_Kelso said:


> Spitfire was big for 1936, but by say, 1941 it's fairly small. The fuselage is comparable to the Bf-109 IMO, though it has larger wings. It's a slender, slim aircraft. It certainly looks small next to say a P-38, an F4U, or a BF 110. Not that small was bad.



Care to post some measurements wrt. why is Spifire a small fighter?
Should not we compare the like with the like, ie. 1-engined V12-powered fighters vs. 1-engined V12 powered fighters?

Bf 109 was able to carry 110-115 imp gals worth of fuel+MW50 in the fuselage by the end of the war, Spitfire was able to carry 160+ imp gals of fuel. Spitfires were operationally using 4 big 20mm cannons, all tucked in the wing, not something Bf 109 was capable for due to wing being small.

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## EwenS (Mar 19, 2022)

Let’s pause for a moment and look at the whole history of bomber offensive v defensive fighters. Is the issue really one of fighters being short of range OR the period from 1943 to c1950 being unique in that the technology existed to allow the bomber to be escorted all the way to its target from bases near its home.

No escorts for Gothas in WW1. Interwar, the bomber will always get through. 1939/40 errrr, no! So RAF and Luftwaffe resort to night bombing. USAAF, no we can still bomb in daylight from high altitude, all we need is enough 0.5” guns. 1943 errrrrr, no! But wait if we stick enough fuel in the fighter designs we already have, we can make long range escort of the bomber fleet work!

But by 1945 even that philosophy is changing. Over Japan, LeMay resorts to night bombing from lower altitudes, despite the coming availability of fighter escort from Iwo Jima. Note, a base not near the bomber base but half way to the target.

Post WW2 ranges that the bomber has to operate over increase further and we have ever faster jet bombers. By 1950 the project to design a jet fighter escort via the XF-88/XF-90/XF-93 is canned as impractical (problem being to provide enough fuel for thirsty jets to escort bombers from the USA to their targets in USSR). Briefly resurrected in the Korean War for escort to slower B-29/B-50/B-36 bombers it finally dies around 1954.

And so the Mosquito concept of the fast, (almost) unarmed bomber relying on fancy electronics to defeat the defences wins out!

There is just that sweet spot for the escort fighter around 1943-45 where the range of the fighter can be extended with drop tanks just far enough to make bomber escort from base to target and back a viable concept.

I’ll get my hat and coat and head for the door!!

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## EwenS (Mar 19, 2022)

Wild_Bill_Kelso said:


> Seeing as Spitfires were being used in North Africa from mid-1942 (actually 145 squadron was there in February) and in the South Pacific by early 1943, they certainly could have used better range. By the time of second El Alamein, the DAF was limited in the use of their Spitfire Mk Vs which flew sorties only half of the days in October. Kittyhawks were having to escort the medium bombers. Toward the end of the battle, P-38s became available in the Theater.
> 
> I've already mentioned the range / endurance related issues over Darwin though I could get into more detail.


While 145, 92 and 601 squadrons left Britain on 10-12 Feb 1942, they did not arrive in the Middle East until mid-April (145 & 92) and June (601) as they had to sail via the Cape. There was then a shortage of Spitfires in that area so 145 didn’t head up the desert until late May with 601 following in June. 92 had to wait until Aug to receive its aircraft.

The first Spitfires outwith Britain began to be shipped to Malta in March 1942 to equip squadrons already on the island and then to send additional units like 601 & 603 (601 later flying to Egypt to join its ground crews).

On 28 May 1942 Churchill agreed to supply a Spitfire wing to protect Darwin. The squadrons selected were 54, 452(Australian) and 457(Australian). These sailed for Australia in late June 1942 but 42 of the 48 aircraft sent with them were diverted to Takoradi to be flown across Africa to the Middle East to allow 92 to become operational there. So it was late Oct before the first major shipment of replacement aircraft reached Australia. No 1 Fighter Wing then became operational in Darwin from Jan 1943.

Spitfires didn’t arrive in India /Burma until Nov 1943.


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## wuzak (Mar 19, 2022)

EwenS said:


> USAAF, no we can still bomb in daylight from high altitude, all we need is enough 0.5” guns. 1943 errrrrr, no! But wait if we stick enough fuel in the fighter designs we already have, we can make long range escort of the bomber fleet work!



They were right about having enough 0.50" HMGs, but not right about which aircraft the guns were in.

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## drgondog (Mar 19, 2022)

Wild_Bill_Kelso said:


> I'd say the Bearcat was pretty close to a sweet spot in terms of range, performance, armament, agility, and so on. A good balance of traits.


Not a candidate for high altitude, long range bomber escort.. Only 150gal internal fuel. Compare vs P-47D-1 through D-22 w/305gal internal fuel and max combat radius of ~400mi.

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## GregP (Mar 19, 2022)

PAT303 said:


> Greg, fighter variants of the Spitfire had all manor of aux and drop tanks fitted, you seem to think only PR Spits did, I'll post this photo again
> View attachment 661839
> This is NOT a PR Spitfire, ALL production MkXVI spits had this tankage arrangement, as has already been posted the MkXVI is just a Packard engined MkIX, which is nothing more than a modified re-engined MkV, which are nothing more than modified re-engined 1940 era MkII's, Spits could have had aux tanks as soon as the engine power allowed the increase in weight.



And you seem to think they all used this entire fuel capacity when they didn't except by special approval, and it wasn't often given. Spitfires were never long-range airplanes. They got longer-legged than early version, but they weren't long-range, by any means. You may WANT them to be long-range, but they were, at best, medium-range fighters. And, if you're going to fly a top-tier air-superiority fighter, that's not a bad type of airplane to be flying. There is NOTHING wrong with the Spitfire flying it's intended missions. It did that quite well, among the best in the world, in fact. 

You can speculate all you want, but you can't turn the Spitfire into something it wasn't. None of them were going to be in the air much more than 3 - 4 hours at economy cruise without any combat or reserve, and most were on the ground by the time 2.5 hours or less had gone by. If they flew patrol, then they could stay up a longer using drop tanks, but they were careful not to venture out beyond the "get home on internal fuel" range, at least until alternate friendly airfields were a possibility beyond D-Day. Once they had basing in continental Europe, then they could start to come into their own as medium-range fighters by virtue of having friendly place to land and refuel within range, and they did.

Of course, once these fields were in Allied use, the P-51s didn't have to take off with full fuselage tanks either and everyone had an easier time planning missions, not just Spitfire planners.

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## GregP (Mar 19, 2022)

tomo pauk said:


> Same thing of 'institutional inertia' - everyone has it, some institutions being with smaller, other with greater inertia. The smaller inertia, the faster the changes to answer the operational needs.
> 
> 
> 
> ...



The Ha-1112 had two 20 mm cannons in the wings firing through a hole in the wing spar. It was basically a Bf 109G-2 with a Merlin in front, so the Bf 109 was capable of having the same mod done during WWII instead of hanging them from gondolas under the wing. Makes one wonder. 

In the real world of production BF 109s, though, you are spot on.


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## tomo pauk (Mar 19, 2022)

GregP said:


> The Ha-1112 had two 20 mm cannons in the wings firing through a hole in the wing spar. It was basically a Bf 109G-2 with a Merlin in front, so the Bf 109 was capable of having the same mod done during WWII instead of hanging them from gondolas under the wing. Makes one wonder.



Ha 1112 have indeed had two (big) 20mm cannons in the wing; post-war. Makes it half as good as the Spitfire VC with 4 (big) 20mm cannons in the wing in early 1942.


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> LR SE fighters were important. That USAAF took a long time to make them shows that the monopoly on institutional inertia does not exist.


Knowing *how* to make one - that can still perform well enough to compete at the highest levels, it's a pretty significant design challenge. I think they kind of got lucky with the high efficiency / low drag design of the Mustang.



tomo pauk said:


> *Bearcat was a short-range fighter*, armed with .50 HMGs when it entered the service. That is despite being a post-war machine.
> Performance was great for 1943, but there was a lot of - especially Allied - fighters that were faster, particularly above 25000 ft.



Maybe I'm not reading this chart right, or maybe I've got a poor grasp of what a baseline is for range but Wikipedia says 1,100 miles, and this 1949 document seems to indicate a range in the ballpark of 1500 nautical miles (1726 miles) in 'escort configuration' (3 x external fuel tanks). If I am reading that right, this looks pretty impressive to me. The speed as well, 388 knots at 28,000 ft is 448 mph right?

As for the .50 cals, they could and did put 20mm Hispanos in it. The .50 cals are just another example of 'institutional inertia' you are speaking of specific to the Americans.

Maybe that's not so impressive for 1945, compared to a jet or a P-47M, but my point was exactly that, - this is kind of what they wanted a bit earlier but didn't put it all together in time.


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## Wild_Bill_Kelso (Mar 19, 2022)

drgondog said:


> Not a candidate for high altitude, long range bomber escort.. Only 150gal internal fuel. Compare vs P-47D-1 through D-22 w/305gal internal fuel and max combat radius of ~400mi.



Apparently they could carry a lot of external fuel, and I suspect based on the size, bearcat could get a little further on a gallon of fuel than a P-47 though I'm ready to be proven wrong...


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## Wild_Bill_Kelso (Mar 19, 2022)

drgondog said:


> Not a candidate for high altitude, long range bomber escort.. Only 150gal internal fuel. Compare vs P-47D-1 through D-22 w/305gal internal fuel and max combat radius of ~400mi.



Anyway, when I talk about longer ranged fighters *or* bomber escort, I guess I am alone in thinking of things _other_ than strategic bombing. There was more to air-war in ww2 than strategic bombing.

WW2 also took place on a tactical level! It's debatable how effective the strategic bombing even was, but it certainly wasn't the only thing. Battles like El Alamein, Stalingrad, Kursk, Midway, Malta, Milne Bay, Guadalcanal, Philippine Sea etc. etc. were also quite important to overall victory, IMO. And tactical bombers need fighter protection too!


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> Care to post some measurements wrt. why is Spifire a small fighter?
> Should not we compare the like with the like, ie. 1-engined V12-powered fighters vs. 1-engined V12 powered fighters?
> 
> Bf 109 was able to carry 110-115 imp gals worth of fuel+MW50 in the fuselage by the end of the war, Spitfire was able to carry 160+ imp gals of fuel. Spitfires were operationally using 4 big 20mm cannons, all tucked in the wing, not something Bf 109 was capable for due to wing being small.



I have models right behind me with every pretty much mid-war WW2 fighter represented in the same scale. Spitfire looks smaller and slimmer than most of them, (for example Hurricane, Typhoon, Wildcat, Hellcat, P-40, P-51, Fulmar, P-47, Corsair, Bf 110) though I'll grant you many of the Japanese, Italian and Russian fighters are as small or smaller. And the BF 109 is also quite small of course.


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## Wild_Bill_Kelso (Mar 19, 2022)

EwenS said:


> But by 1945 even that philosophy is changing. Over Japan, LeMay resorts to night bombing from lower altitudes, despite the coming availability of fighter escort from Iwo Jima. Note, a base not near the bomber base but half way to the target.


I think that is reflective of a different attitude toward the Japanese on the part of the Americans than toward Continental Europe.



EwenS said:


> Post WW2 ranges that the bomber has to operate over increase further and we have ever faster jet bombers. By 1950 the project to design a jet fighter escort via the XF-88/XF-90/XF-93 is canned as impractical (problem being to provide enough fuel for thirsty jets to escort bombers from the USA to their targets in USSR). Briefly resurrected in the Korean War for escort to slower B-29/B-50/B-36 bombers it finally dies around 1954.
> 
> And so the Mosquito concept of the fast, (almost) unarmed bomber relying on fancy electronics to defeat the defences wins out!
> 
> There is just that sweet spot for the escort fighter around 1943-45 where the range of the fighter can be extended with drop tanks just far enough to make bomber escort from base to target and back a viable concept.



I think maybe missiles kind of make escort fighters pointless by some point in the 60s. At least until you have fighter aircraft which can effectively shoot down air to air and surface to air missiles. But with the advent of air to air refueling fighters can go farther than ever, and when it comes to tactical bombing, fighters are in fact what are used most often, with the fast / unarmed / fancy electronics fighter bomber type ala Mosquito playing a smaller role (B-1B for example or maybe F-111, Panavia Tornado etc.) and the heavy / strategic bomber basically relegated to the slowest branch of the nuclear deterrence "triad".




EwenS said:


> I’ll get my hat and coat and head for the door!!


Nah you made good points bruv! lol


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## Wild_Bill_Kelso (Mar 19, 2022)

EwenS said:


> While 145, 92 and 601 squadrons left Britain on 10-12 Feb 1942, they did not arrive in the Middle East until mid-April (145 & 92) and June (601) as they had to sail via the Cape. There was then a shortage of Spitfires in that area so 145 didn’t head up the desert until late May with 601 following in June. 92 had to wait until Aug to receive its aircraft.
> 
> The first Spitfires outwith Britain began to be shipped to Malta in March 1942 to equip squadrons already on the island and then to send additional units like 601 & 603 (601 later flying to Egypt to join its ground crews).
> 
> ...



Ok mea culpa, 145 sqn wasn't there as early as I thought - Mid 1942 for North Africa, and early 1943 for Darwin which I think is what I originally said.


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## drgondog (Mar 19, 2022)

Wild_Bill_Kelso said:


> Apparently they could carry a lot of external fuel, and I suspect based on the size, bearcat could get a little further on a gallon of fuel than a P-47 though I'm ready to be proven wrong...


Internal fuel remaining after external tanks dropped determines combat radius. Both will burn about the same amount for warm up, take of, formation assy and start of climb before switching to externals, both will have about the same estimate applied to 'loiter time reserve', both will burn about the same fuel at Combat Power in Radius calcs dropping tanks - but P-47D began ops with 2X internal fuel for -23 and lower dash number and 2.5X internal fuel for P-47D-25 and higher dash number - which was dominant in combat from late 1944 through EOW. 

It might have even have a better spc through 20K but P47 had less total drag than F8F. The F4U/F6F/F8F all had parasite drag higher than P-47 but I am not sure about Induced drag as that is more a function of W/L. That said, at cruising speed at high altitude, the CL was pretty low for the P-47D.

F8F was designed as carrier defense, point interceptor, short range (by AAF standards) escort.

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## GregP (Mar 19, 2022)

tomo pauk said:


> Ha 1112 have indeed had two (big) 20mm cannons in the wing; post-war. Makes it half as good as the Spitfire VC with 4 (big) 20mm cannons in the wing in early 1942.



The Ha-1112 was developed by virtue of necessity, and I suppose two 20 mm cannons was a decent minimum armament. The Merlin engine precluded nose-mounted guns, so they HAD to come up with SOMETHING. In retrospect, they didn't do badly out of necessity, but the He-1112 was basically a stop-gap airplane so the Spanish would have a fighter to fly until they got jets. In light of that, and also in light of not having to fight in a widespread war, it wasn't a bad solution. Not the best, but not bad, either, to maintain flight-time.

The U.S.A also had some "interim" types a bit later. The F-86D comes to mind with its tray of unguided rockets as armament. The F-89 also sort of floats to the top of the pile as an interim type with less-than-wonderful armament.


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## Wild_Bill_Kelso (Mar 19, 2022)

drgondog said:


> Internal fuel remaining after external tanks dropped determines combat radius. Both will burn about the same amount for warm up, take of, formation assy and start of climb before switching to externals, both will have about the same estimate applied to 'loiter time reserve', both will burn about the same fuel at Combat Power in Radius calcs dropping tanks - but P-47D began ops with 2X internal fuel for -23 and lower dash number and 2.5X internal fuel for P-47D-25 and higher dash number - which was dominant in combat from late 1944 through EOW.



Fair points. The thing is, the P-47 was specialized as a high altitude fighter, which is a job it didn't do that much of. A lot of the actual air combat in WW2 was considerably below 30,000 ft. I don't think a P-47D series was as good of a fighter at say, 20,000 ft or 10,000 ft as an F8F, do you? 

The altitude of the fight depends on what kind of bombing is going on. Tactical bombing of ground targets / armies, means relatively low combat, as does air strikes against naval assets.



drgondog said:


> It might have even have a better spc through 20K but P47 had less total drag than F8F. The F4U/F6F/F8F all had parasite drag higher than P-47 but I am not sure about Induced drag as that is more a function of W/L. That said, at cruising speed at high altitude, the CL was pretty low for the P-47D.
> 
> F8F was designed as carrier defense, point interceptor, short range (by AAF standards) escort.



Maybe 'short range' compared to an A6M, but it seems to have had better range than an F4F, I'd say probably better than an F6, and certainly better than any fighter mark of Spitfire (barring recon versions) which was my actual point. Or any Bf 109. I originally brought up the F8F simply in terms of a balance of performance + range.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> Knowing *how* to make one - that can still perform well enough to compete at the highest levels, it's a pretty significant design challenge. I think they kind of got lucky with the high efficiency / low drag design of the Mustang.



I'd chalk the high efficiency / low drag of the Mustang to the talent and hard work of the engineers, technicians and draughtsmen at NACA and NAA, rather than to the luck.
P-47 was also a rangy aircraft once outfitted with drop tanks..



Wild_Bill_Kelso said:


> Maybe I'm not reading this chart right, or maybe I've got a poor grasp of what a baseline is for range but Wikipedia says 1,100 miles, and this 1949 document seems to indicate a range in the ballpark of 1500 nautical miles (1726 miles) in 'escort configuration' (3 x external fuel tanks). If I am reading that right, this looks pretty impressive to me. The speed as well, 388 knots at 28,000 ft is 448 mph right?
> 
> As for the .50 cals, they could and did put 20mm Hispanos in it. The .50 cals are just another example of 'institutional inertia' you are speaking of specific to the Americans.
> 
> Maybe that's not so impressive for 1945, compared to a jet or a P-47M, but my point was exactly that, - this is kind of what they wanted a bit earlier but didn't put it all together in time.



You are reading that right, but there is a host of caveats. Thing is that there was the F8F-1 3-4 years before the F8F-2, that one was under 425 mph, and was armed with 4 HMGs. Yes, it got the cannons later.
For the F8F-2 to be had, P&W needs to design and produce the post-war R-2800-30 engine from the 'E' series.
Ferry range was good, since that meant that drop tanks can be used for as long there is fuel (all 350 gals) in them. The USN combat range, that was supposed to be 679 miles was unworkable for ETO situation in 1940-44, since it presumed inbound cruising at 230 mph at 15000 ft, and outbound cruining at 195 mph at 1500 (!!) ft. USAF for ETO prescribed cruising at 25000 ft, at 310 mph TAS, lest the enemy fighters and/or AAA don't kill you. Having 185 US gals of internal fuel for R-2800 is enough for short-range duties, it compares badly with P-47D bubbletop with 370 US gals, let alone with 265 gals fuel on the most of Merlin Mustangs with a much more frugal engine.
Thing with having almost double the fuel in drop tanks is that that gets one to a position so far away from the friendly airbase where that there is no come back.

US-made Hispano cannon was a victim of bad production tolerances that led to the "light primer strike" problem rendering them very unreliable. For example, British removed the cannons from Mustang IA and installed the British-made cannons instead.

F8F-2 was a fine aircraft, but was way too late for ww2, and it does not solve the USAF problems of escorting the heavy bombers above Europe even if it was available. British have the Spitfire XIV for the high-performance short-range needs, with jet aircraft in the pipeline to take the role from 1945 on.

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## EwenS (Mar 19, 2022)

The F8F-1 Bearcat wasn’t built to maximise range. It was built to maximise rate of climb.
F8F-1 4,465 ft/min
F6F-5 2,600 ft/min
P-51D 3,200 ft/min
Spitfire V 4,750 ft/min
Spitfire IX 4,100 ft/min
Spitfire XIV 4,580 ft/min

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## tomo pauk (Mar 19, 2022)

EwenS said:


> The F8F-1 Bearcat wasn’t built to maximise range. It was built to maximise rate of climb.


Bingo.


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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> Well the US had longer ranged fighters than a Spitfire, with the exception maybe of the P-39 and the F2A, the main US Pursuit types like P-40 and F4F, had ~700 - 800 mile range (equivalent of a Spitfire Mk VIII or a bit better). They needed longer still particularly for China and the Pacific, and they kept pushing the boundaries, but the P-51 wasn't the only long-ranged US fighter. The (twin engined) P-38 eventually had a range of 1,000-1,300 miles, the P-47, F6F and F4U each managed ~800 -1,000 miles or (depending on various conditions and configurations).
> 
> Arguably the main reason the US were in fact pushing for longer ranged aircraft was the necessity or possibility to have to fight over the Pacific. But the extra range was helpful in many Theaters.
> 
> ...


One of the main reasons US planes had a longer range is that the USA is a much bigger country, even in peacetime getting from one airfield to another requires more range. The P-47 was an interceptor at the start what it became is a matter of history. Range is only of use when the performance is there, the P-40 and P-39 were tried by the RAF operating from UK, they just didnt have the performance, while the Mustang Mk I with the same engine did. In RAF service the 180 gallons of internal fuel translated into a "range" on operations of 90 miles in from the enemy coast.

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## MIflyer (Mar 19, 2022)

Note there was a hideous modification to the Spitfire Mk1 that added a large unsightly fixed tank sticking out of one wing to improve the range. And as for size the BF-109 and FW-190 both were smaller than the F4F Wildcat; they did not have a lot of room for extra gas. The RAF considered the Mustang Mk 1 to be huge compered to the Spitfire and Hurricane. When they built the MkXII and XIV they added small gas tanks (12 gal) in the leading edges of the outer wing because the larger Griffin engine consumed so much more fuel than the Merlin, and they did not have that much to start out with. 12 gal sounds almost absurdly small for a gas tank but they needed all they could get. 

In the Pacific Lindberg taught first the F4U pilots (as an employee of United Aircraft) and then the P-38 and P-47 pilots to fly at high boost and low revs at low altitude to extend their range, This worked in the Pacific since any long range mission involved most of the flying being over water, an area where the chance of encountering either enemy aircraft or AAA was all but nonexistent and virtually "nought feet" was feasible. The ETO before the Normandy Invasion was nothing like that, with only a little of a mission flying over the Channel and even then having to climb to avoid AAA on the coast as well as inland.

But that same Lindberg approach eventually was adopted in the ETO, after the Allies occupied airfields in France and had nothing to fear from flights over France to ground targets in Germany.

"One of the main reasons US planes had a longer range is that the USA is a much bigger country, even in peacetime getting from one airfield to another requires more range."

Yes, as it has been pointed out, most European fighters of the day could not make it out of Texas without landing to gas up. Even the P-6E could carry an external fuel tank.


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> I'd chalk the high efficiency / low drag of the Mustang to the talent and hard work of the engineers, technicians and draughtsmen at NACA and NAA, rather than to the luck.
> P-47 was also a rangy aircraft once outfitted with drop tanks..



P-47 was a lot heavier (10,400 lbs vs 7,650 empty for F8), had a much larger wingspan (40' vs 35') and a much bigger / fatter fuselage. Somebody said it had a lower induced drag or something, I am not an engineer but i find it hard to believe that the P-47 had lower drag than an F8F.


tomo pauk said:


> You are reading that right, but there is a host of caveats. Thing is that there was the F8F-1 3-4 years before the F8F-2, that one was under 425 mph, and was armed with 4 HMGs. Yes, it got the cannons later.
> For the F8F-2 to be had, P&W needs to design and produce the post-war R-2800-30 engine from the 'E' series.
> Ferry range was good, since that meant that drop tanks can be used for as long there is fuel (all 350 gals) in them. The USN combat range, that was supposed to be 679 miles was unworkable for ETO situation in 1940-44, since it presumed inbound cruising at 230 mph at 15000 ft, and outbound cruining at 195 mph at 1500 (!!) ft. USAF for ETO prescribed cruising at 25000 ft, at 310 mph TAS, lest the enemy fighters and/or AAA don't kill you. Having 185 US gals of internal fuel for R-2800 is enough for short-range duties, it compares badly with P-47D bubbletop with 370 US gals, let alone with 265 gals fuel on the most of Merlin Mustangs with a much more frugal engine.
> Thing with having almost double the fuel in drop tanks is that that gets one to a position so far away from the friendly airbase where that there is no come back.



Fair points but this again seems to assume strategic bomber escort. A long ranged spitfire wouldn't necessarily be used that way ... I mean it could, but it would help the war effort a lot for example in places like North Africa, Malta, Darwin, New Guinea, China / Burma etc. This was the context from my point of view. Even with 150 gallons that F8F compares very well to a Spitfire or a Bf 109 in range, IMO, while having far more combat capability than say an A6M. If you are flying over the Pacific, through vast areas of China or Burma, or say, from Malta to North Africa or Sicily, you can probably use your drop tanks, though you may have to fly home right after an engagement.



tomo pauk said:


> US-made Hispano cannon was a victim of bad production tolerances that led to the "light primer strike" problem rendering them very unreliable. For example, British removed the cannons from Mustang IA and installed the British-made cannons instead.


I'm aware of the problem with the US-made Hispano, It is somewhat incredible that they seem to have had trouble with this long after the war as well. But the context here was not specific to the US, I was just referring to threading the needle between range, agility, and performance. Presumably if they had the F8F flying in say, 1943 the British could have put their own guns in it like they did with the Corsair.



tomo pauk said:


> F8F-2 was a fine aircraft, but was way too late for ww2, and it does not solve the USAF problems of escorting the heavy bombers above Europe even if it was available. British have the Spitfire XIV for the high-performance short-range needs, with jet aircraft in the pipeline to take the role from 1945 on.



Again, for me when I'm thinking of the usefulness of something like a longer-ranged Spitfire, I'm not thinking exclusively of strategic bombing escorts to Berlin. I'm not sure you have a better option than a P-51, unless maybe it's a twin-engined fighter like a late model P-38, an earlier incarnation of a F7F, a de Havilland Horne_t_ or something like that.

Most fighter marks of the Spitfire were limited to around 500 miles range which relegated them to the status of point defense fighters or air superiority fighters deployed right at the front line. Something with the combat capabilities of a Spitfire, which were IMO a bit better than a P-51 depending on the specific marks, but with a 1,000 mile instead of 500 mile range, would have been very helpful for tactical escort, fighter bomber, and medium range air superiority missions.


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> F8F-2 was a fine aircraft, *but was way too late for ww2*, and it does not solve the USAF problems of escorting the heavy bombers above Europe even if it was available. British have the Spitfire XIV for the high-performance short-range needs, with jet aircraft in the pipeline to take the role from 1945 on.


My original point in bringing up the F8F was exactly that - striking such a balance as you see in that aircraft was possible but very hard, and in this example (among many others) came too late to play a role in the war.


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## Wild_Bill_Kelso (Mar 19, 2022)

EwenS said:


> The F8F-1 Bearcat wasn’t built to maximise range. It was built to maximise rate of climb.
> F8F-1 4,465 ft/min
> F6F-5 2,600 ft/min
> P-51D 3,200 ft/min
> ...



And yet it still carried almost twice as much fuel as most marks of the Spitfire!


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## tomo pauk (Mar 19, 2022)

MIflyer said:


> Note there was a hideous modification to the Spitfire Mk1 that added a large unsightly fixed tank sticking out of one wing to improve the range. And as for size the BF-109 and FW-190 both were smaller than the F4F Wildcat; they did not have a lot of room for extra gas. The RAF considered the Mustang Mk 1 to be huge compered to the Spitfire and Hurricane. When they built the MkXII and XIV they added small gas tanks (12 gal) in the leading edges of the outer wing because the larger Griffin engine consumed so much more fuel than the Merlin, and they did not have that much to start out with. 12 gal sounds almost absurdly small for a gas tank but they needed all they could get.



Wing areas, in sq ft, (main versions):
- Hurricane: 257 
- F4F: 260
- P-51: 242
- Spitfire: 235
- P-40: 236
- Zero: 242
- G.55: 227
- Re.2001 & 2005: 220
- F8F: 244

Smaller fighters:
- Bf 109: 173
- Fw 190: 200
- Soviet fighters: ~185 mostly; Yak 3: 160
- MC.202: 181
- D.520: 171
- MS.406: 170

Yes, wing area is not the be all end all measurement of aircraft's dimensions.

There was a lot of space on the Fw 190 besides the 139 US gals in the main tanks, like the rear fuselage tank, and the volume between the spars. Spitfire fighters with LE tanks have had them in the inner part of the wing, started with Mk.VII.

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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> And yet it still carried almost twice as much fuel as most marks of the Spitfire!


It was almost a decade later in design and started with a 2000+ HP engine, it first flew after jets were in service.

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## Wild_Bill_Kelso (Mar 19, 2022)

pbehn said:


> It was almost a decade later in design and started with a 2000+ HP engine, it first flew after jets were in service.



My original point in bringing it up was that creating something like an F8 (as an example of performance + range + agility) was hard, and that it came too late... I wasn't trying to belittle the Spitfire  .


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> My original point in bringing up the F8F was exactly that - striking such a balance as you see in that aircraft was possible but very hard, and in this example (among many others) came too late to play a role in the war.



It was hard, but it was achieved by 1943 on the Allied side, and even more so in 1944.



Wild_Bill_Kelso said:


> P-47 was a lot heavier (10,400 lbs vs 7,650 empty for F8), had a much larger wingspan (40' vs 35') and a much bigger / fatter fuselage. Somebody said it had a lower induced drag or something, I am not an engineer but i find it hard to believe that the P-47 had lower drag than an F8F.



Even if the P-47 have had a bit greater drag (possible, I don't have the exact numbers), it still flew with twice as much fuel in internal tanks when compared with F8F.
We can compare the drag, fuel carried and fuel mileage of F8F vs. P-51D and arrive at conclusion that F8F was capable for perhaps 50% of combat radius under the USAF ETO rules.



Wild_Bill_Kelso said:


> Fair points but this again seems to assume strategic bomber escort. A long ranged spitfire wouldn't necessarily be used that way ... I mean it could, but it would help the war effort a lot for example in places like North Africa, Malta, Darwin, New Guinea, China / Burma etc. This was the context from my point of view. Even with 150 gallons that F8F compares very well to a Spitfire or a Bf 109 in range, IMO, while having far more combat capability than say an A6M. If you are flying over the Pacific, through vast areas of China or Burma, or say, from Malta to North Africa or Sicily, you can probably use your drop tanks, though you may have to fly home right after an engagement.






Wild_Bill_Kelso said:


> Presumably if they had the F8F flying in say, 1943 the British could have put their own guns in it like they did with the Corsair.



Spitfire was carrying 100 US gals (84 imp gals); Mk.VII and VIII carried 144 US gals (120 imp gals). That is unless the rear fuselage tanks are installed. F8F carried 185 US gals. All internal fuel figures.
Having more fuel does not mean greater range if the new fighter has a thirsty engine and more drag than the legacy fighter. Allies have had the short-range fighters by thousands in 1942 and later, what they did not have were the long-range performers to match the Luftwaffe's best until late 1943.
Any post-war fighter will have far more combat capability than the Zero, there was a lot of wartime fighters capable for that.



Wild_Bill_Kelso said:


> Most fighter marks of the Spitfire were limited to around 500 miles range which relegated them to the status of point defense fighters or air superiority fighters deployed right at the front line. Something with the combat capabilities of a Spitfire, which were IMO a bit better than a P-51 depending on the specific marks, but with a 1,000 mile instead of 500 mile range, would have been very helpful for tactical escort, fighter bomber, and medium range air superiority missions.



See here, the 1500 mile range on Spitfire, 1700+ on Tempest, doc kindly provided by 
G
 Glider
. Unfortunately, from late 1944 on:

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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> My original point in bringing it up was that creating something like an F8 (as an example of performance + range + agility) was hard, and that it came too late... I wasn't trying to belittle the Spitfire  .


All designs are a compromise, you have to make more compromises with a 1000BHP engine than a 2000BHP engine. For the Spitfire as originally designed, take off run, rate of climb and speed were paramount but this was with a circa 1000BHP engine driving a fixed pitch prop that gave around 660 BHP on take off. 

 tomo pauk
posted the wing areas but the advantage of the Spitfire design over others such as the Hurricane was that the wings were thin, leaving little room for fuel. Maintaining air superiority over a battle front is difficult at range, the RAF struggled over Dunkerque while the allies shortened the range as soon as possibe by moving to Normandy, that 100 mile stretch of water is a problem especially if your aircraft is damaged.


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> It was hard, but it was achieved by 1943 on the Allied side, and even more so in 1944.
> 
> 
> 
> ...



The thing about the P-47 is that it was a high altitude bird, (at least by design) being big and fat with huge wings etc. wasn't a disadvantage at 38,000 feet, to the contrary.

but the P-47 was in fact often used as a fighter bomber and for local air superiority over battlefields at much lower altitudes, and that is where it becomes a problem

I am certain the P-51D had better range than the F8F so no need for that. But I suspect the F8, like the Spitfire, probably had a slight edge over the P-51 in air combat, maybe more so since it was almost as fast.



tomo pauk said:


> Spitfire was carrying 100 US gals (84 imp gals); Mk.VII and VIII carried 144 US gals (120 imp gals). That is unless the rear fuselage tanks are installed. F8F carried 185 US gals. All internal fuel figures.
> Having more fuel does not mean greater range if the new fighter has a thirsty engine and more drag than the legacy fighter. Allies have had the short-range fighters by thousands in 1942 and later, what they did not have were the long-range performers to match the Luftwaffe's best until late 1943.
> Any post-war fighter will have far more combat capability than the Zero, there was a lot of wartime fighters capable for that.
> 
> ...




Yes but isn't the above chart showing quite large external tanks, and if that the case doesn't it bring you back to the same problem the F8 ostensibly has with external tanks?


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## Wild_Bill_Kelso (Mar 19, 2022)

pbehn said:


> All designs are a compromise, you have to make more compromises with a 1000BHP engine than a 2000BHP engine.



This is almost exactly the context of where I originally brought up the F8, upthread. That is just about what i said verbatim.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> The thing about the P-47 is that it was a high altitude bird, (at least by design) being big and fat with huge wings etc. wasn't a disadvantage at 38,000 feet, to the contrary.
> 
> but the P-47 was in fact often used as a fighter bomber and for local air superiority over battlefields at much lower altitudes, and that is where it becomes a problem
> 
> I am certain the P-51D had better range than the F8F so no need for that. But I suspect the F8, like the Spitfire, probably had a slight edge over the P-51 in air combat, maybe more so since it was almost as fast.



If we want to compare the fighters from 1945, the 420-425 mph F8F-1 is badly outpaced by 470-480 mph P-51H. Less firepower, too.
P-47 was indeed used as a fighter bomber. Once it wrestled the air superiority (in concert with other Allied aircraft) from the Axis air forces, and was a very good fighter bomber, with good payload, guns' firepower (double of what F8F-1 had), range and performance.
P-47 being a high-altitude bird was a feature, not a bug.



Wild_Bill_Kelso said:


> Yes but isn't the above chart showing quite large external tanks, and if that the case doesn't it bring you back to the same problem the F8 ostensibly has with external tanks?


90 imp gal (108 US gal) external tanks max, one per aircraft. Internal ('permanent') fuel was ~160 imp gals. Granted, some of the fuel in the rear tanks needed to be used up before entering the combat, just like on Mustangs with fuselage tanks.
Similar fuel system was used post-war on the Seafire 45 and 47, but with even more fuel, both internal and external.


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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> This is almost exactly the context of where I originally brought up the F8, upthread. That is just about what i said verbatim.


You cannot design an F8 in 1935, first you need the engine and the fuels, then you need to have learned what you learned on the F4F and F6F. The P-40 couldnt have been designed with the aerodynamic profiles that the P-51 used, they didnt exist at that time. Wanting a F8 in the early or mid stage of the war is like wanting Spitfire MkIXs in the Battle of Britain, it would have been great, but just couldnt happen, the engine and fuels werent there.

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## Wild_Bill_Kelso (Mar 19, 2022)

pbehn said:


> You cannot design an F8 in 1935, first you need the engine and the fuels, then you need to have learned what you learned on the F4F and F6F. The P-40 couldnt have been designed with the aerodynamic profiles that the P-51 used, they didnt exist at that time. Wanting a F8 in the early or mid stage of the war is like wanting Spitfire MkIXs in the Battle of Britain, it would have been great, but just couldnt happen, the engine and fuels werent there.



This was actually the point i was making mate


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> If we want to compare the fighters from 1945, the 420-425 mph F8F-1 is badly outpaced by 470-480 mph P-51H. Less firepower, too.
> P-47 was indeed used as a fighter bomber. Once it wrestled the air superiority (in concert with other Allied aircraft) from the Axis air forces, and was a very good fighter bomber, with good payload, guns' firepower (double of what F8F-1 had), range and performance.
> P-47 being a high-altitude bird was a feature, not a bug.



Well, I guess that depends how good you think the P-47 was in air combat down low, which is where it did have to tangle with German fighters quite a bit. And I don't think it was so good because of all the drag and weight.

To me, if you are designed for 35,000 ft but actually end up being used mostly at 5-10,000 ft where you (arguably) aren't so good, then it is a bug, IMO. That's why the Soviets didn't want it.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> Well, I guess that depends how good you think the P-47 was in air combat down low, which is where it did have to tangle with German fighters quite a bit. And I don't think it was so good because of all the drag and weight.



We have a saying here:
- Someone good has 1000 shortcomings. Someone bad have just one shortcoming: being bad.
P-47 was a good fighter. F8F have had just one shortcoming: not being there.



Wild_Bill_Kelso said:


> To me, if you are designed for 35,000 ft but actually end up being used mostly at 5-10,000 ft where you (arguably) aren't so good, then it is a bug, IMO. That's why the Soviets didn't want it.



Soviets were not trying to escort their bombers at 25000 ft, 400-600 miles deep behind the frontlines. What Soviets wanted or not had no bearing on how the air war was fought in the West.

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## MIflyer (Mar 19, 2022)

Quoting Maj Gen Richard Rohmer a WWII Mustang I pilot, in his book, "Patton's Gap."

"It was a big impressive fighter, a much larger machine than the Spitfires of the day."

Aside from the much larger fuselage I think the Mustang Mk I sat a lot higher than Spitfires or Hurricanes.

By the way, I know of not much in the way personal accounts written by Mustang I pilots and I recommend the book.

And as for the P-47, do y'all recall the info I posted that showed the P-47 could out turn the FW-190, even at lower altitudes?

If you really wanted to start a contentious thread, why did the RAF not use the P-47 in the ETO? It was better than the Typhoon and a vastly better fighter bomber than the Spitfire.

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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> This was actually the point i was making mate


But your point is mainly based on range where US fighters had an advantage, mainly because they entered the war later. There were key battles that had to be won, like the battle over Dunkerque, the battle of Britain and the battle of Malta, in these range was not important, the Hurricane and Spitfire only had 12 seconds of firing time and so were more likely to run out of guns than fuel. These battles were fought at altitudes that didnt suit the P-51, P-40 and P-39 even if they were available. The Beaufighter had long range, not great performance compared to a single engined fighter but that puts it in the same bracket as the Bf110, as a heavy fighter against shipping, Condors and Ju88s and night fighter it did its job well at the time. Dismissing the P-47 because it wasnt great at low altitude ignores the fact that it was great at high altitude which was what the US strategic campaign needed, in the early days of the strategic campaign the P-47 provided the bulk of the escort force.


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## pbehn (Mar 19, 2022)

tomo pauk said:


> We have a saying here:
> - Someone good has 1000 shortcomings. Someone bad have just one shortcoming: being bad.
> P-47 was a good fighter. F8F have had just one shortcoming: not being there.
> 
> ...


Not a saying, but a legal term in English law "time is of the essence of the contract" a war isnt a contract, but it does carry penalties for lateness and not being there Time of the Essence clauses: Business Contracts (time critical performance)


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> We have a saying here:
> - Someone good has 1000 shortcomings. Someone bad have just one shortcoming: being bad.
> P-47 was a good fighter. F8F have had just one shortcoming: not being there.


My point about the F8F was (this is a direct quote from post 155:

_"What everybody wants of course is something like a bearcat, *but we didn't see anything that close to the sweet spot until the end of the war*, and by then you are in the jet age, with a whole new balance to strike..."_

So in other words, my original point was precisely that the Bearcat was too late for the war, and striking this balance wasn't easy. I don't think the P-47 really did it by the way in spite of the legendary status of that aircraft. But no aircraft design was perfect, every design was a tradeoff. And by the time they came up with the 'almost perfect' designs for piston engined fighers the jet age was already well under way.



tomo pauk said:


> Soviets were not trying to escort their bombers at 25000 ft, 400-600 miles deep behind the frontlines. What Soviets wanted or not had no bearing on how the air war was fought in the West.



War on the Russian front was actually pretty similar to War in the Western Desert, in Sicily and (to a somewhat lesser extent) in Italy, and definitely also to war on the ground in France and Belgium, Holland, Germany etc. after D-Day. I the support of friendly fighter bomber or ground attack aircraft and the destruction of the enemy ones. War in the Pacific and China Theaters had their own unique characteristics but escorting heavy bombers at 25,000 ft didn't come into play until pretty late in the game (well after the outcome had already been decided).

I don't understand why everything seems to always devolve to 'strategic bombing is the only air war'. I really don't think it was.


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## Wild_Bill_Kelso (Mar 19, 2022)

pbehn said:


> But your point is mainly based on range where US fighters had an advantage, mainly because they entered the war later. There were key battles that had to be won, like the battle over Dunkerque, the battle of Britain and the battle of Malta, in these range was not important, the Hurricane and Spitfire only had 12 seconds of firing time and so were more likely to run out of guns than fuel.



Actually at Malta, and especially Dunkirque, from my understanding fuel limitations were indeed a factor.

My original post was:

_"Getting back to the fighter / fuel capacity thing, I guess the difference is, once you have more than ~1,000 - 1,200 hp engines, you start to have the power to move heavier aircraft around the sky. Then it's time to go back to the drawing board and give yourself a bit more fuel, guns, armor, and other things. The Fw 190 was much heavier than a Bf 109 but by no means less capable. The P-51 was also a heavy aircraft, as was the F4U, F6F, P-47, P-38, Typhoon, Tempest etc."_

I.e. I recognize that with a 1,000 hp (or less) engine you could not have all the features you might want, especially range. Once the 1,500 to 2,000 hp engines (and the appropriate fuel) are available then it's time to improve the range.



pbehn said:


> These battles were fought at altitudes that didnt suit the P-51, P-40 and P-39 even if they were available.


The P-39 had quite short range. The Allison P-51 seemed to have other issues besides altitude performance, which limited it's efficacy as a fighter, but these were cleared up at the same time as the B model appeared. That said, over Malta or Dunkirque*, against SM 79, Ju 88, Ju 87 etc., i think (Allison) P-51 and P-40s certainly could have been useful, and even P-39s probably if they had the range. Certainly Martlets. Kittyhawks were certainly very useful in similar battles such as around Pantelleria, Sicily, Milne Bay etc.

* I realize most of these fighters weren't available in time for Dunkirque


pbehn said:


> The Beaufighter had long range, not great performance compared to a single engined fighter but that puts it in the same bracket as the Bf110, as a heavy fighter against shipping, Condors and Ju88s and night fighter it did its job well at the time.



I personally think the Beaufighter was an outstanding aircraft. It wasn't a fighter in the same way as a Spitfire or say a P-38 was, but it played many very useful roles and was quite dangerous opponent at low altitude. I think aside from night-fighting, it was much better than a BF 110, and in general was one of the most successful twin engined fighter / fighter bomber designs of the war.


pbehn said:


> Dismissing the P-47 because it wasnt great at low altitude ignores the fact that it was great at high altitude which was what the US strategic campaign needed, in the early days of the strategic campaign the P-47 provided the bulk of the escort force.



I'm not dismissing the P-47 at all, I just think it's flaws were a bit larger than are typically acknowledged. And I don't think the strategic campaign was the only one that mattered.

Personally if I had to engage a Bf 109 below 20,000 ft I'd rather be in a Spitfire, or a P-51, or an F8F if they had existed at the time.


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## pbehn (Mar 19, 2022)

Wild_Bill_Kelso said:


> I don't understand why everything seems to always devolve to 'strategic bombing is the only air war'. I really don't think it was.


Not from my part, I see a need from 1939 for short range high performance planes at all altitudes which you dont seem to. The strategic bomber campaign in 1944 was in part to eliminate the Luftwaffe as an effective force, which was achieved as far as the Normandy landings were concerned.


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## Wild_Bill_Kelso (Mar 19, 2022)

pbehn said:


> Not from my part, I see a need from 1939 for short range high performance planes at all altitudes which you dont seem to. The strategic bomber campaign in 1944 was in part to eliminate the Luftwaffe as an effective force, which was achieved as far as the Normandy landings were concerned.



Sure, but per the thread subject, I was suggesting that a longer range Spitfire could have been produced earlier, and was certainly needed. Not that it was an easy problem to solve from a technical perspective. And I don't mean necessarily a version which can fly to Berlin and back.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> War on the Russian front was actually pretty similar to War in the Western Desert, in Sicily and (to a somewhat lesser extent) in Italy, and to war on the ground in France and Belgium etc. after D-Day. War in the Pacific and China had their own unique characteristics but escorting heavy bombers at 25,000 ft didn't come into play until pretty late in the game.
> 
> I don't understand why everything seems to always devolve to 'strategic bombing is the only air war'



There is certainly a lot to the air war besides the strategic bombing. Allies have had a good, if not the great grasp on anti-Uboat warfare, air defense, fighter-bombers, tactical and strategic reconnaissance, night fighting etc. This thread is about long-range Spitfires, so using them in support of strategic bombing is not a stretch.
Ww2 was about defeating the Nazi Germany (while not disparging the effort and sacrifices of Allied servicemen fighting Japan). In order to do so, Luftwaffe needs to be defeated, lest the Allied invasions of Europe are in jeopardy, and Soviets are left to fend with German ground forces all by themselves. The escorted daylight bombers ranging deep in the German-held territory at high altitude represented the hammer-and-anvil situation to the LW, to what they were not prepared - not in technical terms ( P-47s and Merlin Mustangs were much better than LW's best, bar jets), nor in logistical terms (WAllies have had far more men and material to throw at war in general and in the air war in particular).

If the Luftwaffe was not rendered inefficient by the RAF and USAF, there would be no ground battles in France and Belgium in 1944.

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## Wild_Bill_Kelso (Mar 19, 2022)

I guess I should have picked a better example of a postwar fighter than an F8F ... what are some other good examples? Tempest? Sea Fuiry? P-51H? F7F? Martin Baker M.B.5? D.H. Hornet? Take your pick.


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## drgondog (Mar 19, 2022)

Wild_Bill_Kelso said:


> Knowing *how* to make one - that can still perform well enough to compete at the highest levels, it's a pretty significant design challenge. I think they kind of got lucky with the high efficiency / low drag design of the Mustang.


Somehow NAA got lucky with AT-6, B-25, P-51, B-45, F-86, F-100, X-15, B-70, B-1, B-2?

Why do you attribute to lucky?


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## Wild_Bill_Kelso (Mar 19, 2022)

tomo pauk said:


> There is certainly a lot to the air war besides the strategic bombing. Allies have had a good, if not the great grasp on anti-Uboat warfare, air defense, fighter-bombers, tactical and strategic reconnaissance, night fighting etc. This thread is about long-range Spitfires, so using them in support of strategic bombing is not a stretch.


No it's not a stretch, but I don't think it was the only reason to want one. If that is all you meant then I'll bow out of the debate. To me a Spitfire with about double the range of a Mk 1 or Mk V would have been very helpful indeed on a tactical level, even though it would not necessarily be ideal to escort strategic bombers.

I'll defer a debate about the importance of the Pacific Theater since that would be too much of a diversion in this discussion.



tomo pauk said:


> If the Luftwaffe was not rendered inefficient by the RAF and USAF, there would be no ground battles in France and Belgium in 1944.



I'm not so sure I buy that. The Luftwaffe was only gradually broken in North Africa, but the Allies still managed to win. The Luftwaffe was still active in Sicily and Italy, but could not prevent the Allied landings and they were pushed back. The Luftwaffe remained powerful on the Russian Front, but the Red Army continued inexorably Westward since Stalingrad at the end of 1942. So I think they certainly would have been fighting in France and Belgium even without the strategic air campaign.

One of the problems the Germans had was that they too had short range fighters, so one their airfields near the front line were destroyed (as in Tunisia for example), their presence over the battlefield was limited. Allied fighters could range further past the front lines and thus (escorted) Allied bombers could interdict German supplies and rear area columns, and destroy supplies coming from Europe by ship and transport aircraft, well beyond the range where Axis fighters could protect them. This made a difference in the outcomes.


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## Wild_Bill_Kelso (Mar 19, 2022)

drgondog said:


> Somehow NAA got lucky with AT-6, B-25, P-51, B-45, F-86, F-100, X-15, B-70, B-1, B-2?
> 
> Why do you attribute to lucky?



I think there is always an element of luck in a military aircraft design working out - especially in the era before computer simulation and computer aided design. I'd also debate how great some of the above listed aircraft really ultimately turned out to be (B-70? Really?) , but I was not denigrating NAA, or Edgar Schmued, Ray Wagoner etc.

Quite a few very promising aircraft from other very accomplished firms with good designers got canceled just because a prototype crashed or somebody somewhere decided to cancel it in favor of another, which I definitely consider a factor of luck.

But you could also say the 'luck' factor was in the right people being in the right positions at the right time, and the right people making decisions on both sides of the pond. NAA was a relatively small company when the British purchasing commission approached them to make P-40s right? The original NA-73 / P-51A etc. had not really worked out that well as a fighter did it? It took somebody making a gamble on trying a British engine in an American fighter and others recognizing the possibilities, then still more people approving the idea and moving it ahead. I would say there is quite a bit of luck in all that.

You don't think any luck was involved in the development of the Merlin engined P-51?

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## ColFord (Mar 19, 2022)

MIflyer said:


> By the way, I know of not much in the way personal accounts written by Mustang I pilots and I recommend the book.


"From Sapper to Spitfire Spy - the WWII Biography of David Greville-Heygate DFC" by Sally-Anne Greville-Heygate, Pen & Sword UK, 2015 - Army Officer seconded to RAF for pilot training, flew Mustang Mk.I on first tour of operations, was then an instructor at the RAF Tac/R School on Mustangs, then Spitfire XIV on second tour.
"Coming in to Land - the memoirs of Wing Commander Bill Malins DFC", Memoirs, UK, 2010. Pre-War RAF Officer, flew Westland Lysanders during Battle of France, then Curtiss Tomahawks, Mustang Mk.I, Mk.IA and Mk.II over various postings from 1942 to 1945.


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## tomo pauk (Mar 19, 2022)

Wild_Bill_Kelso said:


> I guess I should have picked a better example of a postwar fighter than an F8F ... what are some other good examples? Tempest? Sea Fuiry? P-51H? F7F? Martin Baker M.B.5? D.H. Hornet? Take your pick.



Depends for what a task? 
For long range work, P-51H, or Hornet if one prefers 2-engined fighters, especially if cannons are needed.
M.B.5 certainly looks impressive, performance-wise. Tempest and Sea Fury are great under 20000 ft and for shorter ranges.
F7F is worse than Hornet wrt. speed, range/radius and RoC.
There is also the P-47N, very rangy and fast. Not much of a climber with full fuel load, though. It was used in ww2.



Wild_Bill_Kelso said:


> No it's not a stretch, but I don't think it was the only reason to want one. If that is all you meant then I'll bow out of the debate. To me a Spitfire with about double the range of a Mk 1 or Mk V would have been very helpful indeed on a tactical level, even though it would not necessarily be ideal to escort strategic bombers.



Agreed 100%.

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## MIflyer (Mar 19, 2022)

Thanks, Colford. I have not heard of those. A book I have on Canadian pilots in WWII does describe some Mustang Mk I missions. The book "Those Were the Days" was written by an A-36 pilot, and along with the A-36 history, "Straight Down" is one of the few about A-36's. I believe I have posted an article or two from the USAF Museum Newsletter by A-36 pilots.


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## DarrenW (Mar 19, 2022)

Wild_Bill_Kelso said:


> Maybe 'short range' compared to an A6M, but it seems to have had better range than an F4F, I'd say probably better than an F6


While the F8F-1 had about a 100 mile greater combat range at 15,000 feet with external 150 US gallon tank, the F6F-5 conversely had about a 100 mile greater radius when using the US Navy's Combat Radius Formula F-1.


EwenS said:


> The F8F-1 Bearcat wasn’t built to maximise range. It was built to maximise rate of climb.
> F8F-1 4,465 ft/min
> F6F-5 2,600 ft/min
> P-51D 3,200 ft/min
> ...


Actually, depending on power settings the F6F-5 had an initial climb rate from 3,000 to 3,250 ft/min and the Spitfire V is around the same. Your figures for the Spitfire IX and XIV are a little pestitimistic while the P-51D could climb about 300 fpm faster in the highest power settings. But your point concerning the reasons behind the F8F's development are correct.


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## DarrenW (Mar 19, 2022)

Wild_Bill_Kelso said:


> Well, I guess that depends how good you think the P-47 was in air combat down low, which is where it did have to tangle with German fighters quite a bit. *And I don't think it was so good because of all the drag and weight.*


Both the F4U and F6F were almost as big and heavy as the P-47 and they did their best work low down, below 20,000 feet. The key was the R-2800 and it's tremendous horsepower.


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## Wild_Bill_Kelso (Mar 19, 2022)

I've got a model of a P-47 and an F4U in the same scale right in front of me, and the P-47 looks a lot bigger especially in the fuselage to me (shrug).

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## wuzak (Mar 19, 2022)

Wild_Bill_Kelso said:


> My original point in bringing it up was that creating something like an F8 (as an example of performance + range + agility) was hard, and that it came too late... I wasn't trying to belittle the Spitfire  .




The F-8* could have quite long range!



https://upload.wikimedia.org/wikipedia/commons/e/e2/DH_98_Mosquito_fore.jpg



Not very useful as a fighter, though.

* I did notice that you used the proper F8F designation for later posts.

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## GregP (Mar 20, 2022)

DarrenW said:


> While the F8F-1 had about a 100 mile greater combat range at 15,000 feet with external 150 US gallon tank, the F6F-5 conversely had about a 100 mile greater radius when using the US Navy's Combat Radius Formula F-1.
> 
> Actually, the F6F-5 had an initial climb rate closer to 3,000 ft/min but your point is well taken.



An unmodified production F8F-1 set a 1946 time-to-climb record (after a run of 115 ft [35 m]) of 10,000 feet (3,048 m) in 94 seconds (6,383 ft/min [32.43 m/s]). The Bearcat held this record for 10 years until it was broken by a jet fighter, which still could not match the Bearcat's short takeoff distance.


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## DarrenW (Mar 20, 2022)

Wild_Bill_Kelso said:


> I've got a model of a P-47 and an F4U in the same scale right in front of me, and the P-47 looks a lot bigger especially in the fuselage to me (shrug).


Yes it definitely looks bulkier but the F4U-1D will tip the scale at 12,000+ lbs so not a small fighter by any measure.The P-47D was a couple of feet longer but they both had roughly the same wingspan with the Corsair having more wing area.

The F6F had the biggest wing of the three and was heavier than the F4U by roughly 500 lbs.

So yes, the P-47D was slightly bigger and also heavier but ultimately it had between 300-500 more horsepower than the F4U-1D and F6F-5 which for the most part made up for this extra weight. Power to weight ratios were close between the three, and no one would say that the Hellcat and Corsair didn't acquit themselves well at low level against their lighter and more agile adversaries. Why wouldn't the P-47 do the same against German fighters, which obviously were less maneuverable than their Japanese counterparts?


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## 33k in the air (Mar 20, 2022)

DarrenW said:


> Both the F4U and F6F were almost as big and heavy as the P-47 and they did their best work low down, below 20,000 feet. The key was the R-2800 and it's tremendous horsepower.



Gross combat weight (i.e. full amount of internal fuel and ammunition but no external load):

13,582 lbs = P-47D (up to -25)
14,411 lbs = P-47D (-25 and up)
12,213 lbs = F6F-3 (-1,369 lbs / -2,198 lbs)
12,483 lbs = F6F-5 (-1,099 lbs / -1,928 lbs)
12,289 lbs = F4U-1D (-1,293 lbs / -2,122 lbs)
12,281 lbs = F4U-4 (-1,301 lbs / -2,130 lbs)

The P-47D was from about 1,100 lbs to over 2,000 lbs heavier than the Hellcat and Corsair.

(Figures from _America's Hundred Thousand_ by Francis Dean, p.122)

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## MIflyer (Mar 20, 2022)

DarrenW said:


> Both the F4U and F6F were almost as big and heavy as the P-47 and they did their best work low down, below 20,000 feet. The key was the R-2800 and it's tremendous horsepower.


Both the F4U and F6F had two stage supercharged engines, as was the F4F. This was driven by the Y1B-17, which showed the USN that unless they could compete with the USAAC they would never make it to war because they would lose the "Battle of Washington DC." Billy Mitchell's battleship tests scared the crap out of the USN and the Y1B-17 showed them their fears were fully justifed. We know it scared the crap out of them because they (1). Penned an agreement with the USAAC that their bombers would not operate beyond a certain distance out at sea and (2). got Grumman to rework their failed F4F prototype into a high altitude fighter.

Actual combat experience showed that the USAAF was the only bomber force at those 20,000 ft plus altitudes; unlike the USN and USAAF expected, no one else had followed them up there. So the F6F and F4U did almost all of their fighting at lower altitudes, where the Japanese flew. As a result, despite having been the first to introduce two stage supercharged high altitude fighters to squadron service, the F7F and F8F had single stage supercharged engines, as did the FM-2 Wildcat.

At the end of the war three new developments changed things again:
1. Jets
2. Nuclear weapons
3. Radar guided fire and forget missiles (the USN Bat).
All these screamed "High Altitude!" 

Imagine B-29's operating at 30,000 ft plus and picking off ships with Bat missiles, day, and night - or dropping nukes. Listen carefully during a thunderstorm and you can hear Billy Mitchell laughing.


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## Geoffrey Sinclair (Mar 20, 2022)

Spitfire XVI production 1 in July 1944, originally considered a mark IX, then from September 1944 on.


GregP said:


> Want to win the war sooner? Leaving everything the same except for the bombing targets.
> Bomb food production / shipping and the industrial electrical grid and the war ends MUCH sooner, with or without longer-range Spitfires.


No one was going to consistently hit the same set of targets until the hostile fighter defences had been accounted for. There was a famine on Greece in 1941/42, the allies ended up sending food. Then another one in Holland 1944/45. The US Army in France in 1944 noted local worker productivity was hampered by malnutrition, operation Dragoon landed with civilian supplies. Amongst the 1940/41 Japanese diplomatic messages the US decoded are some from the French embassy pleading for food. The Nazis ended up taking 100% of the Norwegian fish catch. The Nazis were quite capable of continuing the war while allowing large scale starvation outside Germany, and it was a continent wide food system. Mass starvation, particularly in the east, was a way to fulfill Nazi war aims. The food production part of economy was much bigger than the oil part. And the bomb loads devoted to oil targets were comparable to the 1943 total bomb tonnage dropped by Bomber Command plus the 8th Air Force.

For transport the allies proved you need the system to come under sustained attack by everything from fighter bombers to heavy bombers.

When it came to the electricity grid no one really tried to attack it, so no one knows how vulnerable to bombing the equipment was, how quick repair and replacement was, how much supply had to be cut for how long, what factories generated their own power or could do so given they had boilers for things like heat already.


tomo pauk said:


> Hawker Hurricane was not a 'top class short range interceptor', yet it was happily made in more than 2700 copies in 1943, and almost 690 pcs in 1944.


1943 Hurricane production of 2,742 included 489 IID and IV, the ground attack versions, in 1944 60 mark IV out of 689 Hurricanes, one reason production continued was the export market, including to the USSR.


EwenS said:


> But by 1945 even that philosophy is changing. Over Japan, LeMay resorts to night bombing from lower altitudes, despite the coming availability of fighter escort from Iwo Jima. Note, a base not near the bomber base but half way to the target.
> 
> There is just that sweet spot for the escort fighter around 1943-45 where the range of the fighter can be extended with drop tanks just far enough to make bomber escort from base to target and back a viable concept.


Still plenty of USAAF day strikes on Japan in 1945, the Japanese largely stopped trying to intercept the raids, preferring to wait for the invasion. I would add the mission flight plans of the USAAF heavy bombers in Europe significantly cut the effective range of the bombers, climb high early, maximum cruise, like around 225 to 240 mph TAS in tight formations. In terms of distance to target more like medium range versus their longest range, the fighters did not need bomber range, rather something smaller, even less if they did not have to perform close escort. Roger Freeman notes a B-17F at 55,000 pounds with 1,760 gallons of fuel on board used 380 gallons in the first hour of the flight, with a 5 hour mission leaving 115 gallons remaining.

In 1941 the ranges of fighters are shown as ranges at maximum economic cruising power on the fuel available, after deducting fuel used in 15 minutes at maximum power at sea level. This allowance is for warming up and climbing to operational height. The above makes no allowance for - (i) The effect of wind, (ii), The effect of formation flying, (iii) The use of full throttle over enemy territory. The effect of these factors must be allowed for when fights are being planned. It is assumed the same rules apply to the 1944/45 ranges.

From Avia 20/3030 and Air 20/3312.
Date is document date
MEC = Most economic cruise, mph/altitude feet
MWM = Maximum weak mixture cruise, mph/altitude feet
Take off is distance in yards to clear a 50 foot obstacle in yards
Internal and external fuel loads in Imperial Gallons
Range in miles a/b is carrying external tanks all the way / external tanks dropped when empty. Otherwise range is dropping the external tanks when empty.
Radius is with combat allowance and 25% "windage, navigation etc." in miles

Note sure Spitfire VIII at least figures are correct, with 35 more gallons on board only goes 118 miles further than the IX, which is 3.4 mpg, or 95 gallons per hour consumption at 324 mph, then with 45 gallon drop tank the VIII goes 100 miles further, with 90 gallon drop tank 90 miles further

As of 13 October 1943, (DCAS to CAS) only 30 and 90 gallon drop tanks available for Spitfires, the 45 gallon tank is about to be produced. Fighter Command states the 90 gallon tank has to be jettisoned when crossing the French Coast owing to its effect on performance, as a result Fighter Command does not have a use for it. With a 30 gallon drop tank Spitfire V and IX have a maximum operational radius of action of 180 miles, absolute maximum radius achieved by 1 or 2 squadrons in ideal conditions on operations is 175 miles, the 45 gallon tank should allow a radius of 210 miles. Typhoons with 2x45 gallon drop tanks have an operational radius of action of 250 miles.

DateAircraftMarkEngineMECMWMTake offInternalexternalMEC rangeMWM rangeRadius5-Jan-44​HornetIn/an/an/a500​378​0​945​n/an/a5-Jan-44​HornetIn/an/an/a500​378​100​1,260​n/an/a5-May-44​HornetI2xRM.14SM270/20,000398/20,000500​430​0​1,530​n/an/a5-May-44​HornetI2xRM.14SM270/20,000398/20,000500​430​100​1,880​n/an/a5-May-44​HornetI2xRM.14SM270/20,000398/20,000500​430​200​2,200​n/a709​5-Jan-44​Mosquito30​n/an/an/a700​450​0​1,350​810​n/a5-Jan-44​Mosquito30​n/an/an/a700​450​63​1,520/?910/?n/a5-Jan-44​Mosquito30​n/an/an/a700​450​163​1,800​1,107​n/a5-Jan-44​MustangIIIn/an/an/a610​221​0​1,370​n/an/a5-Jan-44​MustangIIIn/an/an/a610​221​125​2,020​n/an/a5-Jan-44​MustangIIIn/an/an/a610​221​190​2,400​n/an/a5-May-44​MustangIIIV-1650-3233/20,000365/20,000610​150​0​970​n/an/a5-May-44​MustangIIIV-1650-3233/20,000365/20,000610​150​125​1,570​n/a652​5-Jan-44​SpitfireVIIIn/an/an/a530​120​0​660​370​n/a5-Jan-44​SpitfireVIIIn/an/an/a530​120​45​885/935500/510n/a5-Jan-44​SpitfireVIIIn/an/an/a530​120​90​1,090/1,180610/640n/a29-Jun-44​SpitfireIXMerlin 63220/20,000324/20,000500​85​0​434​252​n/a29-Jun-44​SpitfireIXMerlin 63220/20,000324/20,000500​85​45​724​410​n/a29-Jun-44​SpitfireIXMerlin 63220/20,000324/20,000500​85​90​980​550​n/a29-Jun-44​SpitfireXIVGriffon 65240/20,000368/20,000590​112​0​550​340​n/a29-Jun-44​SpitfireXIVGriffon 65240/20,000368/20,000590​112​30​730​460​n/a29-Jun-44​SpitfireXIVGriffon 65240/20,000368/20,000590​112​90​1,000​680​n/a5-Jan-44​Spitfire21​n/an/an/a625​120​0​572​366​n/a5-Jan-44​Spitfire21​n/an/an/a625​120​90​945/1,034620/690n/a5-May-44​Spitfire21​Griffon 65249/20,000368/20,000625​120​0​575​n/an/a5-May-44​Spitfire21​Griffon 65249/20,000368/20,000625​120​30​744​n/an/a5-May-44​Spitfire21​Griffon 65249/20,000368/20,000625​120​90​1,034​n/a275​5-May-44​Spitefuln/aGriffon 65260/20,000370/20,000625​133​0​550​n/an/a5-May-44​Spitefuln/aGriffon 65260/20,000370/20,000625​133​30​715​n/a357​5-May-44​Spitefuln/aGriffon 65260/20,000370/20,000625​133​90​1,000​n/an/a5-Jan-44​TempestIICentaurusn/an/a770​160​0​660​500​n/a5-Jan-44​TempestIICentaurusn/an/a770​160​90​940​770​n/a5-Jan-44​Spitfire21​n/an/an/a625​120​30​697/744450/470n/a5-May-44​TempestIICentaurus VII248/15,000359/15,000770​160​0​770​n/an/a5-May-44​TempestIICentaurus VII248/15,000359/15,000770​160​90​1,210​n/a392​29-Jun-44​TempestVSabre IIA246/15,000370/15,000600​162​0​740​460​n/a29-Jun-44​TempestVSabre IIA246/15,000370/15,000600​162​90​1,190​760​n/a29-Jun-44​TempestVSabre IIA246/15,000370/15,000600​162​180​1,530​1,050​n/a5-Jan-44​Thunderboltn/an/an/an/a1,100​263​0​790​n/an/a5-Jan-44​Thunderboltn/an/an/an/a1,100​263​166​1,300​n/an/a5-May-44​Thunderboltn/aR2800-21267/20,000286/20,0001,100​263​0​790​n/an/a5-May-44​Thunderboltn/aR2800-21267/20,000286/20,0001,100​263​166​1,300​n/an/a5-May-44​Thunderboltn/aR2800-21267/20,000286/20,0001,100​263​250​1,550​n/a506​

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## Geoffrey Sinclair (Mar 20, 2022)

Part 2

5-May-44​HornetIDeduct 330 miles from MEC range for 15 minutes combat allowance5-May-44​MustangIIIDeduct 260 miles from MEC for 15 minutes combat allowance, radius may be for 346 gallons of fuel29-Jun-44​SpitfireIXDeduct 246 miles from MEC and 144 from MWM range for 15 minutes combat allowance29-Jun-44​SpitfireXIVDeduct 300 miles from MEC and 180 from MWM range for 15 minutes combat allowance5-May-44​Spitfire21​Deduct 300 miles from MEC for 15 minutes combat allowance.5-May-44​Spitefuln/aDeduct 337 miles from MEC for 15 minutes combat allowance, performance figures still approximate.5-May-44​TempestIIDeduct 297 miles from MEC for 15 minutes combat allowance, radius may be for 275 gallons of fuel.29-Jun-44​TempestVDeduct 270 miles from MEC and 168 from MWM range for 15 minutes combat allowance5-May-44​Thunderboltn/aDeduct 200 miles from MEC for 15 minutes combat allowance, radius may be for 346 gallons of fuel

Proposed increases of internal and external fuelAircraftmarkInternalexternalrangeradiusSpitfireIX155​102​436​SpitfireXIV180​120​477​Spitfire21​190​126​502​Spiteful213​142​562​TempestII180​120​442​TempestV192​128​400​F.2/43174​116​397​HornetI550​366​3,290​1,189​MustangIII221​146​722​MustangIII(radius considered optimistic, 650 miles maybe more correct)

Merlin RM.14SM, power, 
100/130 grade fuel, 20 pounds boost, 1,850 HP @ 10,000 feet, 1,690 HP @ 22,400 feet,
100/150 grade fuel, 25 pounds boost, 2,080 HP @ 6,000 feet, 1,890 HP @ 18,700 feet

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## drgondog (Mar 20, 2022)

Wild_Bill_Kelso said:


> I think there is always an element of luck in a military aircraft design working out - especially in the era before computer simulation and computer aided design. I'd also debate how great some of the above listed aircraft really ultimately turned out to be (B-70? Really?) , but I was not denigrating NAA, or Edgar Schmued, Ray Wagoner etc.



I suppose I would need a better definition of "luck" to comment, but also need a definition of "great". As an illustration, help me understand your view of a 'greater' Mach 3, 70,000 ft altitude cruise, long range Nuclear bomber - before or after 1960s?

The point I was making in naming those aircraft was to give you an opportunity to put forth your notion of great design team in the same era covered by my list and contrast 'better' design and manufacturing and broad delivery of different airframes for the missions they served?

I'm also curious why you lump author Ray Wagner in with discussion of Edgard Schmued?



Wild_Bill_Kelso said:


> Quite a few very promising aircraft from other very accomplished firms with good designers got canceled just because a prototype crashed or somebody somewhere decided to cancel it in favor of another, which I definitely consider a factor of luck.


I agree


Wild_Bill_Kelso said:


> But you could also say the 'luck' factor was in the right people being in the right positions at the right time, and the right people making decisions on both sides of the pond. NAA was a relatively small company when the British purchasing commission approached them to make P-40s right? The original NA-73 / P-51A etc. had not really worked out that well as a fighter did it?


"Worked' well enough to be the first AAF fighter to be in squadron level ops (compared to P-38 and P-47), worked well enough to be deemed by test pilots at Eglin as the 'best US fighter tested so far'" in Fall 1942 - below 20000 feet (P-38, P-39, P-40 and P-47 cited as comparisons). The P-51A was the 'insert' between A-36 and P-51B and contract truncated in favor of the P-51B. It acquitted itself quite well, particularly wrt better overall performance than P-39/40, much longer range, much greater payload and adaptability to ordnance arrangements. In fact, with WI in latter stages of development of V-1710-81 it climbed better and was faster than P-51B-1-NA at 61"/3000 RPM. Actually, it fits your definition of a high quality all around fighter in tactical role perhaps best of all in 1943.

You may not know that the P-51A 'mission' was to be improved A-36 w/o dive bombing requirement - and matched to Tactical command requirements for low/medium level Pursuit/battlefield air superiority/recon and glide bombing. The P-51B was to be dedicated to replace P-51A and P-40 and P-39 - not LR escort. For tasked missions below 15000 feet it is debatable to give the P-51B a significant edge over the P-51A.



Wild_Bill_Kelso said:


> It took somebody making a gamble on trying a British engine in an American fighter and others recognizing the possibilities, then still more people approving the idea and moving it ahead. I would say there is quite a bit of luck in all that.
> 
> You don't think any luck was involved in the development of the Merlin engined P-51?


No, at least not on the design and integration side of R-R into the Allison Mustang airframe. Dutch Kindelberger started the NAA investigation into the swap of Merlin XX for V-17170-39 in 1941. He was denied permission by GM Board to pursue the project, but NAA did devote the time to carefully analyze the actual integration requirements from the 18 page technical dump delivered by R-R's Ellor, managing R-R in US. They were past the design feasibility stage, the weights and balance and General Arrangement stage when the Merlin project was given 'go' in May 1942. The PRIMARY design issues were focused on the Cooling system as neither A-36 nor P-51A production glycol/oil cooling design was near satisfactory in May 1942.

Yes to the combination of factors that pushed NAA Mustang past roadblocks imposed by Materiel Command's obstruction (Oliver Echols) via AAF-Hq requirement for Fast Attack Pursuit type with funding available for Dive bomber, which came from AAF-HQ Planning & Requirements aligned with Close Air Support Directorate. There were several key AAF officers influential in that process but Ira Eaker urged Arnold and Spaatz to 'take a look' at NAA Mustang in December 1941 - which they did in January 1942. The 'luck' in this story is that highly respected officers at AAF-Hq were thoroughly dissatisfied with projects coming out of Materiel Command - in this case the Curtiss XP-46, XP-60, Brewster XA-32 - that were not satisfactory with respect to performance or tactical suitabiltiy deemed important crucial to many AAF missions.

Yes to the speed of action stimulated by R-R Chief Test Pilot for R-R Liason for Allied aircraft test pilot Ronnie Harker, when urged to fly the Mustang I by Wing Commander Ord, AFDU. He did so and was astounded by the performance in comparison to Spit V - with much less HP. So 'luck' was involved that Merlin 61/Spit IX was in final stages of testing before production installation to convert Spit V to Spit IX and Harker's report immediately influenced the manager at Hucknall R-R to seek audience with Director/GM Hives. Then the Sir Wilfrid Freeman Vice Chief Air Staff. So, 'luck' or 'visionary'?

No, to the speed and political savvy of NAA senior management to connect activities at R-R/RAF to Ambassador Winant and thence to AAF-Hq to allocate two Packard Merlins to NAA for the project - and let NAA proceed without lengthy Materiel Command specification red tape. As an illustration of the speed and co-ordination between UK and AAF-Hq and NAA, the XP-78 (NA-101) began about the same time as R-R (May 1942), using Merlin XX as foundation for both Powerplant installation and Cooling system studies. So, 'luck' or 'visionary'?

No, to the decision by Rice/Atwood to propose NA-101 as a 'modification' rather than a new fighter, to bypass MC at Wright Field from looking over their shoulders in Advanced design. 'Luck' or good politics combined with design savvy?

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## wuzak (Mar 20, 2022)

drgondog said:


> No, at least not on the design and integration side of R-R into the Allison Mustang airframe. Dutch Kindelberger started the NAA investigation into the swap of Merlin XX for V-17170-39 in 1941. He was denied permission by GM Board to pursue the project, but NAA did devote the time to carefully analyze the actual integration requirements from the 18 page technical dump delivered by R-R's Ellor, managing R-R in US.



Denied permission because GM owned Allison and NAA?


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## Wild_Bill_Kelso (Mar 20, 2022)

drgondog said:


> I suppose I would need a better definition of "luck" to comment, but also need a definition of "great". As an illustration, help me understand your view of a 'greater' Mach 3, 70,000 ft altitude cruise, long range Nuclear bomber - before or after 1960s?


I would say the B-70 was cancelled for a reason and leave it at that.


drgondog said:


> "Worked' well enough to be the first AAF fighter to be in squadron level ops (compared to P-38 and P-47), worked well enough to be deemed by test pilots at Eglin as the 'best US fighter tested so far'" in Fall 1942 - below 20000 feet (P-38, P-39, P-40 and P-47 cited as comparisons). The P-51A was the 'insert' between A-36 and P-51B and contract truncated in favor of the P-51B. It acquitted itself quite well, particularly wrt better overall performance than P-39/40, much longer range, much greater payload and adaptability to ordnance arrangements. In fact, with WI in latter stages of development of V-1710-81 it climbed better and was faster than P-51B-1-NA at 61"/3000 RPM. Actually, it fits your definition of a high quality all around fighter in tactical role perhaps best of all in 1943.
> 
> You may not know that the P-51A 'mission' was to be improved A-36 w/o dive bombing requirement - and matched to Tactical command requirements for low/medium level Pursuit/battlefield air superiority/recon and glide bombing. The P-51B was to be dedicated to replace P-51A and P-40 and P-39 - not LR escort. For tasked missions below 15000 feet it is debatable to give the P-51B a significant edge over the P-51A.



Well, the proof is in the pudding. P-51B immediately started racking up victories and generating aces as soon as pilots started flying it in combat zones. P-51A and various other Allison versions no such luck as a fighter. The British found success with it as a recon aircraft and the Americans used the A-36 (eventually) with some success as a dive-bomber in Italy until bent wings forced them to retire it. How many aces do you know of who flew that aircraft? It was used in combat in China / Burma and didn't do so well. If it was effective it would have been put into much wider use in the Pacific and the Med (as a fighter). Because it was definitely needed.


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## pbehn (Mar 20, 2022)

Wild_Bill_Kelso said:


> I would say the B-70 was cancelled for a reason and leave it at that.
> 
> 
> Well, the proof is in the pudding. P-51B immediately started racking up victories and generating aces as soon as pilots started flying it in combat zones. P-51A and various other Allison versions no such luck as a fighter. The British found success with it as a recon aircraft and the Americans used the A-36 (eventually) with some success as a dive-bomber in Italy until bent wings forced them to retire it. How many aces do you know of who flew that aircraft? It was used in combat in China / Burma and didn't do so well. If it was effective it would have been put into much wider use in the Pacific and the Med (as a fighter). Because it was definitely needed.


The Mustang I had its first victory (Fw 190) and first loss at Dieppe in August 1942, it was used in tactical recon because that was what it was best suited for, no other plane could do what it did. The P-39 lasted one mission with the RAF from UK. The P-40 did a few more but was not up to the job. of taking a picture or attacking a ground target and getting back again.

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## pbehn (Mar 20, 2022)

drgondog said:


> I suppose I would need a better definition of "luck" to comment,


As I see it NAA had the sort of luck that Jack Nicklaus had, the more he practiced the luckier he got. NAA were not in a great position at the start, if it was a game of cards, they hadnt been dealt the best hand, a lot of hard work and more importantly, good work by a lot of people got the Mustang P-51 to where it ended up despite being left on the grid at the start.

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## Wild_Bill_Kelso (Mar 20, 2022)

pbehn said:


> The Mustang I had its first victory (Fw 190) and first loss at Dieppe in August 1942, it was used in tactical recon because that was what it was best suited for, no other plane could do what it did. The P-39 lasted one mission with the RAF from UK. The P-40 did a few more but was not up to the job. of taking a picture or attacking a ground target and getting back again.



Yeah I am well aware the British didn't like P-40s for missions flying out of Britain. But P-40s were in _heavy_ use by the RAF and ANZAC forces from 1941, in fact they were the main British fighter in the Western Desert from late 1941 through mid 1942. And there were something like 150 P-40 Aces during WW2, at least 46 of whom were British / Commonwealth. The P-39 did very well in Russia, but there was only one US Ace flying P-39s, and no British / Commonwealth, though they were in fairly heavy use in the Pacific and racked up a fair number of victory claims in the NG area. As far as I know there was only ever one US ace flying Allison engined P-51, an A-36 pilot flying in Italy. I am not sure about British, there might have been a handful of aces but I don't think there were many air to air combat victories with that type.

There was a pressing need for a faster, longer ranged fighter in 1942, in all three of the Theaters I mentioned. I suspect the Russians would have liked it too. Recon is an important mission too but there was a serious need for fighters, especially those which could outrun Bf 109s and reach targets farther away. If it had been viable as a fighter (as distinct from recon / fighter-bomber) I believe it would have been in heavy use in North Africa, China and the Pacific. It may have only been available in relatively small numbers but so was the P-38, and look at the impact it had in the Pacific.


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## SaparotRob (Mar 20, 2022)

In mid 1942, the Allies were still trying to figure out what it was they needed, and what to do with the “not enough “ they already had. You know, the stuff did not quite work. 
There was a lot of noise coming from various Commands, politicians and manufacturers, all knowing what had to be done. Even though many didn’t. The U.S. was just gearing up to get geared up. That’s why it didn’t happen.


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## GregP (Mar 20, 2022)

Wild_Bill_Kelso said:


> I think there is always an element of luck in a military aircraft design working out - especially in the era before computer simulation and computer aided design. I'd also debate how great some of the above listed aircraft really ultimately turned out to be (B-70? Really?) , but I was not denigrating NAA, or Edgar Schmued, Ray Wagoner etc.
> 
> Quite a few very promising aircraft from other very accomplished firms with good designers got canceled just because a prototype crashed or somebody somewhere decided to cancel it in favor of another, which I definitely consider a factor of luck.
> 
> ...



No.

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## Wild_Bill_Kelso (Mar 20, 2022)

The P-51A / NA-73 was available, and due to it's excellent performance, they kept the project going, but they had some kind of problems with agility i still don't fully understand. I gather the P-51B saw a change in ailerons. All I can say is that the Allison P-51 _did _see action but it didn't really work out well in combat. If it had, I believe they would have made much wider use of it well before the Merlin-60 versions were available.

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## Wild_Bill_Kelso (Mar 20, 2022)

GregP said:


> No.


Well I disagree.

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## SaparotRob (Mar 20, 2022)

Wild_Bill_Kelso said:


> Well I disagree.


I like your moxie, kid!

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## GregP (Mar 20, 2022)

Wild_Bill_Kelso said:


> Well I disagree.



It's OK if you disagree. Nobody ever said we all have to agree. The P-51A worked out just fine in combat *and was still flying at war's end*. The Merlin gave it a much better ceiling, but the P-51A was still faster down low.

I can tell you this from working on them. North American products are very well built, and have solid systems in them. There is no apparent "jury-rigging." Everything fits and is robust. That doesn't happen by luck. It happens from solid engineering and good production line processes.

One change from P-51A to P-51B, other than the obvious engine change, and on was metal ailerons and elevators. All P-51s had fabric rudders. The difference between the metal and fabric wasn't very apparent until the speed hit above about 300 mph, and then the metal didn't deflect like fabric, so the non-deflecting metal gave the later P-51s better roll and pitch at higher speeds than the fabric surface did. At under 250 mph, there was little to chose between them.

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## DarrenW (Mar 20, 2022)

SaparotRob said:


> I like your moxie, kid!


And I like his fresh line of questioning. I'm unfamiliar concerning the P-51A and it's combat history so I'm certainly learning a lot.

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## pbehn (Mar 20, 2022)

Wild_Bill_Kelso said:


> Yeah I am well aware the British didn't like P-40s for missions flying out of Britain. But P-40s were in _heavy_ use by the RAF and ANZAC forces from 1941, in fact they were the main British fighter in the Western Desert from late 1941 through mid 1942. And there were something like 150 P-40 Aces during WW2, at least 46 of whom were British / Commonwealth. The P-39 did very well in Russia, but there was only one US Ace flying P-39s, and no British / Commonwealth, though they were in fairly heavy use in the Pacific and racked up a fair number of victory claims in the NG area. As far as I know there was only ever one US ace flying Allison engined P-51, an A-36 pilot flying in Italy. I am not sure about British, there might have been a handful of aces but I don't think there were many air to air combat victories with that type.
> 
> There was a pressing need for a faster, longer ranged fighter in 1942, in all three of the Theaters I mentioned. I suspect the Russians would have liked it too. Recon is an important mission too but there was a serious need for fighters, especially those which could outrun Bf 109s and reach targets farther away. If it had been viable as a fighter (as distinct from recon / fighter-bomber) I believe it would have been in heavy use in North Africa, China and the Pacific. It may have only been available in relatively small numbers but so was the P-38, and look at the impact it had in the Pacific.


It was not a question of liking, it couldnt do the job of crossing the channel and getting back again. The P-40 was not the main British fighter in the period, it was not considered to take on the Fw 190 Jabo raids or for the battle of Malta. The English Channel and the defences the Germans had on their side dictated other pressing needs before range you had to outperform the Abbeville boys in their Fw 190s or you didnt get back home.

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## GregP (Mar 20, 2022)

Wild_Bill_Kelso said:


> I think there is always an element of luck in a military aircraft design working out - especially in the era before computer simulation and computer aided design. I'd also debate how great some of the above listed aircraft really ultimately turned out to be (B-70? Really?) , but I was not denigrating NAA, or Edgar Schmued, Ray Wagoner etc.
> 
> Quite a few very promising aircraft from other very accomplished firms with good designers got canceled just because a prototype crashed or somebody somewhere decided to cancel it in favor of another, which I definitely consider a factor of luck.
> 
> ...



The B-70 was a masterpiece of engineering and performance. I was lucky enough to see one of them flying down in Florida once in 1967, going into Eglin AFB. What killed it wasn't the fact that it couldn't perform as designed; it could. The death of the B-70 was the combination of accurate ICBMs and development of effective high-altitude anti-aircraft missiles, making Mach 3 at 70,000 feet something not quite as invulnerable as we thought it would be. Instead, we turned to low-level penetration and stealth.

The only reason the SR-71 was almost invulnerable (at 70,000 feet and Mach 3) was that fact that is turned out to be quite stealthy, unlike the B-70. If the B-70 had the radar cross section of the SR-71, it would have gone into quantity production. Alas, it had quite a large radar cross section, with a giant rectangular air intake that reflected every bit of energy radiated at it from anywhere. So, it was fast and high-flying, but you couldn't sneak up on anyone with a good radar.

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## ColFord (Mar 20, 2022)

pbehn said:


> The Mustang I had its first victory (Fw 190) and first loss at Dieppe in August 1942, it was used in tactical recon because that was what it was best suited for, no other plane could do what it did.


First RAF Mustang Mk.I operational loss on 14 July 1942, aircraft of No.26 Squadron RAF flown by Pilot Officer H Taylor crashed at low level whilst strafing German troops near Le Touquet, France - either hit by ground fire or misjudged height during attack. (First non-operational RAF loss on 9 May 1942 in take-off accident.)

First RAF Mustang air to air combat victory, now known to predate that claimed during the Dieppe operation in August 1942. 'Kill' confirmed by RAF records declassified post-war, surviving Luftwaffe loss records and other records in Government Archives and dates from July 1942. 



Wild_Bill_Kelso said:


> The P-51A / NA-73 was available, and due to it's excellent performance, they kept the project going, but they had some kind of problems with agility i still don't fully understand. I gather the P-51B saw a change in ailerons. All I can say is that the Allison P-51 _did _see action but it didn't really work out well in combat. If it had, I believe they would have made much wider use of it well before the Merlin-60 versions were available.


You obviously know little about the early Mustangs.

NA-73 North American Mustang Mk.I - no US 'P' designation as direct purchase contract between UK Government and NAA. Two aircraft from order provided to USAAC/USAAF for testing given XP-51 designation. 320 built.

NA-83 North American Mustang Mk.I - no US 'P' designation as direct purchase contract between UK Government and NAA. Minor changes and modifications identified in production of NA-73 implemented into NA-83. 300 built.

NA-91 North American P-51 Mustang, Mustang Mk.IA in RAF service. Lend Lease order for RAF, 150 aircraft. First with P-51 designation, no suffix. Basically similar to NA-83, but with change in armament to 4 x 20mm Hispano cannon. Number of these aircraft retained by USAAC/USAAF after Pearl Harbor and were first P-51 to enter US service.

NA-97 North American A-36A Mustang. First order officially for USAAF, 500 aircraft.

NA-99 North American P-51A Mustang, Mustang Mk.II in RAF service. Second order for USAAF, 310 built - originally was going to be more but production switched to Merlin engined P-51B/C.

As far as the RAF was concerned, the Allison engined Mustang worked out very well in combat, particularly in the role of a low altitude tactical reconnaissance fighter. In 1944 and 1945 in studies conducted by RAF staff in comparing the potential available aircraft for that role, they repeatedly came to the conclusion that the best possible replacement was more Allison engined Mustangs - not Hawker Typhoons, not various versions of Merlin or Griffon engined Spitfires, not Merlin engined Mustangs. Only problem was, they could not get them because the production lines had been fully switched to producing Merlin engined Mustangs for the 'pure' fighter role. Down low, with the engine modifications made by the RAF to the Allison engines in their Mustangs, they were fast, lighter than the Merlin Mustang, and had control responses that the pilots found more than matched their requirements. RAF, reluctantly, retired the last of the their Allison engined Tac/R Mustangs in August 1945 - they basically wore out the aircraft they had, combined with combat losses, usual training losses, etc. Pilots flying Mustang Mk.IA and Mk.II were still engaging in air to air combat - altho that was not their primary role - on an opportunity basis in and scoring 'kills' and 'damaged', confirmed, as late as February 1945 against types such as Me-262 and 'long nosed' FW-190s. They also racked up a very impressive score in strafing of ground targets, particularly railway steam engines and rolling stock, enemy transport, river barges and the like. Plus their best 'scores' were racked up by the Typhoon and Spitfire pilots, or the Squadrons of RAF or USAAF medium bombers who were called in as a result of their sighting reports on concentrations of enemy armour, transport, artillery positions and the like. RAF pilots in Allison engine Mustangs flew operations in them from 10 May 1942 until VE-Day, in May 1945, including first operation of single engine fighters based in UK against Western Germany in October 1942, first long range low level bomber escort against targets outside range of Spitfires and Hurricanes in September 1942, and a whole lot more.

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## drgondog (Mar 20, 2022)

wuzak said:


> Denied permission because GM owned Allison and NAA?


Yes. Later, when the P-51B was a done deal with Merlin, Allison appealed to GMC to create an opportunity for the two stage (auxiliary) V-1710. NAA shot it down with design studies made late 1941 on Continental and Allison engine installation issue and associated re-design required of Mustang to incorporate a 20" movement (forward) of the wing to accommodate CG changes.

There was no love lost between Allison and NAA early in the Mustang life when Allison was 90 days late in delivering the commited engine for X-73 - on the basis that 'nobody actually believed the NAA fcst'.


Wild_Bill_Kelso said:


> I would say the B-70 was cancelled for a reason and leave it at that.


That would expose a lack of knowledge. Please expand.


Wild_Bill_Kelso said:


> Well, the proof is in the pudding. P-51B immediately started racking up victories and generating aces as soon as pilots started flying it in combat zones. P-51A and various other Allison versions no such luck as a fighter. The British found success with it as a recon aircraft and the Americans used the A-36 (eventually) with some success as a dive-bomber in Italy until bent wings forced them to retire it. How many aces do you know of who flew that aircraft? It was used in combat in China / Burma and didn't do so well. If it was effective it would have been put into much wider use in the Pacific and the Med (as a fighter). Because it was definitely needed.


The first P-51B ace was Jim Howard 354FG six weeks into Combat ops with 2.33 carried over from AVG, The next two Aces in 354th FG were in mid and late February 1944, seven weeks after combat ops. 

How do you define 'didn't do so well' for CBI, look to number of P-38s and P-40s deployed and start counting 'Ace in Type', then look for P-47D aces?

How about P-47N - in combat from March 1945 to EOW?


The CBI was only operational theatre with recipients in 1st Air Commando, 51st FG and 23rd FG. There were only 3 operational squadrons deployed as fighters and all were primarily engaged in tactical operations, mostly ground support and escort for light and medium bombers in tactical role.

To answer your question, England (10) and Mulhollem (6) achieved Ace status (311FG). Others including Tex Hill (2 P-51A) scored in the short time before replacement - when the P-51A was shifted to Recon and 311th/23rd received P-51B/C after about 2 months.

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## Wild_Bill_Kelso (Mar 20, 2022)

GregP said:


> It's OK if you disagree. Nobody ever said we all have to agree. The P-51A worked out just fine in combat *and was still flying at war's end*. The Merlin gave it a much better ceiling, but the P-51A was still faster down low.
> 
> I can tell you this from working on them. North American products are very well built, and have solid systems in them. There is no apparent "jury-rigging." Everything fits and is robust. That doesn't happen by luck. It happens from solid engineering and good production line processes.
> 
> One change from P-51A to P-51B, other than the obvious engine change, and on was metal ailerons and elevators. All P-51s had fabric rudders. The difference between the metal and fabric wasn't very apparent until the speed hit above about 300 mph, and then the metal didn't deflect like fabric, so the non-deflecting metal gave the later P-51s better roll and pitch at higher speeds than the fabric surface did. At under 250 mph, there was little to chose between them.



The Allison engined P-51 did have a niche and it was good in it's niche to the end of the war, but that niche wasn't really as a fighter.

I gather aside from the metal rudders, there was also something about the rigging of the ailerons...? Does that ring a bell?


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## Wild_Bill_Kelso (Mar 20, 2022)

ColFord said:


> You obviously know little about the early Mustangs.



That would be an incorrect assumption on your part.



ColFord said:


> NA-73 North American Mustang Mk.I - no US 'P' designation as direct purchase contract between UK Government and NAA. Two aircraft from order provided to USAAC/USAAF for testing given XP-51 designation. 320 built.
> 
> NA-83 North American Mustang Mk.I - no US 'P' designation as direct purchase contract between UK Government and NAA. Minor changes and modifications identified in production of NA-73 implemented into NA-83. 300 built.
> 
> ...



I never said any of these subvariants didn't exist, nor does their existence come as any kind of surprise to me. Did you expect me to list them all out every time I mentioned the Allison engined mustang fighter variants? Even that is too long. Hence P-51A / NA-73 etc.



ColFord said:


> As far as the RAF was concerned, the Allison engined Mustang worked out very well in combat, particularly in the role of a low altitude tactical reconnaissance fighter.



Yeah but the emphasis there is on the reconnaissance. Yes it did have a role, especially in British use, which I mentioned already. And it also had a role for the Americans for a while as the A-36 "don't dare call it Apache" dive bomber, which I think was actually a bit more important in that role than is typically recognized.

What it didn't do particularly well was fly combat missions as a Fighter with a capital F. As in air superiority, fighter escort, point defense, fighter sweep, etc. They flew some missions in China and they didn't go so well. If you need me to I can get a book down off the shelf and transcribe some details, but I thought this was common knowledge.



ColFord said:


> Pilots flying Mustang Mk.IA and Mk.II were still engaging in air to air combat - altho that was not their primary role - on an opportunity basis in and scoring 'kills' and 'damaged', confirmed, as late as February 1945 against types such as Me-262 and 'long nosed' FW-190s.


Yeah but how many victory claims, how many aces? This way we can compare to other fighter types, for example, compare it with the Merlin engined types. Or with the Tempest or pick your own favorite.


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## drgondog (Mar 20, 2022)

Wild_Bill_Kelso said:


> The Allison engined P-51 did have a niche and it was good in it's niche to the end of the war, but that niche wasn't really as a fighter.
> 
> I gather aside from the metal rudders, there was also something about the rigging of the ailerons...? Does that ring a bell?


Yes - the P-51B/D introduced 15 degree throw ailerons, the P-51D-25 had factory metal elevators and reduced horizontal stabilizer incidence for better dive stability.

You have a curious definition of 'fighter'. Care to expand?

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## MIflyer (Mar 20, 2022)

Read somewhere that an NACA employee was given the task of improving the V-1710 and complained, "Why bother with this piece of junk?" That guy had a real attitude problem! While improving the V-1710 would not have been exactly pushing back the boundaries of knowledge, simply adding a 2nd speed to the V-1710 single stage supercharger would have really helped the P-39, P-40, and P-51, and might have even given the P-38 more flexibility. At the start of WWII just about everyone had only single speed single stage superchargers, but the V-1710 never incorporated that simple improvement while everyone else did. Ironically it would have been easier to do on the V-1710 than the Merlin, since the gearcase and rear accessory section could be unbolted from the block, unlike the Merlin.

Allison chose to not build a new version of the rear accessory section to accommodate a 2nd speed and instead coupled the auxillary supercharger used on the P-63 and F-82 via the starter drive coupling. As has been noted, this made the engine a lot longer than the basic V-1710 and unsuitable for easy introduction into the existing production fighters.

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## Wild_Bill_Kelso (Mar 20, 2022)

drgondog said:


> That would expose a lack of knowledge. Please expand.



I wouldn't be so certain. But I don't want to derail this thread. Maybe we can start another one for the B-70?



drgondog said:


> The first P-51B ace was Jim Howard 354FG six weeks into Combat ops with 2.33 carried over from AVG, The next two Aces in 354th FG were in mid and late February 1944, seven weeks ater combat ops.


I am well aware there were tons of (Merlin series) P-51 Aces. I was talking specifically about the Allison engined P-51s. 



drgondog said:


> How do you define 'didn't do so well' for CBI, look to number of P-38s and P-40s deployed and start counting 'Ace in Type', then look for P-47D aces?


Actually P-40s shot down the largest number of enemy aircraft (or at any rate, had the highest number of claims) in the CBI at 973, followed by P-51 (Merlin) at 345, then P-38s at 157, then P-47s at 16.



drgondog said:


> How about P-47N - in combat from March 1945 to EOW?


Great fighter, though a little late arriving. I certainly never said otherwise. No idea how many claims, but there weren't that many enemy aircraft lying after March 1945.


drgondog said:


> The CBI was only operational theatre with recipients in 1st Air Commando, 51st FG and 23rd FG. There were only 3 operational squadrons deployed as fighters and all were primarily engaged in tactical operations, mostly ground support and escort for light and medium bombers in tactical role.



Well A-36 was flying in Italy, and there are all the British variants as well.



drgondog said:


> To answer your question, England (10) and Mulhollem (6) achieved Ace status (311FG). Others including Tex Hill (2 P-51A) scored in the short time before replacement - when the P-51A was shifted to Recon and 311th/23rd received P-51B/C after about 2 months.



Right. So two? There were at least 37 US pilots who made ace while flying P-40s in the CBI, including Tex Hill who you mentioned. A large proportion of those were AVG pilots who had relatively few aircraft and were only in action for a comparatively short time. I don't know the exact count of P-38 aces in the PTO, but I just counted more than 70 on this list here, in spite of a relatively small number of P-38 units, at least initially.

Clearly the P-51 was a great design, it ended up being the best fighter of the USAAF in my opinion, and certainly in the top 5 fighters of the war in my book. But it did not seem to reach it's potential until after conversion to the Merlin.


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## Wild_Bill_Kelso (Mar 20, 2022)

drgondog said:


> Yes - the P-51B/D introduced 15 degree throw ailerons, the P-51D-25 had factory metal elevators and reduced horizontal stabilizer incidence for better dive stability.


I think that was a significant change.


drgondog said:


> You have a curious definition of 'fighter'. Care to expand?


Fighter is obviously a broad term, and there is wiggle room, but I think there is also a common sense definition. Is an aircraft which never flies air superiority, interception, combat air patrol, fighter escort or fighter sweep missions a fighter? Some 'fighters' were and are really tactical bombers in my opinion. But there are also some you wouldn't put on CAP which are still 'fighters' - a Beaufighter is a still fighter in my book for example, but with a more of a niche role. Same for any number of night-fighters. Or most floatplane fighters. Some aircraft might be fighters in one Theater while having reverted to tactical bombers in another. For example, the Hurricane was basically used as a tactical bomber in the Med by 1943, but was still being used as a Fighter (capital F) in the CBI at that stage, if not necessarily with great outcomes.

A tactical recon aircraft like one of the British Allison-engined Mustang variants isn't really a fighter IMO, or if it is, it's one with a very narrow niche. I think the Allison-engined Mustang _could_ have had a substantial role in basically every Theater other than NW Europe if it had been able to do the missions listed above. Probably all it really needed was some tweaking to elevator and ailerons.


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## Wild_Bill_Kelso (Mar 20, 2022)

I'd say the super basic definition of a fighter is an aircraft which destroys enemy aircraft. Which is the criteria I have been applying here.


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## SaparotRob (Mar 20, 2022)

Hot diggity. The Anson IS a fighter!

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## GregP (Mar 20, 2022)

Wild_Bill_Kelso said:


> The Allison engined P-51 did have a niche and it was good in it's niche to the end of the war, but that niche wasn't really as a fighter.
> 
> I gather aside from the metal rudders, there was also something about the rigging of the ailerons...? Does that ring a bell?



Yes and no. There is something about ALL ailerons, but you don't say what. There was and IS nothing wrong with the ailerons on a P-51A.

Yes, there were two sets of aileron rigging: ±10° and ±15°. From the factory. Naturally, the ones with the ±15° rigging rolled better. The Mustang was prohibited from snap-rolls as the horizontal tail wasn't stressed for it. A half snap-roll was taught in basic flight training and it was called a vertical reverse. The P-51A was prohibited from doing vertical reverses and other snap rolling maneuvers. So were a few OTHER airplanes otherwise called fighters. It wasn't a "deficiency." It was a matter of structural strength that wasn't needed in a front-line fighter. If you were doing snap rolls, you were WAY too slow and were likely not doing things correctly.

The P-51A could hold its own with ANY fighter below 15,000 feet, where the Allison was strong. Above about 15,000 feet, the power started dropping off due to the single-stage supercharger that was specified by the U.S. government in the contracts. The Merlin was fitted to the P-51 because Rolls Royce developed the Merlin with private funds, and so could experiment as they saw fit with the design. When they came up with an integrated 2-stage supercharger, courtesy of Sir Stanley Hooker, it seemed like a good thing to try it in a Mustang, and both the British AND the U.S.A. built 2-stage Merlin Mustang prototypes. 

The British unit was called the Mustang X and had a Merlin 61 in it. It first flew 13 Oct 1942. They built five Mustang Xs. Obviously, they liked what they flew when they tried it.

The first XP-51B first flew 30 Nov 42. It was a more thorough redesign. Both the U.S.A. and the British liked it better than the Mustang X. 

The P-51B-5-NA also introduced the infamous 85-gallon fuselage tank that turned the P-51 into the best escort fighter available to the Allies. I'm sure the British could have fitted such a tank to the Mustang X, but they weren't in the P-51 manufacturing business, so they bought P-51B/Cs instead from North American, who WERE in the P-51 manufacturing business. Thank heavens SOMEONE was.

After the P-51B/C had the kinked leading edge added and the horizontal tail was strengthened, the aileron and elevators surfaces were metalized, and the dorsal fillet was added for the D/K models, the P-51 lost any "deficiencies" it may or may not have had.

If you check, you'll find almost ALL of the great piston fighters went through similar development modifications one one kind or another, including the Spitfire, the Typhoon, the P-47, the Tempest, the Bf 109, the Fw 190, and several others.

Many fighters went through several engine trials. Here is a Fairey Battle with a radial engine installation:






Didn't exactly turn it into a world-beater, but it WAS different from the single-stage Merlin usually seen in Battles.

With the above, I think I digress, so I'll stop. Cheers to you.

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## GregP (Mar 20, 2022)

Wild_Bill_Kelso said:


> I wouldn't be so certain. But I don't want to derail this thread. Maybe we can start another one for the B-70?
> 
> 
> I am well aware there were tons of (Merlin series) P-51 Aces. I was talking specifically about the Allison engined P-51s.
> ...



You probably don't know this, but Drgondog is an author and has written books (including _Our Might Always_ and _Angels, Bulldogs, & Dragons_) that include type-specific victories by the Eighth Air Force as well as the P-51 in general. He has flown P-51s, is an aeronautical engineer, his father flew P-51s in WWII, he grew up talking with WWII P-51 aces at his home, and I daresay he is an authority WAY beyond whoever you may be referencing in your posts.

He is currently working on a book containing the enumerated aerial victories in the MTO.

You may want to go read his past 15 - 20 years of posts before you question his ability to comment on WWII much more, and you may not since I don't know YOUR background at this time. Perhaps you, too, are a recognized expert on the subject of the P-51 and WWII aerial victories.

Cheers to you.

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## Wild_Bill_Kelso (Mar 20, 2022)

GregP said:


> before you *question his ability to comment on WWII *much more,



I don't recall ever having done that, did you want to point out where I did?



GregP said:


> and you may not since I don't know YOUR background at this time. Perhaps you, too, are a recognized expert on the subject of the P-51 and WWII aerial victories.



I didn't realize there was a forum rule here that you have to have published a book, or been posting here for 15 - 20 years, before you can comment, reply, or hold an opinion?

It seems like you are questioning my ability to comment on WWII. I assure you, I have that ability. So do a lot of people. If that wasn't the case, there wouldn't be much point in having forums for discussing it.



GregP said:


> Cheers to you.



Right back at you.


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## ColFord (Mar 20, 2022)

Wild_Bill_Kelso said:


> What it didn't do particularly well was fly combat missions as a Fighter with a capital F. As in air superiority, fighter escort, point defense, fighter sweep, etc.


I'll leave it these gentlemen as testament to flying the Allison engined Mustang as a 'capital F' fighter with the RAF in WW2. Two of them pictured here, shot down six Luftwaffe aircraft between them in a single sortie in mid 1943. Another made the last recorded kill by an RAF Allison Mustang, against a FW-190 in February 1945. Another made two kills on RAF Allison Mustangs - and numerous steam engines, barges, enemy MET, marching troops and even an E-Boat - before being moved onto the Merlin engine Mustangs to take command of one of the newly re-equipped RAF Squadrons on Mustang IIIs. Another commanded a number of the pioneering RAF early long range operational sorties on the Allison Mustangs, and a couple of others pictured where there as well. Many flew numerous Rhubarbs, Sweeps, Lagoons, Rangers, Populars; performed dangerous low level sorties against V-1 sites in Northern France; along with directing the guns of the Allied Navies onto the beaches of Normandy on D-Day; and directed Allied artillery accurately onto enemy armour and troop concentrations, flak positions ad supply dumps many times. A couple even sunk German mini-subs! A number of those pictured were present when the RAF got its first Allison Mustangs, and when they retired their last, flying operations on Allison Mustangs from 1942 to 1945. (Note: some of them even flew Spitfires at various times during the war, including Spitfire PR.XI and PR.XIX, Spitfire FR.IX and Spitfire FR.XIVe, so they did have a good basis for comparison of the two types.)

I'll leave it to them and a few hundred others of their friends and comrades who certainly regarded themselves as FIGHTER-reconnaissance pilots, wore their battle dress with the top button undone, and a number of whom when the RAF started to receive Merlin engined Mustangs, were moved across to the Fighter Command Mustang Squadrons being re-equipped, in senior roles to show the Fighter pilots how to get the best out of the Mustang.







Wild_Bill_Kelso said:


> never said any of these subvariants didn't exist, nor does their existence come as any kind of surprise to me. Did you expect me to list them all out every time I mentioned the Allison engined mustang fighter variants? Even that is too long. Hence P-51A / NA-73 etc.


Using "P-51A / NA-73" in the way that you did certainly did not indicate you understood the lineage of the early Mustangs and the order in which they were produced and entered service. Too many people out there seem to think the P-51A equated to the first Mustang in service, so therefore we tend to try and be precise about how we refer to them so as not to leave room for ambiguity or misunderstanding.


SaparotRob said:


> Hot diggity. The Anson IS a fighter!


And on the definition given, a whole lot of aircraft could be considered a "fighter" by virtue of destroying an enemy aircraft.

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## Wild_Bill_Kelso (Mar 20, 2022)

Pointing out that a given aircraft didn't work out that well as a fighter - which by the way is done here all day long in dozens of threads going back decades - *is in no way casting aspersions on any of the men who flew said aircraft*. It's completely disingenuous to imply that it does.

I never once said recon pilots weren't brave, or that bomber or fighter-bomber pilots weren't brave, or any of the above. Nor did I ever so much as suggest they didn't contribute to the war effort.

If I post pictures of all the guys who died flying Fairy Battles, Boulton Paul Defiants, or Brewster Buffalos does that mean those aircraft were great fighters all the sudden?


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## Wild_Bill_Kelso (Mar 20, 2022)

SaparotRob said:


> Hot diggity. The Anson IS a fighter!



Ok how about, has the mission of shooting down enemy aircraft.


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## SaparotRob (Mar 20, 2022)

Wild_Bill_Kelso said:


> Ok how about, has the mission of shooting down enemy aircraft.


Killjoy.

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## Wild_Bill_Kelso (Mar 20, 2022)

Hey anybody who fought a Bf 109 in an Anson is a hero in my book...

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## SaparotRob (Mar 20, 2022)

Although the basis of my aviation knowledge is from documentation provided by Martin Caidin and DC's Johnny Cloud -Navajo Ace, you might want think a bit before trashing the Buffalo.

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## Wild_Bill_Kelso (Mar 20, 2022)

Well I'm not actually trashing it, I know the Finns loved it, some British and Commonwealth pilots in the Pacific did fairly well with it. But I am confident it doesn't rate as one of the top fighters of the war no matter how many faces somebody posts.

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## SaparotRob (Mar 20, 2022)

Don't go there. Someone will post them all. 

Hey, what are your opinions on the P-39?

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## Wild_Bill_Kelso (Mar 20, 2022)

I try to avoid it, but I respect the pilots who flew it!

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## Shortround6 (Mar 21, 2022)

pbehn said:


> The British were looking to have more range, that is why they got heavily involved with NAA and the Mustang with its 180 gallons of internal fuel ordered in 1940, it was known as a P-51 when the USA eventually started using it.


Actually NA told the British they could build a better plane than the P-40 Tomahawk instead of building Tomahawks under license.
Using the same engine as the the P-40D The Mustang did do even better

A lot of confusion and overlapping in 1940-41. The British signed several contracts for Tomahawks while still talking to NAA. NAA was supposed to deliver the prototype Mustang in the fall of 1940. The British would not see a Tomahawk until Sept of 1940(?) and then it was an ex French aircraft. Meanwhile, Curtiss had come up with the P-40D & E and the XP-46. Those two use the same engine the Mustang did. The P-40D starts delivery in April/May of 1941. 

Now we have coincidence or planning or............???
The Mustang (better plane than the Tomahawk) held exactly the same amount of fuel as the Tomahawk without protected tanks. The tanks don't get protection on the production line until late summer of 1940 and until Sept or later to even get better protection planned for the P-40C and late Tomahawks. As the Tomahawks get protected tanks the fuel capcity falls from 180 us gallons to about 160 gallons and then to under 140 gallons in the later Tomahawks and P-40Cs. The Late Tomahawks and P-40Cs get teh 52 US gallon drop tank to basically bring them back up to near the 180 gallon mark. The P-40D and E also had the 52 gallon drop tank and total fuel was about 196-200 gallons. 

However "normal" fuel was 120 gallons. Pilots weren't supposed to use the behind the seat tank in combat with the tank full. Also note that performance specifications at listed gross weights were for 120 gallons or less fuel. 

Going back to the Mustang, somehow they managed to get 180 gallons into a pair of protected fuel tanks. However the "normal" fuel load was 120 gallons according to some sources. 105 gallons is sometimes given but one wing tank had two different fuel taps and 15-16 gallons were kept as "reserve". The Mustangs had no drop tanks. 

FWI the early P-40s with unprotected tanks and 180 gallons had a "book" range of over 1000 miles. 

NAA kept their promise about building a better fighter than the P-40/Tomahawk. Using the same engine (or close to it) and the same amount of fuel it was faster and longer ranged due to less drag, not because of any large amount of extra fuel. It would take over 1 1/2 years for a Mustang (A-36) to carry more fuel than a P-40. 

The F8F and some of the other stuff is just chaff/window.
The F8F used an engine that didn't exist until late 1944. It used the same basic engine as the P-47*M. 
NO *interchangeable parts with earlier R-2800 engines.
So yes you can find a "sweet spot" using an engine (and supercharger) that did not exist earlier. In an airframe that was kept low weight by relaxing the stress standards. 
And by using everything that had been learned over two-three years about aerodynamics, propellers and how to cool air cooled engines.
The R-2800 'C" series engine needed 10% less airflow through the cowling at the same power as older engines for the same amount of cooling due to better fining and baffles. 
Which means less drag. 

You could not build an F8F in 1942 that would perform nearly the same as the 1944 prototypes because the knowledge didn't exist.

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## Wild_Bill_Kelso (Mar 21, 2022)

I never once said, implied, or suggested that anyone could build an F8F in 1942. In fact I said exactly the opposite of that.

I brought up the F8F as an example of a late war fighter that was closer to a 'sweet spot', noting that this was hard to achieve, and that examples such as the F8F came too late. In a previous post I noted this could just as easily be P-51H or some other "really good but just a bit too late" bird (take your pick).

The Mustang was a very good fighter, it just wasn't finished as such until they merged it with the Merlin engine (and did a few other significant updates at the same time)

If it was, they wouldn't have had to use inferior fighters in all the theaters where the big land and sea battles were taking place in 1941-43.


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## GregP (Mar 21, 2022)

Wild_Bill_Kelso said:


> I never once said, implied, or suggested that anyone could build an F8F in 1942. In fact I said exactly the opposite of that.
> 
> I brought up the F8F as an example of a late war fighter that was closer to a 'sweet spot', noting that this was hard to achieve, and that examples such as the F8F came too late. In a previous post I noted this could just as easily be P-51H or some other "really good but just a bit too late" bird (take your pick).
> 
> ...



That kind of funny since the last version of the Mustang used an Allison. That would be the F-82 Twin Mustang.

But, you knew that.

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## ThomasP (Mar 21, 2022)

Only because they did not want to pay royalties to Rolls-Royce (and maybe some corporate greed and national pride thrown in).

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## Geoffrey Sinclair (Mar 21, 2022)

In 1939? French contract number 273 for HK-75A-4 (P-36) has 100 HK-87A (P-40/Tomahawk) added and the last 130 HK-75A-4 changed to HK-87A, according to Air Arsenal North America Britain had a proposed P-40 order, contract number 84, pre war but that was put on hold while the joint British-French purchasing arrangements were created. In early 1940 Anglo-French letters of intent for 500 more P-40 signed. After the collapse of France arrangements became contract number 273 covered the first 100 Tomahawk built, while contract A-84/BR-84 was for 630 aircraft (130+500), ultimately the contract became 1,080 aircraft, with later orders for another 150 then another 300 added to it. Overlaying the contractual arrangements is production by mark was 140 Tomahawk I, 110 Tomahawk IIA and 930 Tomahawk IIB.

May 1940, British sign contract number 250 with North American for 320 NA-73, P-40 production begins.
June 1940, Tomahawk I/HK-87A production begins, under French then British contract 273.
August 1940, First Tomahawk export from US and import into Britain, 1 sent and received
September 1940, First Tomahawk delivered to RAF (in week ending 14th), no imports for month. British sign contract 1493 for a further 300 Mustang. Acceptances from Tomahawk contract A-84 begin.

October 1940, 69 Tomahawks imported into Britain, none delivered to RAF. NA-73 first flight 25 October 1940. P-40 and Tomahawk I production end, Tomahawk IIA production begins, it has as standard fuel and pilot protection.

November 1940, 50 Tomahawks imported into Britain, 26 delivered to RAF, Tomahawk IIA production ends, IIB begins.
February 1941, first Tomahawk ex USA arrive Takoradi, West Africa (week ending 14th), 2 February 1941 XP-46 first flight, P-40B production begins.
March 1941, P-40C production begins
May 1941, P-40D first production, P-40B and C production ends.
June 1941, P-40E first production
August 1941, NA-73/Mustang I first production, monthly total 1, first XP-51 officially accepted.
September 1941, First Mustang exported from US
October 1941, First Mustang arrives in Britain.


GregP said:


> That kind of funny since the last version of the Mustang used an Allison. That would be the F-82 Twin Mustang. But, you knew that.


Ah yes, the F-82E, kind of funny since first production was in September 1947, using a version of the Allison not available during the war and well after Merlin production in the US had stopped. But, you knew that.

In the quest for knowledge could you tell us where on the net you found the incorrect Supermarine Spitfire and Hawker Hurricane production figures you used?


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## drgondog (Mar 21, 2022)

ThomasP said:


> Only because they did not want to pay royalties to Rolls-Royce (and maybe some corporate greed and national pride thrown in).


It was combination of AAF/Royalty distaste for continued purchase of Merlins and political interference by Secretary of War. The Air Force gave the contract for P-82D and subsequent on the basis that Allison deliver the same performance as the boosted/water injected. The delivered 1710-143/145 did not have the backfire screen which limited boost without detonation - but Allison refused to fix it and was supported by AAF Secy.

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## drgondog (Mar 21, 2022)

Wild_Bill_Kelso said:


> I wouldn't be so certain. But I don't want to derail this thread. Maybe we can start another one for the B-70?
> 
> 
> I am well aware there were tons of (Merlin series) P-51 Aces. I was talking specifically about the Allison engined P-51s.
> ...


The MTO VC for A-36/F-6 totaled 67. The CBI P-51A/A-36 victory credits through D-Day totaled 53 (air). Consider the very short span of time during which the Allison Mustang replaced P-40 which had been operational from May 1942 through Nov 1943 in 51st FG. The P-51B/C replaced the P-51A/A-36 in May 1944. For the 311th FG, The A-36/P-51A had a similar operational history. Two A-36 squadrons and one P-51A. The 311th only had 4 aces - all Mustang, two P-51A aces (England/Mulhollem) and two P51C aces (Reeves, Arasmith). 

The 23rd FG had P-51A as 'bridge Mustang' for one squadron for five months, and the P-51As when replaced became Recon F-6. 

I don't know what your source of VC by type, by theatre, but if it's not Frank Olynyk or USAF 85 - then dubious. 


Wild_Bill_Kelso said:


> Right. So two? There were at least 37 US pilots who made ace while flying P-40s in the CBI, including Tex Hill who you mentioned. A large proportion of those were AVG pilots who had relatively few aircraft and were only in action for a comparatively short time. I don't know the exact count of P-38 aces in the PTO, but I just counted more than 70 on this list here, in spite of a relatively small number of P-38 units, at least initially.


Your link opened to a Facebook page? Using the P-38 ace count, or even P-40 ace count in CBI and SW Pacific is not logical simply on available force counts and total number of sorties flown. The quantities of each delivered the fight against Japan was at least 20:1 in sheer numbersand deployed for multiple yeas vs multiple months.

The P-51A sorties in CBI were far fewer than P-39 in SW Pacific, and miniscule compared to P-40 in CBI and less than P-38 in CBI. I get your disdain for Allison powered Mustangs if your criteria is the number of aces that attained that status in that airframe - probably about the same as Ta 152 or He 162, maybe even the FW 190D-9. Which, by many discerning historians, are considered 'Fighters'. Ditto for Ki 84 and Ki 100. 

'Acedom' is more about pilot skill and target rich environments than vastly superior performance. 

No objective pilot that has flown Allison powered Mustangs and P-40s cite the P-40 as a 'superior' fighter (or Pursuit as used in WWII to define type).
.



Wild_Bill_Kelso said:


> Clearly the P-51 was a great design, it ended up being the best fighter of the USAAF in my opinion, and certainly in the top 5 fighters of the war in my book. But it did not seem to reach it's potential until after conversion to the Merlin.


Well, that is a no brainer. But that judgment may also apply to Spit V to Spit IX or FW 190A to FW 190D for similar reasons - upgrade of engine to an already excellent airframe/fighter.

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## Wild_Bill_Kelso (Mar 21, 2022)

drgondog said:


> Your link opened to a Facebook page?



Sorry, not sure what happened there, multi-tasking I guess






Aces – Full Listing | P-38 Assn







p38assn.org


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## Wild_Bill_Kelso (Mar 21, 2022)

GregP said:


> That kind of funny since the last version of the Mustang used an Allison. That would be the F-82 Twin Mustang.
> 
> But, you knew that.



I did not, though I knew there was an Allison with a two stage supercharger.


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## GregP (Mar 21, 2022)

Geoffrey Sinclair said:


> In 1939? French contract number 273 for HK-75A-4 (P-36) has 100 HK-87A (P-40/Tomahawk) added and the last 130 HK-75A-4 changed to HK-87A, according to Air Arsenal North America Britain had a proposed P-40 order, contract number 84, pre war but that was put on hold while the joint British-French purchasing arrangements were created. In early 1940 Anglo-French letters of intent for 500 more P-40 signed. After the collapse of France arrangements became contract number 273 covered the first 100 Tomahawk built, while contract A-84/BR-84 was for 630 aircraft (130+500), ultimately the contract became 1,080 aircraft, with later orders for another 150 then another 300 added to it. Overlaying the contractual arrangements is production by mark was 140 Tomahawk I, 110 Tomahawk IIA and 930 Tomahawk IIB.
> 
> May 1940, British sign contract number 250 with North American for 320 NA-73, P-40 production begins.
> June 1940, Tomahawk I/HK-87A production begins, under French then British contract 273.
> ...



All aircraft built 3 or more years after the first version used engines not available when the first unit was built. Kelso said the P-51 was not completed until the Allison was replaced with a Merlin. I was pointing out that later versions had an Allison. I didn't say or imply it was during WWII. 

I was using this:






But you can also find lists with different numbers. For instance, at: K5083 - Aircraft Production Summary , the list totals 14,053 instead of 14,570 Hurricanes. Another generally-accepted number is 14,487 Hurricanes, but if you add up the breakout shown in that source, it doesn't tally if you add up the numbers by variant. Several sources for Spitfires have different totals, depending on whether or not they include Seafire, Spiteful (I show 22 built), and Seafang (I show 18 built) as "Spitfires" and just general slight disagreement. Sometimes they include conversion as part of the production and sometimes not. Some lists show production only and do not show prototypes and/or conversions.

In any case, there were somewhere around 20,000 Spitfires built exclusive of similar-shaped airplanes that were called by other names, and there were about 14,500 Hurricanes built. The exact numbers seem to change with the source, even when seemingly-exhaustive detail is given.

I have a source for U.S. production, _U.S. Army Aircraft 1908 - 1946, SC-AEF-AAS-AAC-AAF by James C, Fahey, First Edition 1946_ that has totals slightly differing from some other sources, but it was generated using official source numbers in 1946 from the people who bought and tracked airplane production in the U.S.A.. It shows 14,066 for P-51s built through 1946, but that number is not what is generally used today. The number we generally use today is 15,586. Yes, I have the breakouts by variant.

You can find similar discrepancies for almost any aircraft built by almost any nation, depending on which source you are looking at, particularly for German aircraft production since many records were lost during the war and there is no evidence that all werknumers assigned by the RLM were built as assigned.. Even some sources that give the starting and ending serial numbers for each variant disagree with each other ... but, the totals aren't usually too far apart.

If you have a purported completely-accurate source for Spitfires and Hurricanes, maybe you can share it and also why you think it is exactly accurate.

Because I guarantee I can find another source in print that disagrees with it.

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## Wild_Bill_Kelso (Mar 21, 2022)

drgondog said:


> The MTO VC for A-36/F-6 totaled 67. The CBI P-51A/A-36 victory credits through D-Day totaled 53 (air). Consider the very short span of time during which the Allison Mustang replaced P-40 which had been operational from May 1942 through Nov 1943 in 51st FG. The P-51B/C replaced the P-51A/A-36 in May 1944. For the 311th FG, The A-36/P-51A had a similar operational history. Two A-36 squadrons and one P-51A. The 311th only had 4 aces - all Mustang, two P-51A aces (England/Mulhollem) and two P51C aces (Reeves, Arasmith).
> 
> The 23rd FG had P-51A as 'bridge Mustang' for one squadron for five months, and the P-51As when replaced became Recon F-6.
> 
> ...



Lets get a couple of things clear.

I never said that P-40 was a 'superior fighter' to the Allison Mustang. I think the Mustang was clearly a better design.
I never "disparaged" the Allison mustang. 
Nor the pilots flying it.
I never said that Allisons were bad engines.

My numbers for victory claims are correct. The 973 figure comes from Molesworth among others. The P-40 was the Allied type with the highest number of claims in the CBI _by far_. I don't think that is exactly news. But the CBI was a tertiary Theater and there weren't a lot of the more high performing Allied types in action there especially early on (in the mid-war).

The AVG probably had fewer planes operational (less than 100 total) in the CBI than the number of early Mustangs (later) operating there, and the AVG was not operational for that long, nor did the 23rd FG have a massive air contingent either. Nor was there a dearth of targets. The same outfits flew missions with different aircraft and got different results. 

Although the Mustang was clearly an excellent design, very fast, long ranged, and quite agile in it's later incarnations, the record of the Allison engined Mustang, as a fighter, wasn't so great. This is worth figuring out, I am not sure precisely why but I suspect it does have something to do with the metal control surfaces, the strengthening of the tail, and / or the rigging of the ailerons. It may have also been other things such a training, maintenance, or specific Theater conditions. Maybe the different configurations of the guns too. Gunsights?

But it's pretty clear the P-51A / A-36 _and_ various British Allison Engined Mustang variants did not perform as well as fighters as they could have. As the later merlin-engined variants did. This is why they were used more for recon and as dive-bombers. And I don't think that is entirely down to the merlin engine either.


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## GregP (Mar 21, 2022)

The P-51A / A-36 / F-6 had a decent record and was well-liked. It just wasn't a high-altitude fighter. They DID perform as well as they could have. They did better when a higher-altitude engine package was fitted for the higher-altitude operations generally seen in the ETO. Only the A-36 was used much as a dive bomber since the non-A-36 Mustang didn't have dive brakes and got going too fast on the way down to be good dive bombers.

Almost all units transferring into the war from stateside were, by definition, "rookies," and required some combat time before learning the things that only veterans knew, despite any training they received.


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## Zipper730 (Mar 21, 2022)

drgondog said:


> Fuel capacity is not the only issue, but clearly without the 90gal drop tank it has more internal fuel than P-51B without 85 gal fuselage tank. The combat radius of Spit powered by 1650-3 or -7 equivalent, and using same set of assumptions AAF set for CR, it should be able to go ~ 300 miles and fight for 20 minutes. Better than P-47 with 108gal combat tank.


That's an interesting observation, but it's an apples to orange one: A Spitfire VII/VIII/IX as described here*(see footnote 1) with the aft tanks filled is tantamount to a P-51B with it's center/aft tank filled as well



AircraftP-51B/C​P-51B/C​Spitfire VII/VIII/IX​Configuration​All Tanks Filled​Wing & Center Tanks Filled​All Tanks Filled​Fuel Load (US Gallons)​184 Gallons​269 Gallons​225.8 Gallons​
​With externals on a full load, you end up with either 419 gal. for the P-51B and 285.8 or 333.9 gal*(see footnote 2) for the Spitfire VII/VIII/IX.

As for 90 imp. gal slipper tank, it seems like it probably was if they operated routinely above 14000'.

*Footnote*
1. I was looking through some FM's on avialogs, and there wasn't any mention of the Mk.IX having 13 gallon tanks in the wings interestingly. That might have been something that evolved into being, but the aft tanks were definitely present as described.
2. There was a proposed 50 imp. gal. tank to be carried in lieu of the 90 imp. gal. slipper tank.



GregP said:


> Note the difference between the early, rounded fin and rudder (mostly converted Mk.V airframes with a 2-stage Merlin (61 or 66) and the Late Mk VII / IX fin and rudder. Center bottom is the stab and elevator change for late Mk. IX. The counterbalance area had been increased to make the pitch forces a bit lighter.


I'm not sure if I missed this earlier, but why weren't these backfitted to the VII/VIII models?



wuzak said:


> VIIIs and XIVs had the 96 gallon main tank, plus 2 x 13.5 gallon tanks in the wing leading edge (inboard of the guns).


Okay, that leaves me with three questions

Did the leading edge tanks used on the VII/VIII have 13 or 13.5 gallon capacity?
Did the VII/VIII have the aft tanks in any sub-variant?
Did the IX have the leading-edge tanks?



> 2 hours cruising is about 360 - 390 miles if you are flying escort since the escorts stayed with the bombers who were on economy cruise at 185 - 190 mph or so. It might be 500 - 600 miles if the mission didn't involve escort but, since we're talking about long-range airplanes, most of the long-range missions WERE escort.


I remember it mentioned that fighters were used to cover the bombers during the lead-up to D-Day, as well as mentions made by Leslie "Willie" Hay (RAF, Bomber Command) in his book about fighter sweeps occurring ahead of his position.

From what it seemed, during Korea, fighter sweeps were usually set-up so that they would R/V with the bombers as they'd approach enemy territory, surge ahead and clear-out the way and head-on back. The USAAF largely used s-weaving over the formations, but there were fans, race-track patterns, and some did appear to just surge ahead to plow out the way.

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## Wild_Bill_Kelso (Mar 21, 2022)

I was looking for my book on the 23rd Fighter Group, which I failed to locate, but i did find the 2012 Osprey "Air Vanguard' book "Allison Engined P-51 Mustang" by Martyn Chorlton. There are a few interesting tidbits of operational history in there, which I'll repeat here in no particular order

*During the Dieppe raid RAF Mustangs (I believe it says RCAF 400 Sqn) claimed a Fw 190 destroyed. They also comprised 11 of the 119 RAF aircraft lost that day, from 26, 239, 400 and 414 sqds. I didn't see any other claims.
*On Oct 22 1942 RAF Mustang Mk1 and 1As escorted Wellington bombers on a raid into Germany - against Dortmund and Essen. The raid was considered a partial success though the targets were obscured by clouds. All the aircraft returned to base. [It's unclear to me why they didn't do more of these escorted raids.]
*An RAF mission on June 29, 1943, a pair of Mustangs (one I and one IA) flown by Archibald MacLachlan and Geoffrey Page (the former flying with a prosthetic arm) flew a daylight raid all the way to Paris. They destroyed six enemy aircraft (four HS 126s and two Ju 88s).
*Twenty three (23) RAF Squadrons were equipped with Allison Mustangs (Mks I and IA)
*On June 6 1944 three RAF Mustangs were active over the D-Day beach, two flying cover for a Tac-R fighter, when they were attacked by four plus then another two FW 190s. One Mustang was destroyed and the other two managed to disengage. Three Mustangs were lost that day in total out of 86 Tac-R and spotting sorties.
*A-36 aircraft flew 23,000 sorties and claimed 86 enemy aircraft in combat (this would be both in USAAF service both in China / India and the MTO)
*311 FBG based in India attempted to use A-36 as transport and bomber-escort but found that (this is a direct quote from the Osprey book) "_the deficiencies of the A-36 in one-on-one aerial combat were soon highlighted. On one of the early sorties to provide fighter protection for a formation of C-47s flying from India to China, three A-36s were lost, presumed shot down."_
*This unit flew both A-36 and P-51A. Both types were used for transport and fighter escort.
*Operations with P-51A began in Oct 1943 for both 23rd FG and 311 FBG
*On Oct 18 1943, P-51A of the 530 FS, 311 FG flew escorts for B-25s in a raid against Rangoon. This was a 450 mile trip coming from Kurmitola, India, the P-51A were using two 75 gallon drop tanks. They were attacked by four Ki-43 from the 64th Sentai, 2nd Chutai based out of Mingaladon. Quoting from the Osprey book: "_A frantic low-level combat ensued at very low altitude, resulting in two Mustangs being shot down_." There were no claims against the Japanese.
*A second raid (no date given) to Insein in Burma resulted in the Mustangs being bounced by Ki-43s from the 64th Sentai again, one mustang shot down in the initial bounce, then 3 more including the 311 FG CO, Colonely Harry Mehon. One Ki-43 was shot down and another made a forced landing.
*On Dec 1, 1943 31 FBG escorted B-24s to Rangoon. Mustangs were bounced again and one was shot down by a Ki-43, another ran out of fuel and crashed on the return trip.
*Feb 14 1944, 1st Air Command Group (ACG) under Philip Cochran (with 30 x P-51As) escorted a formation of B-25s against Zaundaing. They were bounced by Ki-43s of the 50th Sentai while strafing the target. Two Mustangs were shot down and three more damaged, for no claims.
*ACG 1 had a successful raid from forward Burmese base at Chowringee" (no date given) against the bases at Shwebo and Onbauk with "_several_" Ki-43s claimed shot down and "_more than 30_" on the ground for no losses.
*On March 16, 1944 however the same unit was bounced by 50th Sentai and 3 x Mustangs were shot down, with no claims against the Japanese.
*On April 4, 1944 1st ACG encountered 50th Sentai again and "_enjoyed complete succes_s", resulting in 50th Sentai being moved to Saigon for a refit. No figures for claims / losses are given here.

These were all the specific combat actions I could find in the book though I might have missed a couple. Now I can compare these actions to those of various P-51 (Merlin), P-40, P-38 and Spitfire units in the Theater and I can promise you they did better, at least in terms of claims made. Hurricanes did not do so well in the CBI and were probably worse than the P-51A / A-36. These are from Osprey books so fairly little effort is made to verify the claims via Axis records. Maybe Bloody Shambles provides a more accurate picture I don't have that book yet.

Overall though, I cannot escape the impression that the Allison Mustang did not reach it's full potential here as a fighter.

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## GregP (Mar 21, 2022)

Hi Zipper.

There was a war on and taking a working Spitfire (or anything else) from the front line to fit a new fin and rudder or to recontour an elevator or stabilizer, etc. likely wasn't high on the priority list. Sure, they COULD have been modified, but they were flying and fighting at the time and changes were generally cut in at some point and not always retrofitted. Things like the dorsal fins fitted to P-51D and some B/C models as well as dorsal fins for P-47s WERE sometimes field-fitted, as were things like P-38 dive flaps.

Here's a good study of four P-51Ds. Only one, the 2nd one, has the dorsal fin extension:






So, the dorsal fun mod was either field-installed or the change was cut in somewhere between 44-1310 and 44-13926 (the two serial numbers of the nearest two). I'd have to look that up to be sure which. Somewhat obviously, these are early D models.

Here's a 2-seat TR IX in formation with an XIV. Note the different vertical tails since the Griffon had quite a bit more horsepower. The XIV has more chord, for sure, and a bigger fin:

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## Wild_Bill_Kelso (Mar 21, 2022)

Giving that one a like just for the photos. That XIV is some sexy...

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## GregP (Mar 21, 2022)

Wild_Bill_Kelso said:


> I was looking for my book on the 23rd Fighter Group, which I failed to locate, but i did find the 2012 Osprey "Air Vanguard' book "Allison Engined P-51 Mustang" by Martyn Chorlton. There are a few interesting tidbits of operational history in there, which I'll repeat here in no particular order
> 
> *During the Dieppe raid RAF Mustangs (I believe it says RCAF 400 Sqn) claimed a Fw 190 destroyed. They also comprised 11 of the 119 RAF aircraft lost that day, from 26, 239, 400 and 414 sqds. I didn't see any other claims.
> *On Oct 22 1942 RAF Mustang Mk1 and 1As escorted Wellington bombers on a raid into Germany - against Dortmund and Essen. The raid was considered a partial success though the targets were obscured by clouds. All the aircraft returned to base. [It's unclear to me why they didn't do more of these escorted raids.]
> ...



You can find many different reports. Usually, when someone was attacked, the attackers had the upper hand by virtue of diving from above or from the sun, or whatever. Find the reports when the P-51A did the attacking and you will find the encounters where the P-5A had the advantage. It DID reach its potential, but the 2-stage Merlin-powered version was produced in WAY higher numbers, flew higher and faster, and got the bulk of the missions where victories over attacking enemy fighters were likely to happen. 

Kelso, you are completely free to feel the P-51 wasn't a good fighter and nobody will obviously be able to change your mind. Perhaps we should not try since everyone has an opinion backed by whatever facts they have dug out over the years. You won't likely change anyone else's opinion, either. It's all good. The war is long over, and discussion of the merits of the various aircraft makes these things interesting.

I've sat through maybe a couple of hundred talks with WWII fighter pilots. Almost every single one of them felt the aircraft they were assigned to fly was the best fighter in the world, regardless of which one they flew. Most only flew ONE fighter, so you can draw your own conclusion from that.

Cheers.

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## drgondog (Mar 21, 2022)

Wild_Bill_Kelso said:


> My numbers for victory claims are correct. The 973 figure comes from Molesworth among others. The P-40 was the Allied type with the highest number of claims in the CBI _by far_. I don't think that is exactly news. But the CBI was a tertiary Theater and there weren't a lot of the more high performing Allied types in action there especially early on (in the mid-war).


I'm not familiar with 'Molesworth', or 'among others'. What are the root citations for your sources? USAF 85 is the root for all WWI and II and Korea US Victory Credits - upon which Dr Olynyk expanded via documented sources and were accepted by USAF Historical Research Center. Olynyk was an excellent researcher and got his PhD thesis on this subject many years ago.

RIP Frank.

For US and Commonwealth VCs you should rely on Olynyk and Shores.



Wild_Bill_Kelso said:


> The AVG probably had fewer planes operational (less than 100 total) in the CBI than the number of early Mustangs (later) operating there, and the AVG was not operational for that long, nor did the 23rd FG have a massive air contingent either. Nor was there a dearth of targets. The same outfits flew missions with different aircraft and got different results.


It was operational for seven months at Group level strength - that fluctuated. In a target rich environment against late 1930s vintage aircraft mix of fighters and bombers.


Wild_Bill_Kelso said:


> Although the Mustang was clearly an excellent design, very fast, long ranged, and quite agile in it's later incarnations, the record of the Allison engined Mustang, as a fighter, wasn't so great. This is worth figuring out, I am not sure precisely why but I suspect it does have something to do with the metal control surfaces, the strengthening of the tail, and / or the rigging of the ailerons. It may have also been other things such a training, maintenance, or specific Theater conditions. Maybe the different configurations of the guns too. Gunsights?


No. The Mustang I and Allison based variants all had fabric control surfaces, as did all the P-51B and D until the D-20/-25 when the metal elevator kits and incidence change kits were delivered to retrofit in early 1945.

The sole 'manuever' deficiency vs P-51B/D was the aileron rigging from +/1 10 degrees to +/- 10, 12, 15 degrees, That said, 'it' (XP-51, P-51, A-36 and P-51A out rolled the P-38, 39, 40 and P-47 at speeds above 300KT TAS. The P-40 our rolled the P-51A in slow, middle airspeed range. The P-51A outclimbed the P-40 and 47 - and climbed with the P-38F/G until 15K+. The P-51-NA (4x20mm) comparison for AAF operational suitability tests vs P-39Q, P-40N, P-38G and P-47D was deemed the 'best fighter below 15000 feet - and it was at least 10mph slower than P-51A across the entire envelope.

Pacific Fighters John Muszala II is one of the Rare warbird pilots who has flown all the primary Allison/Merlin Mustang variants including the P-51A/B/C/D and he will tell you that the P-51A is more agile than B/D- which it Should be in every domain except roll - because of excess HP to drag and lower W/L


Wild_Bill_Kelso said:


> But it's pretty clear the P-51A / A-36 _and_ various British Allison Engined Mustang variants did not perform as well as fighters as they could have. As the later merlin-engined variants did. This is why they were used more for recon and as dive-bombers. And I don't think that is entirely down to the merlin engine either.


You can argue 'did not SCORE as well' but not 'did not Perform as well as fighters as they could have' - had they been in-theatre in quantity with their P-39D/N, P-38F/G, P-47C/early D counterparts for 1942 and 1943. Scoring was a function of quantity deployed in combat at the same time period.

I don't know if you are familiar with Mike Williams' spitfireperformance.com website. If not, you should take a deep dive into test pilot reports for the various marks as well as comparisons. If so, you should spend more time studying them.

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## GregP (Mar 21, 2022)

Nice post, Bill.

Have you published your work on the MTO yet with victory tally? If so, where can I get a copy?


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## drgondog (Mar 21, 2022)

GregP said:


> Hi Zipper.
> 
> There was a war on and taking a working Spitfire (or anything else) from the front line to fit a new fin and rudder or to recontour an elevator or stabilizer, etc. likely wasn't high on the priority list. Sure, they COULD have been modified, but they were flying and fighting at the time and changes were generally cut in at some point and not always retrofitted. Things like the dorsal fins fitted to P-51D and some B/C models as well as dorsal fins for P-47s WERE sometimes field-fitted, as were things like P-38 dive flaps.
> 
> ...


Greg - the Factory DF was installed on 44-13903. 953 is a factory dorsal fin inst'l. 953 arrived at 361st around very late July/early August. Dad was shot down by flak (and rescued by Priest) in 950 on August 18th. The kits began rolling in in early September, so I'm guessing that pic was in August/September 1944.


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## tommayer (Mar 21, 2022)

Wild_Bill_Kelso said:


> I'd say the super basic definition of a fighter is an aircraft which destroys enemy aircraft. Which is the criteria I have been applying here.


Does that mean B-17s-24s etc were fighters? They destroyed enemy e/a.


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## drgondog (Mar 21, 2022)

GregP said:


> Nice post, Bill.
> 
> Have you published your work on the MTO yet with victory tally? If so, where can I get a copy?


Greg - I'm currently working on P-51D/Lightweights. I have the Olynyk database.

As you probably know he passed away about two weeks ago. He was working on an Opus with Christopher Shores to integrate Commonwealth/US Victory credits.


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## Wild_Bill_Kelso (Mar 21, 2022)

drgondog said:


> I'm not familiar with 'Molesworth', or 'among others'. What are the root citations for your sources? USAF 85 is the root for all WWI and II and Korea US Victory Credits - upon which Dr Olynyk expanded via documented sources and were accepted by USAF Historical Research Center. Olynyk was an excellent researcher and got his PhD thesis on this subject many years ago.



Carl Molesworth who wrote about a dozen or so books on the P-40, including most of the Osprey books, and some on other aircraft including P-51. But this same number was also found in several other sources.






Publications — Carl Molesworth







www.carlmolesworth.com





I'd like to understand better what you are getting at here. It's quite _possible_ that 973 is off slightly, I believe it is correct however sometimes incorrect statistics get repeated by many fairly reputable sources. But I really doubt it's off a lot, and seeing as the next highest victory claim total is about 1/3 of that, overturning the overall conclusion that P-40s got by far the most VC in the CBI does not seem to be likely to me. Do you have a substantially different figure?



drgondog said:


> For US and Commonwealth VCs you should rely on Olynyk and Shores.



I do have several of Shores books, though he isn't immune to mistakes (his books don't all agree with each other for one thing). But he's a good researcher and I've learned a lot from his work.



drgondog said:


> It was operational for seven months at Group level strength - that fluctuated. In a target rich environment against late 1930s vintage aircraft mix of fighters and bombers.


Yes and the 23rd FG, though operational far longer, didn't have that many aircraft either. We know AVG did face Ki 43s and the 23rd FG certainly did. Basically the same aircraft that P-51A (etc.) had a lot of trouble with. I think you can compare like with like in the CBI in terms of number of aircraft available in a given period, sorties flown against basically the same opponents, and what the outcomes were.



drgondog said:


> No. The Mustang I and Allison based variants all had fabric control surfaces, as did all the P-51B and D until the D-20/-25 when the metal elevator kits and incidence change kits were delivered to retrofit in early 1945.
> 
> The sole 'manuever' deficiency vs P-51B/D was the aileron rigging from +/1 10 degrees to +/- 10, 12, 15 degrees, That said, 'it' (XP-51, P-51, A-36 and P-51A out rolled the P-38, 39, 40 and P-47 at speeds above 300KT TAS. The P-40 our rolled the P-51A in slow, middle airspeed range. The P-51A outclimbed the P-40 and 47 - and climbed with the P-38F/G until 15K+. The P-51-NA (4x20mm) comparison for AAF operational suitability tests vs P-39Q, P-40N, P-38G and P-47D was deemed the 'best fighter below 15000 feet - and it was at least 10mph slower than P-51A across the entire envelope.


I'll take your word for that, as I acknowledged earlier, I don't know what the details of the precise issue was. But i believe there was an issue - and I have spoken to several pilots from the CBI including two who flew both P-40 and P-51 in the CBI and they told me as much. Admittedly one of them only had a single flight in a P-51 and was badly injured during that flight so he was probably biased.


drgondog said:


> Pacific Fighters John Musula II is one of the Rare warbird pilots who has flown all the primary Allison/Merlin Mustang variants including the P-51A/B/C/D and he will tell you that the P-51A is more agile than B/D- which it Should be in every domain except roll - because of excess HP to drag and lower W/L
> 
> You can argue 'did not SCORE as well' but not 'did not Perform as well as fighters as they could have' - had they been in-theatre in quantity with their P-39D/N, P-38F/G, P-47C/early D counterparts for 1942 and 1943. Scoring was a function of quantity deployed in combat at the same time period.
> 
> I don't know if you are familiar with Mike Williams' spitfireperformance.com website. If not, you should take a deep dive into test pilot reports for the various marks as well as comparisons. If so, you should spend more time studying them.



I see different units with different aircraft types flying on the same missions (for example with 23rd FG) and getting markedly different results. I don't know why this is such an unpopular observation but it's not arising from my imagination, or any malice or prejudice on my part. Frankly i was surprised.

Not that anyone cares, but I actually _like_ the Allison Mustang, it just seems like there was some kind of issue with it. It could have been just a training issue but there is some evidence against that. It could have also been a maintenance, leadership or tactics issue. But there seems to have been an issue.

And I know which one the test pilots liked the best, but I'm talking about operational history here. Not tests.


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## Wild_Bill_Kelso (Mar 21, 2022)

GregP said:


> You can find many different reports. Usually, when someone was attacked, the attackers had the upper hand by virtue of diving from above or from the sun, or whatever. Find the reports when the P-51A did the attacking and you will find the encounters where the P-5A had the advantage. It DID reach its potential, but the 2-stage Merlin-powered version was produced in WAY higher numbers, flew higher and faster, and got the bulk of the missions where victories over attacking enemy fighters were likely to happen.
> 
> Kelso, you are completely free to feel the P-51 wasn't a good fighter and nobody will obviously be able to change your mind. Perhaps we should not try since everyone has an opinion backed by whatever facts they have dug out over the years. You won't likely change anyone else's opinion, either. It's all good. The war is long over, and discussion of the merits of the various aircraft makes these things interesting.
> 
> ...



I appreciate the sentiment, and agree for the most part, but I never said this:

"_you are completely free to feel the P-51 wasn't a good fighter_"

Why do people keep putting words in my mouth here? Haven't I literally said the opposite of that several times?


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## GregP (Mar 21, 2022)

Hi Bill.

Since last emailing you, I have a new email: will PM.

Would love to acquire your work when completed or help review anything you like. As you know, I'd also love to help with databases, should that happen to be of any assistance. If not, I'll take ... err ... buy a copy when it is finished.

Manually inputting Frank's database is something that will have to wait until I am no longer restoring aircraft. Currently working on various components in a G-73 Grumman Mallard and am starting to help restore a pair of teardrop Erco turrets from a PB4Y Privateer with partner Phil Laidure. Same Erco as made the Ercoupe. The aim is to make them able to function except, of course, non-firing guns, and to perhaps get them back in the PB4Y at Yanks Air Museum. They're just about finished with a Bell P-63A and it is nearing first flight. Frank Wright's team (Randy Purdey and Casey Wright, mainly) have done an amazing job. It looks quite factory-fresh. These guys are good.

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## GregP (Mar 21, 2022)

Wild_Bill_Kelso said:


> I appreciate the sentiment, and agree for the most part, but I never said this:
> 
> "_you are completely free to feel the P-51 wasn't a good fighter_"
> 
> Why do people keep putting words in my mouth here? Haven't I literally said the opposite of that several times?



Funny, I have that definite impression. You didn't say it quite in those words, but you strongly convey it. Recall your chosen screen name said, in Animal House, "Did we give in when the Germans bomber Pearl Harbor? I don't THINK so!" or words to that effect. So, maybe John Belushi has something to do with it?

That being said, we all maybe tend to read a bit between the lines. Everyone except ME, that is ...

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## Milosh (Mar 21, 2022)

GregP, are you looking for trouble by posting your e-mail addy?

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## Wild_Bill_Kelso (Mar 21, 2022)

Ok fair enough. My point was that the *Allison-engined* Mustang seems to have had some issues which restricted it's effective role somewhat, and I suspect these were design issues that weren't fully tweaked, though I acknowledge that may have been really to do with some other factors than the physical characteristics of the aircraft (like training, tactics or maintenance). I think the Mustang in general was (obviously) one of the best aircraft of the war.

This was all part of a point that getting to the 'sweet spot' with a fighter design was quite difficult. I think it took a while to get there with the Mustang, though unlike many other promising designs, the Mustang was in production early enough to have a significant effect on the war.

This is basically the same point I was making, or trying to make about the F8F, vis a vis a longer ranged Spitfire. The devil is in the details and it was certainly hard to make a fast, agile (and combat ready) fighter with long range. Especially one which could excel at higher altitudes. Maybe impossible in the 1930s to 1940 or 41. I think that was becoming more possible as the engines got more powerful, though still clearly very difficult.


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## Wild_Bill_Kelso (Mar 21, 2022)

Milosh said:


> GregP, are you looking for trouble by posting your e-mail addy?



Yeah i was going to mention that too. Better to send that via PM and edit your post above to remove it.

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## GregP (Mar 21, 2022)

Milosh said:


> GregP, are you looking for trouble by posting your e-mail addy?



No, but I suppose you have a point. Thanks, Milosh and Kelso. Duhhh ...


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## GregP (Mar 21, 2022)

It certainly is a different world when an email can make trouble for you. But, the reason I have a new email is the old one got hacked.

Open keyboard, insert foot.

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## Wild_Bill_Kelso (Mar 21, 2022)

The interwebs are an amazing resource, but also amazingly treacherous...


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## GregP (Mar 21, 2022)

Sounds exactly like Washington D.C.

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## pbehn (Mar 21, 2022)

Zipper730 said:


> That's an interesting observation, but it's an apples to orange one: A Spitfire VII/VIII/IX as described here*(see footnote 1) with the aft tanks filled is tantamount to a P-51B with it's center/aft tank filled as well
> 
> 
> 
> ...


Unfortunately for the Spitfire, the Mustangs aerodynamic advantages were not just in speed. On the same engine the Mustang was approx. 30MPH faster than the Spitfire but the same was true on cruise settings, not just maximum power, so the Mustang went 30miles further per hour as a ball park figure, with the same fuel load, six hours cruising took the Mustang 180 miles further or 90 miles range.

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## Wild_Bill_Kelso (Mar 21, 2022)

They made a lot of changes to the design of the Spitfire over the years. Spit I and Spit XIV or XXII look pretty different. Could they have done something to the wing or fuselage etc. to substantially reduce the drag? Without making a totally new aircraft I mean?


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## pbehn (Mar 21, 2022)

Wild_Bill_Kelso said:


> They made a lot of changes to the design of the Spitfire over the years. Spit I and Spit XIV or XXII look pretty different. Could they have done something to the wing or fuselage etc. to substantially reduce the drag? Without making a totally new aircraft I mean?


They could and many things were proposed but why would they. The first Griffon (single stage) Spitfires appeared in 1942, the Mk XIV was in squadron service from December 1943. The strategic bomber offensive was one niche in the allies needs. Defence of the UK was another. Attacks across the North Sea from Norway stopped after a few missions but they could start again. Attacks at high altitude and recon missions stopped when one Ju 86 was damaged over UK, but there was no guarantee that the Germans wouldnt come back with something better. Night time attacks didnt stop at the Blitz in 1940-41, the British had to have a night defence force to cope with the "baby blitz" of 1944 where Goring threw away much of his last remaining bomber force and intruder attacks like operation Gisela March 1945. There was always a need for a top class, balls out interceptor. Spitfire pilots may have been envious of Mustangs being able to fly to Berlin, Mustang pilots were happy that they werent facing 1000 Spitfire Mk IX and Mk XIVs when they got there.

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## Wild_Bill_Kelso (Mar 21, 2022)

Well adding fuel might affect performance, or it might not. FW 190 was heavier than a Spit V but it pretty much pwned them. I am not sure improved aerodynamics / reduced drag would negatively affect Spitfire performance any. An extra 30 miles per hour of range + 10 -20 mph of speed seems like it would be an overall improvement. I suppose it could affect lift and therefore turning radius, but i gather wing loading increased a bit with later mark Spitfires regardless. Why would less drag make for a worse interceptor? Do you think it would affect climb rate?


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## GregP (Mar 21, 2022)

They DID produce the Spiteful (land-based) and the Seafang (carrier-based). These were basically late Spitfire fuselages mated to a new, laminar-flow wing. They were somewhat of a wonder for pistons, but jets were flitting by at 100+ mph faster speeds, so they weren't put into production. Had the jets not showed up, they likely would have been among the best of the pistons.

You could say the Spiteful/Seafang/Tempest/Sea Fury, P-51H, Ta 152 and the like were the last superprops. The jets couldn't maneuver with them or usually outclimb them, for the most part, but they were generally 100+ mph faster. So ... out with the pistons and in with the jets. It didn't hurt that the jet engines required many fewer hours of maintenance, either.

The early jets were basically jet-powered versions of the last superprops.

The Attacker was a single-jet version of the Spiteful/Seafang, It evolved into the Scimitar. The Sea Hawk was basically a single-jet version of the Fury/Sea Fury with bifurcated exhaust, which became the P.1052 and P.1081 and, finally, the Hunter.

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## pbehn (Mar 21, 2022)

Wild_Bill_Kelso said:


> Well adding fuel might affect performance, or it might not. FW 190 was heavier than a Spit V but it pretty much pwned them. I am not sure improved aerodynamics / reduced drag would negatively affect Spitfire performance any. An extra 30 miles per hour of range + 10 -20 mph of speed seems like it would be an overall improvement. I suppose it could affect lift and therefore turning radius, but i gather wing loading increased a bit with later mark Spitfires regardless. Why would less drag make for a worse interceptor? Do you think it would affect climb rate?


Not only was the Fw 190 a later design, it had a bigger more powerful engine. The drag of the Spitfire increased with age because the cooling drag increased, from start to finish it doubled in weight. Why does the Spitfire have to match the Mustang when the British were using both? They also had the Typhoon and Tempest which filled other needs. The Mustang as a plane was superior in 3 major areas, cooling drag, aerodynamic drag from wing profile and fit and finish drag. Changing the cooling drag needs a new design, changing the wings is also a new plane, the "fit and finish" of the Spitfire was improved but much of the difference was in the design and method of manufacture which not only needs a new plane but a new factory and production process. Look at the radiators on the XIV, they are huge, and not very efficient in the Meredith effect.

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## pbehn (Mar 21, 2022)

GregP said:


> They DID produce the Spiteful (land-based) and the Seafang (carrier-based). These were basically late Spitfire fuselages mated to a new, laminar-flow wing. They were somewhat of a wonder for pistons, but jets were flitting by at 100+ mph faster speeds, so they weren't put into production. Had the jets not showed up, they likely would have been among the best of the pistons.
> 
> You could say the Spiteful/Seafang/Tempest/Sea Fury, P-51H, Ta 152 and the like were the last superprops. The jets couldn't maneuver with them or usually outclimb them, for the most part, but they were generally 100+ mph faster. So ... out with the pistons and in with the jets. It didn't hurt that the jet engines required many fewer hours of maintenance, either.
> 
> ...


When the Gloster E28.39 "Whittle" matched a Spitfire in level speed almost from its first flight in 1941 and later went up to 42,000ft the writing on the wall for piston engines was huge.

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## tomo pauk (Mar 21, 2022)

Wild_Bill_Kelso said:


> They made a lot of changes to the design of the Spitfire over the years. Spit I and Spit XIV or XXII look pretty different. Could they have done something to the wing or fuselage etc. to substantially reduce the drag? Without making a totally new aircraft I mean?



Some things were improved, other left to be desired. A non-exhaustive list of improvements: internal bullet-prrof glass ( on Mk.VII, VIII, IX etc vs. the external, as used on Mk.II, V and VI), less draggy exhausts, less draggy rearwiev mirror, retractable U/C (Mk.VII, VIII, XIV, later marks), fully covered wheel wells (Mk.22 IIRC).
Cooling system was draggy, however, and was getting draggier with more powerful engines, especially with 2-stage Griffons. One possibility IMO was the relocation of cooling system in the leading edges (like the Mosquito had, as well as Tempest I, Fury and Hornet), but that was never done.



Wild_Bill_Kelso said:


> Well adding fuel might affect performance, or it might not. FW 190 was heavier than a Spit V but it pretty much pwned them. I am not sure improved aerodynamics / reduced drag would negatively affect Spitfire performance any. An extra 30 miles per hour of range + 10 -20 mph of speed seems like it would be an overall improvement. I suppose it could affect lift and therefore turning radius, but i gather wing loading increased a bit with later mark Spitfires regardless. Why would less drag make for a worse interceptor? Do you think it would affect climb rate?



"Drag is cruel", per Bill Marshall. Weight is a factor, but drag is a problem when striving to the high speeds.
Less drag = better interceptor, if the weight remains the same.

Fw 190 came right in the time when Spitfire was very ... imperfect. Combination of bad workmanship, draggy items and features, and bad carburetors meant that most of the Spitfire Vs (with 'normal' engines, non-tropicalized) were barely making 370 mph. A Spitfire V with good fit & finish, some nip and tuck was doing 388 mph per RAE - very close to the early Fw 190s.

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## ColFord (Mar 21, 2022)

Wild_Bill_Kelso said:


> I was looking for my book on the 23rd Fighter Group, which I failed to locate, but i did find the 2012 Osprey "Air Vanguard' book "Allison Engined P-51 Mustang" by Martyn Chorlton. There are a few interesting tidbits of operational history in there, which I'll repeat here in no particular order
> 
> *During the Dieppe raid RAF Mustangs (I believe it says RCAF 400 Sqn) claimed a Fw 190 destroyed. They also comprised 11 of the 119 RAF aircraft lost that day, from 26, 239, 400 and 414 sqds. I didn't see any other claims.
> *On Oct 22 1942 RAF Mustang Mk1 and 1As escorted Wellington bombers on a raid into Germany - against Dortmund and Essen. The raid was considered a partial success though the targets were obscured by clouds. All the aircraft returned to base. [It's unclear to me why they didn't do more of these escorted raids.]
> ...



And therein lies the problem.

The information in the source you quote, at least for the RAF component of the story, is somewhat flawed.

Dieppe 19 August 1942 - 10 Mustang Mk.I aircraft lost to all causes, including enemy fighters, enemy flak and 'friendly fire'. No.414 (RCAF) Squadron, at time claim of one FW-190 destroyed, post war analysis of Luftwaffe records would support a 'damaged'; No.239 Sqdn RAF one claim 'half-share' of a FW-190 matches to post war analysis of Luftwaffe records for a confirmed loss. Squadrons involved, No.26 and No.239 RAF had both been flying operational sorties using the Mustang Mk.I and so had some experience on the type. For both No.400 (RCAF) Squadron and No.414 (RCAF) Squadron, the Dieppe operation was the first time that their pilots had flown the Mustang Mk.I in operations - in most instances the Dieppe operation was the first time their pilots had flown operationally - so a bunch of very 'green' pilots. A review of the Mustang losses incurred during the Dieppe operation indicates that the cause of losses was potentially 1/3 to enemy fighters, 1/3 to enemy flak, 1/3 to 'friendly fire' - both naval AA and other RAF fighters attacking the Mustangs thinking they were Me-109s. A key thing to note about the Dieppe operation and the RAF/RCAF Mustang squadrons involved was the operational directives the pilots had been given before the operation was to try and avoid combat with enemy fighters and to only engage in combat in self defence. The directives, which were subject to critical review after Dieppe, also placed the Mustangs at a disadvantage in terms of the altitudes they were directed to fly, the airspeed over the operational area and their entry and exit areas from the coast which placed them near known concentratons of enemy flak and where they were likely to get tangled up in combat between the two fighter forces - they didn't really understand the concept of operational deconfliction at the time.

22 October 1942 sortie as written up there never happened. Also, as the Mustang Mk.IA didn't get introduced to RAF Squadron service until beginning of June 1943..........

Actually what happened was:

On 21 October 1942, four Mustang Mk.I aircraft of No.268 Squadron RAF, led by Wing Commander AF Anderson DSO DFC became the first single engine fighters based in the UK to penetrate the German border. They flew over Holland to the area of the Dortmund-Ems Canal in western Germany and shot up a number of objectives along the way, including a steam locomotive, canal barges, lock gates, hutten enemy camp, gasometer, factory and a number of small ships or tugs. They were supported by another group of four Mustang Mk.I from the same Squadron who conducted an offensive sweep through parts of Holland, also shooting up a number of target of opportunity. None of the aircraft involved lost or damaged. Over the next few months the Mustang Mk.I aircraft of No.268 Squadron made a number of further similar operations through Holland and into west Germany to shoot up targets of opportunity.

Then, on the night of 21-22 October 1942, in a very separate series of operations by Wellington bombers of the RAF also attacked targets in the region of the Dortmund-Ems Canal in western Germany - some 8 hours after the Mustangs were back home and the pilots happily tucked in bed after some post operation celebrations in the Mess.

How do the two get combined into one? Best I can find is the series of Air Ministry Offical Communiques issued on 22-23 October 1942. The communique lists the operations separately. The communique then gets edited to reduce the word count for onwards transmission to overseas news agencies by their representative in the UK, and in this case one of the US news agencies contracts the wording in the communique so that the separation between the operations is a bit vague. When that communique arrives in the USA, it is then further edited and sent out to all the affiliated newspapers of that agency - at this point the two separate operations have become one and a bit of journalistic licence has been applied in describing the operations. Years later, in trying to find information on early RAF Mustang operations, a US author finds a copy of the article in a period newspaper in a local library/archive, and quotes it in his book. It then gets requoted repeatedly in other books on the Mustang, with none of the authors in between thinking to check the original source. 

Re long range bomber escort, the Mustang Mk.I aircraft of the RAF ACC Squadron had been conducting escort operations for the light-medium bombers of No.2 Group RAF since September 1942 and continued to do so until around February 1943. The post action reports from the 2 Group bomber units were generally complimentary about the escort they received from the Mustang Squadrons as they usually actually made the rendezvous with the bombers on time and at the correct place, they stayed with the bombers at the same low level approach and attack altitudes and similar airspeeds, rejoined with the bombers after the bomb run and then stayed with them on the flight back. The same reports contained criticism of the escort being given in a number of instances by the fighter squadrons of FC flying Spitfires, Hurricanes or Typhoons who had either not made the RV, arrived late to the RV, or left the escort role early due to fuel concerns. Criticism from the bomber units also included failure of the FC Squadrons to arrive at the post bombing RV leaving the target area and leaving the bombers early on the return flight due to fuel shortages. The criticism of course did not go down well with HQ FC and as a result, the ACC Mustang Squadrons were no longer invited to partake of that role - separation between Command structures where ACC operations were flown under operational control of FC, convoluted RAF wartime politics and command structures.

MacLachlan and Page flew to Luftwaffe airfields to the south-west and south of Paris - 44kms to south-west and 26kms to south respectively. The description given by Chorlton is similar to the wartime press release about the operation.

21 RAF/RCAF/PAF Squadrons equipped with the Mustang Mk.I, Mk.IA and Mk.II in the ETO, plus the small numbers of Mustangs placed with various Flights and Units for trials, training and support in non-operational roles. Of the 21 RAF/RCAF/PAF Squadrons with the Mustang Mk.I, Mk.IA or Mk.II, four did not fly their Mustangs on operations whilst equipped with them in the UK - some were only equipped with the Allison engine Mustang for a short period before either being re-equipped with another type, or transferred overseas. Three RAF Squadrons and one RAF Flight operated P-51 and A-36 aircraft borrowed from the USAAF in the MTO in limited numbers for a limited time to conduct operational flying in the MTO - usually because the RAF did not have suitable aircraft available to meet the operational needs of those Squadrons in the MTO at the time. 

6 June 1944, D-Day, sorties flown between 04.55hrs and 21:15hrs. Three Mustangs lost that day - one to enemy fighters, one to 'friendly fire' from Naval flak (very likely USN vessels) and one that was returning to base with engine problems and went 'missing' in the Channel - potential here is engine quit and pilot ditched and was not seen, also possibility that he was also shot down in error by naval gunners as due to his engine problems he may have approached an Allied ship with intention of ditching near it and he was shot down in error. More than 86 Tac/R and Naval Gunfire Direction 'sorties' conducted by Mustang Mk.I, Mk.IA and Mk.II on D-Day - I suspect Chorlton has taken "tasking" an operational task that can be conducted by a number of aircraft and loosely translated that to 'sortie'. In official RAF terms a 'sortie' is conducted by an individual aircraft/pilot. There were around 86 'taskings' for Allison engine Mustang Squadrons on D-Day, with the 'tasking' requiring groupings of aircraft anywhere between the usual pair, to two pairs of Mustangs. The wartime analysis of D-Day operations conducted by HQ 2TAF gives a figure for individual Mustang sorties for D-Day closer to 200 individual aircraft flights on the day. The loss figures in their analysis, of three Mustangs for the day to all causes, was well below their predicted loss rate for the type given the operating environment and level of opposition associated with the landing. The loss rate for the Tac/R Mustangs went up dramatically - but still well below pre invasion HQ 2TAF predictions - after D-Day in the period up until the beginning of September 1944. This was primarily losses to enemy flak and an increase in losses to enemy fighters. In mid to late June 1944 a directive was issued to all Luftwaffe fighter units in France to particularly target low flying Tac/R aircraft and enemy flak units also specifically targetted the low flying Tac/R aircraft. In turn this lead to Montgomery (seeing the loss numbers increase with consequent loss of intelligence information) issuing a directive to HQ 2TAF requesting that the low level Tac/R units be requested not to engage in strafing of targets of opportunity, that they be reminded that he was depending on the reconnaissance coverage they were obtaining to help him in his decision making of the Army ground campaign, and also requested 2TAF where possible to provide either close or loose escort for the low level Tac/R aircraft to prevent Luftwaffe intereference with their work. That is why in the period from late June to late August 1944, on occasions, pairs of low level Tac/R Mustangs - sometimes with an escort of other RAF fighters - were intercepted by formations of Luftwaffe fighters of anywhere up to 20 enemy aircraft. 

Not the least of the errors in fact in Mr Chorlton's book.

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## Shortround6 (Mar 21, 2022)

Sometimes they were trying to build the most "good" fighters in a given period of time rather than a fewer number of "best" fighters. 

The huge radiators under the wings of the MK XIV helped balance the Griffon engine up front. 
Move hundreds of pounds of radiators and coolant even a few feet from behind the CG to infront of it and you may need to do more flight testing. You need to change more wing panels. You need to move stuff, if not the wing itself to get the CG back to where you want it. You also want to make sure you don't put too many propellers into the ground when landing/taxing.

Given enough time and change enough parts and a much more streamline Spitfire could have been made.
Now do you want the super Spitfire one year from now or do you want the MK XIV six months from now?

The Hurricane II was an attempt to keep the Hurricane competitive with the 109E. It might have worked, except the Germans came out with the 109F. There is an example of gaining around 30 mph by cleaning up the airframe while using the same engine. But you had to change a lot of stuff to do it.
The Spitfire had become the only game in town after the Hurricane reached the end of the line and the Typhoon threw up in the bushes on both sides of the road on the way home from the pub. It took just over 3 years for Hawker to go from starting work on the Tempest to getting 2-3 squadrons into operation with it. But hey, it was "just" a Typhoon with a new wing right?

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## pbehn (Mar 21, 2022)

Shortround6 said:


> *Given enough time and change enough parts and a much more streamline Spitfire could have been made.
> Now do you want the super Spitfire one year from now or do you want the MK XIV six months from now?*


As I understand it the fuselage sections were made in advance of production, so to produce a super duper Spitfire "now" means scrapping those fuselages, so you get better Spitfires but not many of them. Same story for the Typhoon, a better Typhoon could have been made but it would have meant less of them.


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## ColFord (Mar 21, 2022)

Wild_Bill_Kelso said:


> If I post pictures of all the guys who died flying Fairy Battles, Boulton Paul Defiants, or Brewster Buffalos does that mean those aircraft were great fighters all the sudden?


Big difference, I can name everyone of those pilots in my post, know what operations they flew during the War on Mustangs and other types, know what their fate was during the war or after, and in the case of over half of those pictured, was fortunate and priviledged enough to be considered by them as a friend and in a couple of instances to help them when they were documenting and producing their wartime memoirs. Nothing like being able to get the story first hand, in their own words, access to their original pilot's log books, photographs and diaries, and in some instances provide a little illumination between what they were told during the War and what actually happened, for example reasons for particular operations, who shot them down, who rescued them after they ditched in the Channel, or the true fate of fellow Squadron pilots listed to this day as "Missing" in the official records. And those photographed were just a small selection of those I could have posted photographs of, who I similarly interacted with and knew or knew directly of. Unfortunately, off all those, to best of my knowledge and that I can ascertain, there remains alive today just one pilot who flew Allison engine Mustangs in the Tac/R role with the RAF and Commonwealth and Allied Air Forces during WW2 - and he is aged 99 years and looking forward to celebrating his centenary if he can.

You also missed the point of my post, these pilots referred to themselves as *Fighter*-Reconnaissance pilots, the RAF officially referred to them as Fighter-Reconnaissance pilots in official correspondence and reports, some of the RAF Squadrons included in their title in all their official documentation and had incorporated into their RAF Squadron Crests when they were approved and given Royal Assent the letters "FR" denoting Fighter-Reconnaissance, as distinct to those who were Reconnaissance, Photographic-Reconnaissance, Maritime-Reconnaissance or General-Reconnaissance. When the pilots did their training during the war, they were selected from their pilot training as being suitable for single engine types, usually being intended to be fighter pilots. At a particular point, based on a number of factors, often above average scores in navigation, above average sight and above average performance in specialised memory tests, they were subjected to, they were then streamed into the Fighter-Reconnaissance role and specialised training for that role. A smaller percentage of those on occasions were streamed off for the Photographic Reconnaissance role and specialised training for that role (plus the high altitude chamber tests for those destined for high altitude PR work).

The RAF adopted the definition of a Fighter-Reconnaissance aircraft was that it was primarily a Fighter, suitable for conducting Reconnaissance operations in a contested and hostile environment. In the RAF wartime studies into aircraft for the role, its first and primary consideration was its suitability as a fighter within the operational parameters required to conduct the low level Tactical and other reconnaissance requirements (speed and handling at lower altitudes - primarily below 15,000ft but optimised below 8,000ft - range on internal fuel only, armament) and then its ability to carry any specialised equipment such as reconnaissance cameras, radio equipment, required for the reconnaissance activity. Overlaid with that was consideration of supportability and serviceability of the aircraft from Advanced Landing Grounds or 'austere' airfields with minimal ground support for servicing and rearming, plus ability to operate from 'rough' airfields including take off and landing distances at loaded operational weights, cross wind and tail wind landing and take off limitations when operating from forward airfields with 'fixed' runway directions - one area where the Mustang was definitely preferred over the Spitfire in the assessments.

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## Wild_Bill_Kelso (Mar 21, 2022)

ColFord said:


> And therein lies the problem.
> 
> The information in the source you quote, at least for the RAF component of the story, is somewhat flawed.
> 
> ...



This is all real interesting, and I enjoy reading such operational details, but i don't see how any of that is relevant to the point. Does it show that Allison Engined Mustangs, of any mark, were able to dominate German fighters? That they were able to consistently fly combat escort or interception or any of the other fighter missions that the Merlin-engined variants routinely did?

All i see here is a much longer winded, though possibly a bit more accurate, rendition of the (admittedly hasty) summary I posted based on the Osprey book. What is your point ?


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## Wild_Bill_Kelso (Mar 21, 2022)

ColFord said:


> Big difference, I can name everyone of those pilots in my post, know what operations they flew during the War on Mustangs and other types, know what their fate was during the war or after, and in the case of over half of those pictured, was fortunate and priviledged enough to be considered by them as a friend and in a couple of instances to help them when they were documenting and producing their wartime memoirs. Nothing like being able to get the story first hand, in their own words, access to their original pilot's log books, photographs and diaries, and in some instances provide a little illumination between what they were told during the War and what actually happened, for example reasons for particular operations, who shot them down, who rescued them after they ditched in the Channel, or the true fate of fellow Squadron pilots listed to this day as "Missing" in the official records. And those photographed were just a small selection of those I could have posted photographs of, who I similarly interacted with and knew or knew directly of. Unfortunately, off all those, to best of my knowledge and that I can ascertain, there remains alive today just one pilot who flew Allison engine Mustangs in the Tac/R role with the RAF and Commonwealth and Allied Air Forces during WW2 - and he is aged 99 years and looking forward to celebrating his centenary if he can.
> 
> You also missed the point of my post, these pilots referred to themselves as *Fighter*-Reconnaissance pilots, the RAF officially referred to them as Fighter-Reconnaissance pilots in official correspondence and reports, some of the RAF Squadrons included in their title in all their official documentation and had incorporated into their RAF Squadron Crests when they were approved and given Royal Assent the letters "FR" denoting Fighter-Reconnaissance, as distinct to those who were Reconnaissance, Photographic-Reconnaissance, Maritime-Reconnaissance or General-Reconnaissance. When the pilots did their training during the war, they were selected from their pilot training as being suitable for single engine types, usually being intended to be fighter pilots. At a particular point, based on a number of factors, often above average scores in navigation, above average sight and above average performance in specialised memory tests, they were subjected to, they were then streamed into the Fighter-Reconnaissance role and specialised training for that role. A smaller percentage of those on occasions were streamed off for the Photographic Reconnaissance role and specialised training for that role (plus the high altitude chamber tests for those destined for high altitude PR work).
> 
> The RAF adopted the definition of a Fighter-Reconnaissance aircraft was that it was primarily a Fighter, suitable for conducting Reconnaissance operations in a contested and hostile environment. In the RAF wartime studies into aircraft for the role, its first and primary consideration was its suitability as a fighter within the operational parameters required to conduct the low level Tactical and other reconnaissance requirements (speed and handling at lower altitudes - primarily below 15,000ft but optimised below 8,000ft - range on internal fuel only, armament) and then its ability to carry any specialised equipment such as reconnaissance cameras, radio equipment, required for the reconnaissance activity. Overlaid with that was consideration of supportability and serviceability of the aircraft from Advanced Landing Grounds or 'austere' airfields with minimal ground support for servicing and rearming, plus ability to operate from 'rough' airfields including take off and landing distances at loaded operational weights, cross wind and tail wind landing and take off limitations when operating from forward airfields with 'fixed' runway directions - one area where the Mustang was definitely preferred over the Spitfire in the assessments.



Again, I actually think you missed my point. I've met and talked to WW2 fighter pilots as well. How does knowing these people, as cool as that is, change the type of missions they flew or the combat record the pilots of these particular aircraft had compared to just as brave and interesting and skilled pilots who flew other types of aircraft? Like Mustang IIIs etc.?


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## Wild_Bill_Kelso (Mar 22, 2022)

GregP said:


> They DID produce the Spiteful (land-based) and the Seafang (carrier-based). These were basically late Spitfire fuselages mated to a new, laminar-flow wing. They were somewhat of a wonder for pistons, but jets were flitting by at 100+ mph faster speeds, so they weren't put into production. Had the jets not showed up, they likely would have been among the best of the pistons.
> 
> You could say the Spiteful/Seafang/Tempest/Sea Fury, P-51H, Ta 152 and the like were the last superprops. The jets couldn't maneuver with them or usually outclimb them, for the most part, but they were generally 100+ mph faster. So ... out with the pistons and in with the jets. It didn't hurt that the jet engines required many fewer hours of maintenance, either.
> 
> ...



Good point. This is kind of what I was getting at, perhaps something like the Spiteful- except with more emphasis on range than pure performance. Or perhaps something more intermediate and less radical of a redesign, but I think something in that general direction. And preferably before the jets took over.

One can indeed ask, "why give a Spitfire the range of a Mustang?" Well I don't think that is needed - assuming you have the Mustang. But there is a time gap here, and a considerable gap when it comes to range, and to a lesser extent, speed. 

There is a lot of daylight between a 500 mile range fighter and a 2000 mile range fighter. Spitfires were indeed excellent interceptors but they were pressed into service where their range was a severe limitation - including in the role of interceptor (see Darwin). In North Africa Spitfires could have done a lot more with say 800-1000 mile range. Or even a bit less like the Mk VIII, but the Mk VIII came out rather slowly. Spitfires that could escort bombers

Seafires could have also greatly benefited from almost any improvement in range / loiter time.

The large number of Mk Vs which were produced were not all needed, many ended up sitting in England doing little. Probably some kind of hasty improved version, along the lines of what was done for the Spit IX but with the emphasis on range rather than speed and altitude performance, could have been really helpful, even if it did mean a bit fewer Mk Vs sitting on the grassy fields. If something like that had been available in 1942-43, I think it might have hastened the turning point of the war and saved a lot of lives.

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## Wild_Bill_Kelso (Mar 22, 2022)

Wild_Bill_Kelso said:


> This is all real interesting, and I enjoy reading such operational details, but i don't see how any of that is relevant to the point. Does it show that Allison Engined Mustangs, of any mark, were able to dominate German fighters? That they were able to consistently fly combat escort or interception or any of the other fighter missions that the Merlin-engined variants routinely did?
> 
> All i see here is a much longer winded, though possibly a bit more accurate, rendition of the (admittedly hasty) summary I posted based on the Osprey book. What is your point ?





ColFord said:


> Big difference, I can name everyone of those pilots in my post, know what operations they flew during the War on Mustangs and other types, know what their fate was during the war or after, and in the case of over half of those pictured, was fortunate and priviledged enough to be considered by them as a friend and in a couple of instances to help them when they were documenting and producing their wartime memoirs. Nothing like being able to get the story first hand, in their own words, access to their original pilot's log books, photographs and diaries, and in some instances provide a little illumination between what they were told during the War and what actually happened, for example reasons for particular operations, who shot them down, who rescued them after they ditched in the Channel, or the true fate of fellow Squadron pilots listed to this day as "Missing" in the official records. And those photographed were just a small selection of those I could have posted photographs of, who I similarly interacted with and knew or knew directly of. Unfortunately, off all those, to best of my knowledge and that I can ascertain, there remains alive today just one pilot who flew Allison engine Mustangs in the Tac/R role with the RAF and Commonwealth and Allied Air Forces during WW2 - and he is aged 99 years and looking forward to celebrating his centenary if he can.
> 
> You also missed the point of my post, these pilots referred to themselves as *Fighter*-Reconnaissance pilots, the RAF officially referred to them as Fighter-Reconnaissance pilots in official correspondence and reports, some of the RAF Squadrons included in their title in all their official documentation and had incorporated into their RAF Squadron Crests when they were approved and given Royal Assent the letters "FR" denoting Fighter-Reconnaissance, as distinct to those who were Reconnaissance, Photographic-Reconnaissance, Maritime-Reconnaissance or General-Reconnaissance. When the pilots did their training during the war, they were selected from their pilot training as being suitable for single engine types, usually being intended to be fighter pilots. At a particular point, based on a number of factors, often above average scores in navigation, above average sight and above average performance in specialised memory tests, they were subjected to, they were then streamed into the Fighter-Reconnaissance role and specialised training for that role. A smaller percentage of those on occasions were streamed off for the Photographic Reconnaissance role and specialised training for that role (plus the high altitude chamber tests for those destined for high altitude PR work).
> 
> The RAF adopted the definition of a Fighter-Reconnaissance aircraft was that it was primarily a Fighter, suitable for conducting Reconnaissance operations in a contested and hostile environment. In the RAF wartime studies into aircraft for the role, its first and primary consideration was its suitability as a fighter within the operational parameters required to conduct the low level Tactical and other reconnaissance requirements (speed and handling at lower altitudes - primarily below 15,000ft but optimised below 8,000ft - range on internal fuel only, armament) and then its ability to carry any specialised equipment such as reconnaissance cameras, radio equipment, required for the reconnaissance activity. Overlaid with that was consideration of supportability and serviceability of the aircraft from Advanced Landing Grounds or 'austere' airfields with minimal ground support for servicing and rearming, plus ability to operate from 'rough' airfields including take off and landing distances at loaded operational weights, cross wind and tail wind landing and take off limitations when operating from forward airfields with 'fixed' runway directions - one area where the Mustang was definitely preferred over the Spitfire in the assessments.



Another maybe better way to put it: I get that armed reconnaissance or '*Fighter* recon' was a successful role for the Mustang I and IA, and I certainly believe you that these pilots considered themselves fighter pilots, and were such. But I don't see how that tells us that this particular aircraft type was successful in the many other_ roles _that fighters were badly needed for in the various Theaters of war in WW2. I.e. interception, bomber escort, fighter-bomber escort, fighter sweeps, and so on.


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## pbehn (Mar 22, 2022)

Wild_Bill_Kelso said:


> Another maybe better way to put it: I get that armed reconnaissance or '*Fighter* recon' was a successful role for the Mustang I and IA, and I certainly believe you that these pilots considered themselves fighter pilots, and were such. But I don't see how that tells us that this particular aircraft type was successful in the many other_ roles _that fighters were badly needed for in the various Theaters of war in WW2. I.e. interception, bomber escort, fighter-bomber escort, fighter sweeps, and so on.


It is the other way around, there were many aircraft that could fill the other niches but non were as good as the Allison engined Mustang at tactical recon.

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## Shortround6 (Mar 22, 2022)

Wild_Bill_Kelso said:


> But I don't see how that tells us that this particular aircraft type was successful in the many other_ roles _that fighters were badly needed for in the various Theaters of war in WW2. I.e. interception, bomber escort, fighter-bomber escort, fighter sweeps, and so on.


 That may be true but a lot of the other fighters (especially in 1939-43) weren't really all that good at a varity of roles. P-40s didn't do well at intercepting anything flying at 20,000ft or above for example, let alone trying to escort B-17s or B-24s unless they were flying low and close to home. 
A Spitfire V was shorter in range than a P-40 but it took rougly 2/3s of the time to get to 20,000ft and when flying above 20,000ft it had around double the rate of climb. 

Now for all the "early long range Spitfire" fans see. 


http://www.spitfireperformance.com/ab320climb.jpg


for times with and without a 90 gallon tank. Granted the tank has drag but we can pretty quickly figure out that the Spitfire V could loose around 200 fpm of climb even with a 45 gallon extra fuel load. and since at 26,000ft the climb rate was only about 1400fpm to begin with losing 10% or more due to to even 45 imp gallons extra fuel might not have been popular. 

Now a MK IX Spit could climb (proving ground) at a bit under 2400fpm while carrying at 30 gallon tank at "Normal" (12lbs boost) rating. 

Now in late 1942 which Spifire do you want to try escort for American B-17s in the mid 20,000ft area of the sky? Even if only over Holland 
The Idea of an escort fighter is to actually provide an escort to the bombers, not provide alternative targets for the enemy to shoot down. 
Simply flying along with or over the bombers isn't enough, the escort fighters need to be able to fight the enemy intercepters with at least some degree of success even if not shooting them down a 1:1 ratio.

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## Zipper730 (Mar 23, 2022)

GregP said:


> There was a war on and taking a working Spitfire (or anything else) from the front line to fit a new fin and rudder or to recontour an elevator or stabilizer, etc. likely wasn't high on the priority list. Sure, they COULD have been modified, but they were flying and fighting at the time and changes were generally cut in at some point and not always retrofitted. Things like the dorsal fins fitted to P-51D and some B/C models as well as dorsal fins for P-47s WERE sometimes field-fitted, as were things like P-38 dive flaps.
> 
> Here's a good study of four P-51Ds. Only one, the 2nd one, has the dorsal fin extension


I've seen that picture before, but I thought that was more like a photo-shoot. That might sound stupid, admittedly.


> So, the dorsal fun mod was either field-installed or the change was cut in somewhere between 44-1310 and 44-13926 (the two serial numbers of the nearest two).


Okay, so the redesigned cockpit and aft-fuselage cutback coincided with the redesigned tailfin? As for the late Mk. IX tail design, when did that take place?

I'm also curious when the Mk.VII/VIII ended compared to the Mk. IX?



drgondog said:


> The P-51-NA (4x20mm) comparison for AAF operational suitability tests vs P-39Q, P-40N, P-38G and P-47D was deemed the 'best fighter below 15000 feet - and it was at least 10mph slower than P-51A across the entire envelope.


Honestly, it's kind of amazing that we didn't use the 4 x 20mm arrangement.



Wild_Bill_Kelso said:


> They made a lot of changes to the design of the Spitfire over the years. Spit I and Spit XIV or XXII look pretty different. Could they have done something to the wing or fuselage etc. to substantially reduce the drag? Without making a totally new aircraft I mean?


From what I remember the draggiest part of the Spitfire was the canopy frame early on because it wasn't highly inclined and had a piece of bulletproof glass on the outside of the frame (the aircraft wasn't designed with bulletproof glass initially, nor was the Me 109): While the last item may/may not have been changed to a cleaner design, I don't know if they ever changed the canopy angle.

I do remember they had a rear-view mirror attached outside the canopy which wasn't terribly conducive to aerodynamic cleanliness, but it probably saved quite a lot of pilots from getting shot down.

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## tomo pauk (Mar 23, 2022)

Shortround6 said:


> Now in late 1942 which Spifire do you want to try escort for American B-17s in the mid 20,000ft area of the sky? Even if only over Holland
> The Idea of an escort fighter is to actually provide an escort to the bombers, not provide alternative targets for the enemy to shoot down.
> Simply flying along with or over the bombers isn't enough, the escort fighters need to be able to fight the enemy intercepters with at least some degree of success even if not shooting them down a 1:1 ratio.



That's an easy question. I pick Spitfire IX to escort B-17s at any altitude they might be, range/radius of Spits permitting. We know that Mk.IX was at least equal to the Fw 190s performance-wise.

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## pbehn (Mar 23, 2022)

tomo pauk said:


> That's an easy question. I pick Spitfire IX to escort B-17s at any altitude they might be, range/radius of Spits permitting. We know that Mk.IX was at least equal to the Fw 190s performance-wise.


Which is what happened, starting at Dieppe.


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## EwenS (Mar 23, 2022)

Zipper730 said:


> I'm also curious when the Mk.VII/VIII ended compared to the Mk. IX?


The 140 high altitude Mk.VII were delivered between 9/42 and 5/44.

The 1,654 Mk.VIII were delivered between 11/42 and 12/44.

Mk.IX production continued until 6/45 and the last Mk.XVI was delivered at the beginning of Aug 1945.

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## drgondog (Mar 23, 2022)

Zipper730 said:


> From what I remember the draggiest part of the Spitfire was the canopy frame early on because it wasn't highly inclined and had a piece of bulletproof glass on the outside of the frame (the aircraft wasn't designed with bulletproof glass initially, nor was the Me 109): While the last item may/may not have been changed to a cleaner design, I don't know if they ever changed the canopy angle.
> 
> I do remember they had a rear-view mirror attached outside the canopy which wasn't terribly conducive to aerodynamic cleanliness, but it probably saved quite a lot of pilots from getting shot down.


No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant - but much less than the wing/fuselage in total parasite drag.

For ALL aircraft, the draggiest features are a.) the wing, b.) the fuselage/empennage

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## pbehn (Mar 23, 2022)

drgondog said:


> No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant - but much less than the wing/fuselage in total parasite drag.
> 
> For ALL aircraft, the draggiest features are a.) the wing, b.) the fuselage/empennage


A poster here (cant remember who) said that during his studies in college he found the first thing on the Spitfire to "shock" was the front of the canopy but as I understand it that doesnt mean it is most significant at lower speeds, and in any case it is quite important to see out of it..

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## drgondog (Mar 23, 2022)

David Lednicer - published a AIAA paper re: Drag Comparisons between P-51B/D, Spit IX and FW 190 - which highlighted the stagnation pressure point at the base of the P-51B and Spitfire IX - and later in a post commenting on the dive tests that resulted in writing off a Spit airframe, that he 'bet' that the first transonic shockwave occurred on the windshield.

I uploaded his paper(s) at least 10 years ago to the Technical Section here.

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## GregP (Mar 23, 2022)

Zipper730 said:


> I've seen that picture before, but I thought that was more like a photo-shoot. That might sound stupid, admittedly.
> Okay, so the redesigned cockpit and aft-fuselage cutback coincided with the redesigned tailfin? As for the late Mk. IX tail design, when did that take place?
> 
> I'm also curious when the Mk.VII/VIII ended compared to the Mk. IX?
> ...



Hi Zipper.

Not too sure about exact dates, but the first Mk. IXs were simply Mk. V airframes, some perhaps retrofitted and many of them new Mk.Vs either on or just coming off the production line, modified and fitted with the 2-stage Merlin 60-series engines, usually a Merlin 61 or 66. Later ... not exactly sure when ... new-production Mk. IXs had the enlarged fin and rudder and recontoured stab and elevators fitted on the assembly line. They are called "late Mk. IXs." The exact dates I don't have. I have seen several Mk. IXs here in Southern California and used to see one over on the Phoenix, Arizona area some 30 years ago.

Woody Woods (Cave Creek, Arizona) had what I believe was a Mk. XVI and it had the "late" tail. It used to be in British camo but his son, Chris, returned it to the correct light blue livery sometime in the past. Here it is in camo:







and here it is after being returned to light blue livery:






I'm pretty sure everyone has seen the early, rounded tail enough times to see the difference ... but ... here's a MK. IX with the early tail:

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## tomo pauk (Mar 23, 2022)

pbehn said:


> A poster here (cant remember who) said that during his studies in college he found the first thing on the Spitfire to "shock" was the front of the canopy but as I understand it that doesnt mean it is most significant at lower speeds, and in any case it is quite important to see out of it..





drgondog said:


> David Lednicer - published a AIAA paper re: Drag Comparisons between P-51B/D, Spit IX and FW 190 - which highlighted the stagnation pressure point at the base of the P-51B and Spitfire IX - and later in a post commenting on the dive tests that resulted in writing off a Spit airframe, that he 'bet' that the first transonic shockwave occurred on the windshield.
> 
> I uploaded his paper(s) at least 10 years ago to the Technical Section here.



This should be the doc: link


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## pbehn (Mar 23, 2022)

tomo pauk said:


> This should be the doc: link


Thanks Tomo, I read that (to the limit that I can follow it) when posted, but I did read in a post here someone who studied aerodynamics saying he was surprised that that the front of the canopy was the fist to "shock".


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## GregP (Mar 23, 2022)

Thanks, Tomo. Read it 10 years ago, but it's nice to see it again.


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## DarrenW (Mar 23, 2022)

33k in the air said:


> Gross combat weight (i.e. full amount of internal fuel and ammunition but no external load):
> 
> 13,582 lbs = P-47D (up to -25)
> 14,411 lbs = P-47D (-25 and up)
> ...


Dean's figures are correct depending on configuration so "combat weight" would vary. According to the US Navy an F6F-5 with dual bomb racks and rocket launchers weighed in at 12,640 lbs and this would be the normal configuration for the aircraft by 1945:



http://www.wwiiaircraftperformance.org/f6f/f6f-5-72731.pdf



Dean's weight for the F6F-3 is for one of the early production versions. According to Grumman by May 1944 the F6F-3 was weighing above 12,400 lbs:



http://www.wwiiaircraftperformance.org/f6f/f6f-3-detail-specification.pdf



The combat weight of the F4U-1D would vary in the same manner. The US Navy had gross weight with two capped pylons at 12,175 lbs, while Chance-Vought put the weight of a "clean" aircraft at 12,086 lbs:



http://www.wwiiaircraftperformance.org/f4u/f4u-1d-acp.pdf





http://www.wwiiaircraftperformance.org/f4u/f4u-1d-detail-specification.pdf



I'm quite sure that the P-47D varied in combat weight too, sometimes more, sometimes less, depending on configuration. For example, I've read that on occasion six guns were used instead of eight, which is just one example of how this could occur. I didn't want to get nit-picky about "combat weight" but only show how it wasn't always an exact figure as some would make it out to be so generalizations are often used for comparison purposes.

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## drgondog (Mar 23, 2022)

DarrenW said:


> Dean's figures are correct depending on configuration so "combat weight" would vary. According to the US Navy an F6F-5 with dual bomb racks and rocket launchers weighed in at 12,640 lbs and this would be the normal configuration for the aircraft by 1945:
> 
> 
> 
> ...


Dean did not seem to have all the Manufacturer Specifications to draw from. His data in my experience has always been close - but in the example of P-51s/A-36/NA-73 etc I drew from the NAA specification Reports to build my tables and identify loading from Empty to Basic to Full (Combat) load of fuel, ammo and guns to help clarify the discussion. When I cite Combat loads I mean max Internal fuel/ammo/oil/200 pound pilot/chute, wing racks.

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## DarrenW (Mar 23, 2022)

drgondog said:


> Dean did not seem to have all the Manufacturer Specifications to draw from. His data in my experience has always been close - but in the example of P-51s/A-36/NA-73 etc I drew from the NAA specification Reports to build my tables and identify loading from Empty to Basic to Full (Combat) load of fuel, ammo and guns to help clarify the discussion. When I cite Combat loads I mean max Internal fuel/ammo/oil/200 pound pilot/chute, wing racks.


I trust your knowledge of the P-51 family of aircraft above all others and would expect you to source manufacturer documents whenever possible. The point I was trying to make earlier was that even though it was a very heavy fighter the P-47D's performance slowly improved through steady increases in horsepower. This kept it reasonably fast and agile at lower altitudes throughout the war, even before the turbo-supercharger would kick in.

I believe the reputation regarding it's performance at low altitude stems from the earlier models without water injection and the paddle propeller. Pilot's transitioning from the Spitfire would obviously find it big and cumbersome when compared to an aircraft roughly half it's weight and known for outstanding agility. Another factor contributing to this belief was that the Thunderbolt's edge over enemy fighters tended to improve as altitude increased so a lot of people mistakenly take this to mean it was a pig low down, which couldn't be farther from the truth. Sure, the turbo-supercharger allowed for excellent horsepower well past 25,000 feet but they either forget or ignore the fact that this same power could also be harnessed at tree top level, giving it great ability down low too.

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## Zipper730 (Mar 23, 2022)

EwenS said:


> The 140 high altitude Mk.VII were delivered between 9/42 and 5/44.
> 
> The 1,654 Mk.VIII were delivered between 11/42 and 12/44.
> 
> Mk.IX production continued until 6/45 and the last Mk.XVI was delivered at the beginning of Aug 1945.


Why did the IX continue after the VII/VIII?



drgondog said:


> No. Compared to P-51D and FW 190 the 'draggiest' features of Spitfire were underwing coolant scoop/cooling drag with windshield & 20mm cannon which were significant...


Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.



GregP said:


> Not too sure about exact dates, but the first Mk. IXs were simply Mk. V airframes, some perhaps retrofitted and many of them new Mk.Vs either on or just coming off the production line, modified and fitted with the 2-stage Merlin 60-series engines, usually a Merlin 61 or 66. Later ... not exactly sure when ... new-production Mk. IXs had the enlarged fin and rudder and recontoured stab and elevators fitted on the assembly line. They are called "late Mk. IXs."


I'm curious what advantages the Mk.IX had over the Mk.VII/VIII off the bat? The Mk.VII/VIII had fuel-tanks in the wing from the outset (I'm not sure how many IX's had them)



Wild_Bill_Kelso said:


> Spitfires were indeed excellent interceptors but they were pressed into service where their range was a severe limitation - including in the role of interceptor (see Darwin).


What happened in Darwin?



ColFord said:


> Mustang Mk.I aircraft of the RAF ACC Squadron had been conducting escort operations for the light-medium bombers of No.2 Group RAF since September 1942 and continued to do so until around February 1943. The post action reports from the 2 Group bomber units were generally complimentary about the escort they received from the Mustang Squadrons as they usually actually made the rendezvous with the bombers on time and at the correct place, they stayed with the bombers at the same low level approach and attack altitudes and similar airspeeds, rejoined with the bombers after the bomb run and then stayed with them on the flight back. The same reports contained criticism of the escort being given in a number of instances by the fighter squadrons of FC flying Spitfires, Hurricanes or Typhoons who had either not made the RV, arrived late to the RV, or left the escort role early due to fuel concerns. Criticism from the bomber units also included failure of the FC Squadrons to arrive at the post bombing RV leaving the target area and leaving the bombers early on the return flight due to fuel shortages. The criticism of course did not go down well with HQ FC and as a result, the ACC Mustang Squadrons were no longer invited to partake of that role - separation between Command structures where ACC operations were flown under operational control of FC, convoluted RAF wartime politics and command structures.


While I know that ADC/TAC and part of SAC became ACC in the United States in 1992, I didn't know there was an ACC entity in either the USAAF/RAF during WWII. Regardless, I gotta say that the decision made was quite foolish, but not an uncommon rationale: "They're making us look bad, so we're edging them out the way so we can get all the glory".


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## wuzak (Mar 23, 2022)

Zipper730 said:


> Why did the IX continue after the VII/VIII?



Perhaps because the facilities making the VIII converted to the XIV/XVIII?




Zipper730 said:


> Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.


 
Windscreen armour was moved from the outside to the inside at some point during Mk V production. Before the IX was born.




Zipper730 said:


> I'm curious what advantages the Mk.IX had over the Mk.VII/VIII off the bat? The Mk.VII/VIII had fuel-tanks in the wing from the outset (I'm not sure how many IX's had them)


 
None, in terms of performance.

In production terms, there were fewer things to be changed.




Zipper730 said:


> What happened in Darwin?


 
There was this cyclone in 1974!

Or he could be referring to the Japanese attacks on Darwin which Spitfire Vs, with high altitude Merlin 46s, opposed.

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## pbehn (Mar 23, 2022)

Zipper730 said:


> Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.


Putting the BP glass outside cost a couple of MPH, I think because it changed the airflow around the canopy, but the front of the windscreen was draggy anyway because of its steep angle and shape.

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## Shortround6 (Mar 23, 2022)

pbehn said:


> Putting the BP glass outside cost a couple of MPH, I think because it changed the airflow around the canopy, but the front of the windscreen was draggy anyway because of its steep angle and shape.


It was usually figured to be about 6mph for the external BP glass.

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## Zipper730 (Mar 23, 2022)

wuzak said:


> Perhaps because the facilities making the VIII converted to the XIV/XVIII?


Okay, that makes sense. I assume the Mk.XIV/XVIII had the redesigned elevator eh?


> Windscreen armour was moved from the outside to the inside at some point during Mk V production.


Understood. I assume the canopy angle wasn't ever changed to give more incline?


> None, in terms of performance.
> 
> In production terms, there were fewer things to be changed.


How many of the Mk.IX's have the 13/13.5 gallon tanks in the wings? A flight-manual I found seemed to indicate none...


> Or he could be referring to the Japanese attacks on Darwin which Spitfire Vs, with high altitude Merlin 46s, opposed.


I'm pretty sure that's likely the case. As for the range, what happened with that?


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## GregP (Mar 23, 2022)

Zipper730 said:


> Why did the IX continue after the VII/VIII?
> 
> 
> Okay, I gotcha. It looks like the Mk.IX (and possibly the Mk.VII/VIII) had a different windscreen with the bulletproof pane inside the frame instead of outside.
> ...



Well, the Mk.VII had a pressurized cabin and a retractable tailwheel along with other minor changes and it was heavier, but could actually fight way up high because the pilots weren't hurting and almost hypoxic. The Mk. VIII was basically a Mk. VII without the cabin pressurization. Other than that, I am not really sure about the differences between a MkVIII and a Mk. IX. They had the same engines and propellers. The Mk. VIII retained the retractable tailwheel held over from the Mk. VII, but other differences between the VIII and IX remain a bit unclear to me. The VIII was likely some 5 - 8 mph faster due to the tailwheel not hanging down in the slipstream. On the other hand, if you had external glass AND the retractable tailwheel, maybe it was a wash, speed-wise.


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## 33k in the air (Mar 24, 2022)

drgondog said:


> For ALL aircraft, the draggiest features are a.) the wing, b.) the fuselage/empennage



Well, clearly, if they could have made a fighter without wings and a fuselage, it would have been an absolute speed demon with such minimal drag!

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## PAT303 (Mar 24, 2022)

Wild_Bill_Kelso said:


> I am not sure improved aerodynamics / reduced drag would negatively affect Spitfire performance any. An extra 30 miles per hour of range + 10 -20 mph of speed seems like it would be an overall


The MkIII from 1940 addressed the drag issue with a retractable tailwheel, enclosed undercarriage, internal bullet proof screen, aerodynamic fairing over the rear view mirror and 3' removed from the wings, the MkIII Seafire had the inner cannon stubs removed, the cannon bulges reduced in size and streamlined and individual fish tail ejectors fitted. What the Spitfire needed was the windscreen sloped back another 10 degree's and a boundary layer splitter fitted to the radiator intakes and she would have been fine.

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## Zipper730 (Mar 24, 2022)

GregP said:


> Well, the Mk.VII had a pressurized cabin and a retractable tailwheel along with other minor changes and it was heavier, but could actually fight way up high because the pilots weren't hurting and almost hypoxic. The Mk. VIII was basically a Mk. VII without the cabin pressurization. Other than that, I am not really sure about the differences between a MkVIII and a Mk. IX. They had the same engines and propellers. The Mk. VIII retained the retractable tailwheel held over from the Mk. VII, but other differences between the VIII and IX remain a bit unclear to me. The VIII was likely some 5 - 8 mph faster due to the tailwheel not hanging down in the slipstream. On the other hand, if you had external glass AND the retractable tailwheel, maybe it was a wash, speed-wise.


Far as I know the Mk.V's already had the internal bulletproof glass pane, so that wasn't an issue. The IX did have a non-retractible tailwheel, however. I'm amazed they never decided to fair that over.



33k in the air said:


> Well, clearly, if they could have made a fighter without wings and a fuselage, it would have been an absolute speed demon with such minimal drag!


Also known as a surface to air missile...



PAT303 said:


> The MkIII from 1940 addressed the drag issue with a retractable tailwheel, enclosed undercarriage, internal bullet proof screen, aerodynamic fairing over the rear view mirror and 3' removed from the wings, the MkIII Seafire had the inner cannon stubs removed, the cannon bulges reduced in size and streamlined and individual fish tail ejectors fitted. What the Spitfire needed was the windscreen sloped back another 10 degree's and a boundary layer splitter fitted to the radiator intakes and she would have been fine.


I am surprised they didn't put the retractible tailwheel into the Mk.V production. As for the boundary layer splitter, I'm not sure why that was never attempted.


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## EwenS (Mar 24, 2022)

Zipper730 said:


> Why did the IX continue after the VII/VIII?


One way of understanding this is to try to understand which company / factory produced which versions.

Supermarine, the parent company produced virtually every version of the Spitfire (except Mk.II)

Westland was brought in to the production scheme early and after 50 Mk.I it switched to Mk.V and then to Seafire production in 1942.

Cunliffe Owen was a major sub-contractor who was later brought in as a second source for Seafire production in 1943.

Then we have the Castle Bromwich Aircraft Factory, a shadow factory built in 1936-40








Castle Bromwich Assembly - Wikipedia







en.m.wikipedia.org





It was set up for mass production and built a progression of types. Starting with Mk.II from June 1940, it moved on to Mk.Vb/Vc and then the IX/XVI, all building on the versions that preceded it, or that were sometimes initially built in parallel. The plan was then for it to move to the intended next mass produced version, the Griffon engined F.21/22 from late 1944.

The Griffon engined Mk.XIV & XVIII were only ever intended to be produced short term pending the arrival of the fully sorted F.21 with the new aileron and wingtip shape designed to restore some of the Spitfire’s manoeuvrability. That took much longer to sort out than anticipated with the result that the first F.21 squadron didn’t receive its aircraft until March/April 1945. That was 91 squadron followed by 1 squadron in May. So pending full production of the F.21/22 CBAF continued producing Mk.IX/XVI to keep the workforce together.

You will find plenty of information on individual Spitfire contracts here





contract summary







www.airhistory.org.uk





And a searchable Spitfire database here


Spitfire pilots and aircraft database -



The Mk.IX was initially only intended as a stopgap to get the Merlin 60 engine into a Mk.V airframe as a matter or urgency in 1942. The intention was that the fully refined Merlin 60 version would be the Mk.VIII. As it turned out, the performance difference was negligible so CBAF kept producing it rather than have the disruption of making more changes to the production line by switching to the Mk.VIII.

You will find notes about the various Spitfire versions here.





List of Spitfire and seafire marks along with recognition points







dingeraviation.net

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## pbehn (Mar 24, 2022)

Shortround6 said:


> It was usually figured to be about 6mph for the external BP glass.


Thanks I couldnt remember the figure and my computer was playing up. There were lots of things at the time like fitting cannon rear view mirrors and changes to rivet type, I was surprised it had any effect at all, but that's why I don't design aircraft.

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## Zipper730 (Mar 24, 2022)

EwenS said:


> One way of understanding this is to try to understand which company / factory produced which versions.


That's a pretty interesting set of information. I didn't know Westland was responsible for the Spitfire Mk.V, though I'll note the Westland Whirlwind has a retractible gear.

It would appear that some Spitfire Mk.I/II were converted into Mk.V's at Supermarine. I'm curious if this precluded a retractible wheel from being included?


> The plan was then for it to move to the intended next mass produced version, the Griffon engined F.21/22 from late 1944.


And there were problems that had to be sorted out with the wing-design that took longer than expected. I'm curious what those were from a purely intellectual standpoint.

From what I heard the Mk.21/22 was to incorporate a modified version of the wing that had laminar-flow features, correct?


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## EwenS (Mar 25, 2022)

Zipper730 said:


> That's a pretty interesting set of information. I didn't know Westland was responsible for the Spitfire Mk.V, though I'll note the Westland Whirlwind has a retractible gear.
> 
> It would appear that some Spitfire Mk.I/II were converted into Mk.V's at Supermarine. I'm curious if this precluded a retractible wheel from being included?
> 
> ...


Westland built the Mk.V, as did Supermarine and CBAF, but I wouldn’t describe them as “responsible” for it. Supermarine were “responsible” for its development along with Rolls Royce for the new engine. 

The successor to the Mk.I/II was intended to be the Mk.III. That aircraft would have had a new engine, clipped wings and a retractable tail wheel. But events intervened. The Mk.V began as an attempt to match the performance of the Bf109F that began to appear over southern England in Nov 1940. The route was to put a new engine in the Mk.I/II airframe as it was needed in service urgently. From initial discussions on Christmas Eve 1940 to having a prototype Mk.V for trials took 7 weeks. By the end of Feb 1941 the first conversions were in service with 92 squadron. By the beginning of March all thoughts of the Mk.III were ditched and the serial numbers allocated to that Mark on order switched to the Mk.V. As time went on other changes, like the Universal wing, were introduced to the Mk.V.

Remember the aphorism that the enemy of good is perfect.

From late 1942 Supermarine was working on new wings for the Spitfire. As their experience with new wing profiles was limited they decided on a two step approach.
1. Produce a high speed wing by modifying the existing Spitfire wing by raising the leading edge by 2 inches and if tests on that proved successful,
2. Design a completely new laminar flow wing.

The former became the wing fitted to the Spitfire F.21 and subsequent Spitfires/Seafires. The latter became the wing first tested on a converted Mk XIV, NN660, from June 1944 that was eventually fitted to the Spiteful/Seafang and later the jet powered Attacker.








File:Supermarine Spiteful.png - Wikimedia Commons







commons.m.wikimedia.org





As for the F.21 wing there is some information here


Concise Guide To Spitfire Wing Types — Variants & Technology | Reference



The object of the F.21 wing was to increase the limiting speed of the Mk.XIV above 470mph by improving the aileron control. That meant bigger ailerons which changed the wing tip shape. When the first F.21 appeared in July 1944 there were problems with aileron tab gearing, aileron control being too light, directional stability required a rudder of increased chord. Spitfire The History has details of all the test flights and changes needed.

Ultimately, when the F.22, with the cut down rear fuselage, was built it was given a larger tailplane designed for the Spiteful that was 27-28% larger to cure some of the issues from the F.21.

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## tomo pauk (Mar 25, 2022)

EwenS said:


> The successor to the Mk.I/II was intended to be the Mk.III. That aircraft would have had a new engine, clipped wings and a retractable tail wheel. But events intervened. The Mk.V began as an attempt to match the performance of the Bf109F that began to appear over southern England in Nov 1940. The route was to put a new engine in the Mk.I/II airframe as it was needed in service urgently. From initial discussions on Christmas Eve 1940 to having a prototype Mk.V for trials took 7 weeks. By the end of Feb 1941 the first conversions were in service with 92 squadron. By the beginning of March all thoughts of the Mk.III were ditched and the serial numbers allocated to that Mark on order switched to the Mk.V. As time went on other changes, like the Universal wing, were introduced to the Mk.V.



The lack of Merlin XXs probably had a lot to do with non-introduction of the Spitfire III already for the BoB IMO. Hurricane acutely needed 'heart transplant' in order to cancel out the performance gap vs. Bf 109E,, and Merlin XX provided that. 
Merlin XX was also in need for Defiant and Beaufighter.


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## EwenS (Mar 25, 2022)

tomo pauk said:


> The lack of Merlin XXs probably had a lot to do with non-introduction of the Spitfire III already for the BoB IMO. Hurricane acutely needed 'heart transplant' in order to cancel out the performance gap vs. Bf 109E,, and Merlin XX provided that.
> Merlin XX was also in need for Defiant and Beaufighter.



As for the Dec 1940 meeting, the way it is put in “ Spitfire The History”

“The Merlin XX engine would have provided power for the Spitfire to fight off the 109F, but it was a fairly complex engine, more difficult to produce than previous Merlins. It had a low-altitude blower and this feature was hindering large scale production. Rolls Royce suggested that the pertinent blower be deleted in order to produce an engine with the necessary high-altitude performance. The final result was the emergence of the Merlin RM 5S or Mk45, which was to increase the Spitfire’s ceiling by 2,000 feet. Mr Hives, for Rolls Royce, said he could provide at least 300 of the modified Merlins by 1 March and a further 200 by 1 April. He also stated that this would not affect Merlin XX production. Sholto-Douglas, also present, said ....’We will have to reserve the entire production of this new engine for the Spitfire as this will be a priceless asset in the struggle for air superiority over the south-east corner of England’.”

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## tomo pauk (Mar 25, 2022)

EwenS said:


> As for the Dec 1940 meeting, the way it is put in “ Spitfire The History”
> 
> “The Merlin XX engine would have provided power for the Spitfire to fight off the 109F, but it was a fairly complex engine, more difficult to produce than previous Merlins. It had a low-altitude blower and this feature was hindering large scale production. Rolls Royce suggested that the pertinent blower be deleted in order to produce an engine with the necessary high-altitude performance.



Thank you for the excerpt.
We can word a thing or two better, though. There was just one blower on either the Mk.XX or MK.45 (or on the Mk.III for that matter). Blower _drive_ was different - a 2-speed gearbox ('MS' and 'FS - or, roughly, low-altitude and high-altitude gearing) for the Mk.XX, and one-speed gearbox ('FS' only - or, high altitude) for the Mk.45. One the Mk.45, the same step-up gearing was used as on the Mk.XII, namely 9.09:1.

Great demand for the Mk.XX coupled with it being a bit more complicated to make than the 1-speed engine of the same family indeed meant a lack of these in 1940. Mk.45 featured the much improved intake before the impeller as it was found on the Mk.XX, and shared the improved impeller with the Mk.X and Mk.XX, thus the performance above ~10000 ft was indeed about the same as on the Mk.XX.


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## Shortround6 (Mar 25, 2022)

Apparently there was some misunderstanding of what was going on with the Merlin or in an effort to keep things simple the writer confused anybody who knows about engines. 
The Merlin XX only had one blower. There was a two speed drive system to turn the impeller instead of the single speed drive system but there was only one "blower".
I am not saying the two speed drive system was easy to produce, however it was the same drive system that was being produced for the Merlin X engine. 
The shadow factories tended to specialize in engines using the single speed drive or the two speed drive. There may have been a difference in the block/crankcase casting. Crew could build both and the short production runs of special engines were made at Crew. 
Something is also a bit off with the description of the Merlin 45 offering a 2000ft increase in ceiling. Again a bit simplistic.
The Merlin XII already offered a bit higher ceiling than the Merlin III. 
The Merlin XX offerd the most ceiling of the engines available in 1940 and early 1941. 
The Merlin 45 was pretty much a Merlin XII fitted with a supercharger (blower) that copied the supercharger used on the Merlin XX. The Merlin 45 used the same single speed drive that the Merlin XII used.
The supercharger used a slightly lower gear ratio and turned the impeller a bit slower than the "high" gear of the Merlin XX and had a slightly lower ceiling. 
Mr. Hives was quite correct when he said the Merlin 45 would not affect Merlin XX production as they were going to stick a Merlin XX "blower" on a Merlin XII engine. In fact it may have been only the supercharger front cover and inlet on the existing supercharger. 

Tomo types faster than me.

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## wuzak (Mar 25, 2022)

IIRC, the Spitfire III's first flight was with a Merlin X, not XX.

For the Mk III there were changes to the radiator system and to the undercarriage, the tail wheel being retractable, and the main gear fully enclosed.

These changes would cause a significant delay to production during the switch over.

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## tomo pauk (Mar 25, 2022)

wuzak said:


> IIRC, the Spitfire III's first flight was with a Merlin X, not XX.



One can get a lot of new gray hair when reading the Spitfire III entry in the 'Spitfire - the history' book. 
We get a lot of how someone _felt_ about this or that, but deducing the date of 1st flight of the Mk.III, what engine it had for that opportunity, what is a projected performance vs. what was achieved, with or without guns, and with what engine - no, no. 
A god book, but, boy, does it request 110% of devotion to read.


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## Shortround6 (Mar 25, 2022)

There are some 3d illustrations of the tail wheel of the Spitfire and the structure around it on the internet.
It was not difficult to really make a retracting tail wheel as in knowing how to it.
But it was going to require a lot of different parts.
In fact you would probably want to manufacture the retracting tail wheel models on different assembly lines than the non retracts.

Edit;










I can't find a good picture of the retractable unit but when you fasten things through or attached to vertical fin frame work there is a lot more involved than sticking a hinge on the tail wheel post and fitting a couple of doors

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## Geoffrey Sinclair (Mar 25, 2022)

GregP said:


> I was using this:


So Spitfire Mark V used 4 bladed propellers, mark I used Merlin II engines, and the PR IV used Griffon engines, there was no such thing as the PR.III or PR.XI, the conversions are counted as new aircraft, and these figures are considered accurate.

The figures the list actually has right is marks II, IV (if PR.IV), VI, X, XII, XIV, XVI, XVIII (in list a XVII) and XIX, ignoring the conversions that is 9 out of 19. There is a dispute about 1,053 or 1,054 mark XVI. Spitfire prototypes K5054 mark I, N3297 mark III, DP845 mark IV and XII, DP851 mark IV, XX and F.21 and PP139 F.21. 3 mark I airframes, N3296, N3298, N3299 delivered to Castle Bromwich in January 1940 as pattern aircraft, they never flew and are not counted.

Heading for the Hurricane figures you will be delighted to note the ones for British output are reasonable, add the 33 IIA made by Gloster, reduce Hawker IIC to 4,711 and you are there.

As for Canada the Hurricane total was 1,451, made up of 486 mark I, 514 mark II, 1 Dutch version, 400 mark XII and 50 Sea Hurricane I, which became XIIA when fitted with Merlin 29, while 30 of the mark I were converted to mark II before export, no C wings. If the web page says the usual mark X = US Merlin, Packard began building Merlins in August 1941 by which time Canada had built 485 Hurricanes. The British report 419 mark I and 447 mark II arrived without engines, 234 mark II did arrive with Merlin 28, apart from some test flights the engines were used in Lancasters. The sometimes quoted 401 mark XII comes about from the 400 actually built plus the 1 found well post war without any identity plates. The Dutch Hurricane explains the 1 in 1,451, it was originally RAF AM270, a serial also used on a Catalina, so plenty of confusion.

Seafires, the list has the mark 45, 46 and 47 correct.

Spiteful, 16 built but 6 marked "for breakdown", Seafang, 9 produced but 5 marked "for breakdown".


GregP said:


> If you have a purported completely-accurate source for Spitfires and Hurricanes, maybe you can share it and also why you think it is exactly accurate.


Highly accurate figures based on a set of primary documents and I did share that list with my first post on Hurricanes.


GregP said:


> Because I guarantee I can find another source in print that disagrees with it.


As you did with the Hurricane figures, found two different totals on the web and called it research, not even trying to reconcile the two. One reason I did a long look at the Hurricanes is the apparent vow that no two sources will give exactly the same total production number.

To give a summary, a fuller list is in the original Hurricane post.

RAF Contract cards, tracking deliveries by order, a bit under 7,000 pages of data, on 1930's and 1940's RAF orders. Also included are summary and notes cards of the various orders. Note cards for some orders are missing.

RAF Serial Registers, an entry for most valid serials between K1000 and RZ400, over 9,000 pages.

Quite a number of files from British, US, Canadian and Australian Archives, and Air Force History Units, covering aircraft production from 1935 or earlier to 1949 or later. Published sources like the US War Production Board Canada Section. And so on, then cross checked, including with people who really want to have accurate production figures.

Find a source backed by the above level of documentation and we can talk. As noted this was all given in my first message here.

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## SaparotRob (Mar 25, 2022)

Spitfires are pretty.

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## Geoffrey Sinclair (Mar 25, 2022)

From AVIA 6/10393 R.A.E. Technical note Aero 1273 (Flight) September 1943. Note on speeds of production Spitfires (Marks I, V and IX) by P.A. Hufton M.Sc., and Wm. Stewart B.Sc., September 1943. Four Spitfires were used to test the effect on top speed of the quality of finish and variations in the external equipment of Spitfires, these results were then compared with test results of standard Spitfires. "it is of course impossible to consider our ideal Spitfire in condition (b) (ideal equipment, smooth finish, well fitting cowling) as being a combat aeroplane."

Ideal conditions and corrections for variations. Calculated speed change in mph at 360 mph by variation

EquipmentIdeal conditionVariationSpeed change mphExhaustsMulti EjectorsOriginal Mk I5.25​ExhaustsMulti EjectorsTriple ejectors with fishtails7.75​ExhaustsMulti Ejectorsfishtails and gun heating.9​Air intakeNo SnowguardSnowguard fitted8.5​Air intakeNo StoneguardStoneguard fitted7.5​WindscreenConicalInternal bullet proof4​WindscreenConicalExternal bullet proof7.75​Rear View MirrorNoneFaired Mirror3.5​Rear View MirrorNoneUnfaired Mirror6.75​Radio MastNoneStandard type1.5​Radio MastNoneWhip type0.75​ArmamentNo cannon projection2 Cannon6.25​ArmamentNo cannon projection2 Cannon, 2 cannon stubs8.5​Cannon wing bulgesNoneSmall bulges0.5​Cannon wing bulgesNoneLarge bulges1.5​Ejector ChutesFlush with surfaceProjecting from surface1.25​

Changes to mark V EN946, modified at R.A.E.

EquipmentFromTogain mphExhaustsTriple ejectors with fishtailsMulti Ejectors7.75​Air intakeExternal SnowguardRemoved8.5​Rear View MirrorRectangular unfairedCircular faired3.25​Radio MastStandard typeWhip type0.75​Ejector ChutesProjectingCut flush1.25​FinishStandardImproved8.5​
Total speed gain expected 30 mph, measured 30 mph, 358 to 388 mph.


Top Speeds mphAs testedIdealIdeal plus improved finishPrototype Mark I367​383​383​Production Mark I357.7​378.7​383​Early mark V371.5​405.3​407​Late mark V356.3​395.8​407​EN946 (Mark V)388​407​407​Prototype Mark IX414​438​445​Production Mark IX403.7​436.3​445​

Standard Spitfires performance reports used
Prototype K9793, Mark I N3171, X4257, K9787, Mark V K9788, N3053, X4922, W3134, AA878, AA937, AB873, EF644, EN946 (original and modified), Mark IX N3297, BF274, JL227, EN498

References
A. & A.E.E. report 692, various parts.
Improvement in performance of Spitfire EN946, R.A.E. Technical note Aero 1217 (Flight) June 1943
Comparison of three production Spitfires, R.A.E. Technical note Aero 1246 (Flight) July 1943

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## MikeMeech (Mar 25, 2022)

Shortround6 said:


> There are some 3d illustrations of the tail wheel of the Spitfire and the structure around it on the internet.
> It was not difficult to really make a retracting tail wheel as in knowing how to it.
> But it was going to require a lot of different parts.
> In fact you would probably want to manufacture the retracting tail wheel models on different assembly lines than the non retracts.
> ...


Hi

Many marks of Spitfire had retractable tail wheels, an official drawing of the Mk. VIII tail wheel below:





Mike

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## PAT303 (Mar 25, 2022)

EwenS said:


> Cunliffe Owen was a major sub-contractor who was later brought in as a second source for Seafire production in 1943.


From what I have read they were the prized models as they where built to the highest standard.

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## Shortround6 (Mar 25, 2022)

MikeMeech said:


> Many marks of Spitfire had retractable tail wheels, an official drawing of the Mk. VIII tail wheel below:




Thank you.

I know some of them had them.
Trying to figure out how it was to change over production.
Or perhaps better said why it was that one or more factories kept the older style landing gear.


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## pbehn (Mar 25, 2022)

Shortround6 said:


> Thank you.
> 
> I know some of them had them.
> Trying to figure out how it was to change over production.
> Or perhaps better said why it was that one or more factories kept the older style landing gear.


I maybe wrong but I think it started with a fuselage which were all the same to start with. When the Mk III was started in development that gave rise to the later Mk VII and VIII but basically a fuselage was a fuselage, what it was kitted out with changed, if it absolutely needed a different tail it got one like with the MK XIV but if a new tail was better but the old tail would do, then the fuselages with old tails were completed and the new ones introduced later. Same with stuff like a retractable tail wheel. As I understand it they were fitted to new production but many fuselages had been made without them. Taking out a fixed wheel and putting in a retractable one just means less Spitfires.

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## PAT303 (Mar 25, 2022)

Retractable tail wheels and closed undercarriage came out in 1940 with the MkIII which later became the MkVIII through too MkXIV models.


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## wuzak (Mar 25, 2022)

Geoffrey Sinclair said:


> So Spitfire Mark V used 4 bladed propellers, mark I used Merlin II engines, and the PR IV used Griffon engines, there was no such thing as the PR.III or PR.XI, the conversions are counted as new aircraft, and these figures are considered accurate.



The Spitfire V had 3 blade prop.
The Mk.IV was powered by a Griffon, but was redesignated Mk.XX. Which was the, essentially, the prototype for the XII.
The PR.I Type C was redesignated PR.III and used Merlin.
The PR.I Type D was redesignated PR.IV and used Merlin. The Type D/PR.IV was not a converted fighter airframe and featured the leading edge wing tanks.
The PR.XI was an unpressurised PR version of the VIII. The PR.X was the pressurised version.

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## wuzak (Mar 25, 2022)

PAT303 said:


> Retractable tail wheels and closed undercarriage came out in 1940 with the MkIII which later became the MkVIII through too MkXIV models.



Closed undercarriage did not make it to VIII/XIV production.


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## PAT303 (Mar 26, 2022)

wuzak said:


> Closed undercarriage did not make it to VIII/XIV production.


It wasn't until the Mk21 that production Spits had closed under carriage but it was developed way back in 1940


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## tomo pauk (Mar 26, 2022)

PAT303 said:


> It wasn't until the Mk21 that production Spits had closed under carriage but it was developed way back in 1940



Not of the same layout and construction, though. The early type was all on the U/C leg, the actual, later type was a device attached directly to the wing (similar as on the Bf 109K).

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## MikeMeech (Mar 26, 2022)

tomo pauk said:


> Not of the same layout and construction, though. The early type was all on the U/C leg, the actual, later type was a device attached directly to the wing (similar as on the Bf 109K).


Hi
The 'early type' is what was originally fitted to the Spitfire prototype K5054 and was removed in July 1936, information on this can be found on page 45 of 'The Spitfire Story' by Alfred Price, the removal appears to have made little difference to performance:





The same source includes images:




Mike

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## MikeMeech (Mar 27, 2022)

Hi
The Hurricane prototype also had a similar undercarriage door arrangement as the Spitfire prototype, in addition it had a retractable tail wheel. Both of these items were not on the production version:




The later Typhoon did have a fully enclosed undercarriage as did the Defiant and Fulmar. The P-40, Wildcat, Hellcat also did not have fully enclosed undercarriages although coming into service later than the Spitfire, while the P-47 and P-51 designs did. 

Reference to rivets has been made previously, the Spitfire prototype was fully flush riveted but this made production more complicated and expensive, probably because thin alloy skin would mean the rivet hole would be "dimpled" rather than countersunk. In turn the structure it was attached to would also be "dimpled" which could also involve heat treatment therefore increasing cost and time to production. Supermarine undertook the famous "split pea" experiment to get accurate data on the drag caused by rivets on different parts of the airframe, an exert from 'The Spitfire Story', page 49 below:




Compromises to aid production and reduce costs, if possible, were always being made.
Mike

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## Zipper730 (Mar 28, 2022)

EwenS said:


> The successor to the Mk.I/II was intended to be the Mk.III. That aircraft would have had a new engine, clipped wings and a retractable tail wheel. But events intervened. The Mk.V began as an attempt to match the performance of the Bf109F that began to appear over southern England in Nov 1940. The route was to put a new engine in the Mk.I/II airframe as it was needed in service urgently. From initial discussions on Christmas Eve 1940 to having a prototype Mk.V for trials took 7 weeks. By the end of Feb 1941 the first conversions were in service with 92 squadron. By the beginning of March all thoughts of the Mk.III were ditched and the serial numbers allocated to that Mark on order switched to the Mk.V. As time went on other changes, like the Universal wing, were introduced to the Mk.V.


So the Mk.V was a product of an emergency need? I assume that would have made a retractible gear impossible to fit into the design?


> From late 1942 Supermarine was working on new wings for the Spitfire. As their experience with new wing profiles was limited they decided on a two step approach.
> 1. Produce a high speed wing by modifying the existing Spitfire wing by raising the leading edge by 2 inches and if tests on that proved successful,
> 2. Design a completely new laminar flow wing.


Okay, so the Mk.21's wing was NOT a laminar flow design?


> The object of the F.21 wing was to increase the limiting speed of the Mk.XIV above 470mph by improving the aileron control. That meant bigger ailerons which changed the wing tip shape. When the first F.21 appeared in July 1944 there were problems with aileron tab gearing, aileron control being too light, directional stability required a rudder of increased chord.


So the problem had to do with the ailerons being too light and reduction in directional stability?


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## PAT303 (Mar 28, 2022)

Zipper730 said:


> Okay, so the Mk.21's wing was NOT a laminar flow design?


Laminar flow wings aren't the be all to end all, one of the reasons pilots of all skill levels could master the Spit and have confidence in it was it's vice free beautiful handling from 400mph down too the stall, laminar flow wings can't give you that, one of the prototype Spiteful's crashed when the laminar flow wings stalled trying to turn with a MkXIV.


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## drgondog (Mar 28, 2022)

PAT303 said:


> Laminar flow wings aren't the be all to end all, one of the reasons pilots of all skill levels could master the Spit and have confidence in it was it's vice free beautiful handling from 400mph down too the stall, laminar flow wings can't give you that, one of the prototype Spiteful's crashed when the laminar flow wings stalled trying to turn with a MkXIV.


Not all Low Drag (there were no laminar flow wings) performed alike. The NACA 66 series adopted and modified by Bell displayed vicious stall characteristics at stall. The NAA/NACA 45-100 series for the pre-Lightweight Mustangs had no serious vices. A Flat spin, if entered, was difficult to recover from - but that is not entirely due to the wing characteristics. High speed departures at high AoA occurred on P-51, Fw 190, Spit, Bf 109, P-47 - etc. Common when outboard wing stalls before inboard, due to 'too high' AoA. The slat deployment on the 109 did, however give better warning.

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## tomo pauk (Mar 28, 2022)

drgondog said:


> Not all Low Drag (there were no laminar flow wings) performed alike. The NACA 66 series adopted and modified by Bell displayed vicious stall characteristics at stall. The NAA/NACA 45-100 series for the pre-Lightweight Mustangs had no serious vices. A Flat spin, if entered, was difficult to recover from - but that is not entirely due to the wing characteristics. High speed departures at high AoA occurred on P-51, Fw 190, Spit, Bf 109, P-47 - etc. Common when outboard wing stalls before inboard, due to 'too high' AoA. The slat deployment on the 109 did, however give better warning.



Bill - how much of the help was the washout at Spitfire (wing root having 2 deg greater incidence angle than tip)?

Wrt. and IMO for the laminar flow wing application to the Spitfire: about as useful as giving an antibiotic to a man with a sprained ankle?


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## Zipper730 (Mar 28, 2022)

PAT303 said:


> Laminar flow wings aren't the be all to end all, one of the reasons pilots of all skill levels could master the Spit and have confidence in it was it's vice free beautiful handling from 400mph down too the stall, laminar flow wings can't give you that, one of the prototype Spiteful's crashed when the laminar flow wings stalled trying to turn with a MkXIV.


 I actually knew that, but I remember somebody saying it was a redesigned foil that was supposedly laminar flow. It appears that it might not be, but I know the Spitfire generally did very well at high speed because of the following...

The wings were very thin and that served to limit the rise of shockwaves until relatively high mach numbers, and were heavily filleted, and this helped keep the airflow smooth over the horizontal stab
The fuselage was also very thin, and this served to limit the degree to which it parted the air, and minimized turbulence, which allowed the tail surfaces to be smaller
The Air Ministry wanted the tails enlarged because they felt they were too small. While the tail wasn't enlarged to the degree the Air Ministry dictated owing to some haggling by supermarine, it was larger than truthfully needed.


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## pbehn (Mar 28, 2022)

Zipper730 said:


> I actually knew that, but I remember somebody saying it was a redesigned foil that was supposedly laminar flow. It appears that it might not be, but I know the Spitfire generally did very well at high speed because of the following...
> 
> The wings were very thin and that served to limit the rise of shockwaves until relatively high mach numbers, and were heavily filleted, and this helped keep the airflow smooth over the horizontal stab
> The fuselage was also very thin, and this served to limit the degree to which it parted the air, and minimized turbulence, which allowed the tail surfaces to be smaller
> The Air Ministry wanted the tails enlarged because they felt they were too small. While the tail wasn't enlarged to the degree the Air Ministry dictated owing to some haggling by supermarine, it was larger than truthfully needed.


No ww2 wings had laminar flow except possibly at taxi speeds.

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## Zipper730 (Mar 28, 2022)

pbehn said:


> No ww2 wings had laminar flow except possibly at taxi speeds.


Well yeah, but the issue was what were generally called laminar flow wings. Have they ever made a wing that was laminar at high speeds without using suction?


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## drgondog (Mar 28, 2022)

tomo pauk said:


> Bill - how much of the help was the washout at Spitfire (wing root having 2 deg greater incidence angle than tip)?
> 
> Wrt. and IMO for the laminar flow wing application to the Spitfire: about as useful as giving an antibiotic to a man with a sprained ankle?


A lot of variables are involved in the discussion of Wing vs Airfoil properties. First the Spit airfoil was NACA 2213 Root and 2209 Tip, with a double ellipse planform to 'nudge' the lifting line along the 25% chord withCenter of pressure consistent along the spar. very efficient structurally with the spar more or less co-incident with the CP, span wise.

IIRC the wash out was 2 1/2 degrees. With CP ~ 26 % Chord

The NAA/NACA 45-100 airfoil was 16% root, 11% tip - with 1 degree 53 minute twist for wash out. CP~ 37% of chord. The Mustang CL was lower, form drag at high speed was lower, but the Spitfire Induced drag was significantly lower - and important at low medium speeds.

The lift distribution was better for the Spitfire Before the twist was introduced to 'push' it out toward the tip with the increased 'tip' washout

The Spit wing combined with low W/L was a superior maneuver aircraft to the P-51, but the wing of the 51 was a marvel


.

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## don4331 (Mar 28, 2022)

drgondog said:


> A lot of variables are involved in the discussion of Wing vs Airfoil properties. First the Spit airfoil was NACA 2213 Root and 2209 Tip, with a double ellipse planform to 'nudge' the lifting line along the 25% chord with Center of pressure consistent along the spar. very efficient structurally with the spar more or less co-incident with the CP, span wise.
> 
> IIRC the wash out was 2 1/2 degrees. With CP ~ 26 % Chord
> 
> ...


I have read 2 things about the Spitfire wing - with emphasis on the Mk.21/22 version.

1. That pilots were experiencing aileron reversal - i.e. when aileron was deflected down, rather than the increase camber increase lift and cause that wing to lift and therefore plane to roll. But rather the whole wing twisted, so in fact less lift was developed and the airplane rolled the opposite direction. Strengthening the wing to prevent the torsion is what delayed the new wing.

2. That at very high speeds, the required angle of attack to fly straight (i.e. along the path you intended, not climbing or diving anymore than intended), that the wing "masked" the radiators, quickly resulting in overheating of the engine. Increasing the initial incidence would seem to be the correct answer for the late Spitfire weighing far more even empty than initial fully loaded, but doesn't seem like correct answer for high speed...

True or another false statement perpetuated over the years?


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## pbehn (Mar 29, 2022)

Zipper730 said:


> Well yeah, but the issue was what were generally called laminar flow wings. Have they ever made a wing that was laminar at high speeds without using suction?


I dont know, from this they were still working on it 9 years ago, even vibration and noise has an effect NASA Chat: Quest for the Holy Grail of Laminar Flow. However the P-51D was a contemporary of the Me 262, research was already focussing on transonic and supersonic stuff.


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## drgondog (Mar 29, 2022)

don4331 said:


> I have read 2 things about the Spitfire wing - with emphasis on the Mk.21/22 version.
> 
> 1. That pilots were experiencing aileron reversal - i.e. when aileron was deflected down, rather than the increase camber increase lift and cause that wing to lift and therefore plane to roll. But rather the whole wing twisted, so in fact less lift was developed and the airplane rolled the opposite direction. Strengthening the wing to prevent the torsion is what delayed the new wing.


Pretty close. The 'down aileron in your example, does effectively increase camber (and local lift in the aileron/tip region, but combined with torsion - increases the local angle of attack too much, inducing a stall of the wing. The other wing remains in 'normal' lift mode - even if torsion exists on that wing because the up aileron/camber combination reduces the local AoA below stall AoA. The FW 190 had the issue of high speed roll reversal also, but perhaps due to curious design of 'zero washout' of outer 20% of the LE. The Spit and Mustang LE washout was constant from root to tip, FW from Root to 80% semi-span.


don4331 said:


> 2. That at very high speeds, the required angle of attack to fly straight (i.e. along the path you intended, not climbing or diving anymore than intended), that the wing "masked" the radiators, quickly resulting in overheating of the engine. Increasing the initial incidence would seem to be the correct answer for the late Spitfire weighing far more even empty than initial fully loaded, but doesn't seem like correct answer for high speed...
> 
> True or another false statement perpetuated over the years?


Depends on the altitude. At low altitude/high speed the required CL requires less angle of attack, which could have an effect on the wing mounted radiators. As altitude increases, the density is lower - forcing increasing CL by increasing AoA - thereby 'keeping radiators unmasked'. The underwing radiator for the Spit (or Bf 109) was never entirely successful, but the Bf 109G (and maybe F but my memory fails me) and later were a better design for reducing drag.

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## PAT303 (Mar 29, 2022)

pbehn said:


> No ww2 wings had laminar flow except possibly at taxi speeds.


We are calling them laminar flow as a general name to distinguish them from everything else

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## drgondog (Mar 29, 2022)

PAT303 said:


> We are calling them laminar flow as a general name to distinguish them from everything else


That said, High Speed/Low Drag wing a better 'name' for the class of airfoils that pushed the max T/C back from 25% T/C for the modern airfoils of the day.


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## MikeMeech (Mar 29, 2022)

don4331 said:


> I have read 2 things about the Spitfire wing - with emphasis on the Mk.21/22 version.
> 
> 1. That pilots were experiencing aileron reversal - i.e. when aileron was deflected down, rather than the increase camber increase lift and cause that wing to lift and therefore plane to roll. But rather the whole wing twisted, so in fact less lift was developed and the airplane rolled the opposite direction. Strengthening the wing to prevent the torsion is what delayed the new wing.
> 
> ...


Hi
The actual problems with the Mk. 21 are well documented in 'The Spitfire Story', which includes five Appendices with copies of some of trials undertaken with this mark, including some of the solutions to the problems that arose. The main text includes the following:













Mike

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## PAT303 (Mar 29, 2022)

drgondog said:


> That said, High Speed/Low Drag wing a better 'name' for the class of airfoils that pushed the max T/C back from 25% T/C for the modern airfoils of the day.


I just want to say thankyou for your posts, very informative

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## tomo pauk (Mar 30, 2022)

drgondog said:


> The Spit wing combined with low W/L was a superior maneuver aircraft to the P-51, but the wing of the 51 was a marvel



It is really impressive how much of the stuff NAA packed in the wing of the P-51, no doubt due to the wing airfoil contributing there, especially with it's relatively thick (for the era) profile. Loads of fuel, armament of up to 4 cannons and sizable ammo count, and obviously the landing gear. Granted, part of the fuel load was, geometrycally, in the wing-fuselage intersection, bu still.
Compare to the _later _wing on the P-63, that carried 70% of fuel of the P-51, while being unable to install a single HMG in the wing proper. And still the P-63A was not able to out-pace the P-51A, despite the former having a 2-stage engine with water injection.



drgondog said:


> The underwing radiator for the Spit (or Bf 109) was never entirely successful, but the Bf 109G (and maybe F but my memory fails me) and later were a better design for reducing drag.



Bf 109F indeed received the redesigned radiators, them being wider, thus allowing for greater percentage of the radiators to be buried in the wing. Experiment with boundary layer tunnel was discontiued with the 109G, where the tunnel was 'deleted' so the bigger radiators were installed.
Spiteful's radiators were similar to the Bf 109G/K, granted these sported oil, coolant and intercooler radiators. Spitfires with 2-stage engines were probably 'dirtiest' wrt. radiator setup.

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## drgondog (Mar 30, 2022)

tomo pauk said:


> It is really impressive how much of the stuff NAA packed in the wing of the P-51, no doubt due to the wing airfoil contributing there, especially with it's relatively thick (for the era) profile. Loads of fuel, armament of up to 4 cannons and sizable ammo count, and obviously the landing gear. Granted, part of the fuel load was, geometrycally, in the wing-fuselage intersection, bu still.
> Compare to the _later _wing on the P-63, that carried 70% of fuel of the P-51, while being unable to install a single HMG in the wing proper. And still the P-63A was not able to out-pace the P-51A, despite the former having a 2-stage engine with water injection.


Tomo - the High Speed/Low drag airfoil enabled the same drag rise characteristics of the thinner Spit wing, but at sustained lower pressure drag at speeds lower than .6M. Additionally the Moment induced pitch down was less severe due to the aft location of max T/C and CP. The aft T/C also enabled complete housing of belt fed armament as well as the large wing fuel cells.

Curiously, neither P-38, P-39, P-40, P-47, F4U, F6F had any washout. All had negative angle of incidence (constant) ranging from 1 degree (P-40 and P-47), 2 degree (P-38, P-39 and F4U) to 3 degree (F6F). The P-51 and Spitfire had nearly the same washout near 2 degree.

The P-47 S-3 airfoil was actually slightly 'thinner' than Spitfire with 11% max T/C at 30%, then Spit 13%, then P-38/39/40 and F6F 15%, then P-51 16.3% and F4U at 18%. 





tomo pauk said:


> Bf 109F indeed received the redesigned radiators, them being wider, thus allowing for greater percentage of the radiators to be buried in the wing. Experiment with boundary layer tunnel was discontiued with the 109G, where the tunnel was 'deleted' so the bigger radiators were installed.
> Spiteful's radiators were similar to the Bf 109G/K, granted these sported oil, coolant and intercooler radiators. Spitfires with 2-stage engines were probably 'dirtiest' wrt. radiator setup.


Thanks for the 'refresher..


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## tomo pauk (Mar 30, 2022)

drgondog said:


> Tomo - the High Speed/Low drag airfoil enabled the same drag rise characteristics of the thinner Spit wing, but at sustained lower pressure drag at speeds lower than .6M. Additionally the Moment induced pitch down was less severe due to the aft location of max T/C and CP. The aft T/C also enabled complete housing of belt fed armament as well as the large wing fuel cells.
> 
> Curiously, neither P-38, P-39, P-40, P-47, F4U, F6F had any washout. All had negative angle of incidence (constant) ranging from 1 degree (P-40 and P-47), 2 degree (P-38, P-39 and F4U) to 3 degree (F6F). The P-51 and Spitfire had nearly the same washout near 2 degree.



Thank you.



drgondog said:


> The P-47 S-3 airfoil was actually slightly 'thinner' than Spitfire with 11% max T/C at 30%, then Spit 13%, then P-38/39/40 and F6F 15%, then P-51 16.3% and F4U at 18%.



Seems like the P-47 max t-t-c was 14% per this table. 
I'd be grateful for the US data wrt. the % t-t-c on the P-47's S-3 airfoil.


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## pbehn (Mar 30, 2022)

drgondog said:


> Curiously, neither *P-38, P-39, P-40, P-47, F4U, F6F had any washout.* All had negative angle of incidence (constant) ranging from 1 degree (P-40 and P-47), 2 degree (P-38, P-39 and F4U) to 3 degree (F6F). The P-51 and Spitfire had nearly the same washout near 2 degree.


Were/ are there any ways to get the same effect without washout?


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## drgondog (Mar 30, 2022)

tomo pauk said:


> Thank you.
> 
> 
> 
> ...


try his - REPUBLIC S-3 AIRFOIL (s3-il)


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## drgondog (Mar 30, 2022)

pbehn said:


> Were/ are there any ways to get the same effect without washout?


Slats.

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## tomo pauk (Mar 30, 2022)

drgondog said:


> try his - REPUBLIC S-3 AIRFOIL (s3-il)



Thank you. Under 'US data', I've meant something sourced by Republic or NACA.
Unfortunately, the discrepancy between 14% and 11% is too great to just accept the 11% figure and discard the 14% figure.


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## drgondog (Mar 30, 2022)

tomo pauk said:


> Thank you. Under 'US data', I've meant something sourced by Republic or NACA.
> Unfortunately, the discrepancy between 14% and 11% is too great to just accept the 11% figure and discard the 14% figure.


Not arguing, but Lednicer is a VERY respectable source. As to NACA, the S-3 was a homegrown airfoil. On the other hand the RAF tables has no cited source, nor is there guarantee that it is not a typo, or the result of physical measurement in error. That said I seem to recall another source in the 14% range.


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## tomo pauk (Mar 30, 2022)

drgondog said:


> Not arguing, but Lednicer is a VERY respectable source. As to NACA, the S-3 was a homegrown airfoil. On the other hand the RAF tables has no cited source, nor is there guarantee that it is not a typo, or the result of physical measurement in error. That said I seem to recall another source in the 14% range.



Unfortunately, the NACA data about the S-3 is very, very 'thin', while the Republic archives ended up in a landfill when they were bough by Fairchild. Damn.

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## tomo pauk (Mar 30, 2022)

Seems like the max t-t-c of 14.6% for the root of the wing of P-47 per this excerpt. The 11% t-t-c figure is for the wing section 2 feet outboard from the flap.


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## drgondog (Mar 30, 2022)

tomo pauk said:


> Seems like the max t-t-c of 14.6% for the root of the wing of P-47 per this excerpt. The 11% t-t-c figure is for the wing section 2 feet outboard from the flap.


I don't have a problem with 14.6 as 11% just seems too low for 1941 aerodynamics. FYI - The XP-47F Laminar Flow wing is cited 15.6 with max T/C at 45%. (Freeman Drawing pg 139).

What is the source for the excerpt?


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## tomo pauk (Mar 30, 2022)

drgondog said:


> What is the source for the excerpt?


Don't know.
I've asked the person that posted it at another forum to post the name of the source of the excerpt.


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## GregP (Mar 30, 2022)

tomo pauk said:


> Thank you.
> 
> 
> 
> ...



Hi Tomo. Where did you find that table? Not questioning it ... just curious so I can see it when I magnify it.


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## tomo pauk (Mar 30, 2022)

GregP said:


> Hi Tomo. Where did you find that table? Not questioning it ... just curious so I can see it when I magnify it.



Here.

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## Jugman (Apr 4, 2022)

drgondog said:


> I don't have a problem with 14.6 as 11% just seems too low for 1941 aerodynamics. FYI - The XP-47F Laminar Flow wing is cited 15.6 with max T/C at 45%. (Freeman Drawing pg 139).
> 
> What is the source for the excerpt?


I think that excrept is from a NACA report that can be found on the NTRS. It seems awfully familiar to me. 11% is to thin to allow the wheels to fit in the wings without bulges.


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## Jugman (Apr 5, 2022)

Found IT! It's on Page six of "Flight Investigation of Boundary-layer and Profile-drag Characteristics of Smooth Wing Sections of a P-47D Airplane".

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## drgondog (Apr 5, 2022)

Jugman said:


> Found IT! It's on Page six of "Flight Investigation of Boundary-layer and Profile-drag Characteristics of Smooth Wing Sections of a P-47D Airplane".


Interesting. Couple of comments:
The S3 wing was 11.7 T/C Max at semi span 63%, 14.7% T/C Max at 25%. Extrapolating to Root chord puts it in the 16% T/C Max range - about the same as P-51.

The Cd profile drag (pure shape, no friction) a low CL (High Speed) in the RN=19 x 10^6 range is 0.0062 for that puttied, primed and sanded smooth wing.

The P-51D wing CD profile drag is 0.0070 at RN=2x10^6, at RN=19x10^6, the P-51D wing CD profile drag =~0.0040.

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## Wild_Bill_Kelso (Apr 6, 2022)

Shortround6 said:


> That may be true but a lot of the other fighters (especially in 1939-43) weren't really all that good at a varity of roles. P-40s didn't do well at intercepting anything flying at 20,000ft or above for example, let alone trying to escort B-17s or B-24s unless they were flying low and close to home.


Well, I agree with that with some qualifiers. P-40s appear to have worked much better for the defense of Darwin than the Spit Mk Vs did, (and these were the early ones with the critical altitude around 12k ft) and the difference seems to be largely down to range / endurance. They could form up, climb laboriously up to altitude, and fly out to intercept the incoming aircraft and still have enough fuel to make multiple attacks and still make it back to base.

P-40s were notoriously bad at escorting heavy bombers, and they were tried for this task a few times, mainly with B-24s, both in the Pacific and the Med, with poor results.

Merlin powered P-40s were used in the Med with considerable success to escort medium bombers, in fact one of the FG there was assigned to the main B-26 bomber group, and they did really well. P-40N and M were used in the pacific and CBI to escort bombers and transports (notably over 'the hump') again in spite of having to fly at relatively high altitudes. 

Generally speaking, I think you wouldn't want this plane to escort any heavy bombers.


Shortround6 said:


> A Spitfire V was shorter in range than a P-40 but it took rougly 2/3s of the time to get to 20,000ft and when flying above 20,000ft it had around double the rate of climb.


Depends on the types, but generally Spit V had an excellent climb rate. Early "Kittyhawk" P-40s as I previously mentioned, had a critical altitude down around 12,000 ft, Tomahawks were a little better, at about 15k. Merlin (F and L) types had a critical altitude at just under 20,000 ft so were good up to about 2,5000 or so. N and M (Allison) model had around 16-17k and were ok up to about 20k.


Shortround6 said:


> Now for all the "early long range Spitfire" fans see.
> 
> 
> http://www.spitfireperformance.com/ab320climb.jpg
> ...


I really wasnt' ever thinking of using Spitfires to escort B-17s or B-24s, at least not as the main escort, though if you had say, Spit VIII range plus a little extra from streamlining etc., it could be quite helpful in covering the return leg of a bombing raid. They did use Spits for this role, but if you had double the range that could really help. 

However, I really think Spits would have been more effective both as interceptors, (especially with Radar / integrated defense system) and as tactical fighters, fighting over the various battlefields, if they had say 50-100% more range, and I think that was probably technically feasible. Whether it was feasible in industrial terms is unclear to me.


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## Wild_Bill_Kelso (Apr 6, 2022)

tomo pauk said:


> That's an easy question. I pick Spitfire IX to escort B-17s at any altitude they might be, range/radius of Spits permitting. We know that Mk.IX was at least equal to the Fw 190s performance-wise.



Longer ranged Spit VIII also pretty good match for a FW 190 too.


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## Wild_Bill_Kelso (Apr 6, 2022)

Zipper730 said:


> What happened in Darwin?
> 
> 
> While I know that ADC/TAC and part of SAC became ACC in the United States in 1992, I didn't know there was an ACC entity in either the USAAF/RAF during WWII. Regardless, I gotta say that the decision made was quite foolish, but not an uncommon rationale: "They're making us look bad, so we're edging them out the way so we can get all the glory".



Spitfire Wing was sent in, under veteran leadership, to defend Darwin after the US 49th FG was rotated out (and soon after, north up to New Guinea). The Spitfire unit had a lot of problems. They took heavy losses to enemy aircraft, accidents, and fuel starvation over the water. Part of this was due to some unique maintenance issues, part was routine teething trouble of deploying these planes at the end of a very long supply line (and in part, relying on Aussie manufacturing which wasn't quite up to speed yet). But arguably the biggest single problem was fuel. Spitfires were used in the Pacific, and they were needed, but short range / endurance largely kept them out of the fight.

Getting back to the main subject of the OP, looking at Geoffrey Sinclair's post with all the Spitfire drag improvements here Spitfire Combat Radius (range) evolution, limitations?

... it seems like with some effort they could have made an improved 'lower drag' Spitfire which was at least 30-40mph faster, and some of this will also translate into better endurance / range... then combine that with the extra fuel carried by the Mk VIII, and I think you have possibly an aircraft with an additional improved range over that of the Mk VIII. 

I do know that the MK VIII had a few of these drag improvements built in, which is part of why it was faster, but there was still room for many more.

Conceivably, you could fit even more fuel in, given that the range of the PR Spits was so good. There has to be some room between 'no guns' and 'six guns' where you could fit some more petrol instead.

I don't necessarily see this as a primary Strategic escort fighter, but I think it would still be a bit of a game changer just by significantly leveraging the advantages of the Spitfire in the various battlefield zones around the world - Med / Malta / Italy, Pacific, and later on in France etc. I think the Russians might have found more use for it as well.


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## Wild_Bill_Kelso (Apr 6, 2022)

pbehn said:


> It is the other way around, there were many aircraft that could fill the other niches but non were as good as the Allison engined Mustang at tactical recon.



I'm not so sure I buy this, but it's an interesting argument. Allison Mustang was useful in a highly specialized niche, I'm not sure if I'm parsing your statement correctly, but are you saying that it would have been used in other roles (say, escorting low level bombing strikes?) if it hadn't been so badly needed as a PR fighter? There were a few other planes which could do that role, though maybe not precisely in the same niche.


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## pbehn (Apr 6, 2022)

Wild_Bill_Kelso said:


> I'm not so sure I buy this, but it's an interesting argument. Allison Mustang was useful in a highly specialized niche, I'm not sure if I'm parsing your statement correctly, but are you saying that it would have been used in other roles (say, escorting low level bombing strikes?) if it hadn't been so badly needed as a PR fighter? There were a few other planes which could do that role, though maybe not precisely in the same niche.


From what I understand the Alisson Mustangs were the best at that role, it is a niche role but a very big niche. The British would have taken many more to do the job, others could do the job but not as well. The fact is that although the British would have taken more that wasnt a possibility, production had switched to the Merlin variants, so they ran what they had until they wore out. In the run up to D-Day and after "intel" came a close second to eliminating the LW as far as air operations go and the Alisson engined Mustang was best at it, the mission is only a success when you land back at base with the film.


ColFord made a post about it on this thread, I will try to find it.

It is on a different thread but here Post #21 Effects of converting of all surviving Mustang Is into LR Mustang X?

Which if the RAF goes down the path of converting all their surviving Mustang Mk.I & Mk.IA, what do the poor b****y Tac/R pilots use to fly all the reconnaissance tasks placed upon them in 1943 and 1944?

ACC and then later 2TAF went down this path in trying to identify potential replacement aircraft types looking forward to the point where the remaining numbers of Mustang Mk.I and Mk.IA would be reduced due to losses from all causes and the numbers of aircraft they needed to conduct all the required task was greater than what they had, with no direct replacements coming.

Up to early 1945, repeated RAF studies on the best low level Tactical Reconnaissance aircraft for the role came to the conclusion that what they wanted was more Allison engine Mustangs - essentially equivalent to the P-51A, but with the 4 x 20mm Hispano armament of the Mk.IA, and with a Malcolm Hood. But they couldn't get them so had to resort to major overhauls and major rebuilds of the existing airframes to keep them going as long as they could. Aircraft that would have previously been written off, wherever possible were repaired, rebuilt and put back into service - which leads to some interesting entries and following of aircraft histories on some of the RAF Aircraft Record Cards. Even required massive pressure by the RAF on the USAAF to get a shipment of new build Allison engines to the specification required by the RAF and engine overhaul kits in late 1943 into early 1944 to keep the RAF's Mustang Mk.I and Mk.IA operational until at least the final quarter of 1944 in order to support the Tac/R requirements for the Invasion. As it was, no more Allison engine Mustangs would be forthcoming in the numbers required by the RAF (the 50 Mustang Mk.IIs were a belated backfill for the aircraft taken from the earlier Mustang Mk.IA order) as by the time all this realistically played out the production line at NAA had already been turned over to Merlin engine Mustang production.

As it was, the additional efforts and demands placed on the Tac/R squadrons in providing reconnaissance on the German V weapons sites in northern France from late 1943 into early 1944 on top of all the invasion related reconnaissance demands, accelerated the reduction in available aircraft to the point where they were considering re-equipping front line RAF Tac/R Squadrons with Hurricane IIc aircraft as a stop gap for the invasion period if the numbers dropped too low. When the pilots in the RAF Tac/R Mustangs squadrons heard that, you can barely begin to imagine the reaction and comments made.

The potential and actual replacements for the Mustang Mk.I and Mk.IA in the RAF Tac/R Squadron all came with a reduction in capability (range, low altitude speed, visibility, camera installations, increased risk) that when the replacements did arrive, led to the RAF Reconnaissance Wings having to 'triage' the reconnaissance demands to match the demand to the capability of the available aircraft. As a result, quite a few demands had to be declined and that in turn led to negative comments from some within the Army about the level of reconnaissance support they were receiving - and they made sure those comments were echoed all the way up the chain of command.

So you 'solve' one problem, but create another with potentially dire consequences to getting the required reconnaissance coverage to support the campaign against the German V weapons, the Invasion and support of the Army in the field following the Invasion. The RAF Tac/R squadrons were not called "The Eyes of the Army" for nothing.

Last​

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## Wild_Bill_Kelso (Apr 6, 2022)

I realize that P-51B etc. is not optimized for super low altitude, (neither is the Allison V-1710 really) but couldn't you still just use P-51B/C for that role? And then later maybe Tempests?

I also wonder if you couldn't add say a pair of guns to a Tac-R Spitfire variant...?

P-38s made fairly good recon birds though not necessarily for low altitude.


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## Wild_Bill_Kelso (Apr 6, 2022)

And that said, I don't personally see a problem with still building some Allison Mustangs through the war if there really was a demand for them, though I can understand why they were making B/C/D etc. instead, since they had more broad applications.


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## tomo pauk (Apr 6, 2022)

Wild_Bill_Kelso said:


> Longer ranged Spit VIII also pretty good match for a FW 190 too.



Any spitfire with a 2-stage Merlin was a good match for the Fw 190. Trick being the Fw 190 still can kill B-17s from east of Saarland, where even Spit VIII as-is was not rangy enough to be there, fight, and reliably return to base.



Wild_Bill_Kelso said:


> ... it seems like with some effort they could have made an improved 'lower drag' Spitfire which was at least 30-40mph faster, and some of this will also translate into better endurance / range... then combine that with the extra fuel carried by the Mk VIII, and I think you have possibly an aircraft with an additional improved range over that of the Mk VIII.



It would've required a major redesign of the Spitfire in order to make it 30-40 mph faster, if the engine remains the same.
A Spitfire VIII with another 40-50 imp gals of fuel behind the pilot was a road not taken, unfortunately.

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## Wild_Bill_Kelso (Apr 6, 2022)

Well I meant 30-40 mph faster than a Spit V. What I'm saying is, you take the 122 gallons of fuel from a Spit VIII, then add eight or nine items from Geoffrey Sinclair's list of drag improvements (many of which did not require a major redesign, I don't think) for example:

Multi ejectors---------------7.75
Remove Snowguard--------8.5
Internal BP windscreen-----3.75
Fared mirror----------------3.25
Whip antenna -------------.75
Flush chutes----------------1.25
Small cannon bulges ------0.25 (This ads up to 25.5 mph already)

Improved Finish -----------8.5 - (this brings it to +34 mph)

That puts you close to or over 400 mph right there, starting with a Spit Mk V and Merlin 40 or 50 series engine. I think all of these are fairly easy, with the exception of "improved finish". Then you get a Merlin 60 series engine, and you gradually introduce a few more changes, perhaps a bit more of the difficult ones:

All this should be both a speed and efficiency improvement. Maybe a 10-20% better version of a Mk VIII in terms of speed, how much would that translate to in terms of range? I am just guessing here as I don't know how much of the improved performance came from 100-200 more HP, how much from just having HP available at higher altitude, and how much from streamlining. But presumably Merlin 61 or whatever gives you another boost in speed.

That is version one of a longer ranged (and faster) Spitfire.

Then do another round of improvements for a second long range Mark:

Maybe some kind of improved venting from the cooler intake like done in the Mustang
Flush rivets? Did they have those already?
Retractable tail wheel (I think the Mk VIII already had this right? I'm not sure my Eduard model kit of a Spit VIII seems to have a fixed tailwheel)
Fully covered landing gear doors
Possibly a two gun version with more fuel?
Internal antenna?

etc.

I bet all that gives you another 15-20 mph

And then for the third long range mark, add still more fuel, like what you get from the PR marks or some of the later fighter marks.

Perhaps the biggest challenge here would be making something like the Mk VIII earlier and in such a way that it could be manufactured in large numbers. Maybe bring in some NAA people to help reorganize the plant


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## pbehn (Apr 6, 2022)

Wild_Bill_Kelso said:


> And that said, I don't personally see a problem with still building some Allison Mustangs through the war if there really was a demand for them, though I can understand why they were making B/C/D etc. instead, since they had more broad applications.


Well there was a demand for them, but the demand for a long range escort was the top priority. The RAF did receive P-51B/C and D but the same situation existed, being a top class escort others had a call on them. Approx half of Spitfire Mk XIV were fitted with a camera but the Mustang ! and II had more than one.


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## tomo pauk (Apr 6, 2022)

Wild_Bill_Kelso said:


> Well I meant 30-40 mph faster than a Spit V. What I'm saying is, you take the 122 gallons of fuel from a Spit VIII, then add eight or nine items from Geoffrey Sinclair's list of drag improvements (many of which did not require a major redesign, I don't think) for example:
> 
> Multi ejectors---------------7.75
> Remove Snowguard--------8.5
> ...



Spitfire VIII was already with internal BP glass, somewhat improved finish (the Spitfire V was the low mark in that regard), small cannon bulges, without snowguard and with multi ejectors. It also had the increased cooling drag due to the radiator set being of greater front area.
Want to make Spitfire VII/VIII/IX really fast? Make the wholesale redesign of the cooling system.



Wild_Bill_Kelso said:


> That puts you close to or over 400 mph right there, starting with a Spit Mk V and Merlin 40 or 50 series engine. I think all of these are fairly easy, with the exception of "improved finish". Then you get a Merlin 60 series engine, and you gradually introduce a few more changes, perhaps a bit more of the difficult ones:



The Spitfire V making 388 mph (after RAE nip and tuck) started as a 358 mph machine.




Wild_Bill_Kelso said:


> All this should be both a speed and efficiency improvement. Maybe a 10-20% better version of a Mk VIII in terms of speed, how much would that translate to in terms of range? I am just guessing here as I don't know how much of the improved performance came from 100-200 more HP, how much from just having HP available at higher altitude, and how much from streamlining. But presumably Merlin 61 or whatever gives you another boost in speed.
> 
> That is version one of a longer ranged (and faster) Spitfire.
> 
> ...



10-20% increase of speed due to nip & tuck aint gonna happen. 
Flush rivets were applied where needed after the tests with split peas. I'm all for retractable tailwheel and fully covered landing gear doors, it took until 1945 to have those on Spitfire (and on Bf 109, for comparison). Internal antenna enclosed within a metallic body will not work well, the Farraday's cage applies. A 2-cannon version was there as-is, though I'm not sure whther the fabric-covered MG muzzles were still a thing by 1943-44.
The major redesign of the cooling system externals might've helped a great deal.



Wild_Bill_Kelso said:


> I bet all that gives you another 15-20 mph
> 
> And then for the third long range mark, add still more fuel, like what you get from the PR marks or some of the later fighter marks.
> 
> Perhaps the biggest challenge here would be making something like the Mk VIII earlier and in such a way that it could be manufactured in large numbers. Maybe bring in some NAA people to help reorganize the plant



More/better/earlier Spitfires are certainly a matter for the what-if sub-forum. Me, I'd have Boulton-Paul and Westland jump at the bandwagon by 1938 - meaning no Defiant, no Whirlwind.
A Spitfire IX and VIII with a good fuel tank behind pilot would've been a great asset for the Allies by early 1943.


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## Zipper730 (Apr 6, 2022)

Wild_Bill_Kelso said:


> Spitfire Wing was sent in, under veteran leadership, to defend Darwin after the US 49th FG was rotated out (and soon after, north up to New Guinea). The Spitfire unit had a lot of problems. They took heavy losses to enemy aircraft, accidents, and fuel starvation over the water. Part of this was due to some unique maintenance issues, part was routine teething trouble of deploying these planes at the end of a very long supply line (and in part, relying on Aussie manufacturing which wasn't quite up to speed yet). But arguably the biggest single problem was fuel. Spitfires were used in the Pacific, and they were needed, but short range / endurance largely kept them out of the fight.


So in terms of range, they couldn't extend far enough out to defend their airspace? As for maintenance issues, it had to do with that weird bent spar thing right?


> Getting back to the main subject of the OP, looking at Geoffrey Sinclair's post with all the Spitfire drag improvements here Spitfire Combat Radius (range) evolution, limitations?


Looking at the figures, I'm not sure how 'ideal' differs from 'realistic combat' mods. Needless to say, some of those modifications look pretty useful, though I'm not sure what mods were fitted to the Mk.IX in the 'ideal' configuration. Regardless lower drag generally means longer range, and you'd also have better acceleration and climb-rates.


> I do know that the MK VIII had a few of these drag improvements built in, which is part of why it was faster, but there was still room for many more.


Which ones, if I may ask?


> Conceivably, you could fit even more fuel in, given that the range of the PR Spits was so good. There has to be some room between 'no guns' and 'six guns' where you could fit some more petrol instead.


I'm not sure how much could be fit in the wing but there were two (I think, they could have been the same idea) proposed tanks: One was 16.5 imperial gallons proposed by the USAAF (they reconfigured a Mk.IX), and another was a 17 imperial gallon set-up (I think) the RAF looked into. Not sure why it was rejected.



Shortround6 said:


> There are some 3d illustrations of the tail wheel of the Spitfire and the structure around it on the internet. . . . In fact you would probably want to manufacture the retracting tail wheel models on different assembly lines than the non retracts.


So, the problem was that it was either incompatible with the Mk.IX or was different past a certain frame on the aircraft and would have required some components from a different assembly line to make the modifications?

While I know the production lines for the Mk.VIII ultimately ended up going to other Spitfire variants, were the jigs used for the tail-wheel used as is, or were they destroyed? I figure if they weren't destroyed, it would be possible to just lift them over and fold it into the late Mk.IX line.



wuzak said:


> The PR.I Type C was redesignated PR.III and used Merlin.
> The PR.I Type D was redesignated PR.IV and used Merlin. The Type D/PR.IV was not a converted fighter airframe and featured the leading edge wing tanks.
> The PR.XI was an unpressurised PR version of the VIII. The PR.X was the pressurised version.


If I recall the PR.I Type-D was the bowser-winged design with 2 x 66.5 imperial gallon tanks, correct? Did it have a tank behind the pilot or not?


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## GregP (Apr 6, 2022)

Wild_Bill_Kelso said:


> Well I meant 30-40 mph faster than a Spit V. What I'm saying is, you take the 122 gallons of fuel from a Spit VIII, then add eight or nine items from Geoffrey Sinclair's list of drag improvements (many of which did not require a major redesign, I don't think) for example:
> 
> Multi ejectors---------------7.75
> Remove Snowguard--------8.5
> ...



Incremental speed improvement don't usually "add up." That is, any single change may add the amount shown, but adding ALL of them doesn't just add up to that much speed gain. Many NACA reports and USAAF reports show this to be true. Would be nice of it di, though ...

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## Wild_Bill_Kelso (Apr 7, 2022)

Zipper730 said:


> So in terms of range, they couldn't extend far enough out to defend their airspace? As for maintenance issues, it had to do with that weird bent spar thing right?
> 
> Looking at the figures, I'm not sure how 'ideal' differs from 'realistic combat' mods. Needless to say, some of those modifications look pretty useful, though I'm not sure what mods were fitted to the Mk.IX in the 'ideal' configuration. Regardless lower drag generally means longer range, and you'd also have better acceleration and climb-rates.
> 
> Which ones, if I may ask?



The Spitfires at Darwin is quite a sad and deeply tricky story. I recommend reading a couple of articles about it as it is a classic example of a military institution under pressure, failing to make the most of a good piece of hardware that was desperately needed. The manufacturing issue was with Australian made ammunition, which apparently had a number of serious problems. Off the top of my head, other issues included guns freezing at altitude (apparently due to heaters either not being installed or not being maintained properly) either hydraulic and / or fuel lines freezing or rupturing because they had not been drained properly before shipment, problems with the radios, and a few other things I've forgotten. I think there was an issue with the coolant in the radiators.

There was a tactical aspect too. The commander, an Australian Ace named Clive Caldwell, had learned the hard way fighting in North Africa that the fighters needed to fly in big, tight formations and turn into enemy attacks, lest they be picked off by speedy, fast climbing, high-flying Bf 109s. But in Australia the fight against the A6M and Ki-43 was different and required different tactics. So a lot of fuel was wasted by mostly inexperienced pilots forming up in large formations before the fight.

The big problem was fuel though. They would climb to altitude, form up, and fly around for a while, being vectored toward the incoming Japanese raids, but by the time they got to them (or before) they often ran low on fuel. This was just one of the dismal incidents:









Raid on Darwin (2 May 1943) - Wikipedia







en.wikipedia.org





It's a good example of why flight endurance matters even for interceptors and point defense aircraft.

_While I know the PR variants aren't realistic examples of combat aircraft, but it does illustrate examples of what can be added to an aircraft._

Agreed! I mean PR variants _are_ combat aircraft, they just aren't equipped to shoot down other aircraft. But if you can make a PR Spit with a 1500 mile range conceivably there is a way to make a fighter Spit with a 900 mile range or so, even if you have to delete a couple of guns.

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## Wild_Bill_Kelso (Apr 7, 2022)

GregP said:


> Incremental speed improvement don't usually "add up." That is, any single change may add the amount shown, but adding ALL of them doesn't just add up to that much speed gain. Many NACA reports and USAAF reports show this to be true. Would be nice of it di, though ...



I can imagine some cases where this might be the case, in the sense that several things may be causing similar types of drag and until you eliminate all of them, you will still have basically the same amount of drag. There are naturally certain design limitations on airframe and engine power that can't be exceeded by reducing drag. No amount of streamlining is going to make a piper cub go 300 mph (unless the 'streamlining' meant removing the wings, and then it's only going to go that fast once....).

But I also suspect that this factor would depend a great deal on which improvements you are referring to. In this case, according to the post I linked by Geoffrey Sinclair, the effects_ were _cumulative on speed, and it increased the speed of a Spt V from 358 to 388 mph. This is what I was referring to. I believe Tomo mentioned the same thing in his post.

The emphasis here though is not just on top speed, but more specifically on drag. As you reduce drag you will not just improve top speed, it will take less time and energy to get up to speed, you will accelerate more quickly and decelerate more slowly at the same engine power. And all this also means range / flight endurance will improve.

There are many other examples of this of course, Bf 109E to F is a good one. I think the differences from the P-40 to P-51 are also illustrative (I mean beyond the superior low-drag wing design). Things like having a retractable tailwheel, removing sway braces, completely covered main landing gear, (and retractable vs. fixed main landing gear), switching from external to internal bracing, and of course, improving engine exhaust flow all do increase speed. But I've also read about field improvements done by different combat units where multiple smaller things (sanding and waxing, faring over rearview mirrors) also had a cumulative effect. So respectfully, I would say there are exceptions to this rule you are referring to.

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## GregP (Apr 7, 2022)

Having small improvements add up to a total speed increase is not my experience with warbirds at all, and it also doesn't work very well with civil aircraft, either, say a Mooney 201. I have a good friend who has one. There are lots of mods out there and each has a speed increase associated with it. Adding them all will NOT give you an additive speed increase.

It might if you add something to a wingtip and another thing to the bottom of the fuselage but, if both the things are on the fuselage, they just don't add up because they tend to interact when both are anywhere near the same airflow. Other posts don't trump real life airplanes trying to go faster, and there are a lot of those. Let's see, the Bonanza crowd (though they shouldn't since they are already almost dangerously near redline at cruise), anyone in the Van's RV family (almost dangerously near the flutter limit when painted like a typical homebuilder chooses paint), Mooney M20s, and all the warbirds at Reno, just to name a few. I don't know of anyone in there who has achieved an additive speed increase with more than two mods that were well-separated in the free airflow. These mods were usually gear doors or better wheelpants and wingtips. These two, at least, do not usually interact with one another.

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## pbehn (Apr 7, 2022)

GregP said:


> Having small improvements add up to a total speed increase is not my experience with warbirds at all, and it also doesn't work very well with civil aircraft, either, say a Mooney 201. I have a good friend who has one. There are lots of mods out there and each has a speed increase associated with it. Adding them all will NOT give you an additive speed increase.
> 
> It might if you add something to a wingtip and another thing to the bottom of the fuselage but, if both the things are on the fuselage, they just don't add up because they tend to interact when both are anywhere near the same airflow. Other posts don't trump real life airplanes trying to go faster, and there are a lot of those. Let's see, the Bonanza crowd (though they shouldn't since they are already almost dangerously near redline at cruise), anyone in the Van's RV family (almost dangerously near the flutter limit when painted like a typical homebuilder chooses paint), Mooney M20s, and all the warbirds at Reno, just to name a few. I don't know of anyone ion there who has achieved an additive speed increase with more than two mods that were well-separated in the free airflow. These mods were usually gear doors or better wheelpants and wingtips. These two, at least, do not usually interact with one another.


Some of the differences quoted like snow guards are in "reverse" taking a snow guard off the air intake may add 8 MPH but how many Spitfires were fitted with snow guards, same with windscreens the biggest difference is between the conical windscreen and others. Air resistance is exponential, try sitting bolt upright on a motorcycle at 40MPH pleasant breeze on a sunny day, 80MPH tiring on long journeys, 120 MPH very hard work only possible for a short time, 160 MPH like hanging from a metal bar with all your family holding your feet. All these drag saving measures were saving from the same speed zone, to jump up you need to be much more slippery or have much more power. NAA proposed to the British that the speed of the nascent Mustang I could be increased by shortening the wingspan, the British declined or would only accept if it had no negative effects on take off runs and rate of climb. In view of its later use that was a great decision, but wouldnt please those who put top speed above all things.


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## Zipper730 (Apr 7, 2022)

GregP said:


> Incremental speed improvement don't usually "add up."


I had thought the same thing, but considering they posted the change in speed measured, I figured they meant the total contribution.



Wild_Bill_Kelso said:


> The Spitfires at Darwin is quite a sad and deeply tricky story.


Yikes...


> There was a tactical aspect too. The commander, an Australian Ace named Clive Caldwell, had learned the hard way fighting in North Africa that the fighters needed to fly in big, tight formations and turn into enemy attacks, lest they be picked off by speedy, fast climbing, high-flying Bf 109s. But in Australia the fight against the A6M and Ki-43 was different and required different tactics.


What tactics were adopted? I assume hit & run because of the Spitfire's speed advantages (particularly in dives).


> if you can make a PR Spit with a 1500 mile range conceivably there is a way to make a fighter Spit with a 900 mile range or so, even if you have to delete a couple of guns.


Yeah, it basically gives ideas of what you can stuff where.

It seems there's some stuff you can put in various locations which were shown in various Spitfire variants that I've noticed

Spitfire PR Type B/PR. Mk.II: 29 imp. gallon tank added behind pilot
Spitfire PR Type C/PR. Mk.III: As with PR. Mk.II, plus 30 gallon tank in a streamlined fairing under one of the wings (counterbalanced a camera in the other).
Doesn't seem terribly useful owing to the fact that drop tanks can be punched off.

Nonspecific PR Variant: Some mention of a 20-30 imp. gallon tank carried directly under the pilot.
Spitfire PR (General): D-winged versions, sometimes called the bowser wing, carried 66.5 imp. gallons in each wing, for a total of 133 imperial gallons in addition to the normal 85 gallons carried on all earlier marks.
Doesn't seem a practical idea for a fighter because the need for cannons. I suppose one could extend the 13 imp. gallon tank in the later Mk.VII/VIII wing to the point where it reaches the structural member that houses the aircraft's armament. It would appear that 4 x 20mm or 2 x 20mm + 2 x 0.50" are the best armament options which still yields around 53 imp. gallons a wings (total of 106 imp gal) provided the pipework can be worked around the guns in a way the RAF would have accepted (I said that in that way intentionally, there's unorthodox ways to get things done, but not everybody will accept them, lol).

Seafire: They mentioned carrying a drop-tank fitted for a P-40 which also improved aerodynamic handling (hey, navies seem to kluge best)
Spitfire Mk.VII/VIII: 13 or 13.5 (unsure which, most sources say 13, but 
W
 wuzak
said 13.5) carried inside the inboard wings.
Spitfire Mk.IX: This variant seemed all over the place!
Early versions had 85 imp. gallons only
Later on they added provision for aft tanks with the upper section carrying either 41 or 42 imp. gallons. (a pilot's manual I've found on avialogs seems to indicate 75 imp gals in the rear tank), the lower carrying 33.
Then they increased the fuel capacity in the forward tank for either 95 (48+47 cited in manual) or 96 imp. gallons (48+48 in a diagram, 49+47 in some sources).
The bubble-canopy variants have 66 imp. gallons aft. It would appear that, in addition to the traditional slipper-tanks, it was possible to carry a 50 imp.gal torpedo tank under the centerline on some of the Mk.IX's.
There was a Mk.IX that was modified in the states: It appeared 16.5 imp. gallon tanks were added in the inboard wing, a 43 imp. gallon aft tank, and a pair of 62.5 imp. gallon external tanks. I'm not sure if the forward tanks carried 95-96 imperial gallons and if the 43 imp. gallon tank was used in lieu of the earlier 41-42 imp. gallon one, but it was said to present problems in the following ways.
When the tanks were jettisoned at speeds of 300 mph or greater, it actually struck the wing, denting it.
There was allegedly strength problems: I'm not sure if this had to do with the rear tank, or the drop-tanks (62.5 imp gals is around 75 US gallons, or 450 pounds of fuel, which is heavier than the normal 250-lb bomb load the plane was cleared to carry).

There appears to have been some Mk.IX that either carried a 17-18 imp. gallon tank (or was proposed to carry them).

Griffon powered variants seem to have some merits as well, though their fuel capacity was shorter, owing to their time-tables

Spitfire XII
First operational 1943/04/03
Notes: Timeline was good, but it had the same fuel capacity as the Mk.I/II

Spitfire Mk.XIV
First Operational 1944/03/12
Notes: It could carry 142 imp. gallons (Forward: 36+49; Wings: 2 x 13; Aft Fuselage: 31) internally with provision for 30, 45, or 90 imp. gallon slipper tanks or a 50 imp. gallon torpedo tank; the time-table definitely was doable (though it wasn't operational during the USAAF's Big Week, it was operational to some extent before April, 1944), but it was initially tied up in operations defending against V-1 attacks, which is kind of more important than escorting bombers.

Spitfire Mk.XVIII: Wasn't operational until after the war. It supposedly had more fuel capacity, but I have no idea what it was.


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## Wild_Bill_Kelso (Apr 7, 2022)

GregP said:


> Having small improvements add up to a total speed increase is not my experience with warbirds at all, and it also doesn't work very well with civil aircraft, either, say a Mooney 201. I have a good friend who has one. There are lots of mods out there and each has a speed increase associated with it. Adding them all will NOT give you an additive speed increase.
> 
> It might if you add something to a wingtip and another thing to the bottom of the fuselage but, if both the things are on the fuselage, they just don't add up because they tend to interact when both are anywhere near the same airflow. Other posts don't trump real life airplanes trying to go faster, and there are a lot of those. Let's see, the Bonanza crowd (though they shouldn't since they are already almost dangerously near redline at cruise), anyone in the Van's RV family (almost dangerously near the flutter limit when painted like a typical homebuilder chooses paint), Mooney M20s, and all the warbirds at Reno, just to name a few. I don't know of anyone ion there who has achieved an additive speed increase with more than two mods that were well-separated in the free airflow. These mods were usually gear doors or better wheelpants and wingtips. These two, at least, do not usually interact with one another.



Well, I appreciate your insights, and I gather that you know whereof you speak, but in this particular case it seems to have been an actual thing that happened. I'm not just relying on some "other post", the one I referenced upthread (I'm not going to link it again, anyone who wanted to read it has done by now) seems to be well attributed. As in, that is what happened in real life - they took a Spit V and made a bunch of fairly minor changes, and it ended up going 30 mph faster so the changes did have cumulative effects. I take you at your word that aerodynamic improvements are tricky to implement in such a way that it has telling effect, but presumably these engineers were aware of that and knew what they were doing. Either that or they got real lucky, who knows. But whatever they did worked. I think that makes it pretty clear it can be done.

I also know of many other cases where this was actually done during the war with other aircraft, not just in the UK. There are several of these reports on WWiiaircraftperformance.org. I also know for a fact that a wheel door cover, flush riveting, retractable tail wheel, improved engine exhaust etc., WILL reduce drag. Whether that necessarily translates into x number of mph in speed increase, I don't know. How applicable it is to modern aircraft made with modern manufacturing standards, or already improved for racing, i can't say. I'm not an engineer, hell I can barely do simple maintenance on my car. But I am familiar with historical documents, research, and like most of you, I've read plenty of primary sources from WW2.

So you can say what you like, but I'm pretty sure this is 100% real.


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## Wild_Bill_Kelso (Apr 7, 2022)

Zipper730 said:


> I had thought the same thing, but considering they posted the change in speed measured, I figured they meant the total contribution.
> 
> 
> Yikes...
> ...



Interesting, I thought Spit Mk VIII had two tanks in the wings plus an increased main fuselage tank.


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## wuzak (Apr 7, 2022)

Wild_Bill_Kelso said:


> Interesting, I thought Spit Mk VIII had two tanks in the wings plus an increased main fuselage tank.



One in each wing, inboard of the gun positions.

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## EwenS (Apr 8, 2022)

Zipper730 said:


> While I know the production lines for the Mk.VII/VIII ultimately ended up going to other Spitfire variants, were the jigs used for the tail-wheel used as is, or were they destroyed? I figure if they weren't destroyed, it would be possible to just lift them over and fold it into the late Mk.IX line.



Supermarine were the sole producer of the Mk.VIII. Production of that model ended in Dec 1944.

By then Mk.IX/XVI was being produced only by CBAF where it continued until Aug 1945. BUT CBAF was, in Dec 1944, already in the process of changing over to producing the Mk.XXI.

Why would you want to further disrupt production at CBAF to implement change on a run out model? Especially when the change will deliver negligible benefit in the real world. In performance terms there is next to nothing to choose between a Mk.VIII and a Mk.IX.

Added to which some of them could probably be switched to the Mk.XIV already being produced in parallel at Supermarine.


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## GregP (Apr 8, 2022)

Wild_Bill_Kelso said:


> Well, I appreciate your insights, and I gather that you know whereof you speak, but in this particular case it seems to have been an actual thing that happened. I'm not just relying on some "other post", the one I referenced upthread (I'm not going to link it again, anyone who wanted to read it has done by now) seems to be well attributed. As in, that is what happened in real life - they took a Spit V and made a bunch of fairly minor changes, and it ended up going 30 mph faster so the changes did have cumulative effects. I take you at your word that aerodynamic improvements are tricky to implement in such a way that it has telling effect, but presumably these engineers were aware of that and knew what they were doing. Either that or they got real lucky, who knows. But whatever they did worked. I think that makes it pretty clear it can be done.
> 
> I also know of many other cases where this was actually done during the war with other aircraft, not just in the UK. There are several of these reports on WWiiaircraftperformance.org. I also know for a fact that a wheel door cover, flush riveting, retractable tail wheel, improved engine exhaust etc., WILL reduce drag. Whether that necessarily translates into x number of mph in speed increase, I don't know. How applicable it is to modern aircraft made with modern manufacturing standards, or already improved for racing, i can't say. I'm not an engineer, hell I can barely do simple maintenance on my car. But I am familiar with historical documents, research, and like most of you, I've read plenty of primary sources from WW2.
> 
> So you can say what you like, but I'm pretty sure this is 100% real.



Not really. They got the general Spitfire up to 408 mph, but it wasn't the same as a Mk V airframe with modifications. Later Griffon Spitfires were also changed airframes and were longer and sleeker. So, yes, they could make a Spitfire go faster, but no, it wasn't a modified Mk. V airframe anymore.

A MK. V was 29 ft 11 in long and came in at 6,525 pounds loaded. Top speed was 371 mph at 20,000 ft and 350 mph at 5,900 ft. This from either 1,470 or 1,585 hp, depending on whether it has a Merlin 45 or a Merlin 50.

A Spitfire XIV was 32 ft 8 in long and came in at 8,574 pounds loaded. Top speed was 449 mph at 24,500 ft. This from a Griffon 65 of 2,050 hp.

Let's take the 371 mph. Using the standard cube root of the power increase, we'd expect the XIV to go 414 mph just due to the power change. Since it went 449 mph, the difference was a change in drag. They weren't much like the same airframe, with the exception of the wing and, rather naturally, the XIV would not turn or handle like a MK. V since it was a ton and half heavier with essentially the same wing. It DID go faster, largely with a huge does of horsepower, but also with reduced drag. That didn't come from a series of small mods but rather from a general cleanup of the fuselage when the Griffon was fitted with a 5-bladed prop and the new tail and overall streamlining were changed.


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## Wild_Bill_Kelso (Apr 8, 2022)

I don't know enough about the production arrangements, but I know that they could have cut a few less promising projects like the Defiant, Fairey Albacore, Bristol Blenheim, Hawker Henley etc., and also make a few hundred less Spit Mk Vs, and maybe you could get something like the Mk VIII into service a bit sooner, and perhaps enhance it a bit further.

I love the Mk IX and those were extremely useful, but I think the VIII is a bit more so because of the enhanced fuel capacity. Once you are at Mk.XIV of course you can rush strait into that.

Of course, hindsight and all that. This seems to be one way to get to a longer ranged spit though.


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## Wild_Bill_Kelso (Apr 8, 2022)

GregP said:


> Not really. They got the general Spitfire up to 408 mph, but it wasn't the same as a Mk V airframe with modifications. Later Griffon Spitfires were also changed airframes and were longer and sleeker. So, yes, they could make a Spitfire go faster, but no, it wasn't a modified Mk. V airframe anymore.
> 
> A MK. V was 259 ft 11 in long and came in at 6,525 pounds loaded. Top speed was 371 mph at 20,000 ft and 350 mph at 5,900 ft. This from either 1,470 or 1,585 hp, depending on whether it has a Merlin 45 or a Merlin 50.
> 
> ...



Wow! 259 feet? Much longer than I thought 

From what I understand, actual factory production Spit Vs ranged from top speed of ~350 mph to 380 or so, and this depended on the engine type and maintenance, but also a lot on the finish and various drag related modifications, for example some of them had external BP window, some internal, some had flat rearview mirror, some fared, etc.

I think small mods clearly do work, and did, but a general cleanup of the fuselage works too, no doubt.


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## Jugman (Apr 8, 2022)

drgondog said:


> Interesting. Couple of comments:
> The S3 wing was 11.7 T/C Max at semi span 63%, 14.7% T/C Max at 25%. Extrapolating to Root chord puts it in the 16% T/C Max range - about the same as P-51.
> 
> The Cd profile drag (pure shape, no friction) a low CL (High Speed) in the RN=19 x 10^6 range is 0.0062 for that puttied, primed and sanded smooth wing.
> ...


Per High-Speed Wind-Tunnel Tests of Dive-Recovery Flaps on a 0.3-Scale Model of the P-47D Airplane it 15%.

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## tomo pauk (Apr 8, 2022)

GregP said:


> A MK. V was 259 ft 11 in long and came in at 6,525 pounds loaded. Top speed was 371 mph at 20,000 ft and 350 mph at 5,900 ft. This from either 1,470 or 1,585 hp, depending on whether it has a Merlin 45 or a Merlin 50.
> 
> A Spitfire XIV was 32 ft 8 in long and came in at 8,574 pounds loaded. Top speed was 449 mph at 24,500 ft. This from a Griffon 65 of 2,050 hp.



Since we're discussing aircraft, stating the altitude where the speed was achieved and horsepower was available might've been handy. Eg. Spitfire XIV using 2050 HP will do 417 mph: data sheet.



GregP said:


> Let's take the 371 mph. Using the standard cube root of the power increase, we'd expect the XIV to go 414 mph just due to the power change. Since it went 449 mph, the difference was a change in drag. They weren't much like the same airframe, with the exception of the wing and, rather naturally, the XIV would not turn or handle like a MK. V since it was a ton and half heavier with essentially the same wing. It DID go faster, largely with a huge does of horsepower, but also with reduced drag. That didn't come from a series of small mods but rather from a general cleanup of the fuselage when the Griffon was fitted with a 5-bladed prop and the new tail and overall streamlining were changed.



Spitfire V going 370+ mph was probably the one with less drag, if just a tad less...
At 26000 ft, where, with ram, the XIV have had 1780 HP, it indeed did just under 450 mph. Spitfire V with Merlin 45 or 50 will have under 900 HP there, even with ram, and do 330-350 mph, depending on carb and state of aircraft?


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## GregP (Apr 8, 2022)

Wild_Bill_Kelso said:


> Wow! 259 feet? Much longer than I thought
> 
> From what I understand, actual factory production Spit Vs ranged from top speed of ~350 mph to 380 or so, and this depended on the engine type and maintenance, but also a lot on the finish and various drag related modifications, for example some of them had external BP window, some internal, some had flat rearview mirror, some fared, etc.
> 
> I think small mods clearly do work, and did, but a general cleanup of the fuselage works too, no doubt.



Seems like maybe a bit longer than the actual 29 ft, doesn't it? 

I am not exactly the best typist in the world, as I'm sure you recognize ....

But, I WOULD like to fly ANY Spitfire, particularly the Mk.IX. It was the Mk. V with a dose of 2-stage power and was likely the best of the Spitfires for eacy handling combined with high climb rate and decent speed.

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## GregP (Apr 8, 2022)

Hi Tomo.

I can find Mk. V at 371 mph at 20,000 feet and 350 mph at 9,500 feet with a stronger engine ... but the specs don't show the Merlin 50 variant at 20,000 feet. I suspect that it was a tad faster due to an extra 100 hp, but was not going to do the complete lookup of the performance envelope for a short post stating that speed increases are not strictly additive in general. That's pretty obvious to anyone who had tried it in their airplane. It gets faster, but not nearly as much as we want it to and hope it will.

My point was that the speed increase was due to a a combination of a few mods and general better finish (I think of it as a "cleanup"), but a Spitfire going faster than 408 mph or so was a combination of the Griffon horsepower and a new fuselage that was cleaner than the Mk. V / IX was, combined with the big, 5 or 6-blade Rotol prop / contra-prop for the Griffon variants.


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## tomo pauk (Apr 8, 2022)

GregP said:


> I can find Mk. V at 371 mph at 20,000 feet and 350 mph at 9,500 feet with a stronger engine ... but the specs don't show the Merlin 50 variant at 20,000 feet. I suspect that it was a tad faster due to an extra 100 hp, but was not going to do the complete lookup of the performance envelope for a short post stating that speed increases are not strictly additive in general. That's pretty obvious to anyone who had tried it in their airplane. It gets faster, but not nearly as much as we want it to and hope it will.


Merlin 50 was making about the same power as the Mk.45. The 'merlin in perspective' boo even gives a bit less power for the Mk.50.



GregP said:


> My point was that the speed increase was due to a a combination of a few mods and general better finish (I think of it as a "cleanup"), but a Spitfire going faster than 408 mph or so was a combination of the Griffon horsepower and a new fuselage that was cleaner than the Mk. V / IX was, combined with the big, 5 or 6-blade Rotol prop / contra-prop for the Griffon variants.



Mk 14 was dirtier than the Mk.IX, due to the much bigger radiators.
Mk.IX was cleaner than the Mk.V in a number of details, bar the cooling system (where the Mk.V was less draggy), making the Cd0 of the Mk.V a bit better than of the Mk.IX. See here.
Brute force coming from the 2-stage Griffon engine made all the difference; granted, a much better better prop was needed for the 2-stage Griffon than for the 2-stage Merlin, let alone for the 1-stage Merlin.

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## Wild_Bill_Kelso (Apr 8, 2022)

GregP said:


> *But, I WOULD like to fly ANY Spitfire*, particularly the Mk.IX. It was the Mk. V with a dose of 2-stage power and was likely the best of the Spitfires for eacy handling combined with high climb rate and decent speed.



Me too brother!!!


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## GregP (Apr 8, 2022)

Mk XIV cannot be dirtier than the Mk. IX because the power increase alone will not give 449 mph. Cannot be possible. If you look at an XIV side by side with a Mk. IX, the cleanup will be rather obvious. The XIV just fits better and has fewer edges and things to produce drag. Well. at least the ones I have seen up close.

The museum used to display a Mk. IX, a freshly-restored Mk. III, and an XIV, sometime side by side. Alas, the Spitfires all departed for their owner's homes along with the Hurricane and the Wildcat painted as a Martlett. Now, they're all in Texas getting quite warm in the hangar.

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## Zipper730 (Apr 8, 2022)

EwenS said:


> Supermarine were the sole producer of the Mk.VIII. Production of that model ended in Dec 1944.


I'm surprised they never added aft fuel to that design then...


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## Shortround6 (Apr 8, 2022)

Zipper730 said:


> I'm surprised they never added aft fuel to that design then...


If you can fit it in you can fly with it??? 

From wiki. 

Provision was made to allow the Mk VIII to carry a single "slipper" drop tank of 30, 90 or 170 gal capacity. With a 170 gal tank, the aeroplane could fly over 1,500 mi (2,400 km). When carrying the* 90* or 175 gal tank the aircraft was *restricted*, once airborne and at cruising altitude,* to straight and level flight.*

Now perhaps better pilots could be allowed a bit more latitude but there was difference between flying a certain distance and _fighting_ with a certain fuel load over and above the "normal fuel load. The MK VIII had the bigger fuselage tanks and had the 11-12 gallon tanks out in the wing. Tanks in back of the pilot tended to screw up the center of gravity. With a tank behind the pilot how much do you want to screw up the CoG even once you get rid of the drop tank. 

Lets Remember that the they had been trying to put more fuel into/under a Spitfire since at least 1940.





At least 3 squadrons tried out this configuration of MK II.

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## Wild_Bill_Kelso (Apr 8, 2022)

Spitfire. Still manages to be pretty even with that ugly bump on the wing.

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## Zipper730 (Apr 8, 2022)

Shortround6 said:


> From wiki.
> 
> Provision was made to allow the Mk VIII to carry a single "slipper" drop tank of 30, 90 or 170 gal capacity. With a 170 gal tank, the aeroplane could fly over 1,500 mi (2,400 km). When carrying the* 90* or 175 gal tank the aircraft was *restricted*, once airborne and at cruising altitude,* to straight and level flight.*


Then why did they fit all that tankage to the Mk.IX? They added like 66-75 gallons of fuel aft on that design!


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## wuzak (Apr 9, 2022)

GregP said:


> Not really. They got the general Spitfire up to 408 mph, but it wasn't the same as a Mk V airframe with modifications.



Mk IX got 408mph with Merlin 63.

404mph with Merlin 66 (LF.IX).

416mph with Merlin 70 (HF.IX).

And it really was a modified Mk V. Most of the modifications were forward of the firewall.




GregP said:


> Later Griffon Spitfires were also changed airframes and were longer and sleeker. So, yes, they could make a Spitfire go faster, but no, it wasn't a modified Mk. V airframe anymore.



Early Mk XIIs were modified Mk.Vs.

XIVs were modified Mk.VIIIs. The "prototypes" were Mk.VIIIG.




GregP said:


> A MK. V was 29 ft 11 in long and came in at 6,525 pounds loaded. Top speed was 371 mph at 20,000 ft and 350 mph at 5,900 ft. This from either 1,470 or 1,585 hp, depending on whether it has a Merlin 45 or a Merlin 50.
> 
> A Spitfire XIV was 32 ft 8 in long and came in at 8,574 pounds loaded. Top speed was 449 mph at 24,500 ft. This from a Griffon 65 of 2,050 hp.




The Griffon was longer, and mounted more forward. In the XIV the engine was tilted down at the front for better pilot visibility. That is the reason for eh 5 blade prop.

And, of course, the wider rudder added to length.




GregP said:


> Let's take the 371 mph. Using the standard cube root of the power increase, we'd expect the XIV to go 414 mph just due to the power change. Since it went 449 mph, the difference was a change in drag. They weren't much like the same airframe, with the exception of the wing and, rather naturally, the XIV would not turn or handle like a MK. V since it was a ton and half heavier with essentially the same wing. It DID go faster, largely with a huge does of horsepower, but also with reduced drag. That didn't come from a series of small mods but rather from a general cleanup of the fuselage when the Griffon was fitted with a 5-bladed prop and the new tail and overall streamlining were changed.



The XIV did have bigger, draggier radiators, but I agree that there was an improvement in drag.


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## wuzak (Apr 9, 2022)

GregP said:


> The museum used to display a Mk. IX, *a freshly-restored Mk. III*, and an XIV, sometime side by side. Alas, the Spitfires all departed for their owner's homes along with the Hurricane and the Wildcat painted as a Martlett. Now, they're all in Texas getting quite warm in the hangar.




There were 40 PR.Mk.IIIs (redesignated PR.Mk.I Type C) built - all converted from Spitfire Mk.Is.

There were two Mk.IIIs built. One was a new build and one was later converted from a Mk.V. The original became the first with a Merlin 61, and was the prototype for the IX.

Which Mk.III do you have?


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## GregP (Apr 9, 2022)

wuzak said:


> Mk IX got 408mph with Merlin 63.
> 
> 404mph with Merlin 66 (LF.IX).
> 
> ...



Yes, including a new, smoother nose that was not exactly the same as the Mk. V nose. And, since it came with a new, baby 2-stage Merlin, it also came with a 4-bladed propeller and a new spinner. All of which combined to go from 380 mph or so at 22,500 feet in the Mk. V to 408 mph in the Mk, IX. 

Let's use the old cube root of the power increase rule.

1,4701 hp, 380 mph @ 22,500 ft for the Mk Vb.

1,720 hp, 408 mph @ 22,000 ft where, with the cube root of the power increase rule, we'd expect 400 mph. So, the new nose, 4-bladed prop, and whatever "cleanup" was done added 8 mph to the expected top speed. Not bad, but not great, either. Still, it WAS a useful jump in performance.


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## Wild_Bill_Kelso (Apr 9, 2022)

But what are they both making at altitude? Is the MK V really making that much at 22,500 feet? I'd think it would be a lot faster!

As I'm sure you are aware, a major factor in top speed is how much power the engine generates _at altitude_ where the air is thin. Two fighters with the same HP output, but one has a low alt blower (like a cropped impeller) and the other a high alt or multi-speed or multi-stage blower, the latter is going to have a faster top speed, though the former is going to be faster down low.


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## GregP (Apr 9, 2022)

wuzak said:


> There were 40 PR.Mk.IIIs (redesignated PR.Mk.I Type C) built - all converted from Spitfire Mk.Is.
> 
> There were two Mk.IIIs built. One was a new build and one was later converted from a Mk.V. The original became the first with a Merlin 61, and was the prototype for the IX.
> 
> Which Mk.III do you have?



Don't have one anymore. 

It was a private Spitfire for an owner in Texas, and is was absolutely beautiful. That owner had four airplanes at the Planes of Fame and some 6 years ago, he had them flown from Chino to Texas, where his home base is.


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## GregP (Apr 9, 2022)

Wild_Bill_Kelso said:


> But what are they both making at altitude? Is the MK V really making that much at 22,500 feet? I'd think it would be a lot faster!
> 
> As I'm sure you are aware, a major factor in top speed is how much power the engine generates _at altitude_ where the air is thin. Two fighters with the same HP output, but one has a low alt blower (like a cropped impeller) and the other a high alt or multi-speed or multi-stage blower, the latter is going to have a faster top speed, though the former is going to be faster down low.



The Mk. V is a rather well-know animal and it wasn't faster. Spitfires got faster as they got engines that retained horsepower up higher, like all WWII fighters did as they were developed. Most of the speed came from maintaining horsepower to a higher altitude, new propellers, and new cowlings to hold the new engines. A small bit came from better streamlining and small mods.

You can see a basic chart of Merlin power versus altitude below. It was in another thread in a reply from member jerryw back in 2008, and I borrowed it from there, but you can find it in Google images, too.

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## DarrenW (Apr 9, 2022)

Wild_Bill_Kelso said:


> But what are they both making at altitude? Is the MK V really making that much at 22,500 feet? I'd think it would be a lot faster!
> 
> As I'm sure you are aware, a major factor in top speed is how much power the engine generates _at altitude_ where the air is thin. Two fighters with the same HP output, but one has a low alt blower (like a cropped impeller) and the other a high alt or multi-speed or multi-stage blower, the latter is going to have a faster top speed, though the former is going to be faster down low.


I did some preliminary checks on www.wwiiaircraftperformance.org and found the maximum speeds of the Mk V and Mk IX at sea level to be as follows:

Spitfire Mk V with Merlin 45 @ 1175 hp (+12 boost) = 302 mph
Spitfire Mk IX with Merlin 66 @ 1575 hp (+18 boost) = 336 mph

This gives the Mk IX 400 more horsepower with a speed difference of 34 mph. To me it looks like the drag conditions of both marks were not very different in a useful sense, as the average WW2 piston engine fighter would need approximately 15 hp to increase top speed at sea level by 1 mph. Not a perfect calculation but it will probably get you in the ballpark. I'm also not sure if the four bladed propeller had anything to do with the speed difference as a three blade can be just as efficient depending on altitude, blade type, and the engine's particular ratings. So it seems like the performance increase of the Mk IX was primarily due to increased engine power output.


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## tomo pauk (Apr 9, 2022)

GregP said:


> 1,4701 hp, 380 mph @ 22,500 ft for the Mk Vb.
> 
> 1,720 hp, 408 mph @ 22,000 ft where, with the cube root of the power increase rule, we'd expect 400 mph. So, the new nose, 4-bladed prop, and whatever "cleanup" was done added 8 mph to the expected top speed. Not bad, but not great, either. Still, it WAS a useful jump in performance.



At 22500 ft, the Merlin 45 or 50 on the Mk.V will be making about 1000 HP with ram, not 1470. Not even the Merlin 46 or 47 (the ones with big S/C) will do more than 1100 at 22500 ft. See your chart.
The pilot of Spitfire VB will be very happy if it can fly at 360 mph at 22500 ft straight and level.
The Merlin 66 will do perhaps 1550 HP at 22500 ft with ram. FWIW: data sheet

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## pbehn (Apr 9, 2022)

There is a chart here of a Spitfire V using 16 lbs boost doing 378 MPH at 15-17,000 ft and circa 370 at 22,500ft http://www.wwiiaircraftperformance.org/Spitfire_V_Level_Speed_RAE.jpg

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## GregP (Apr 9, 2022)

Those must be sea level speeds.


tomo pauk said:


> At 22500 ft, the Merlin 45 or 50 on the Mk.V will be making about 1000 HP with ram, not 1470. Not even the Merlin 46 or 47 (the ones with big S/C) will do more than 1100 at 22500 ft. See your chart.
> The pilot of Spitfire VB will be very happy if it can fly at 360 mph at 22500 ft straight and level.
> The Merlin 66 will do perhaps 1550 HP at 22500 ft with ram. FWIW: data sheet



Hi Tomo.

The formula is: New Speed = (cube root [new power / old power]) * old speed for estimate of speed increase due to power alone.

It may surprise you that I have spreadsheets with the Merlins, Griffons, and Allisons, etc. in them, but not all of them report power at the same altitudes. I don't mind doing a power chart at all, but I sort of flinch when someone wants me to go to the trouble of doing power charts for all models of two separate engine designs. It isn't that important since we basically KNOW what these airplanes will do.

For the purposes of estimating a change in performance due to power increase alone, knowing the power of one of them at some altitude does nothing unless we know the power of the other one at the same altitude. Since I see and work on warbirds almost every week, I'm not that interested in spending time digging around for no good reason, and there isn't in this case. 80%+ of the increase in performance of the MK. IX over the Mk. V was from the increased engine power. I wouldn't be surprised at all if it turned out to be 90%+. Take a MK. IX and put in a Merlin 45 and you'd have almost an exact clone of a Mk. V.

And there's nothing new to either you or me in the above at all.

Edit:

Sorry, Tomo.

When I re-read the post above, it doesn't come off very nice. Unintended originally. So, apologies and I attach one of my Merlin charts with Horsepower versus altitude for P.V. 12 up through Merlin 66. From there, we could make some decent estimates. The chart I made from the original Rolls-Royce chart is on the second tab.


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## pbehn (Apr 9, 2022)

GregP said:


> Those must be sea level speeds.
> 
> 
> Hi Tomo.
> ...


As I understand it a single stage Merlin could produce the same power as a two stage Merlin if it had the fuel and uprated parts and maybe bigger radiator(s), but why would you do that, a lot of time and effort to make a sows ear out of a sows ear?

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## GregP (Apr 9, 2022)

A single-stage Merlin could produce about the same power at sea level and, likely be decently close up to it's critical altitude. The single-stage engine might even make a few more hp down low since it is not driving the same supercharger and therefore uses less power than the 2-stage engine supercharger.

After that critical altitude for the single-stage, the single and two -stage engine will stay decently close until the altitude where the pilot changes supercharger gears in the 2-stage aircraft. Then, the 2-stage guy will pull away dramatically and continue to perform quite well until his critical altitude, after which he will gradually lose performance like a normal engine does until he reaches the altitude where the max power he can make is just the power required for level flight. That will be absolute ceiling.

The above assumes the pilot has oxygen and/or a pressure cabin or he will likely pass out before reaching critical altitude. 

Edit:

The above is theoretical and makes some assumptions. The assumptions made are as follows:
1. Both engines are running the same fuel.
2. Both engines are running the same boost.

So, a single-stage Merlin 45 made 1,480 hp at 12,500 feet.
A 2-stage Merlin 63 made 1,710 hp at 8,500 feet, and did so be virtue of running more boost due to have an extra compressor stage.

These engines were about a year apart, and development usually results in better numbers up until the limit has been reached. This assumes a real development effort and not just an experiment.

But, in real life, they didn't follow assumption 1 and 2. In WWII, Merlins were cleared for more boost on a VERY regular basis. If you look at the single-stage engines and 2-stage engines, almost every new Merlin model gave an increase in boost and HP. Not EVERY one, but most of them. By way of example, the Merlin 45M could make 1,580 hp and the Merlin 61 only made 1,565. But the Merlin 45 was well-tweaked for HP and the Merlin 61's main intent was to make better HP up a lot higher. It DID that, but the Merlin 45M was the superior engine at 3,000 feet ... assuming you were flying a Spitfire at 3,000 feet, that is. If you were in Mk. IX, you were much more likely at 18 - 25,000 feet.


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## PAT303 (Apr 10, 2022)

GregP said:


> Having small improvements add up to a total speed increase is not my experience with warbirds at all, and it also doesn't work very well with civil aircraft, either, say a Mooney 201. I have a good friend who has one. There are lots of mods out there and each has a speed increase associated with it. Adding them all will NOT give you an additive speed increase.


You have lost me here, you only have to look at Reno racers to see the effect all the little improvements make.


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## PAT303 (Apr 10, 2022)

Wild_Bill_Kelso said:


> There was a tactical aspect too. The commander, an Australian Ace named Clive Caldwell,


He was not a very liked man, too many times he had Spitfires endlessly circling until he was happy everyone formed up under him before attacking while the Betty's flew off into the distance. No aircraft could catch a Betty with a 10 mile head start in that situation.


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## PAT303 (Apr 10, 2022)

Zipper730 said:


> I'm surprised they never added aft fuel to that design then...


So is everyone else considering how blindingly obvious it was


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## PAT303 (Apr 10, 2022)

Shortround6 said:


> When carrying the* 90* or 175 gal tank the aircraft was *restricted*, once airborne and at cruising altitude,* to straight and level flight.*


So was every other aircraft when loaded with drop tanks or bombs, the much vaunted P51 would stall and pancake if not flown straight and level when fueled up, I remember reading once about a red tail pilot that would take off with the canopy unlocked so he had a chance to get out at low level if his plane stalled. The MkXIV could fight with the 90G combat tank fitted and outperform the Me109 and FW190 with it attached.


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## GregP (Apr 10, 2022)

PAT303 said:


> You have lost me here, you only have to look at Reno racers to see the effect all the little improvements make.



You must be kidding.

The lion's part of the speed increase is the power increase. If a stock P-51 makes a 360 mph lap with 1,490 hp (pretty darn close to a stock P-51D lap) at Reno and makes NO OTHER changes other than bumping the power to 3,850 (can you say "Strega" or "Voodoo"?) the expected speed is 494 mph using the standard cube root rule. Voodoo's fastest lap is 512 with MOST in the 495 mph range, so all the little "extra" mods made a whole 18 mph bump after the 134 mpg bump that came from the power increase.

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## tomo pauk (Apr 10, 2022)

GregP said:


> Hi Tomo.


A simple "yes, I'm wrong, Merlin 45 was not near 1470 HP at 22500 ft" would've been just fine.



GregP said:


> 80%+ of the increase in performance of the MK. IX over the Mk. V was from the increased engine power. I wouldn't be surprised at all if it turned out to be 90%+.



Bingo.



GregP said:


> Take a MK. IX and put in a Merlin 45 and you'd have almost an exact clone of a Mk. V.



A Mk.IX with Merlin 45 would've been faster than the Mk.V, featuring less draggy exhausts, less draggy BP glass layout, no ice guard, and a bit better fit & finish. 



pbehn said:


> As I understand it a single stage Merlin could produce the same power as a two stage Merlin if it had the fuel and uprated parts and maybe bigger radiator(s), but why would you do that, a lot of time and effort to make a sows ear out of a sows ear?





GregP said:


> A single-stage Merlin could produce about the same power at sea level and, likely be decently close up to it's critical altitude. The single-stage engine might even make a few more hp down low since it is not driving the same supercharger and therefore uses less power than the 2-stage engine supercharger.



1600+ HP for the latest 1-stage Merlins, 2000+ HP for the latest 2-stage Merlins (both for the cases with latest fuel and no water-alcohol injection, and at low altitude).




GregP said:


> After that critical altitude for the single-stage, the single and two -stage engine will stay decently close until the altitude where the pilot changes supercharger gears in the 2-stage aircraft. Then, the 2-stage guy will pull away dramatically and continue to perform quite well until his critical altitude, after which he will gradually lose performance like a normal engine does until he reaches the altitude where the max power he can make is just the power required for level flight.



The pilot of an aircraft with a 2-stage engine already has the advantage down low.
There is such a thing as an 1-stage 2-speed supercharged engine, too.


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## Shortround6 (Apr 10, 2022)

Trouble is that the cube root rule needs a correction factor once you get into the high 300mph range. 
Some planes will start showing a difference due to airfoil or local air flows/ compressability even if they tracked the cube root rule pretty well over a range of several hundred mph.

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## Shortround6 (Apr 10, 2022)

The single stage Merlins topped out at 18lb of boost. 
You might be able to get more low down without a boost limiter.

The two stage engines started out at 12lbs of boost and worked their way up to 25lbs of boost. 

There were a few things that limited power at times. The single stage engines didn't get to use 18lb of boost until the supercharger drive system was beefed up. Somewhere between 14lbs and over 16lbs it was possible to start breaking the drive shaft and or clutches. The up graded drive system didn’t arrive until after the 2 stage supercharger showed up.
A two stage system actually makes things a bit easier on the engine. A two stage supercharger will actually take less power to drive for the same manifold pressure and heat the intake charge less. And that is without the intercooler. The 2 stage engine is flowing more air ( it is denser) that a single stage engine using the same manifold pressure.

The corrections for different bobs and bits on the Spitfire (outside bullet proof glass, IFF aerials, snow guards,etc)
Need a bit of interpretation to. As the speed goes up from 360-370mph to over 400mph the actual effect will go up slightly, it was just easier to use a fast mph correction than figure out the percentage. 
Two of fittings can actually make a difference in power. I have never really seen any charts or much talk about the difference in thrust between exhaust manifolds. We are told that one style had less drag than another but believing that both had the same amount of thrust is a bit harder to swallow. But since exhaust thrust varies with both altitude and speed of the aircraft even with the engine burning the same amount of air it gets simplified in most explanations.
The "snow guard" is another piece that has some different effects. We are told it was worth about 6mph.
But what it did was disrupt the airflow going into the intake and lower the ram effect. This lowered the critical altitude (FTH) of the engine. So the engine is making less power at a given height than a plane without the snow guard, this is somewhat altitude dependent.

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## tomo pauk (Apr 10, 2022)

Shortround6 said:


> The single stage Merlins topped out at 18lb of boost.
> You might be able to get more low down without a boost limiter.
> 
> The two stage engines started out at 12lbs of boost and worked their way up to 25lbs of boost.
> ...



1-stage Merlin* with 'normal'-sized impellers were making +16 psi max. The ones with cropped impeller were the ones allowed for +18 psi.



Shortround6 said:


> A two stage system actually makes things a bit easier on the engine. A two stage supercharger will actually take less power to drive for the same manifold pressure and heat the intake charge less. And that is without the intercooler. The 2 stage engine is flowing more air ( it is denser) that a single stage engine using the same manifold pressure.



Very true.



Shortround6 said:


> Two of fittings can actually make a difference in power. I have never really seen any charts or much talk about the difference in thrust between exhaust manifolds. We are told that one style had less drag than another but believing that both had the same amount of thrust is a bit harder to swallow. But since exhaust thrust varies with both altitude and speed of the aircraft even with the engine burning the same amount of air it gets simplified in most explanations.



The bigger bulk of the 3-per-side exhausts vs. the 6-per-side is apparent looking at pictures and drawings. Eg. here vs. here.
The 'individual' exhausts will certainly also give a bit better exhaust thrust, the 2-stage Merlin already making the better exhaust thrust on it's own than the 1-stage type.
Cutting the drag by some fixed percentage usually gives more extra speed than increasing the propulsive power by the same percentage. The cube root law is ... evil; or, the "drag is cruel" saying I've 1st heard by Bill Marshall.
Granted, many times in ww2 was easier to increase the power by a good deal than it was to cut the drag by a good deal.



Shortround6 said:


> The "snow guard" is another piece that has some different effects. We are told it was worth about 6mph.
> But what it did was disrupt the airflow going into the intake and lower the ram effect. This lowered the critical altitude (FTH) of the engine. So the engine is making less power at a given height than a plane without the snow guard, this is somewhat altitude dependent.



Agreed again.

* goes for the Merlins usually found on Spitfires like the 40s and 50s series

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## Geoffrey Sinclair (Apr 10, 2022)

The early Spitfire PR types are worthy of several here be dragon signs. Conversions, conversions of the conversions, conversions of the converted conversions, new builds along with designation changes. Starting with the letter codes, PR A, B, C, D, E, F, G, which are reported to later been called PR mark I, II, III, IV, V, VI, VII. The designations covering different fuel capacity, camera and engine arrangements.

In 1940 the mark III and IV were allocated to fighter versions but the III was cancelled and the IV redesignated mark 20 during 1941 to early 1942, clearing the way for the mark numbers to be used by PR types. When doing so the letter C and mark III was used to designate short range, while D and mark IV long range (wing leading edge tanks usually), regardless of engine and camera fit, with the official production total of thirty PR mark III and two hundred and twenty nine PR mark IV reported by both the RAF and Ministry of Aircraft Production, totals which exclude the two prototype mark III, which were type D, long range, P9551 (September 1940), P9552 (March 1941) to PRIII type D (leading edge wing fuel tanks), prototypes on contract S.B. 2415/C.23A.

The other PR.III were R7029 to 7034, X4332 to 35, X4383 to 4386, X4491 to 4505 and X4538, with the R serials delivered last.

So 32 III and 229 IV produced as such. Mark III production, 9 August/September 1940, then the remainder November 1940 to May 1941, with mark IV production starting in June, probably.

The RAF census as of February 1943 only has PR.III, IV. XI and XIII, with 30/30 III ordered/delivered, 229/232 IV, 152/31 XI (yes, more delivered than ordered) Nett conversions are 18 to III, 68 to IV and 4 to XIII. For June 1944 it is PR III, IV, X, XI, XIII, XIX and Spitfire PR (Griffon 66) with 30/30 III, 229/229 IV, 471/335 XI, 22/22 XIX and 229/0 Spitfire PR (Griffon 66) Nett conversions are 13 to III, 71 to IV, 16 to X, 25 to XIII.

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## ThomasP (Apr 10, 2022)

Mosquito Merlin 25 (normal Ø10.25" impeller and 8.15/9.49:1 S/C ratios) 1-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade
Spitfire Merlin 66 2-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade


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## tomo pauk (Apr 10, 2022)

ThomasP said:


> Mosquito Merlin 25 (normal Ø10.25" impeller and 8.15/9.49:1 S/C ratios) 1-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade
> Spitfire Merlin 66 2-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade



Of course you're right. I'll edit my post above.


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## GregP (Apr 10, 2022)

tomo pauk said:


> A simple "yes, I'm wrong, Merlin 45 was not near 1470 HP at 22500 ft" would've been just fine.
> 
> 
> 
> ...



I should have realized in doesn't matter. Noted.


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## drgondog (Apr 10, 2022)

Jugman said:


> Per High-Speed Wind-Tunnel Tests of Dive-Recovery Flaps on a 0.3-Scale Model of the P-47D Airplane it 15%.


Just looked at the report and the model dimensions - Several model table dimensions are 'off' from 0.3 scale Model dimensions in Fig 1, and off from actual dimensions.
Actual vs Model values and ratios:
i.e Wing Area 300 ft. vs 27 ft (11.1:1); Wing Span 40' 10" vs 12.23 ft. (3.34:1); Wing Mean Aero Dyn Chord 87.5 in. vs 2.187 ft (26,25 in.) (3.33:1)
OTOH Tail Area (Stab and Elev) are 59.6sqft(actual) to 4.95ft (Table), Ratio of model to actual for Table is 12:1. 
The Table Data for H.Tail Area should say "17.88sqft".
The H.Tail Span are 16ft (Actual) to 57.63in. (Fig 1) but the Table value is 6.786 ft for a ratio of 2.35:1. I believe the H.Tail Span in the Table should be = 57.63x 0.3 = 4.8ft.

The reference P-47C/D dimensions are from Dean - 1st value, the second value is from table in NACA Report. The Table data in the report do not all agree the physical dimensions of the model shown in Fig 1 so the errors are curious. I also suspect that 15% is measured from model MAC - obviously not root.

This report states that the Root Chord is 15% but that implies extraction from another document. The other NACA report that I commented on explicitly stated the T/C at the 25in WS is 14.7%, considerably down slope from the root to the tip. OTOH if the P-47 Root chord is at the edge of the fuselage - not C/L - then 15% probably is correct.

Just looked root chord is at Fuselage location - not C/L like Mustang.

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## Shortround6 (Apr 10, 2022)

ThomasP said:


> Mosquito Merlin 25 (normal Ø10.25" impeller and 8.15/9.49:1 S/C ratios) 1-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade
> Spitfire Merlin 66 2-stage 2-speed low & high gear was rated at +25 lb boost with 150 grade


I would have my doubts about the single stage two speed engines making 25lbs of boost. 

They were rated at 14lbs at 6000-6250ft and were rated at 18lbs at 2250ft in low gear. You either need a crap load of RAM or you have to be flying well below sea level to pick up another 7lbs (14 in?) of pressure. 

Since high gear was supposed to be good for 18lbs at 9250ft that may be possible. However since the supercharger was taking 125hp more to run than when in low gear (and around 30% of the power was going into to heating the intake charge and only around 70% was actually compressing the air) you would be running on a very thin margin

Merlin type................................HP.......................Boost.......................Altitude.
XX-Low....................................1485........................14lbs.......................6000ft
XX-Hi........................................1490........................16lbs.....................12500ft
22/23 Low..............................1460.........................14lbs......................6250ft
22/23 Hi.................................1435..........................16lbs....................11000ft
24/25 Low..............................1635..........................18lbs....................2250ft
24/25 Hi..................................1510..........................18lbs....................9250ft

You might be able to it in high gear at under 3000ft? But even with 150 fuel you have to wonder if the detonation level is going to kick in before the you get to 25lbs of boost. 

Remember that the two stage engine is heating the air just a bit less to begin with and the intercooler is taking several hundred degrees back out of the intake mixture.

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## Wild_Bill_Kelso (Apr 10, 2022)

Geoffrey Sinclair said:


> The RAF census as of February 1943 only has PR.III, IV. XI and XIII, with 30/30 III ordered/delivered, 229/232 IV, 152/31 XI (yes, more delivered than ordered) Nett conversions are 18 to III, 68 to IV and 4 to XIII. For June 1944 it is PR III, IV, X, XI, XIII, XIX and Spitfire PR (Griffon 66) with 30/30 III, 229/229 IV, 471/335 XI, 22/22 XIX and 229/0 Spitfire PR (Griffon 66) Nett conversions are 13 to III, 71 to IV, 16 to X, 25 to XIII.


I imagine the PR Spits went away pretty quickly as they certainly seemed to have a high attrition rate, at least in the Med. Not as bad as the Tac-R Hurricanes, but pretty bad. P-38 / F-4/5 recon planes too, very, very dangerous job. The Luftwaffe seemed to press far more resources into killing recon birds than to stopping bombers. It speaks to the importance of reconnaissance! The original military mission of aircraft.


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## ThomasP (Apr 10, 2022)

Hey Shortround6,

Sorry, I should have posted a link to the following:

"http://www.wwiiaircraftperformance.org/mosquito/hx809.pdf"
"http://www.wwiiaircraftperformance.org/150grade/157sqdn-ORB-25lbs-3july44.jpg"

and







Somewhere on the internet . . . there is a very good write-up on the Mosquito using +25 lb boost operationally. IIRC it was mainly used in the anti-V1 (ie 'diver') and cross channel intruder roles. Unfortunately I do not remember where it is.

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## Shortround6 (Apr 10, 2022)

It wouldn't be the first time a set of pilot's notes listed something that is nearly impossible to do. 
Pilot's manual for an A-36A says that you can pull 52in _with RAM _at 2500rpm. 
The engine chart (estimated performance) _without RAM _says max power at sea level was about 1450hp at just over 50in. 

To put this into perspective the manual says you can hit 1325hp military power at 5400ft at 47in using RAM.
The engine chart says that without ram you hit about 1350/60hp at 2500ft about 46.75in. 

You need a crap load of RAM to hit the book numbers.


I don't doubt that some of those Mosquitos exceeded 18lbs of boost using 150 fuel. But getting close to 25lbs of boost means running the engines at full throttle while diving (even a shallow dive) or over revving the engines or operating very close to sea level (or a combination of all three). It might also require ability to override the supercharger shift device to engage Hi gear below normal altitude?

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## SaparotRob (Apr 10, 2022)

Is that an Imperial crap load or a Metric crap load?

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## GregP (Apr 10, 2022)

I'd imagine the altitude at which you can GET +25 psi boost was pretty low. So, it was very likely used as a V-1 chaser. The Merlin 25 was a Merlin 24 that turned the opposite direction. It was rated at 9,250 feet.

You certainly weren't going to get +25 psi at typical ETO combat heights. Power usually reduces by about 3% per 1,000 feet in the absence of boost but, when a supercharged engine reached critical altitude, it reduces that way anyway.


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## Zipper730 (Apr 10, 2022)

PAT303 said:


> The MkXIV could fight with the 90G combat tank fitted and outperform the Me109 and FW190 with it attached.


Fascinating, but could the Mk.VII/VIII? While it had less fuel up front, it also had a heavier engine further forward, which might give it a center of gravity that would allow you to get away with stuff you couldn't do otherwise.



Shortround6 said:


> Trouble is that the cube root rule needs a correction factor once you get into the high 300mph range.


While I knew eventually mach effects would start to throw a monkey-wrench into that formula (almost always you'll never see something simple apply over a large array of conditions), I'm curious what correction factor is that?


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## eagledad (Apr 10, 2022)

Gentlemen

From the Australian Archive check pages 140 to 147 in the PDF frame. There is data for the Mosquito FB VI at 25 pound boost. 

FYI

Eagledad

147

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## wuzak (Apr 10, 2022)

GregP said:


> The Merlin 25 was a Merlin 24 that turned the opposite direction. It was rated at 9,250 feet.



No, the Merlin 25 had a "reversed flow cooling system". Though the actual internal flow was the same, the external cooling system was rearranged to suit the Mosquito's radiators.

The 25 turned the same way as most Merlins - the exceptions being engines like the 131 for the Hornet, which was the same as the 130 on the other wing but with reversed rotation.


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## EwenS (Apr 11, 2022)

wuzak said:


> No, the Merlin 25 had a "reversed flow cooling system". Though the actual internal flow was the same, the external cooling system was rearranged to suit the Mosquito's radiators.
> 
> The 25 turned the same way as most Merlins - the exceptions being engines like the 131 for the Hornet, which was the same as the 130 on the other wing but with reversed rotation.


The reversal of the rotation in the Merlin 131, 133 and 135 was achieved by use of an extra gear in the reduction gear casing. The crankshaft turned in the same direction as the Merlin 130, 132 & 134 and all other Merlins.

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## GregP (Apr 11, 2022)

wuzak said:


> No, the Merlin 25 had a "reversed flow cooling system". Though the actual internal flow was the same, the external cooling system was rearranged to suit the Mosquito's radiators.
> 
> The 25 turned the same way as most Merlins - the exceptions being engines like the 131 for the Hornet, which was the same as the 130 on the other wing but with reversed rotation.



My bad. You are correct ... similar to Merlin24 / 224 except for reverse cooling, not reverse rotation. I was one line off.

I'm really surprised to see a Merlin 25 with a line for +25 psi boost at 25,000 feet, and I'd not guess you could get that. That's 80.82 inches of Mercury, and that's a lot for a WWII engine at 3,000 rpm. I wonder if that was at 3,200 or 3,400 rpm? You can get 90 inches from an Allison, but it would be a G-series with the big impeller, turning at 3,200 - 3,400 rpm on the best fuel you can make ... at LEAST 140 or so. I see in the text that it is a short-duration power setting, but it is still surprising.


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## PAT303 (Apr 11, 2022)

GregP said:


> The lion's part of the speed increase is the power increase. If a stock P-51 makes a 360 mph lap with 1,490 hp (pretty darn close to a stock P-51D lap) at Reno and makes NO OTHER changes other than bumping the power to 3,850 (can you say "Strega" or "Voodoo"?) the expected speed is 494 mph using the standard cube root rule. Voodoo's fastest lap is 512 with MOST in the 495 mph range, so all the little "extra" mods made a whole 18 mph bump after the 134 mpg bump that came from the power increase.







So the obvious streamlining, cut down canopy, blended joints and overall perfect fit and finish only added 18mph?.

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## PAT303 (Apr 11, 2022)

Zipper730 said:


> Fascinating, but could the Mk.VII/VIII? While it had less fuel up front, it also had a heavier engine further forward, which might give it a center of gravity that would allow you to get away with stuff you couldn't do otherwise.


It didn't need too, there is more than enough space in the leading edge to increase the tank capacity from 26G to 50G, add 75G in the rear, 96G main and a 90G dropper and you have the range to fight deep over the continent.


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## GregP (Apr 11, 2022)

PAT303 said:


> View attachment 664337
> 
> So the obvious streamlining, cut down canopy, blended joints and overall perfect fit and finish only added 18mph?.



Over and above the expected increase from the addition of power? Yes.

But, Reno is not a straight line. In a straight line, either Voodoo or Strega can probably make 540 mph at full tilt boogie. But, and here's the thing to note: we don't know the atmospheric conditions where it will make 540 mph (I figure warm and higher than sea level), so we don't know what a stock P-51D will do in a straight line at whatever altitude that is.

I DO know a stock P-51D will make about 360 mph around Reno with a completely stock engine. And we know Voodoo's and Strega's record speeds there. I made the calculation, but it's possible the speed would be higher for the P-51 than for, say, Rare Bear, because rare Bear has lower aspect ratio wings after race mods, and I don't know how much of the speed increase is due to a higher aspect ratio wing than Rare Bear, especially considering Rare Bear will ALSO make 540 mph in a straight line at full power.

So, it's an educated guess, but it's decently close.

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## PAT303 (Apr 11, 2022)

All the power in the world is pointless without the aerodynamic improvements to go with it, the Spitfire's speed improved with every little mod, not much, 5mph here and there but add up a couple and the gains, as well as more power are worthwhile. To give an example the Seafire Mk111 was 12mph faster than the MkII just by deleting the cannon stubs, reducing the cannon bulges by half and changing from triple ejectors to individual fishtail exhausts.

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## drgondog (Apr 11, 2022)

Zipper730 said:


> Fascinating, but could the Mk.VII/VIII? While it had less fuel up front, it also had a heavier engine further forward, which might give it a center of gravity that would allow you to get away with stuff you couldn't do otherwise.
> 
> 
> While I knew eventually mach effects would start to throw a monkey-wrench into that formula (almost always you'll never see something simple apply over a large array of conditions), I'm curious what correction factor is that?


Mach correction factor. The rough border between Incompressible Fluid and Compressible Fluid for aero is about M=0.3. Afterwards the Mach correction factor is applied to all Parasite and Form drag. 1/(1-M^2) is the multiplier. Refined in wind tunnel.

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## GregP (Apr 11, 2022)

PAT303 said:


> All the power in the world is pointless without the aerodynamic improvements to go with it, the Spitfire's speed improved with every little mod, not much, 5mph here and there but add up a couple and the gains, as well as more power are worthwhile. To give an example the Seafire Mk111 was 12mph faster than the MkII just by deleting the cannon stubs, reducing the cannon bulges by half and changing from triple ejectors to individual fishtail exhausts.



Of all the changes you can make to go faster, power is far and away the biggest. If you believe streamlining is more important, stay away from Reno, which is the very temple of power changes.


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## wuzak (Apr 11, 2022)

EwenS said:


> The reversal of the rotation in the Merlin 131, 133 and 135 was achieved by use of an extra gear in the reduction gear casing. The crankshaft turned in the same direction as the Merlin 130, 132 & 134 and all other Merlins.



Yes, I should have said reverse rotation propeller.


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## pbehn (Apr 11, 2022)

GregP said:


> Of all the changes you can make to go faster, power is far and away the biggest. If you believe streamlining is more important, stay away from Reno, which is the very temple of power changes.


Well I think it is about fruit picking. Initially the quickest and cheapest way to make a P-51D go faster is to take all the guns and ammo out along with everything else you dont need, cover holes smooth and fill in gaps etc, but you can only do that once. The aerodynamic improvements have now been made, making a substantially better version than Voodoo would cost a fortune and is probably against the competition regs. All the low hanging fruit has been picked, only more power/thrust remains.

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## Zipper730 (Apr 11, 2022)

drgondog said:


> Mach correction factor. The rough border between Incompressible Fluid and Compressible Fluid for aero is about M=0.3. Afterwards the Mach correction factor is applied to all Parasite and Form drag. 1/(1-M^2) is the multiplier. Refined in wind tunnel.


So you'd cube root, then multiply by (1/(1-(M^2))? Or do you convert the airspeed to mach then do that?


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## MikeMeech (Apr 12, 2022)

Hi
The Harleyford book, 'Spitfire - The Story of a Famous Fighter', despite being rather 'old' now does have some things of interest, including a list of Spitfire/Seafire 'variants':
























The book 'Spitfire, The History' has much more detail and drawings on many of these variants. The SAM Publications Modellers Datafiles No. 3 'The Supermarine Spitfire Part 1: Merlin Powered' and No. 5 'Part 2: Griffon-Powered' also have many of the 'official' drawings in that helps to illustrate the variations and improvements, including added fuel tanks and drag improvements.

Mike

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## BiffF15 (Apr 12, 2022)

MikeMeech said:


> Hi
> The Harleyford book, 'Spitfire - The Story of a Famous Fighter', despite being rather 'old' now does have some things of interest, including a list of Spitfire/Seafire 'variants':
> View attachment 664536
> 
> ...


The secret decoder ring reveals its secrets.

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## MikeMeech (Apr 12, 2022)

Hi
Alfred Price's 'The Spitfire Story' also has useful information and photographs, including reference drag reduction:









Many ideas were tried out some introduced others rejected for various reasons, indeed I think nearly every idea on this thread turns up in Spitfire development during WW2.
It should also be noted that during 1942 the 'Type S finish' for camouflage paint was introduced, this was a smooth, slightly reflective glossy finish that with a spot of polishing could give an increase in speed of up to 10 mph. However, service use can diminish effectiveness due to weathering, damage to the skin and hand painting large black and white stripes on wings and fuselage for operational purposes. Everything was a compromise.
Another image from Price's book, that might be of interest, is the filler point for for a 75 gallon rear tank on a late production Mk. IX (RR228) in February 1945: 




The various different marks of of Spitfire and the 'improvements' added at various stages did keep the Spitfire very competitive with both enemy fighters and newer allied designs. The Mk. IX and the Mk. VIII were both in operational service before the P. 51B arrived for use by the USAAF in Europe. The Mk. XIV was in operational service before the arrival of the P. 51D, and were shooting down enemy aircraft prior to the arrival of those fine aircraft. Range was very useful but so was performance when it was needed, and it was probably not a good idea to wait for a longer range development when enemy high quality fighters were the other side of the channel.

Mike

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## EwenS (Apr 12, 2022)

MikeMeech said:


> Hi
> The Harleyford book, 'Spitfire - The Story of a Famous Fighter', despite being rather 'old' now does have some things of interest, including a list of Spitfire/Seafire 'variants':
> View attachment 664536
> 
> ...


Being 60 years old it is hardly surprising that there are errors in that list. For example, there were at least 11 high backed FR.XIV and not all flew with clipped wings.


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## drgondog (Apr 12, 2022)

Zipper730 said:


> So you'd cube root, then multiply by (1/(1-(M^2))? Or do you convert the airspeed to mach then do that?


No.


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## Wild_Bill_Kelso (Apr 12, 2022)

Zipper730 said:


> What tactics were adopted? I assume hit & run because of the Spitfire's speed advantages (particularly in dives).



Yes, the 49th FG in Dawin, operating under very similar, arguably even worse conditions than the Spitfire unit, and with less capable fighters (P-40Es) successfully adopted hit and run tactics using flights of four aircraft at a time, which kept the Japanese CAP busy and minimized losses as they would use an escape maneuver and dive away once they became engaged. They did pretty well with this. I don't know what happened in terms of a debriefing between the 49th FG and 1st RAAF Fighter Wing but it seems like they didn't exchange enough information, and this was something that kept happening during the early war all over the Pacific.

Anyway from my understanding, Spitfires used similar tactics later in the war (i.e. hit and run) though they may have also been able to escape / disengage with a shallow high speed climb the way P-38s did it.









The USAAF 49th Fighter Group over Darwin: a forgotten campaign | The Strategist


This year has seen many 75th anniversaries of battles and campaigns from the darkest hours of 1942, with the Battle of the Coral Sea (4 to 8 May) prominent. But in all these commemorative activities ...




www.aspistrategist.org.au

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## Zipper730 (Apr 12, 2022)

drgondog said:


> No.


How do you apply the correction factor then? I know this might sound stupid, but I'm seriously interested in better calculating the performance figures of WWII aircraft.



Wild_Bill_Kelso said:


> Yes, the 49th FG in Dawin, operating under very similar, arguably even worse conditions than the Spitfire unit, and with less capable fighters (P-40Es) successfully adopted hit and run tactics using flights of four aircraft at a time, which kept the Japanese CAP busy and minimized losses as they would use an escape maneuver and dive away once they became engaged. They did pretty well with this.


Yeah, the P-40 could pick-up speed decently in dives, retained aileron control more effectively at high-speed, and might have been stressed for higher airspeeds


> Anyway from my understanding, Spitfires used similar tactics later in the war (i.e. hit and run)


I'm surprised it took as long for them to conclude this. Part of it probably had to do with the commanding officers (they dictate ultimately what can/cannot be done), since that seems like a form/function matter. The spitfire can dive very fast compared to the A6M.


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## Wild_Bill_Kelso (Apr 12, 2022)

I suspect they did figure out to dive away pretty quickly, including at Darwin. The issue was more the 'Big Wing' tactic which Caldwell was used to, but it wasted some fuel and they were covering a fairly wide area, so it exacerbated the fuel capacity issue they had.


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## DarrenW (Apr 13, 2022)

Zipper730 said:


> How do you apply the correction factor then? I know this might sound stupid, but I'm seriously interested in better calculating the performance figures of WWII aircraft


Let me take a stab at it. You will first need the following (let's use the Spitfire Mk V vs. Mk IX example):

1) hp to develop 380 mph
2) new horsepower (speed unknown)
3) Cube root formula: ​3​√

1) First take cube root of each horsepower:

3​√1470=11.37
3​√1720=11.98

2) Divide greater number by smaller number to get speed increase quotient:

11.98/11.37= 1.0537

3) Multiply original speed by the above figure to get new speed:

380 mph × 1.0537= *400.406* mph

So with an increase of 250 horsepower speed will likely increase from 380 mph to roughly 400 mph if other factors stayed the same such as altitude, drag, propeller type, ect.


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## Zipper730 (Apr 13, 2022)

DarrenW said:


> Let me take a stab at it. You will first need the following (let's use the Spitfire Mk V vs. Mk IX example):
> 
> 1) hp to develop 380 mph
> 2) new horsepower (speed unknown)
> ...


No, I get that. I was talking about the correction factor needed to correct for mach number. 

 drgondog
listed it as 1/1-(M^2). When I asked him if I calculated this correctly, he said no.

I was merely confused about that.


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## Vincenzo (Apr 13, 2022)

DarrenW said:


> Let me take a stab at it. You will first need the following (let's use the Spitfire Mk V vs. Mk IX example):
> 
> 1) hp to develop 380 mph
> 2) new horsepower (speed unknown)
> ...


the result is the same but the logic want
1) divide 1720/1470=1.17..
2) cube root of 1.17=1.05..
3) same as above

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## drgondog (Apr 13, 2022)

Zipper730 said:


> No, I get that. I was talking about the correction factor needed to correct for mach number.
> 
> drgondog
> listed it as 1/1-(M^2). When I asked him if I calculated this correctly, he said no.
> ...


CDtotal = (CDparasite +CDform)*CDmach + CDinduced

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## DarrenW (Apr 13, 2022)

Vincenzo said:


> the result is the same but the logic want
> 1) divide 1720/1470=1.17..
> 2) cube root of 1.17=1.05..
> 3) same as above


Thanks Vincenzo one less math step is always a good thing!

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## Jabberwocky (Apr 14, 2022)

ThomasP said:


> Somewhere on the internet . . . there is a very good write-up on the Mosquito using +25 lb boost operationally. IIRC it was mainly used in the anti-V1 (ie 'diver') and cross channel intruder roles. Unfortunately I do not remember where it is.



I recall a very long and detailed discussion on this topic on the Ubisoft Il-2 forums from about 2006 or 2007. Even though those forums are no longer around (they finally went offline earlier this year), you might be able to find it via the Wayback Machine.

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## mstennes (Apr 18, 2022)

MIflyer said:


> An article I read a few years back said the Spit IX, used a fighter bomber after the Normandy invasion, with two 500 lb bombs, had a combat radius of 90 miles.


I have read that as well, but I always thought it was limited to 1000 pounds total and could only carry a 250 pound bomb on the wings? I also read that it was not a good ground attack platform for the same reason, and that the empty shell casings from the 20’s would hit the bombs so deflectors had to be made to keep from potentially blowing it up.

I was reading the Royal Aeronautical Society’s article on the Spit and they said it was briefly looked into about a long range variant and it was simply not suitable. It would need a new heavier duty landing gear, and a redesign of the wing to make it a semi wet wing based on the D yet having buns.

I guess none of these were acceptable, and in fact that when loaded the range gained was not allot more? This seems to be one case where you desing a plane to be the best at climbing and turning you make so many trade offs that it’s pretty much a specific use plane with little adaptability to other uses.
It’s been a while snce I read that so I may have forgotten or gotten it wrong.


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## mstennes (Apr 18, 2022)

PAT303 said:


> The biggest problem dive bombing with the Spit was speed, during training they practiced with smoke bombs but when they started operations over Normandy with real 500 pounders they found they would hit 400+ mph within seconds giving the pilots very little time to adjust, also the bombs fuses wouldn't work effectively, they were designed to arm after being dropped horizontally from a bomber not vertically in a dive.


I also read that they would land behind the intended target, so often the would have to bomb from behind, which placed them in AAA flying over and then back.

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## mstennes (Apr 18, 2022)

pbehn said:


> I don't disagree, if you take all the possible internal fuel and put it in a Mk VIII then you have maybe 140-150 gallons. The Merlin uses about 150 G/hr at maximum and 50 G/hr on cruise. So you have 20 minutes on combat power and enough for 2 hrs cruise home, but the Spitfire doesn't cruise as far as a Mustang on the same settings so they are 60 miles shorter than a Mustang with the same internal fuel. Then there are the other issues, the British made Mk VII and VIII and sent them to Malta and the far east. What aircraft would they escort? Neither the British nor the USA had suitable bombers for daylight raids until 1943. To have an escort force on a long range mission you need at least three waves, very quickly you need 1000 planes and pilots to mount the campaign. The British had invested massively in night bombing and bombed Cologne with 1000 bombers in May 1942, how do you make a case for more investment in day bombers and fighters to do the same job?


Didn’t the British do that 1000 plane raid to show Hitler that the RAF was not down to almost zero planes? It also was made up of pretty
Much anything that would fly that far and overall it was a nuisance bombing and moral builder not unlike Doolittle’s raid on Tokyo.


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## pbehn (Apr 18, 2022)

mstennes said:


> Didn’t the British do that 1000 plane raid to show Hitler that the RAF was not down to almost zero planes? It also was made up of pretty
> Much anything that would fly that far and overall it was a nuisance bombing and moral builder not unlike Doolittle’s raid on Tokyo.


Three thousand buildings destroyed and 9,000 damaged with 2,500 fires started of which 1,700 were classed as large. Most planes were Wellingtons but Lancasters Halifaxes Whitleys and Manchesters, many were from training units but they were all flying bombers. The number involved was certainly propaganda, and letting Adolf know he had just got himself involved in a war on many fronts, the LW had never been capable of such a raid.

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## 33k in the air (Apr 18, 2022)

mstennes said:


> Didn’t the British do that 1000 plane raid to show Hitler that the RAF was not down to almost zero planes? It also was made up of pretty
> Much anything that would fly that far and overall it was a nuisance bombing and moral builder not unlike Doolittle’s raid on Tokyo.



The reasons, according to the following excerpt from _The Bomber Command War Diaries_ by Martin Middlebrook and Chris Everett (p.269):


> Sir Arthur Harris was determined to capitalize on the undoubted success against Lubeck and Rostock. He knew the future of Bomber Command was still in doubt and he approached both Winston Churchill and Sir Charles Portal with the bold idea of assembling a force of 1,000 bombers and sending them out in one massive raid on a German city. Churchill and Portal were both impressed and they agreed. Although Harris had only a little over 400 aircraft with trained crews which were regularly used for front-line operational work, he did have a considerable number of further aircraft in the various 'conversion units' attached to groups with four-engined aircraft and in Bomber Command's own operational training units 91 and 92 Groups. This secondary Bomber Command strength could be crewed by a combination of instructors, many of them ex-operational, and by men in the later stages of their training. To complete the 1,000 aircraft required, Harris asked for the help of of his fellow commanders-in-chief in Coastal Command and Flying Training Command. Both officers were willing to help. Sir Philip Joubert of Coastal Command immediately offered to provide 250 bombers, many of them being from squadrons which had once served in Bomber Command. Flying Training Command offered fifty aircraft but many of these were later found to be insufficiently equipped for night bombing and only for Wellingtons were eventually provided from this source.

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## pbehn (Apr 19, 2022)

33k in the air said:


> The reasons, according to the following excerpt from _The Bomber Command War Diaries_ by Martin Middlebrook and Chris Everett (p.269):


It was also the first use of the "bomber stream" tactic, if you are going to start using such a tactic, it makes sense to use the biggest number possible and scale back, though I have never read that as a reason, more an opportunity taken.


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## Geoffrey Sinclair (Apr 19, 2022)

mstennes said:


> Didn’t the British do that 1000 plane raid to show Hitler that the RAF was not down to almost zero planes? It also was made up of pretty
> Much anything that would fly that far and overall it was a nuisance bombing and moral builder not unlike Doolittle’s raid on Tokyo.


Bomber Command did three 1,000 bomber raids in 1942. Apart from the reasons already mentioned the raids were proof of concept, whether that many aircraft could attack a single target in the one raid in a short space of time with acceptable risks of collisions and friendly fire. Cologne, the first 1,000 bomber raid by Charles Messenger is a 64 page book on the first raid.

Bomber Command had around 600 to 700 aircraft on strength in operational squadrons during May 1942, which gave 400 to 500 serviceable aircraft and with around the same number of available crews, it translated to 300 to 400 serviceable aircraft with a crew. In the final week of May, by reducing operations (helped by days of bad weather) and probably juggling leave the aircraft strength figure did not change much but serviceable aircraft and available crews climbed to 633 and 644 on 30 May. On 2 June things were largely back to the May averages.

On 30 May, the night of a full moon, the regular units sent 645 aircraft, the Bomber Command training units 436 and 15 Army Co-operation Blenheims operated under Bomber Command, the Admiralty vetoed Coastal Command participation. Bomber Command reports aircraft sent/attacking by target was 1047/940 Cologne, 17/12 airfields in Germany, 0/10 other targets in Germany, 25/22 airfields in the low countries, 0/6 other targets in the low countries, 9/8 airfields in France. 564.7 long tons of HE and 999.3 of incendiary dropped.

The Bomber Command Summaries have 3 more Whitley and 3 less Wellington sorties than the Bomber Command War Diaries. Apart from the 43 aircraft classed as missing 9 more were written off.

The German raid report, (ARP = Air Raid Precautions, factories over a given size had ARP personnel)
COLOGNE, A.399 - Police President, E. 624 – Cologne Office of Min. of Pub. Inf. & Propaganda, CD1262 - Factory ARP Area Niedersachean. 30/31 MAY. The attack was obviously in great strength and carried out in a series of waves. H.E. and incendiary bombs were dropped over a period of about 1.5 hours, the H.E.'s following about a quarter hour after the first incendiaries. Some of the aircraft flew in low over the City. From the beginning of the raid bombs were dropped evenly over the whole City, this being repeated at short intervals. There was evidently no specific target, the residential areas being mainly hit, with numerous public buildings, hospitals, churches etc.

Bombs dropped: 9 mines, 959 H.E., 112,000 incendiaries, of which 565 were Phosphorus bombs or drums.

In addition there were dropped in ARP Area Cologne-Aachen a further 388 H.E, 11 mines, 38,713 Incendiaries killing 20 (including 16 service personnel) and injuring 47. In the Administrative Area of the Cologne Office of the Ministry of Public information and Propaganda a total of 1,347 H.E., 20 mines, 150,713 incendiaries were dropped, killing 494, and injuring 5180.

Damage; Houses: 3,330 destroyed, 9,150 damaged, about 1,200 by fire, and the rest by H.E.'s 13,010 dwellings destroyed and 29,130 damaged are accounted for in these figures.

Official Buildings and Installations: Police H.Q. severely damaged, the ARP Section being totally destroyed. County Court slightly damaged. 50% of the Transformer plant in the Fiusstrasse destroyed.

Tramways and Railways: Tramways services in the City centre interrupted for a week. Numerous instances of damage to railway tracks, rolling stock, installations and stations. Regional Offices and also the Goods Station Gereon, including 100 loaded trucks, partially destroyed. Meulheim Station destroyed. Locomotive sheds and a store at the repair works, Nippes, destroyed. Post and Teelgr; 3 Post Offices destroyed and 3 damaged. Maintenance depot for Post Office also damaged.

Shops: 6 large Stores severely damaged.

Harbour Inst. The Rheinau Harbour suffered considerable damage by H.E.'s and incendiaries in buildings, stocks and stores. 1 ship sunk, 1 burnt out and 2 others damaged. In Deuts Harbour 1 wheat silo severely damaged by H.E. and Corn Mill Leyseiffer and Lietzmann suffered damage by fire.

Military: Army Reserve Stores burnt down

Industrial: 1,505 works destroyed and 1,055 damaged. 328 concerns with factory ARP organisation were damaged with the following results, 36 – 100% decrease in production, 70 – 50-80% decrease in production, 222 - less than 50% decrease in production. The foundry, laboratory and telephone exchange of Kloeckner-Humboldt-Deuts A.G. destroyed. Hospelt Paint Factory hit by 4 H.E.'s and a number of phosphorous drums. Majority of buildings destroyed. Total loss of all raw materials and finished products. PW camp within the works also hit by H.E. Textile firms of F.W. Burggelmann & Sons and Biegans totally destroyed with all stocks. The workshops, stores and all fittings and stocks of the Accumulatorfabrik A.G. completely destroyed. Also a number of textile firms manufacturing items of uniform suffered damage.

17 water mains, 32 electricity cables, 12 telephone cables, 5 gas mains destroyed.

Casualties: 474 dead, 5061 injured and 45132 homeless, of which latter 14825 only temporarily. Those who found lodging with friends or relatives are not included.

In the Ministry at Public Information and Propaganda report dated 2nd June, it is stated that in addition in other ARP Areas, mainly Duesseldorf, 50 H.E. and 1700 incendiary bombs were dropped. "The number of bombs, particularly incendiaries, is according to experiences in reality is far in excess of that given."

In a Factory ARP report dated 9th June the number of attacking aircraft is given as "some 60". It further reports casualties in other towns as: Dusseldorf: 16 dead, 44 injured, Essen: 1 dead, 2 injured, Beur-Mitte: 7 dead, 30 injured. The last casualties mentioned were caused by the crash of an aircraft shot down.

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## 33k in the air (Apr 19, 2022)

pbehn said:


> It was also the first use of the "bomber stream" tactic, if you are going to start using such a tactic, it makes sense to use the biggest number possible and scale back, though I have never read that as a reason, more an opportunity taken.



Yes, that was mentioned in the next paragraph in the book. I stopped at citing one paragraph for brevity's sake.

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## PAT303 (Apr 20, 2022)

mstennes said:


> I was reading the Royal Aeronautical Society’s article on the Spit and they said it was briefly looked into about a long range variant and it was simply not suitable. It would need a new heavier duty landing gear, and a redesign of the wing to make it a semi wet wing based on the D yet having buns.


The MkV had a rear 30G tank designed for it plus 45G drop tanks, VIII had leading edge tanks plus drop tanks, the MkIX had 17G leading edge tanks plus 66 or 75G rear aux tanks plus drop tanks, the MkXIV could outfight everything the Luftwaffe had in the air with a 90G combat tank fitted and all MkXVI's had rear 75G tanks fitted from the factory, to say the Spit was not suitable for having it's fuel capacity increased is stupidity in the extreme.


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## GregP (Apr 20, 2022)

Nobody is saying it wasn't suitable. They are saying it didn't, which is pretty true until very late in the series.


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## tomo pauk (Apr 20, 2022)

mstennes said:


> I was reading the Royal Aeronautical Society’s article on the Spit and they said it was briefly looked into about a long range variant and it was simply not suitable. It would need a new heavier duty landing gear, and a redesign of the wing to make it a semi wet wing based on the D yet having buns.



Care to provide a link to the article?


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## EwenS (Apr 20, 2022)

PAT303 said:


> ............all MkXVI's had rear 75G tanks fitted from the factory, to say the Spit was not suitable for having it's fuel capacity increased is stupidity in the extreme.



Are you sure about that? On the thread about fighters for Australia etc. I posted info that it was not a production line mod, but carried out on some aircraft only at an MU level. Post #1222. Sorry can't post a direct link on this device.

Edit sorry it was the critical analysis of raf air superiority in far East thread.


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## PAT303 (Apr 20, 2022)

EwenS said:


> Are you sure about that? On the thread about fighters for Australia etc. I posted info that it was not a production line mod, but carried out on some aircraft only at an MU level. Post #1222. Sorry can't post a direct link on this device.
> 
> Edit sorry it was the critical analysis of raf air superiority in far East thread.


All MkXIV's had the rear tanks and like the Mustang in RAF service were wired shut in many cases so they couldn't be used


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## PAT303 (Apr 20, 2022)

GregP said:


> Nobody is saying it wasn't suitable. They are saying it didn't, which is pretty true until very late in the series.


Which is even more baffling as the USAF was fitting ferry tanks to P47's in 1943 which only gave them an escort range of around 370 miles give or take when at the same time Spitfires could have gone to 450-500 miles. Why the RAF were so against adding fuel when the need for escort fighters was there is mind blowing.


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## wuzak (Apr 21, 2022)

PAT303 said:


> Which is even more baffling as the USAF was fitting ferry tanks to P47's in 1943 which only gave them an escort range of around 370 miles give or take when at the same time Spitfires could have gone to 450-500 miles. Why the RAF were so against adding fuel when the need for escort fighters was there is mind blowing.



The USAAF needed escort fighters, the RAF, not so much.

Unless you wanted night-fighter Spitfires?

And, for a while, the USAAF weren't convinced they were needed.


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## PAT303 (Apr 21, 2022)

wuzak said:


> The USAAF needed escort fighters, the RAF, not so much.
> 
> Unless you wanted night-fighter Spitfires?
> 
> And, for a while, the USAAF weren't convinced they were needed.


The RAF had hundreds of Spitfires either sitting idle or doing pointless short range sweeps across the low countries, they could have been relaying with P47's escorting daylight bomber raids all the way to the German border. The Spit could have been filling the gap between the Jug and the P51 when it came into service.

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## Zipper730 (Apr 21, 2022)

P
 PAT303


So, what you are suggesting was that when the Spitfires weren't used for defense of the UK, they could be used to help cover American day-bombers on their way in?


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## pbehn (Apr 21, 2022)

Zipper730 said:


> P
> PAT303
> 
> 
> So, what you are suggesting was that when the Spitfires weren't used for defense of the UK, they could be used to help cover American day-bombers on their way in?


They were.

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## Milosh (Apr 21, 2022)

Zipper730 said:


> P
> PAT303
> 
> 
> So, what you are suggesting was that when the Spitfires weren't used for defense of the UK, they could be used to help cover American day-bombers on their way in?


And on the way out.

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## PAT303 (Apr 21, 2022)

pbehn said:


> They were.


Only for the first and last leg, without a Luftwaffe aircraft in sight.

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## PAT303 (Apr 21, 2022)

Zipper730 said:


> P
> PAT303
> 
> 
> So, what you are suggesting was that when the Spitfires weren't used for defense of the UK, they could be used to help cover American day-bombers on their way in?


The USAF were using Jugs about to around 370 miles, the Luftwaffe new this so didn't engage until they turned back, the Spit could have stretched that coverage out to 450-500 miles making a worthwhile contribution to the daylight air war

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## Zipper730 (Apr 21, 2022)

P
 PAT303


Did anybody have a relay system in place?


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## Milosh (Apr 21, 2022)

PAT303 said:


> The USAF were using Jugs about to around 370 miles, the Luftwaffe new this so didn't engage until they turned back, t*he Spit could have stretched that coverage out to 450-500 miles* making a worthwhile contribution to the daylight air war


Are you saying Spitfires could escort to Berlin?


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## Milosh (Apr 21, 2022)

Zipper730 said:


> P
> PAT303
> 
> 
> Did anybody have a relay system in place?


Yes it has been mentioned/described numerous times on this board.


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## pbehn (Apr 21, 2022)

PAT303 said:


> Only for the first and last leg, without a Luftwaffe aircraft in sight.


I remember reading an account of two Spitfires fending of a Fw 190 while escorting a B-17 straggler.

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## PAT303 (Apr 21, 2022)

Milosh said:


> Are you saying Spitfires could escort to Berlin?


Take a Spit IX, the rear top 33G tank is burned off warming up/taxi/take off and have it sitting over the channel at 25,000ft, switch to the 90G drop tank and cruise out behind the P47's that are in front of you saving fuel, once the Jugs hit their limit and start to turn back the Spits increase speed and take over going as far as the 90G will take them which is around 500 miles, once they get there they still have around 175G of internal fuel to fight and get home. by using a relay system, P47's and Spitfires could have escorted the bomber stream out to around 500 miles if they mutually supported each other by the front groups clearing the sky enabling the rear groups to save fuel before they took over. Those same planes could have then been supported on the return leg so once again they can fly at economical speeds safely. Both aircraft could have then done likewise, the P47's actually did, to the P51 when they came into service and bridged the final gap in coverage.


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## PAT303 (Apr 21, 2022)

pbehn said:


> I remember reading an account of two Spitfires fending of a Fw 190 while escorting a B-17 straggler.


Johnny Johnson mentioned numerous times in his writings of fly around empty skies and his squadron was elated when they finally got aux tanks in their MkXIV's and flew across the border into Germany for the first time.


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## pbehn (Apr 21, 2022)

PAT303 said:


> Johnny Johnson mentioned numerous times in his writings of fly around empty skies and his squadron was elated when they finally got aux tanks in their MkXIV's and flew across the border into Germany for the first time.


What does that matter, Spitfires were used from the very start escorting Fortress Is and B17s, they certainly did encounter opposition from the start, there were loses on both sides, it is a gross insult to the men who were lost to say it never happened. By the time the P-47 was used as a second wave escort taking over from Spitfires as the first wave the USA had been mounting bombing operations for a long time.

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## Shortround6 (Apr 21, 2022)

PAT303 said:


> Take a Spit IX, the rear top 33G tank is burned off warming up/taxi/take off and have it sitting over the channel at 25,000ft,


And nobody was going to do that. 
Standard procedure in just about any air force was to warm up, taxi and take off on one of the main tanks. 
You can switch tanks to drop tanks OR internal auxiliary fuel tank/s at somewhere between 2,000ft and 5,000ft. Whatever it takes to give you the option of a "safe" landing (gliding) if the fuel system doesn't switch over to the new tank. 
Standard procedure is also to have the fuel return line piped to the main tank/s. If you take off on a non main tank the over flow from the return line is lost and may or may not create a fire hazard. For instance on a P-40E the warming up and tank off was done on the forward wing tank. Once the "safe" altitude was reached they switched to the drop tank, once the drop tank was used the tank was switched to the rear fuselage tank. and then sequencing back to the forward wing tank as the reserve as 1-2 gallons an hour should have been going back to it from the fuel return line. 
Last, you may have switch tanks well before you get 25,000ft. The Mustang was heavier but even running clean it could burn 36-41 us gallons just getting to 20,000ft from sea level (take off not counted let alone warm up.) Normal climb power could burn another 6 US gallons to get to 25,000ft.

33 Imp gallon is not going to be enough to start/warm up, taxi, take-off and get to 25,000ft.

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## PAT303 (Apr 22, 2022)

Plumb the rear return lines to the main so it fills up after take off that way you have a full main and weight shifted forward at the same time, win win. All I'm saying is the Spit could have done much more ''if'' it was given more fuel, all MkXVI's had rear 66 or 75G rear tanks fitted from the factory in 1944 so there's nothing stopping the MkIX from having them 2 years earlier.


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## Geoffrey Sinclair (Apr 22, 2022)

PAT303 said:


> Which is even more baffling as the USAF was fitting ferry tanks to P47's in 1943 which only gave them an escort range of around 370 miles give or take when at the same time Spitfires could have gone to 450-500 miles. Why the RAF were so against adding fuel when the need for escort fighters was there is mind blowing.


There are a whole lot of moving parts involved and which are selected often says more about the writer. The USAAF delayed its order for drop tanks from British sources in the first half of 1943, the need became more urgent as the year went on, but it took until October for the final decision of no unescorted raids. The P-47 could range out to 280 miles with a 75 gallon drop tank in August 1943, 325 miles with a 108 gallon tank in September 1943, and 375 miles with a 150 gallon tank in February 1944. The standard Spitfire VIII with a 20 gallon fuel reserve allowance could range out to around 300 miles with a 90 gallon external tank and the ability to transfer fuel from the external tank to the main ones, a 33 gallon rear fuselage tank would add another 80 miles. As it was Spitfires did insert and withdrawal cover and did score kills on these missions, there is a story about James Stewart's B-24 formation having the arrival of Spitfires drive off attacking Luftwaffe fighters.

As of end 1942 the Spitfire had just had a major upgrade, was needed in numbers as soon as possible, no one was asking for even longer range, the RAF had number of a longer range and faster fighter on the way, and as we know the Spitfire had stability problems when rear fuselage tanks were fitted that took time to resolve. The 1943 priorities became production and an even higher performance. You make your predictions of the future and then wait for time to reveal how correct you were.

The RAF did not think in terms of US long range, rather something like being able to fight over say all of France, from both the point of view of a performance penalty from the extra fuel and the workload on the pilots, like the time in the air and need for navigation. The phased fighter escort tactics had the bonus an escort mission to a target around 500 miles away at fighter speeds took around an hour less than at heavy bomber speeds.

Consider the war situation at the end of 1942, capturing North Africa was behind schedule, with the Luftwaffe contesting the airspace quite well. The U-boats had been very effective in 1942, and were moving back into the North Atlantic in numbers. Would the allies be able to sustain even defensive operations in Europe against continued U-boat successes? The eastern front had established the pattern of German advance in summer, Red Army advance in winter, would that continue? Given this how important was it to be able to insert an allied ground force into France in 1943, what had to be done for a 1944 invasion? The Luftwaffe still had a viable bomber force and Britain had plenty of targets the Luftwaffe wanted to attack. Day fighter defences had to be maintained and quality improved as the average Luftwaffe bomber improved, rotating the RAF home fighter forces through southern England to give them combat experience was important. Both the German and Japanese advances seemed to have been stopped but that had taken a lot of fighting and evicting them from further territory was, if anything, proving even harder.

At the end of 1942 the Spitfire was the only allied single engine fighter proven to match German fighter performance, with a pushing year long gap in 1941/42 where it did not. Given the level of improvement in German fighters 1938 to 1942 what chance their performance would keep improving, say like the Bf109K and Fw190D arriving in late 1943 or early 1944?

The British economy was working flat out in 1942/43, major changes to an aircraft would reduce the numbers produced and in 1942/43 every front wanted Spitfires and the 2 stage Merlin ones in particular, special shipments were sent to Tunisia and an elite fighter unit formed to use them (The Polish Fighter Flight) with a brief to only hunt for Luftwaffe fighters for example. The demands helped push mark IX production, versus switching to mark VIII. The invasion of France was expected to provoke a major air fight, so lots of reserve aircraft were needed to replace the expected losses, the fights happened but the Luftwaffe was much less effective than any planner was willing to believe.

The USAAF indifference to the P-51, versus the RAF's only US fighter we want attitude end 1942 meant the RAF could look forward to a large Merlin P-51 force in 1943/44 as per the current deliveries schedule, the P-51 easily reaching the France Germany border at least. And the USAAF would have the remainder available for Europe. Production was delayed and a greater percentage allocated to the USAAF versus that original schedule.

The USAAF build up in Britain was behind schedule due to delays and diversions, would the USAAF force grow to the planned size and when? The USAAF in Britain was not talking about long range escort, even as the USAAF in the Mediterranean was moving to escorting all raids. In any case as flown by the 8th Air Force the early B-17F radius of action was around 300 miles. If the USAAF wanted escorts, how many? Was there a difference in the number of escorts needed for say a B-17 versus B-26 or versus a Lancaster? How would the Luftwaffe react, keep its fighters dispersed near the front lines or pull many of them back to Germany and/or France? Would it increase the size of the force? Would the escort missions be flown at bomber speeds?

The planned standard USAAF fighter was the P-47, would all that extra weight provide the performance to at least break even with the 1943 and 1944 German fighters?

The allies had plenty of potential fighter bombers, the Hurricane and P-40 for a start, along with twin engine bombers whose day targets tended to be within fighter escort range. Fundamentally an allied escort fighter needed to range out a couple of hundred miles to cover most operations being run or would be run in support of the armies, the tactical targets. As Germany had not really used the economies of France, Belgium and Holland, plus most Italian Industry was in the north of the county, plus places like Ploesti in Romania, there was a disconnect between the fighter range required for tactical operations and the 500 to 600 miles needed for the strategic strikes. As we know now the Spitfire extreme limit, assuming it could handle the fuel load, was around 500 miles radius under European conditions, and more under Pacific conditions.

The longest range missions are when you are sure enemy reaction will only be around the target, the shortest is probably when you have to cope with layered defences where your aircraft could easily find themselves in multiple combats on the way in and out. Would there be a layered defence of Germany and if so would shorter range allied airpower help defeat or push the first defence line further back? How much could the allies control the 1943 air war, where, how, when and why missions were undertaken?

To the Spitfire, the 1941/42 changes had increased the internal fuel from 87 to 124 gallons, giving a 150 miles radius, less reserves, a 45 gallon external tank would add around 100 miles, at 320 mph, and longer at 240 mph. Which covered range requirements wanted at the time. In 1943 the main effort was upgrading to the Griffon engine at 1,980 pounds versus the Merlin 66 at 1,650 pounds, 6 mark VIII airframes allocated to the program, the intention being to give either a superior performance versus the German fighters or at least matching any upgrades.

In early 1943 the Spitfire was still mostly needed as an interceptor, it had just received a major performance and range upgrade, the P-51 was on the way which was faster and longer ranged, while every Spitfire was needed at once. We now know the outcomes, 1943 would be a year of allied advances, the 8th Air Force could do with every escort it could find in 1943, even getting standard Spitfire VIII into Fighter Command would have helped, adding a 33 gallon rear fuselage tank helping further, medium term switching to VIII instead of IX would have given the RAF a more effective Spitfire for the operations it ended doing. However the Spitfire was sensitive enough work was needed to allow for rear fuselage fuel tanks and that took a while, it became the 1944 project. The expected upgrades in German fighter performance were delayed until the final quarter of 1944.

Effort in man hours, Spitfire production, mark / design / jigging and tooling

I / 339,400 / 800,000
II / 9,267 / unknown
III / 91,120 / 75,000
V / 90,000 / 105,000
VI 14,340 / 50,000
IX 43,830 / 30,000
XII / 27,210 / 16,000
VII / 86,150 / 150,000
VIII / 24,970 / 250,000
XIV / 26,120 / 17,000
21 / 168,500 / unknown
PR XI / 12,415 / unknown
Seafire I / 10,130 / 18,000
Seafire II / 3,685 / 40,000
Seafire III / 8,938 / 9,000
Seafire XV / 9,150 / unknown
Spitfire on floats 22,260 / 35,000

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## SaparotRob (Apr 22, 2022)

Geoffrey Sinclair said:


> There are a whole lot of moving parts involved and which are selected often says more about the writer. The USAAF delayed its order for drop tanks from British sources in the first half of 1943, the need became more urgent as the year went on, but it took until October for the final decision of no unescorted raids. The P-47 could range out to 280 miles with a 75 gallon drop tank in August 1943, 325 miles with a 108 gallon tank in September 1943, and 375 miles with a 150 gallon tank in February 1944. The standard Spitfire VIII with a 20 gallon fuel reserve allowance could range out to around 300 miles with a 90 gallon external tank and the ability to transfer fuel from the external tank to the main ones, a 33 gallon rear fuselage tank would add another 80 miles. As it was Spitfires did insert and withdrawal cover and did score kills on these missions, there is a story about James Stewart's B-24 formation having the arrival of Spitfires drive off attacking Luftwaffe fighters.
> 
> As of end 1942 the Spitfire had just had a major upgrade, was needed in numbers as soon as possible, no one was asking for even longer range, the RAF had number of a longer range and faster fighter on the way, and as we know the Spitfire had stability problems when rear fuselage tanks were fitted that took time to resolve. The 1943 priorities became production and an even higher performance. You make your predictions of the future and then wait for time to reveal how correct you were.
> 
> ...


Great post!


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## Shortround6 (Apr 22, 2022)

From the test report I listed above.


 The changes of loading due to fitting the metal airscrew are as follow:



I.​Increase of airscrew weight 262 lb., that is Wooden airscrew 83 lb., Metal 345 lb.​II.​Removal of 135 lb. lead from engine bearers.​III.​Fitting 40 lb. lead in the rear end of the fuselagefor normal load, with an additional 22 lb. to give the extended aft position of the centre of gravity.​



 The above ballasting does not represent armour plating and blind approach apparatus in weight or position but it was estimated by thy Royal Aircraft Establishment that the inertia of the aeroplane about the lateral axis would not exceed this arrangement of ballasting when the above items are subsequently fitted.

The test was from July 12th 1939. Date of the report, not date of tests. 

I don't know if there were any modifications made to the DH 2 speed propellers.
The Rotol propeller had a total pitch change of 35 degrees. And may not have been in final form as the plane was 4mph faster at 2800rpm than it was at 3000rpm. 

We also know that they were having trouble with the Spitfire handling at this time due to the elevators being too sensitive/too powerful. They did several things to help fix that but with the center of gravity changing as equipment was added/moved there may have been a bit of chasing back and forth?
Also the early Spitfires (and Hurricanes and Gladiators and????) had a pair of flare tubes in behind the cockpit. 





Now the 29 gallon tank fitted to some MK Vs may have been between the pilots and seat and flare tubes. 
The MK II Spits used for ASR used the flare tubes to hold the dingy and recue supplies. 

Also note that the 29 gallon tank was ONLY to be used when the 170 gallon tank was fitted. I don't know it that was solely because of the ferry tank tank or if it was to help balance out the large oil tank they mounted in the nose. Or if the 170 gallon tank shifted the CG forward by itself?




The fattest part of the tank is forward of the CG?

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## tomo pauk (Apr 22, 2022)

Shortround6 said:


> And nobody was going to do that.
> Standard procedure in just about any air force was to warm up, taxi and take off on one of the main tanks.
> You can switch tanks to drop tanks OR internal auxiliary fuel tank/s at somewhere between 2,000ft and 5,000ft. Whatever it takes to give you the option of a "safe" landing (gliding) if the fuel system doesn't switch over to the new tank.
> Standard procedure is also to have the fuel return line piped to the main tank/s. If you take off on a non main tank the over flow from the return line is lost and may or may not create a fire hazard. For instance on a P-40E the warming up and tank off was done on the forward wing tank. Once the "safe" altitude was reached they switched to the drop tank, once the drop tank was used the tank was switched to the rear fuselage tank. and then sequencing back to the forward wing tank as the reserve as 1-2 gallons an hour should have been going back to it from the fuel return line.
> ...



The SOP on Spitfire V was to warm up, take off and climb to 2000 ft on main tanks, switch to drop tank, and then switch back on main tanks (or the 29 gal rear tank if used).
On Spitfire IX and XVI with rear tanks, SOP was: main tanks to 2000 ft, rear tank until there is 30 gals left, drop tank, back to the rear tank, back to the main tanks. Without the rear tanks, it was main tank up to 2000 ft, drop tank, then main tanks again.



Geoffrey Sinclair said:


> At the end of 1942 the Spitfire was the only allied single engine fighter proven to match German fighter performance, with a pushing year long gap in 1941/42 where it did not. Given the level of improvement in German fighters 1938 to 1942 what chance their performance would keep improving, say like the Bf109K and Fw190D arriving in late 1943 or early 1944?





Geoffrey Sinclair said:


> The USAAF build up in Britain was behind schedule due to delays and diversions, would the USAAF force grow to the planned size and when? The USAAF in Britain was not talking about long range escort, even as the USAAF in the Mediterranean was moving to escorting all raids. In any case as flown by the 8th Air Force the early B-17F radius of action was around 300 miles. If the USAAF wanted escorts, how many? Was there a difference in the number of escorts needed for say a B-17 versus B-26 or versus a Lancaster? How would the Luftwaffe react, keep its fighters dispersed near the front lines or pull many of them back to Germany and/or France? Would it increase the size of the force? Would the escort missions be flown at bomber speeds?
> 
> The planned standard USAAF fighter was the P-47, would all that extra weight provide the performance to at least break even with the 1943 and 1944 German fighters?



You've left out the crucial thing: Germany/RLM/Luftwaffe can't make and fuel enough of these over-performing fighters with enough of capable pilots vs. what Allies can deploy against them. Not in 1943, not in 1944.
BTW - the Fw 190D-9 sported perhaps 60% of the firepower the standard Fw 190A-7 or A-8 had. To have Bf 109K materialzed in late 1943, someone needs to do hand-wave the DB 605D, as well as the airframe clean-up.

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## Zipper730 (Apr 22, 2022)

Shortround6 said:


> And nobody was going to do that.


Even the P-51 ran on the wing-tanks on the ground? I honestly thought they used the center-tank when they were on the ground and climbing.



 drgondog
& 
W
 wuzak
do you have anything on this?

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## PAT303 (Apr 22, 2022)

Shortround6 said:


> We also know that they were having trouble with the Spitfire handling at this time due to the elevators being too sensitive/too powerful.


No ballooning at speed, they changed to metal elevators which fixed the problem until the speed increased at which point they changed the profile which eliminated it completely and replaced the original hinges with a piano type, all before the BoB.


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## PAT303 (Apr 22, 2022)

Geoffrey Sinclair said:


> There are a whole lot of moving parts involved and which are selected often says more about the writer.


The FAA had Seafire MkII's then III's which had folding wings, leading edge tanks, drop tanks from 30 up to 90G, deleted cannon stubs, the cannon bulges were reduced in size and streamlined, streamlined ejector exhaust, streamlined rear view mirrors, streamlined engine air intake and with the Cunliffe-Owen models flush fitting rivets, even JATO rockets were trialed and proofed for service, from 1942, funny how the FAA could get all their moving parts moving in the right direction when the RAF couldn't move past volkes filtered Mk V's with only 85G of internal fuel

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## ThomasP (Apr 22, 2022)

Hey PAT303,

RATOG was first trialled on Seafires (Mk II) in Feb'1943, but to a large degree I agree with you that a longer range Spitfire was a missed opportunity.


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## PAT303 (Apr 23, 2022)

ThomasP said:


> Hey PAT303,
> 
> RATOG was first trialled on Seafires (Mk II) in Feb'1943, but to a large degree I agree with you that a longer range Spitfire was a missed opportunity.


Okay I'll give you a few months but my argument still stands, the FAA got the best out of their Spits, they even acquired ex RAAF Kittyhawk drop tanks and used them to good effect when again the RAF had nothing but a few 30G slippers on selected squadron aircraft.


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## Geoffrey Sinclair (Apr 23, 2022)

PAT303 said:


> The FAA had Seafire MkII's then III's which had folding wings, leading edge tanks, drop tanks from 30 up to 90G, deleted cannon stubs, the cannon bulges were reduced in size and streamlined, streamlined ejector exhaust, streamlined rear view mirrors, streamlined engine air intake and with the Cunliffe-Owen models flush fitting rivets, even JATO rockets were trialed and proofed for service, from 1942, funny how the FAA could get all their moving parts moving in the right direction when the RAF couldn't move past volkes filtered Mk V's with only 85G of internal fuel


Could you put some dates on the changes, the removal of cannon stubs and reduction of cannon bulges was done to Spitfires, when were the leading edge tanks fitted (the mark XV had them) plus the other streamlining done to Seafires?

Armoured Aircraft Carriers has a wing diagram with the tank but not which mark(s) it applied to.
http://www.spitfireperformance.com/seafirel2cads.jpg has the IIC fuel loads.

The pilot's notes I have combine the Spifire V and Seafire I, II and III and only list the fuselage fuel tanks, including the 29 gallon rear one, along with the external 30 and 90 gallon tanks plus the 170 gallon ferry tank. The Ministry of Aircraft Production drop tank report has no mention of 90 gallon tanks specifically for Seafires, as of January 1945 it was 90 gallon Spitfire, 50 gallon Spitfire and Seafire, 30 gallon Seafire, all tanks being metal.

June 1942, Supermarine begins Seafire IIc production.
December 1942, Westland begins Seafire IIc production.
February 1943 JATO trials.
April 1943 Supermarine ends Seafire mark IIc production, Westland starts mark III production
August 1943 Spitfire Mark V production ends
September 1943 Westland ends Seafire mark IIc production
November 1943 Cunliffe Owen Seafire mark III production begins.

Morgan and Shacklady state the switch from the bulky air filter at Cunliffe Owen was mark III production number 90, which would be around September 1944.



PAT303 said:


> they even acquired ex RAAF Kittyhawk drop tanks and used them to good effect when again the RAF had nothing but a few 30G slippers on selected squadron aircraft.



The Kittyhawk tanks were a trade done by HMS Implacable in June 1945, one RAN Destroyer cargo capacity worth. Cases of Scotch were valuable in the Pacific area at the time.

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## EwenS (Apr 23, 2022)

PAT303 said:


> All MkXIV's had the rear tanks and like the Mustang in RAF service were wired shut in many cases so they couldn't be used


In my post #505 I was referring to your post #502 in which you referred to all the Mk.*XVI* (not *XIV*)having the rear fuselage tanks being factory fitted. You said _*"....and all MkXVI's had rear 75G tanks fitted from the factory...."*_. That does not seem to have been the case as per my post on another thread.






A Critical Analysis of the RAF Air Superiority Campaign in India, Burma and Malaya in 1941-45


@XBe02Drvr the firewall on the Mk.IX is heavier than the Mk.VII/VIII?



ww2aircraft.net









PAT303 said:


> Johnny Johnson mentioned numerous times in his writings of fly around empty skies and his squadron was elated when they finally got aux tanks in their MkXIV's and flew across the border into Germany for the first time.


The problem I have with this is Johnson's commands in 1944/45. He commanded 144 Wing and then 127 Wing from Feb 1944 to late March 1945. 144 Wing was a Mk.IX wing and never used the Mk.XIV. It was disbanded on 14 July 1944. 127 Wing only had Mk.*XIV *was during the month of Dec 1944 when 130 & 350 joined 127 Wing temporarily. The rest of the time 127 Wing flew Mk.*IX* or Mk.*XVI *when Johnson was in command. 

At the beginning of Dec 1944, 350 and 610 with Spitfire *XIV*, were temporarily attached to 127 Wing, belatedly having moved to the Continent from ADGB, where they had been flying escort cover for bombers operating from the UK. At the end of Dec they then moved to join other Mk.*XIV* squadrons in 125 Wing. Johnson then moved to command 125 Wing in late March 1945 which, by that point had 3 squadrons of Mk.*XIV* (41, 130 & 350)

The first two Mk.*XIV* squadrons moved to the Continent at the end of Sept 1944 (130 & 402) to join 125 Wing and were operating over Germany from the beginning of Oct 1944. And there is photo evidence that they had the drop tanks from the start.

I have a report to hand of an air to air action by 7 Mk.XIV of 350 squadron against Fw190s on the evening of 20th April 1945 just west of Berlin, while the squadron was based at Celle in Germany So distance is 140 miles from base (the account says 175 miles). That is the day that the Russians began their final assault on Berlin. So the RAF 2nd TAF squadrons would not be flying beyond that point. So would a drop tank actually have been necessary?

So Johnson's comments only make sense in terms of a temporary shortage in March / April 1945 if the tanks were necessary. Given that 125 Wing moved 3 times between the end of March, when it was based at Eindhoven, and 6-9 May 1945 when it finally settled on airfields at Fassberg in Germany (130 & 350 squadrons) and Kastrup in Denmark (41 squadron) that seems possible if the logistics couldn't keep up.


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## MikeMeech (Apr 23, 2022)

PAT303 said:


> Johnny Johnson mentioned numerous times in his writings of fly around empty skies and his squadron was elated when they finally got aux tanks in their MkXIV's and flew across the border into Germany for the first time.


Hi
JEJ does not mention much about "empty skies" while flying Spitfire XIVs in Chapter 19 'The Fated Sky' in his book 'Wing Leader', in fact he appears to have had a busy time, what source are you quoting?

Mike

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## PAT303 (Apr 23, 2022)

Geoffrey Sinclair said:


> Could you put some dates on the changes, the removal of cannon stubs and reduction of cannon bulges was done to Spitfires, when were the leading edge tanks fitted (the mark XV had them) plus the other streamlining done to Seafires?







All mark III's had leading edge tanks


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## PAT303 (Apr 23, 2022)

This is a model but it's a clear image of the deleted stubs and smaller bulges


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## PAT303 (Apr 23, 2022)

Compared to the MkIX wing, the smaller bulges and deleted stubs plus the other changes increased the speed by approx 12mph


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## GregP (Apr 23, 2022)

PAT303 said:


> View attachment 665577
> 
> All mark III's had leading edge tanks



Both of them? They only made 2. 

Edit: Sorry Pat, that's Spitfires, not Seafires. They made 1,218 Seafire Mk. IIIs.


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## Thumpalumpacus (Apr 24, 2022)

mstennes said:


> Didn’t the British do that 1000 plane raid to show Hitler that the RAF was not down to almost zero planes? It also was made up of pretty
> Much anything that would fly that far and overall it was a nuisance bombing and moral builder not unlike Doolittle’s raid on Tokyo.



Can't say I agree with this. 16 planes is a gesture, but a thousand is a message.

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## EwenS (Apr 24, 2022)

PAT303 said:


> View attachment 665577
> 
> All mark III's had leading edge tanks


Did they?

That diagram appears exactly as captioned in the Crowood book by Kev Darling on the Seafire p61. Yes it purports to have been provided by the FAAM (Fleet Air Arm Museum) but does it represent a Seafire III wing? In Appendix IV in that book then goes on to list the internal fuel capacities as follows:-
Merlin powered - 48gal (fuselage tp tank) 37gal (fuselage lower) for a total of 85gals.
Griffon powered (Mk.XV & XVII) - 80.5gal (fuselage tanks) 19.5gal (wing root tanks)

This from David Brown's "The Seafire. The Spitfire that went to Sea" about the development of the Griffon powered Seafire XV:-
_"....To the Spitfire VB-based fuselage and the LIII folding wings were added ...... wing root fuel tanks from the Spitfire IX ....."_

And from "Spitfire the History" in the section on the development of the Seafire XV and the changes to get to that mark:-
_"F Mk IX Mareng fuel cells were specified for internal wing fuel."_
And that same diagram, without the blurb in the bottom left hand corner appears, but with some additional details on spar construction, not in the section on the Mk.III, but in the section on the Mk.XV. See page 554.

David Brown lists the internal fuel capacity as 85gals for ALL Merlin Seafires. For the Seafire XV & XVII 80.5gals in fuselage tanks and 19.5gals in wing-root tanks. These figures are supported by "Spitfire the History", and, as pointed out by Geoffrey Sinclair, the Pilots Notes.

So other than the diagram that you posted, I can't put my hands on any evidence that the Seafire III was fitted with wing tanks. Everything else points to the contrary.

As for the fitting of Vokes air filters to the Seafires, David Brown notes in the section on development of the Seafire IIc, that a number of aircraft were fitted with them but then a decision was taken to delete it from later production aircraft _"*and the risk of excessive engine wear was accepted*". _So you will find photos of Seafire IIc on Formidable in 1943 fitted with the bulky Vokes filters. But L.IIc/LRIIc (both production line and by conversion) and early production Mk.III did without any filter at all and the photo evidence supports that. The smaller filter, as fitted to Spitfire VIII/IX etc, was then fitted on the production line from later in 1944 and probably retrofitted to earlier surviving aircraft. So I would question whether any Cunliffe Owen Mk.III were actually fitted with the Vokes filter before the neater version was introduced around Sept 1944.

The Spitfire 'C' wing, as used on the Seafire IIc/LIIc/LRIIc/early fixed wing Mk.III was modified internally for later Mk.III, including deletion of the outboard cannon bay and blast tube. Not sure when that occurred but it must have been later in 1943 or even earl 1944 as there are photos around of early folding wing F.III with cannon stubs. The first 30 or so Mk.III got fixed wings. It was Oct/Nov 1943 before folding wing versions began coming off the production lines.

As for the ejector exhausts this was a later introduction. Even early F.III produced in late 1943 didn't have them. At the moment I suspect that they were introduced initially on the low level rated Merlin engined aircraft like the L.IIc/LR.IIc and which then formed the bulk of later Mk.III production (i.e. all bar about the first 103 Mk.III). David Brown puts the first conversions of Mk.IIc to L.IIc as March 1943 but as the Barracuda had priority for the low level rated Merlin 32 it was mid-May 1943 before the first squadron received its full complement, but by Aug 76 were in service.

As for the change to the slim cannon bulges that was being made on Spitfires from early 1943 (Mk.VIII for example from sometime around Jan-Mar). There are photos of early Seafire Mk.IIc with the broad bulges.


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## PAT303 (Apr 24, 2022)

If you read up on the Seafires service in the Med the FAA found the MkII's couldn't catch Ju88's so started looking at ways to solve that, like all Spitfire development war production came first but the FAA started to look for solutions to the problem of lack of performance and lack of range straight away. From what I have found the MkIII was hampered by the production line jigs being wrongly made but the first ones were used at the Salerno landings in 1943, the MkIII also got the Hispano MkV cannons. The FAA did more with less compared to the RAF.


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## PAT303 (Apr 24, 2022)

EwenS said:


> This from David Brown's "The Seafire. The Spitfire that went to Sea" about the development of the Griffon powered Seafire XV:-
> _"....To the Spitfire VB-based fuselage and the LIII folding wings were added ...... wing root fuel tanks from the Spitfire IX ....."_


Seafire tanks were 13.5G from the MkVII/VIII


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## PAT303 (Apr 24, 2022)

MikeMeech said:


> Hi
> JEJ does not mention much about "empty skies" while flying Spitfire XIVs in Chapter 19 'The Fated Sky' in his book 'Wing Leader', in fact he appears to have had a busy time, what source are you quoting?
> 
> Mike


He was in combat 57 times in 3 years, is that considered busy?.


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## Shortround6 (Apr 24, 2022)

I have my doubts about the introduction of the 20mm Hispano MK V cannon. 

Land based Spitfires didn't get them until after WW II. Even MK 24s show the longer cannon.
The Tempest didn't get them until the end (?) of the first production batch of 100 aircraft which took until May of 1944 to complete. 

Since the barrels were about 10in shorter and had shorter recoil springs good photographs should show the difference in barrel lengths/shrouds. 
Fitting a short barrel cannon in a long shroud/fairing is not going to work well.


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## EwenS (Apr 24, 2022)

PAT303 said:


> If you read up on the Seafires service in the Med the FAA found the MkII's couldn't catch Ju88's so started looking at ways to solve that, like all Spitfire development war production came first but the FAA started to look for solutions to the problem of lack of performance and lack of range straight away. From what I have found the MkIII was hampered by the production line jigs being wrongly made but the first ones were used at the Salerno landings in 1943, the MkIII also got the Hispano MkV cannons. The FAA did more with less compared to the RAF.



I'm well aware of the history of the Seafire and its problems. Perhaps more so than you it would appear.

The first operational use of the Seafire was during Operation Torch in Nov 1942. That was a MK.Ib/IIc show. And yes the Admiralty were trying to get the max out of the aircraft. But any improvements to it were in 1943 after that experience during Torch.

The first Seafire III were not used at Salerno. Salerno was a Mk.IIc/LIIc affair. The first issue of the Mk.III was to 894 squadron in Nov 1943, being 12 F.III, after it returned from operating from Illustrious and Unicorn at Salerno. By the time of Salerno (9-16 Sept 1943) less than a dozen Mk.III had left the production line. 

As for the switch from the Hispano Mk.II to Mk.V, no one has so far managed to pin down exactly when that change occurred but it wasn't until well into 1944. I took part in a detailed discussion on another site over 2 years ago and the conclusion that we reached collectively was that the changeover must have happpened on the Westland production line late in 1944 (probably sometime between Sept and Nov 1944) with Cunliffe Owen probably being a few months behind that. That was from an analysis of many, many photos by a number of people until we were all going blind looking at Seafires! Many of the aircraft around then were being packed up and sent to the Far East & Australia so relatively few made it to the front line squadrons before the end of the war.

So there were lot of changes to the Mk.III during its production run from April 1943 to July 1945. Some of which I noted in my previous post.

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## Zipper730 (Apr 24, 2022)

PAT303 said:


> Seafire tanks were 13.5G from the MkVII/VIII


Why do some sources say 13 and others say 13.5 gallons for the inboard wing-tanks?


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## EwenS (Apr 24, 2022)

Shortround6 said:


> I have my doubts about the introduction of the 20mm Hispano MK V cannon.
> 
> Land based Spitfires didn't get them until after WW II. Even MK 24s show the longer cannon.
> The Tempest didn't get them until the end (?) of the first production batch of 100 aircraft which took until May of 1944 to complete.
> ...


I agree about the Tempest. The Mk.V was introduced on the Tempest V Series II, in other words after the first 100 aircraft had been produced.

See my comments about the Seafire in my last post. 

The Spitfire's issue with the Mk.V cannon becomes more complicated. One point that came out in that discussion two years ago was about a confusion between short barrelled cannon and the position in the wing that the Mk.II cannon was placed in resulting in it needing a shorter shroud when it protrudes from the wing. Compare the Mk.II cannon in a 'C' wing in the inboard cannon bay with an 'E' wing where the cannon is fitted in the outer bay. The former sits further forward in the wing and so needs a longer shroud.

I would agree that most of the Spitfires up to the Mk.24 had the long barrelled Mk.II cannon. But all? I offer you a photo of F.24 VN479 that left the factory in April 1948.





Supermarine Spitfire Mk24 serial VN479 | World War Photos


Spitfire Mk24 serial VN479 on the ground



www.worldwarphotos.info





Compare that with F.22 PK684 that was built in 1946.





Spitfire Mk24 serial PK684 on the ground | World War Photos


Supermarine Spitfire Mk24 serial PK684 on the ground



www.worldwarphotos.info






As I noted in a previous post the wing structure on the Seafire III was reworked at some point to delete the outer cannon bay altogether, a feature inherited by the Seafire XV/XVII. So the position of the cannon in the wing can't account for the shorter shroud on later Seafire III.


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## MikeMeech (Apr 24, 2022)

PAT303 said:


> He was in combat 57 times in 3 years, is that considered busy?.


Hi
Sorry I do not understand. It was you who said that in his writings JEJ mentioned that he was flying around "empty skies" in his Spitfire Mk. XIV, I just stated that in the relevant chapter in his book 'Wing Leader' he does not appear to be saying that at all. I just wondered where the information you stated came from? After all he was not flying Mk. XIVs all the time in those three years so what is the relevance to your statement?

Mike


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## PAT303 (Apr 24, 2022)

Shortround6 said:


> I have my doubts about the introduction of the 20mm Hispano MK V cannon.


Can only go off what I read on the Spitfire/Seafire/FAA web pages/forums, I also think its a bit early but the FAA didn't stuff around with the Seafire, the MkIII was a totally different animal to the MkV based Seafire II, it took a development line similar to the Spitfire MkIII/VIII/XIV not the interim MkV/IX route.


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## PAT303 (Apr 24, 2022)

MikeMeech said:


> Hi
> Sorry I do not understand. It was you who said that in his writings JEJ mentioned that he was flying around "empty skies" in his Spitfire Mk. XIV, I just stated that in the relevant chapter in his book 'Wing Leader' he does not appear to be saying that at all. I just wondered where the information you stated came from? After all he was not flying Mk. XIVs all the time in those three years so what is the relevance to your statement?


I have read he stated that, I will go back and look for the source where I found it, to give you another example, he was the leader of 610 squadron, the first time they had aux tanks fitted and flew across the German border was in September 1944, that's a long time after aux/drop tanks were designed for the Spit and approved for service. He liked the MkIXe the best, it was specifically designed to fight the FW190 at around 20,000ft, it's best altitude.


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## PAT303 (Apr 24, 2022)

EwenS said:


> So the position of the cannon in the wing can't account for the shorter shroud on later Seafire III.


MkIX's also got the smaller bulges but for some reason kept the stub's, it's a bit like they threw the standards out the window sometimes which makes it difficult, but interesting


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## PAT303 (Apr 24, 2022)

Zipper730 said:


> Why do some sources say 13 and others say 13.5 gallons for the inboard wing-tanks?


The extra 0.5 could be in the lines?, honestly don't know. What's silly is there is enough room for double that but the space wasn't used, look at the diagram, heaps of space for more fuel.


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## EwenS (Apr 24, 2022)

PAT303 said:


> I have read he stated that, I will go back and look for the source where I found it, to give you another example, he was the leader of 610 squadron, the first time they had aux tanks fitted and flew across the German border was in September 1944, that's a long time after aux/drop tanks were designed for the Spit and approved for service. He liked the MkIXe the best, it was specifically designed to fight the FW190 at around 20,000ft, it's best altitude.


Except he wasn’t involved with 610 squadron in Sept 1944. He had been commander of 610 between July 1942 and March 1943. Check out the squadron’s own website. During his time with that unit they were flying Spitfire V.





No. 610 (County of Chester) Squadron


Led by keen and courageous pilots and supported by a loyal and efficient ground staff, No. 610 (County of Chester) Auxiliary Squadron was a R.A.F. unit of which, not only the County of Chester, but the whole of Britain can indeed be proud.



web.archive.org





In Sept 1942 610 was based at Ludham in Norfolk. You can get the squadron ORB as a free download from The National Archives provided you register, which will let you see exactly what the squadron was doing.

In Sept 1944 JEJ commanded 127 Wing comprising 403, 421, 416 and 443 squadrons. These were all Spitfire IX equipped until Dec 1944 / Jan 1945 when they received Spitfire XVI. 403 and 421 disbanded in June and July 1945 without another change of equipment. 416 finally got Spitfire XIV in Sept *1945 *while 443 got them in Jan *1946. *Both those units disbanded in March 1946.

As I pointed out 610 squadron was only in 127 Wing in Dec 1944 after which it moved to 125 Wing. By the time JEJ arrived to command 125 Wing at the end of March 1945, 610 squadron was gone. It had returned to Britain on 21 Feb 1945 and disbanded on 3 March 1945.

So the story as you are telling it is nonsense and doesn’t fit the facts. Time to go back and reread the book.


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## Shortround6 (Apr 24, 2022)

PAT303 said:


> Can only go off what I read on the Spitfire/Seafire/FAA web pages/forums, I also think its a bit early but the FAA didn't stuff around with the Seafire, the MkIII was a totally different animal to the MkV based Seafire II, it took a development line similar to the Spitfire MkIII/VIII/XIV not the interim MkV/IX route.


Doesn't matter what the did with airframe/s.
When were the MK V guns ready?

The MK V was shorter, lighter and fired faster.
Would seem like a no Brainer to fit it in as many planes as you could.
Throw in the shorter barrel shrouds have less drag and there isn't any real down side.

The 10in shorter barrels and shorter barrel shrouds should show up in any decent photo


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## GregP (Apr 24, 2022)

PAT303 said:


> He was in combat 57 times in 3 years, is that considered busy?.



You might read on JEJ a bit, if only out of curiosity. No dig intended, Pat; interesting reading, really. He was wounded and spent considerable time in the hospital and in recovery. So, he missed some combat time but, when he WAS in combat, he did quite well.


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## FLYBOYJ (Apr 25, 2022)

PAT303 said:


> He was in combat 57 times in 3 years, is that considered busy?.


57 missions or 57 enemy encounters?


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## MikeMeech (Apr 25, 2022)

FLYBOYJ said:


> 57 missions or 57 enemy encounters?


Hi
According to 'Wing Leader', at the end of Chapter 18, when he left to go onto Spitfire XIVs he states that in his previous Spitfire IX "... during the previous twelve months, had carried me on nearly 200 operations." The book 'Aces High' by Shores and Williams, pages 357-358, has JEJ with claims of 34 and 7 shared destroyed, 3 and 7 shared probables, 10 and 3 shared damaged. He also of course flew with the USAF in the Korean War during 1950-51 while on an exchange tour (from 1948).

Mike

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## PAT303 (Apr 25, 2022)

EwenS said:


> Except he wasn’t involved with 610 squadron in Sept 1944. He had been commander of 610 between July 1942 and March 1943. Check out the squadron’s own website. During his time with that unit they were flying Spitfire V.


I'm using it as an example of just how slow the RAF was to fit aux fuel tanks onto the Spitfire, the MkXIV was a brute, it even had a 90G tank approved for combat that wasn't utilized as much as it should


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## PAT303 (Apr 25, 2022)

GregP said:


> You might read on JEJ a bit, if only out of curiosity. No dig intended, Pat; interesting reading, really. He was wounded and spent considerable time in the hospital and in recovery. So, he missed some combat time but, when he WAS in combat, he did quite well.


He was a hell of a pilot, he shot down a lot of 190's, not doubting that, problem is the RAF had many pilots like him flying the Spitfire that could have made a major contribution to the daylight bombing compain ''IF'' they were given the chance.


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## PAT303 (Apr 25, 2022)

FLYBOYJ said:


> 57 missions or 57 enemy encounters?


In combat 57 times, or just over one a month on average, kinda backs up the fruitless sweeps statement.


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## PAT303 (Apr 25, 2022)

EwenS said:


> So the story as you are telling it is nonsense and doesn’t fit the facts. Time to go back and reread the book.


I'm talking about long range fighter sweeps, I have a report on 610 squadron mentioning how excited they were to fly over German, years after everyone else had been doing even though the aux tanks and drop tanks were approved for the spit. http://www.wwiiaircraftperformance.org/610-ORB-1sept44.jpg


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## PAT303 (Apr 25, 2022)

We are getting off topic a bit, could the Spitfire fill the role as an escort fighter, the answer is yes out to around 500 miles, did it, no, why, no idea, RAF stubbornness?.


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## FLYBOYJ (Apr 25, 2022)

PAT303 said:


> In combat 57 times, or just over one a month on average, kinda backs up the fruitless sweeps statement.


There have been pilots who flew hundreds of "missions" and saw little to no combat where an enemy was *engaged* so I still don't understand where you're coming from.


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## FLYBOYJ (Apr 25, 2022)

MikeMeech said:


> Hi
> According to 'Wing Leader', at the end of Chapter 18, when he left to go onto Spitfire XIVs he states that in his previous Spitfire IX "... during the previous twelve months, had carried me on nearly* 200 operations."* The book 'Aces High' by Shores and Williams, pages 357-358, has JEJ with claims of 34 and 7 shared destroyed, 3 and 7 shared probables, 10 and 3 shared damaged. He also of course flew with the USAF in the Korean War during 1950-51 while on an exchange tour (from 1948).
> 
> Mike


So 57 enemy encounters in 200 operations (missions?), 34 claims. Sounds about average (or even better then average) when comparing to other allied aces who were given leave during the course of the war.


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## Milosh (Apr 25, 2022)

PAT303 said:


> We are getting off topic a bit, could the Spitfire fill the role as an escort fighter, the answer is yes out to around 500 miles, did it, no, why, no idea, RAF stubbornness?.


So a Spit could travel 1000 miles plus.


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## drgondog (Apr 25, 2022)

Milosh said:


> So a Spit could travel 1000 miles plus.


It would have to have a Range (straight line optimal cruise) of 1700-2000 mi (with combined Interna/Externals for 500mi combat radius and 20 min of MP/WEP combat. For a 500 mi radius after combat it would need more than 120 gal internal fuel remaining - to cruise bac and have a 20-30minreserve.

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## GregP (Apr 25, 2022)

PAT303 said:


> He was a hell of a pilot, he shot down a lot of 190's, not doubting that, problem is the RAF had many pilots like him flying the Spitfire that could have made a major contribution to the daylight bombing compain ''IF'' they were given the chance.



Why is that a problem? Almost all RAF pilots were "given the chance" at combat during WWII. 

Not all, but a very good percent. I'm sure some of the instructors would like to have flown combat, but somebody has to jeep the new pilot supply train going. Somebody has to fly transports / liaison / clandestine special missions / etc. Somebody has to fly bombers, IF you are bombing. That leaves a cadre to fly fighters, and they were hard-pressed to keep a sufficient supply of fighter pilots at times, especially early-on.

That being the case, what Spitfire pilots are you talking about that didn't get the chance? If they were flying Spitfires and didn't get the chance at combat, I am assuming they were assigned to places where the Germans didn't attack, but might have, and so had to be covered by fighters. Is that it?


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## pbehn (Apr 25, 2022)

GregP said:


> Why is that a problem? Almost all RAF pilots were "given the chance" at combat during WWII.
> 
> Not all, but a very good percent. I'm sure some of the instructors would like to have flown combat, but somebody has to jeep the new pilot supply train going. Somebody has to fly transports / liaison / clandestine special missions / etc. Somebody has to fly bombers, IF you are bombing. That leaves a cadre to fly fighters, and they were hard-pressed to keep a sufficient supply of fighter pilots at times, especially early-on.
> 
> That being the case, what Spitfire pilots are you talking about that didn't get the chance? If they were flying Spitfires and didn't get the chance at combat, I am assuming they were assigned to places where the Germans didn't attack, but might have, and so had to be covered by fighters. Is that it?


A BoB pilot commented that even during the Battle of Britain most of the pilots most of the time were not involved in combat. Many were stationed outside of the LW range, there were days without any ops and even on a raid Park put up a screen of patrols to cover possibilities, obviously many of these never saw the enemy. There were also a few standing patrols, rarely mentioned because they rarely saw anything.

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## tomo pauk (Apr 25, 2022)

PAT303 said:


> We are getting off topic a bit, could the Spitfire fill the role as an escort fighter, the answer is yes out to around 500 miles, did it, no, why, no idea, RAF stubbornness?.



There was no such a doctrine/requirement by the RAF. 
When the topic of long-range fighters was brought out mid-war, dogma was that a LR fighter will be inferior to a short range fighter, thus not worth it.


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## pbehn (Apr 25, 2022)

tomo pauk said:


> There was no such a doctrine/requirement by the RAF.
> When the topic of long-range fighters was brought out mid-war, dogma was that a LR fighter will be inferior to a short range fighter, thus not worth it.


Well they werent far wrong as far as the RAF were concerned. They didnt have anything to escort during the day. The numbers British industry could make would not be sufficient to provide a L/R escort in the required numbers and in terms of quality not numbers the Me 262 was contemporary with the P-51D. Spitfires did assist a lot in the early days, but for the RAF to escort to and from the target on long range missions needs a whole lot more Spitfires, but the Spitfire wasnt as good as the P-51B/C D, so better for the RAF to operate those which is what they did.


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## GregP (Apr 25, 2022)

Hi pbehn,

People can ALWAYS look back at a battle or a war and see where things might have been done differently to better overall effect. Not intimating you are one of them. These same people would likely never make those decisions in real time, without the knowledge of what would soon come to pass, but they now know 70 years after the events happened. Hindsight always has 20-20 vision. How many would commit ALL the Spitfire pilots at once back then, leaving no reserves, and if they were shot down somehow, lose the entire country's fighter air arm and possibly the entire war?

The guys who ran the war ran it with the resources they had and could generally develop during the war. They didn't know, in advance that they could, for instance, not build the Lancaster at all and instead make a huge force of Mosquitoes, as had been suggested in here several times. They made their decisions based upon maximum likelihood of national survival at present and in the near, foreseeable future and, in the case of the real world, did a pretty damned good job of it --- they won.

The Spitfire pilots who weren't engaged in the real fighting were "the reserves" that would be sorely needed, and needed quickly, if the BOB and a few other early events had not gone as well as they did. I'll say that, in my opinion, the British / Allied planners did about as well as they could with the information they had and the resources they had to work with. Heck, even the Normandy invasion wasn't without potentially disastrous weather possibilities, and Eisenhower received about as much advice to postpone it as he did to go through with it. In the end, he made a good decision with fewer casualties than could reasonably be expected had even a small number of things gone the way the Germans wanted them to go.

I'm guessing that many of the Spitfire pilots who missed out in the BOB and other early actions didn't miss out for the rest of the war. If they did, then that is another story that I haven't seen investigated in here as yet.

Maybe another thread on the subject?

Cheers!

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## tomo pauk (Apr 25, 2022)

pbehn said:


> 1 - Well they werent far wrong as far as the RAF were concerned. They didnt have anything to escort during the day. 2 - The numbers British industry could make would not be sufficient to provide a L/R escort in the required numbers and in terms of quality not numbers the Me 262 was contemporary with the P-51D. Spitfires did assist a lot in the early days, but for the RAF to escort to and from the target on long range missions needs a whole lot more Spitfires, but the Spitfire wasnt as good as the P-51B/C D, so better for the RAF to operate those which is what they did.



1 - Who was supposed to provide the escort for Battles and Blenheims above Ardenes (or anywhere) in 1940? Escort to the Wellingtons trying to attack KM assets? Escort over Africa and Med? Bomber Command's doctrine was to attack during daylingt (since the bomber will always get through), before Luftwaffe made them reconsider. So there was certainly enough of stuff to escort.
2 - Hurricanes were produced into 1944. 1000+ Defiants was produced. Blenheims in many hundreds past 1940. Lets introduce a biplane fighter in 1937, and produce it in 740+ copies. Botha - 580 examples. I can understand the 1st 500 Battles, even the 1st 1000 - but more than 2000, all with Merlins?? So yes, with hundreds of clunkers on the production lines, there was certainly not enough capacity left to make more Spitfires or other over-performers. 
Not having 200 imp gals of internal fuel on day one on the Typhoons, Tempests and Spitfire 14s is AM's/RAF's idea. 
Me 262 vs. P-51D is a red herring. There were years of air war well before Luftwaffe was able to get 50, let alone 100 of 262s in the air.

Everyone was entitled on mistakes and missing opportunities. Not having a day fighter with 500 mile escort footprint was British AM's missed opportunity.


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## Zipper730 (Apr 25, 2022)

PAT303 said:


> The extra 0.5 could be in the lines?


Unsure, but I have heard different figures in manuals even


> What's silly is there is enough room for double that but the space wasn't used, look at the diagram, heaps of space for more fuel.
> View attachment 665688


That is pretty strange, I do remember seeing proposals to put larger fuel tanks in there including some


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## ssnider (Apr 25, 2022)

How much weight would be added to a mk. V pr early IX to make this long rabe spitfire? Effect on wing loading, wt/hp., max G loading?

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## pbehn (Apr 25, 2022)

GregP said:


> Hi pbehn,
> 
> People can ALWAYS look back at a battle or a war and see where things might have been done differently to better overall effect. Not intimating you are one of them. These same people would likely never make those decisions in real time, without the knowledge of what would soon come to pass, but they now know 70 years after the events happened. Hindsight always has 20-20 vision. How many would commit ALL the Spitfire pilots at once back then, leaving no reserves, and if they were shot down somehow, lose the entire country's fighter air arm and possibly the entire war?
> 
> ...


I agree completely. Dowding had to both husband his resources and ensure that the whole of the south and east coasts were protected. My point was that even in what is considered a fairly long and intense battle most spent most of the time at readiness or on patrol, training, reforming etc. A bit like I have read of infantry soldiers life 99% boredom 1% homicidal terrifying madness.

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## pbehn (Apr 25, 2022)

tomo pauk said:


> 1 - Who was supposed to provide the escort for Battles and Blenheims above Ardenes (or anywhere) in 1940? Escort to the Wellingtons trying to attack KM assets? Escort over Africa and Med? Bomber Command's doctrine was to attack during daylingt (since the bomber will always get through), before Luftwaffe made them reconsider. So there was certainly enough of stuff to escort.
> 2 - Hurricanes were produced into 1944. 1000+ Defiants was produced. Blenheims in many hundreds past 1940. Lets introduce a biplane fighter in 1937, and produce it in 740+ copies. Botha - 580 examples. I can understand the 1st 500 Battles, even the 1st 1000 - but more than 2000, all with Merlins?? So yes, with hundreds of clunkers on the production lines, there was certainly not enough capacity left to make more Spitfires or other over-performers.
> Not having 200 imp gals of internal fuel on day one on the Typhoons, Tempests and Spitfire 14s is AM's/RAF's idea.
> Me 262 vs. P-51D is a red herring. There were years of air war well before Luftwaffe was able to get 50, let alone 100 of 262s in the air.
> ...


Sorry I thought we were discussing long range escort, how far did Battles and Blenheim's fly to get to the Ardennes? The RAF couldnt get air superiority over Dieppe in 1942 so maybe they were wise not to get involved in a long range daylight bombing campaign?


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## MikeMeech (Apr 25, 2022)

Hi
There was quite a lot going on in northern Europe between the BoB and D-Day. Looking at the summaries of 'Fighter Command War Diaries' Volumes 2-4 by John Foreman illustrates some of this activity:













The first P-51Bs did not arrive for use by the USAAF in Britain until late 1943, the Mk. IX Spitfire entered service in July 1942. The Mk. IX was introduced to help deal with aircraft like the FW 190, trying to make it long range as well at the time would probably been mistaken, after all the FW 190 was based on the other side of the Channel. The Spitfire Mk. VIII (with the wing tanks) was in service in the Med in August 1943. The P-51D did not arrive until just before D-Day, the Spitfire XIV had entered service in January 1944, again it was designed to be competitive with newer enemy fighters, both the IX (and VIII) and XIV succeeded in that role. Trying to make both long range would probably delayed their introduction (although any extra range is very useful but not totally at the expense of performance) which would have been detrimental to the war effort. The P-51 was a later larger/heavier design than the Spitfire and if the USAAF wanted long-range fighters earlier to escort 8th AF bombers maybe it would have been better to get the P-51B in service quicker (but there are always problems with that in real life). As it was the RAF (and USAAF) Spitfires did escort the 8th AF bombers on their early missions as they were mainly over France, the bomber crews had to get experience in combat before risking longer range missions. Of course there were a lot of enemy assets that needed attacking that were nearer than Germany it was never one or the other, so if there is a belief that only attacking Germany was useful then I think a closer look at the war situation is needed.

Mike

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## PAT303 (Apr 25, 2022)

Milosh said:


> So a Spit could travel 1000 miles plus.


Read the report I posted on 610 Squadron, they flew 800 miles and back with 50-60G of fuel remaining, obviously combat will shorten that distance but they didn't use leading edge tanks either so it's possible.


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## PAT303 (Apr 25, 2022)

FLYBOYJ said:


> So 57 enemy encounters in 200 operations (missions?), 34 claims. Sounds about average (or even better then average) when comparing to other allied aces who were given leave during the course of the war.


He was a very good pilot, he used to stretch his squadron out line abreast for over a mile or more hunting for enemy aircraft, everything I have read about him shows he was keen for combat, very well liked by his fellow pilots also. All up over 700 missions but like posted earlier he injured himself which kept him out of action for a while.


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## PAT303 (Apr 25, 2022)

GregP said:


> That being the case, what Spitfire pilots are you talking about that didn't get the chance? If they were flying Spitfires and didn't get the chance at combat, I am assuming they were assigned to places where the Germans didn't attack, but might have, and so had to be covered by fighters. Is that it?


Spitfires were used for the first and last leg out and back in daylight raids but only to about 150 miles which really was pointless, at the same time the P47 was limited to about 350 miles before turning back, the Spit ''if'' fitted with aux/drop tanks that were approved for service it could have gone out to 450-500 miles depending on circumstances, my argument is the Spit could have done more if they simply filled them with more fuel but they weren't, the P47 started escorting with ferry tanks, that's how desperate the USAF were for escort fighters.


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## Shortround6 (Apr 25, 2022)

We keep going round and round on this. 

Battles and Blenheim's used the Ardennes were based (at least Battles) in France. Distance for the Hurricane escorts would have been?????

Of course it would have helped if the Battles and Blenheims were only attacking things 2-20 miles over the front lines instead scores of miles behind the front lines. 
Major error in targeting that was not solvable by changing the type of fighter. 
You also have to change the way you escort. 
In 1940 British "escorts" tended to fly a fighter sweep in the general area that the bombers were expected to fly and at the general time the bombers were expected to be there with no real effort expended on seeing that the fighters actually saw the bombers they were supposed to be escorting. Makes the German fighter sweeps in the BoB look like close escort. 

Then we get back to 


ssnider said:


> How much weight would be added to a mk. V pr early IX to make this long rabe spitfire? Effect on wing loading, wt/hp., max G loading?


And some people want to back it up further.
How much weight added to the MK I Spitfire to make it a long range fighter in April of 1940 in France? 
We do know what the performance penalty was for the Spitfire MK II with the 40 gallon tank. 

We also have several performance tests of MK V Spits. Like the one with four 20mm cannon costing around 350fpm in climb compared to a MK V with just two 20mm and four .303s.
guns. For some reason the RAF thought that the weight of four 20 mm guns over the weight of the standard cannon/mg armament was too great a penalty but the addition 40 gallons or so extra fuel and tank/s would have been no problem? 
See MK V with 90 gallon drop tank and split the difference to estimate 45 gallons. 

Double check to see what engine ratings were being used when. A MK V using 9lb of boost doesn't have the same options as a MK V using 12 or 14lbs of boost. 
A MK V doing escort duty has to be able to fight a Bf 109F-4 in the summer of 1941. The British may not have known this in April/May of 1941 but by Aug/Sept it would have been all too apparent. 

The MK IX has a set of tests both with and without a 30imp gallon drop tank. The difference is not as great due to the fact than the MK IX is 700-800lbs heaver than the MK V to begin with so addition of 30 gallons of fuel + tank is a smaller percentage. Then you have the much greater power of the Merlin 61. 
A Spitfire V _without extra fuel _at around 25,000-26,000ft is climbing about 2/3rds as well as a Spitfire IX was carrying a 30 gallon drop tank and using "normal" power. 
At lower altitudes the MK V is a lot closer but you better pick what planes you want to escort and at what altitudes. 

I have tried comparing climb performance for several reason, it cuts down on the drag difference which internal fuel will minimize compared to external fuel 
and climb performance is not just getting to altitude. The climb performance is an indicator of the surplus power available at climbing speed to assist in maintaining performance while doing maneuvers. Two planes otherwise identical but with plane B having 10% more climbing power will be able to sustain speed in a turn better without descending for instance.

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## Shortround6 (Apr 25, 2022)

PAT303 said:


> Read the report I posted on 610 Squadron, they flew 800 miles and back with 50-60G of fuel remaining, obviously combat will shorten that distance but they didn't use leading edge tanks either so it's possible.



It is "possible" for a P-40 to fly over 1000 miles. And that is with just a 52 US gallon drop tank. But you aren't going to escort much of anything.
A P-40 with a 52 gallon tank could burn 30 gallons just taking off and getting to 10,000ft. It could take another 30 gallons to reach 25,000ft. 
That 30 gallons was worth around 50 minutes or 150 miles at low latitude and very economical cruising speed. 
15 minutes at military power on the P-40E was worth about 33 gallon depending on altitude. 
A P-40E held about 123 IMP (148US gallons) gallons not including the drop tank.
The P-40E is not that far off an early Spitfire at lower altitude for speed compared to power for a guestimate on drag. 

So which Spitfire, the 
MK I
MK II
MK V 
Or the MK IX (or MI VIII) 
are we going to to turn into the early long range escort? Or several versions with increasing ranges? 

Or try to compare the P-40F with the Merlin engine to what kind of escort it would make (can't climb well but it could over 360mph at 20,000ft using the Merlin XX so it shouldn't be that far off the Spit the V.


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## 33k in the air (Apr 25, 2022)

Shortround6 said:


> It is "possible" for a P-40 to fly over 1000 miles. And that is with just a 52 US gallon drop tank. But you aren't going to escort much of anything.



Not in the European theatre. In the Pacific, this quote from _Development of the Long-Range Fighter Escort_ may be of interest:



> An effort was made to increase the range of P-40's in the V Fighter Command's 49th Group still more by equipping them with three external droppable fuel tanks, one belly tank, and two wing tanks, instead of the two normally considered maximum. Thus equipped and with the pilot using the cruise-control technique, the plane flew for 7 hours and 35 minutes and still had sufficient fuel for another hour and one-quarter. This indicated that the P-40 could achieve an effective radius of 650 miles. [68]
> 
> _-- p.249 of PDF (227 of document)
> 
> [68] Hist. V FC, July-Dec. 1944, Chap. 4_

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## Zipper730 (Apr 25, 2022)

I was curious about two matters

1. There was a mention on of an early PR variant that possessed a 20 imperial gallon tank underneath the pilot's seat: I can't seem to find anything specific on this one. I can find mention of a 29 gallon tank that was located behind the pilot (this was also fitted to the Spitfire Mk.V for ferrying), as well as one variant that had a 30 gallon tank in a blister under one wing (it counterbalanced the weight of a cam in the other wing). I'm curious if it existed at all, or was mixed-up with these developments (This keeps getting lost in the discussion, and honestly, it's like trying to nail jello to a wall).

2. I remember that, when the early Spitfire Mk.I's were switched from a fixed propeller, to a twin-pitch propeller, to a constant-speed propeller, that there was ballast added in the aft fuselage to balance this out. In the Mk.VII/VIII/IX and beyond, was this ever removed in non PR variants? I remember this was done on the P-51B/C's that were fitted with the 85 US gallon tank since it would have put the plane out of the C/G limits, and when the fuel was lowered to either 55-60 gallons, you'd end up with the C/G in roughly the same position you'd be in if the ballast was retained.

3. When did the Seafire's adopt the 89 US gallon P-40 tank? I know it was definitely in place by 1945 (and that might very well be the year it was adapted to the aircraft, for all I know).



wuzak said:


> Perhaps because the facilities making the VIII converted to the XIV/XVIII?


While I thought the lines making the Mk.VII & VIII were converted to the Mk.XIV/XVIII, what happened to the lines that produced the Mk.VII?



EwenS said:


> David Brown lists the internal fuel capacity as 85gals for ALL Merlin Seafires. For the Seafire XV & XVII 80.5gals in fuselage tanks and 19.5gals in wing-root tanks. These figures are supported by "Spitfire the History", and, as pointed out by Geoffrey Sinclair, the Pilots Notes.


The XV's flight manual indicates 9-3/4 imperial gallons per wing not 19.5 per wing.



PAT303 said:


> It didn't need too, there is more than enough space in the leading edge to increase the tank capacity from 26G to 50G, add 75G in the rear, 96G main and a 90G dropper and you have the range to fight deep over the continent.


Which variant are we talking about? As for the wing-capacity, do you mean 25 imperial gallons in the wing-root, or 50 gallons in each wing? I remember hearing that it was possible to put room for 53 imperial gallons of fuel in the wing-leading edge inboard of and outboard of the 20mm cannon, though I'm not sure the RAF would have accepted such a configuration even if it was possible to work a fuel line around the back side of the Hispano cannon.


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## Shortround6 (Apr 25, 2022)

Something to remember about the photo recon aircraft.

They weren't supposed to dogfight/ do hi G maneuvers.

Which means they could operate at higher gross weights and also operate at Center of gravity locations that might be dangerous for a plane trying to pull 5-6 gees.


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## Zipper730 (Apr 25, 2022)

Shortround6 said:


> Something to remember about the photo recon aircraft.
> 
> They weren't supposed to dogfight/ do hi G maneuvers.


I understand that detail: I'm mostly curious if the tank even existed to begin with (there's lots of information that ends up getting written down by mistake, and then it ends up becoming myth instead of fact).

As for the matter of center of gravity: That is a legitimate issue, but i'd be more concerned about the aft tanks than an underseat tank since the underseat tank is further forward (and smaller.


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## EwenS (Apr 26, 2022)

Zipper730 said:


> 3. When did the Seafire's adopt the 89 US gallon P-40 tank? I know it was definitely in place by 1945 (and that might very well be the year it was adapted to the aircraft, for all I know).


When the British Pacific Fleet formed in Nov 1944, Indefatigable was the only carrier with Seafires as its main fighter type. The others three were using Corsairs and Hellcats. Due to its short range and good performance at lower levels Indefatigable's Seafire squadrons were initially used to provide CAP for the Fleet. At that time only the 30 & 45 gal slipper tanks seem to have been available to them. However in June 1945 it became apparent that both Indefatigable and the newly arrived Implacable, also with Seafires, would need to play a far greater offensive role in upcoming operations over Japan itself. Why? Because Seafires would form a much greater proportion of the fighters on the carriers (Indomitable with Hellcats was in refit so it was going to be 2 with Corsairs and 2 with Seafires). Both ships then began looking for a solution to increase the range of their Seafire III.

Indefatigable, being in Australia at the time, after operation Iceberg, talked to the RAAF, and obtained a supply of 90 gal slipper tanks from them.

Implacable was in Manus in the Admiralty Is at the beginning of June 1945. Her Seafire squadrons experimented with the 30, 45 and 90 gal slipper tanks but they experienced problems with the connections on them. After talking to the Americans, it was discovered that there was a supply of 89 or 90 imp gal drop tanks (sources vary on the exact size) at a base in New Guinea that looked, from the drawings they were able to obtain, like they might prove suitable. A deal was done (currency changed hands - 2 "crates" of Johnny Walker whisky according to Commander Mike Crosley, the 880 squadron CO on Implacable) and a destroyer despatched to collect them. 100 "rusty" P-40 drop tanks were put aboard the carrier on her return to Manus on 17 June from Operation Inmate to Truk. The Seafire bomb racks were then modified by the ship's engineering staff to allow these tanks to be carried. That work was complete by the time she sailed for Japanese waters with the rest of the Fleet on 28 June 1945. And very successful they proved in July/Aug operations off Japan. But there was never an official clearance for the use of these tanks.

That is not to say that they 45 90 gal slipper tanks did not prove equally successful in these operations. Implacable was, by all accounts, a very happy and efficient ship. It is just that her air group has attracted much more attention. She carried official photographers and a film crew so there is much more coverage of her July/Aug operations off japan than probably any of the other RN carriers. And of course Mike Crosley and others who were serving aboard her have written their autobiographies covering the period.


Zipper730 said:


> While I thought the lines making the Mk.VII & VIII were converted to the Mk.XIV/XVIII, what happened to the lines that produced the Mk.VII?


Supermarine was solely responsible for production of the Mk.VII, VIII, XIV and XVIII. A couple of points:-

1. There was a war on. While stating the obvious it affected production in Britain in ways that the US was not affected by, which necessitated a different approach to aircraft production in many cases. After its factory in Southampton was bombed in 1940 Supermarine used a system of dispersed production. There was then not a single Supermarine production line / factory. Sub-assemblies were built all over the south of England and then brought together at a number of airfield sites to create complete Spitfires to be test flown. You will find much information about the production of Spitfires by Supermarine here:-








Supermarine


The name “Supermarine” is inextricably linked to “The Spitfire”, the iconic aircraft that symbolised British defiance during World War II, but the name masks a more complex …




supermariners.wordpress.com





The shadow Castle Bromwich Aircraft Factory was an entirely different kettle of fish. It was set up for mass production, which took some time to achieve. But it only built a limited number of Marks. (Mk.II/V/IX/XVI/XXI)

2. There was not a clean movement from one mark to another at Supermarine as happened with most US types (e.g. P-51 to P-51A to P-51B/C to P-51D/K to P-51H). Supermarine produced various marks in parallel. So the various marks and their production periods were as follows:-

Mk.VII - 140 produced between August 1942 and May 1944. Final assembly for all was at Eastleigh
Mk.VIII - 1,654 produced Nov 1942 and Dec 1944. Final assembly was at a number of sites starting at Eastleigh and then expanding to places like Chattis Hill, Keevil etc
Mk.XIV - 957 produced Oct 1943 to Dec 1945. Final assembly started at Eastleigh then expanded to other sites like Chattis Hill, Keevil & Aldermaston
Mk.XVIII - 300 produced June 1945 to Jan 1946. Final assembly at Eastleigh, Keevil & Aldermaston


Zipper730 said:


> The XV's flight manual indicates 9-3/4 imperial gallons per wing not 19.5 per wing.


Where did I say 19.5gal in "*each*" tank? What I said was ".... *19.5gals in wing-root tanks*...." Note the use of the plural. 2x9-3/4 = 19.5 total per my maths.

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## MikeMeech (Apr 26, 2022)

PAT303 said:


> He was a very good pilot, he used to stretch his squadron out line abreast for over a mile or more hunting for enemy aircraft, everything I have read about him shows he was keen for combat, very well liked by his fellow pilots also. All up over 700 missions but like posted earlier he injured himself which kept him out of action for a while.


Hi
Here is the brief bio for JEJ from 'Aces High':









It is interesting to note that he was only hit once (August 1944) by enemy fire in air to air combat (lucky or skilled or a bit of both) even though he was in combat with FW 190s during 1941/42 while flying Spitfire Vs. His biggest gap in flying was when he was on a 6 month ground tour. His book 'Wing Leader' (published 1956 originally) is a useful read for those interested.

Mike

Mike

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## MikeMeech (Apr 26, 2022)

Hi
The first 8th AF B 17 operation was escorted by Spitfires Part 3 of the 'Fighter Command War Diaries' by John Foreman, page 170, has the following:




Roger Freeman's 'The Mighty Eighth' page 12 has this on it:




The same author's 'The Mighty Eighth War Diary' pages 9-10 has this information:








A lot of the RAF's Spitfire IXs, then available, appear to have been used to protect the US bombers.

Mike

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## tomo pauk (Apr 26, 2022)

pbehn said:


> Sorry I thought we were discussing long range escort, how far did Battles and Blenheim's fly to get to the Ardennes? The RAF couldnt get air superiority over Dieppe in 1942 so maybe they were wise not to get involved in a long range daylight bombing campaign?



No need to feel sorry. 
The long-range fighters can do short-range escort, opposite is not true. RAF needs to achieve air superiority over Belgium and the closest 1/2 of France - ain't gonna happen on short notice and with short-ranged fighters.


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## tomo pauk (Apr 26, 2022)

Shortround6 said:


> So which Spitfire, the
> MK I
> MK II
> MK V
> ...



I'd start with Hurricane I; Gloster makes the Hurricanes instead of Gladiators from early 1938 (no Gladiator) so there is a lot of Hurricanes to have.
Spitfire I gets a LR version, to be produced at Boulton Paul (no Defiant). Carry on with improved versions.


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## Shortround6 (Apr 26, 2022)

tomo pauk said:


> No need to feel sorry.
> The long-range fighters can do short-range escort, opposite is not true. RAF needs to achieve air superiority over Belgium and the closest 1/2 of France - ain't gonna happen on short notice and with short-ranged fighters.



You are going to need a crap load more Hurricanes. And a major change in operations.
Trying to establish air Superiority over Belgium and France from bases in England isn't going to work very well for a number of reasons.
1. No radar.
2. Very poor communications./No command center/fighter direction centers.

Even with a fighters with double the endurance of a Hurricane I or Spitfire you won't get any more time on station, if as much, from planes flying from England than from the short range planes flying from France. 

In some cases the British were doing recon work in the very early morning, information was going to headquarters and target selection was sometimes decided by staff in England which passed the orders back down to the strike squadrons and escort squadrons. This meant the strike aircraft and the fighters that were supposed to clear the way for them (actual escort was very rare) were setting out hours after the recon flights had landed and reported. In many cases the strike aircraft passes over targets of opportunity and flew several dozen miles further into German held territory to reach the designated strike points, except the German columns of troops/equipment were no longer there. 

You can base planes in England but adding 1/2 hour to an hour flight time each way for tactical response isn't going to do much good.
It is about 190 miles (300km) from Folkstone/Dover to Sedan. About 150 miles from Ipswich to Antwerp. 

You don't have the command structure to control the planes to intercept or counter the the German aircraft raids/missions.
Flying long range standing patrols just sucks up fuel and wears out engines and pilots.

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## Shortround6 (Apr 26, 2022)

tomo pauk said:


> I'd start with Hurricane I; Gloster makes the Hurricanes instead of Gladiators from early 1938 (no Gladiator) so there is a lot of Hurricanes to have.
> Spitfire I gets a LR version, to be produced at Boulton Paul (no Defiant).



Not sure that building more fabric wing Hurricanes get you very much. 
Do you have an extra 500-700 Merlins in 1938/early 1939? 
Gloster was able to get into building Hurricanes quickly when they stopped building Gladiators, in part because they had a large and well trained work force. 

You can have Boulton Paul build Spitfires instead of Defiants but until you sort the engine and propeller situation (summer of 1940?) you aren't going to get a very good even mid range Spitfire.


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## drgondog (Apr 26, 2022)

Zipper730 said:


> Even the P-51 ran on the wing-tanks on the ground? I honestly thought they used the center-tank when they were on the ground and climbing.
> 
> 
> 
> ...


No, the left wing tank is used and fuel system has a overflow/return flow to left main tank only. The C/L tank frequently used after forming up and starting climb.

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## Zipper730 (Apr 26, 2022)

drgondog
, thank you for clarifying


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## Milosh (Apr 26, 2022)

Notice that first B-17 mission had Col Paul W. Tibbets as the pilot of the lead a/c.

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## PAT303 (Apr 26, 2022)

Shortround6 said:


> For some reason the RAF thought that the weight of four 20 mm guns over the weight of the standard cannon/mg armament was too great a penalty but the addition 40 gallons or so extra fuel and tank/s would have been no problem


The fuel is burnt off, the guns aren't.


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## PAT303 (Apr 26, 2022)

MikeMeech said:


> A lot of the RAF's Spitfire IXs, then available, appear to have been used to protect the US bombers.


They only went just inside French territory to the limit of their 85G tanks, Rouen is just over the channel.


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## PAT303 (Apr 26, 2022)

Shortround6 said:


> It is "possible" for a P-40 to fly over 1000 miles. And that is with just a 52 US gallon drop tank. But you aren't going to escort much of anything.
> A P-40 with a 52 gallon tank could burn 30 gallons just taking off and getting to 10,000ft. It could take another 30 gallons to reach 25,000ft.
> That 30 gallons was worth around 50 minutes or 150 miles at low latitude and very economical cruising speed.
> 15 minutes at military power on the P-40E was worth about 33 gallon depending on altitude.
> ...


I'm not arguing with you, the fact is they did it, it's that simple. Once the 60 series Merlin arrived the Spit had the engine power to get more fuel off the ground that was it and every other single engined fighters biggest problem pre 1942.


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## PAT303 (Apr 26, 2022)

Shortround6 said:


> Something to remember about the photo recon aircraft.
> 
> They weren't supposed to dogfight/ do hi G maneuvers.
> 
> Which means they could operate at higher gross weights and also operate at Center of gravity locations that might be dangerous for a plane trying to pull 5-6 gees.


The fuel is burnt off, P51's didn't dogfight with full rear tanks or drop tanks and it had dangerous handling at take off, I find the mentality on here interesting, lets find every reason to not make it work instead of ways it can.


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## nuuumannn (Apr 26, 2022)

Shortround6 said:


> You can have Boulton Paul build Spitfires instead of Defiants but until you sort the engine and propeller situation (summer of 1940?) you aren't going to get a very good even mid range Spitfire.



Earlier than that, the first Hurricanes received VP props in February 1939 and de Hav was fitting VP props to spits before 1940, the C/S prop came along for Spits in Spring/Summer 1940. But let's not forget that VP/C/S props were already fitted to other RAF types at the time, which makes the decision to keep lumps of wood aboard fighter aircraft that could have benefitted with them better than any other type a strange one.

With our retrospectoscope we could state that BP built Spits had de Havilland props as fitted to Defiants, as standard, as the Daffy never had a wooden lump up front.

Fabric winged Hurris did perform poorly and definitely couldn't reach 300 mph in squadron service in 1938, despite what was advertised, but the benefit of the design was that the all-metal wing could be retrofitted as it was just the outboard wing panels that were fabric covered, the centre-sections were all metal, so the outer wings could be exchanged. Production of the all-metal outer wings standardised in 1939. The primary difference being the arrangement in gun bay access. We also know that the VP and C/S prop mods didn't take much time at all to implement, the Rotol C/S prop mod could be fitted to a fighter within the space of an hour or so, taking into account engine runs and paperwork etc...


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## Shortround6 (Apr 26, 2022)

PAT303 said:


> The fuel is burnt off, P51's didn't dogfight with full rear tanks or drop tanks and it had dangerous handling at take off, I find the mentality on here interesting, lets find every reason to not make it work instead of ways it can.


What I find interesting is idea that because something was doable in 1942 then they should have been doing it in 1939 or 1940. 

It is not just the power to get the loaded plane off the runway. Although that applies in 1939-40
It is the power needed to get the loaded plane to perform at different altitudes. Like above FTH. 
A lot of planes did pretty good down low, some didn't do so well at altitude. The P-40 being a prime example. And yet it's engine was only about 2000ft lower in FTH to a Merlin III.
The difference was it was trying to carry about 1 ton on the same engine power as a MK I Spitfire. 

We also never seem to specify what "long range" means except that the long range Spitfire should have a radius of 75-100 miles more than a standard Spitfire ??
That seems to depend on the year it is being suggested. And/or drop tanks. 

Of course objections are countered by the excuse of the long range Spitfire will burn off any extra weight and be in perfect fighting weight (over England weight)at whatever distance the Germans decide to engage. 

A early Spitfire will burn around 120-150 gallons an hour for a single stage engine in combat. The MK Vs will burn 150 gallons an hour (at 16lbs boost) or 37 gallons for 15 minutes in combat. 
so lets call it 30 gallons after any external tank is dropped. It is going to take around 30 gallons to get back across the channel (assuming a 100 mile crossing and giving you abut 30 minutes to find the airfield after you find land. 
So on a regular Spitfire you have about 25 gallons to get back from wherever you engaged in combat over Belgium or France and get back to the coast where you can slow down. 
With a 30 gallon tank in the rear of the fuselage that does extend things quite a bit but it depends on speed. If you are running at 2650rpm and 6lbs of boost you are using 70 gallons an hour. Granted you are flying at 331mph at 10,000ft. 
Now can you drop down to 225mph or so just as soon as you are over water or will you wait a few minutes?
Of course the winds will automatically stop blowing for the Spitfire pilot. 
And of course the Spitfire will have undiminished climb in combat because somehow it burned off the extra fuel load of the extra 30 gallon tank before it went into combat but it back (????) for the fight home.

If you only use a 30 gallon internal tank and no drop tank you aren't going to fly much further than using a 30 gallon drop tank. Don't think A Spitfire with a 30 or 34 gallon drop tank qualifies as a long range fighter. 

P-51 had several advantages over the Spitfire for this type of work, One of which was that they decided to run the planes heavier than "normal". The P-51 was rated at 8 Gs at 8000lbs gross weight and they ran them much heavier even without the rear tank. However if you stick about 500lbs of fuel in a 9600lb airplane things don't change as much as they do if your try to stick 500lbs of fuel in a 7500lb airplane. Of course that is putting the 500lbs of fuel in a plane with a Merlin 60 series engine. 
You have room to put 500lbs inside a Spitfire V but now you have an under 7000lb plane you are putting it into. You have to be a little more careful where things go and what happens to the performance. 
Oh yeah, I keep forgetting, all the extra weight will disappear when the long range Spitfire actually has to fight. 
If you are planning on sticking the fuel tanks in the back of the fuselage from the factory of the Spits you can beef up whatever you need to to.

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## drgondog (Apr 27, 2022)

PAT303 said:


> Spitfires were used for the first and last leg out and back in daylight raids but only to about 150 miles which really was pointless, at the same time the P47 was limited to about 350 miles before turning back, the Spit ''if'' fitted with aux/drop tanks that were approved for service it could have gone out to 450-500 miles depending on circumstances, my argument is the Spit could have done more if they simply filled them with more fuel but they weren't, the P47 started escorting with ferry tanks, that's how desperate the USAF were for escort fighters.


Initial P-47C/D Combat Radius in May 1943 through June 1943 was 125mi +. 350mi CR wasn't attained until Jan 1944.

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## drgondog (Apr 27, 2022)

PAT303 said:


> I'm not arguing with you, the fact is they did it, it's that simple. Once the 60 series Merlin arrived the Spit had the engine power to get more fuel off the ground that was it and every other single engined fighters biggest problem pre 1942.


Not so. The issue wasn't horsepower but a combination of a.) insufficient internal fuel and b.) external wing racks plus plumbing.

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## GregP (Apr 27, 2022)

PAT303 said:


> The fuel is burnt off, P51's didn't dogfight with full rear tanks or drop tanks and it had dangerous handling at take off, I find the mentality on here interesting, lets find every reason to not make it work instead of ways it can.



I find your mentality interesting, too. The Spitfire was one of the greatest fighters ever produced. Why are you so hot to change it? It performed it's job exceedingly well in most cases, and a couple of late models got more fuel, as you suggest. The earlier ones DID NOT and were still used to great effect and as they were designed to be used.

Your attempt to make everyone realize that it COULD have been a long range fighter is a "What If," and what ifs have no correct answers because real events trump any "might have been" with what actually happened. There is absolutely nothing wrong with your "What If," but it will forever remain a "What If," and will never get realized. Since YOU know what you want from the modified Spitfire, then yes, it could have been done, very likely as you want it to have been done.

But, in real life, it wasn't until the PR Mk. IX and the PR Mk. XIX ... and their fuel additions weren't an exact match for what you suggest, but they did have additional fuel for some long-range reconnaissance. They weren't front-line fighters due to the extra fuel and reduced armament package and, as a result, lower load factors when fully-fueled, too. That was not what a front-line air-superiority fighter needed to be competitive, but yes, they COULD have been made into all long-range PR aircraft. They just weren't and very certainly didn't need to be. They were pretty darned good as they were actually built, and other aircraft fulfilled the long-range missions. It makes no sense to modify Spitfires into long-range airplanes and then have already-long-range Mustangs / Thunderbolts / Lightnings fly the missions the modified Spitfires would otherwise have flown ... all it does is cost money and reduce readiness.

But, hey, sure they COULD have done it. It's just that nobody who mattered at the time pushed for it as a course of action.

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## Shortround6 (Apr 27, 2022)

To further expand on this.


Shortround6 said:


> So which Spitfire, the
> MK I
> MK II
> MK V
> Or the MK IX (or MI VIII)


Spitfire I 1938, wooden prop and 1030hp at around 18,000ft using RAM but Performance is severely restricting at other altitudes. S
Spitfire I 1939. two pitch prop, performance is somewhat better ?(at least take-off is) , At some point in 1938-39 you know that 100 octane is coming but you don't know when and you don't know what increase in performance it will allow.
Now there are a few things that a really limiting the Spitfires performance here in the first year or so of production.
One is that you can't actually use the the performance of the Merlin engine with _either _propeller unless you are near the 16,250ft FTL. The props (both of them) require the engine to be throttled down to around 2400rpm or less at low altitude instead of the 880hp at 3000rpm that the engine was capable of making with 87 octane fuel. Spitfire with wooden prop can't use 2400rpm until 3,000ft is reached in level flight. 100 octane fuel with be of absolutely no help because the engine can already turn the prop too fast and cause a loss of thrust.
This is the British self inflicted wound. They have the fasted fighter in the world if everything was running right but low altitude speed and climb are both crippled by the crappy propellers.
The Spitfire and Hurricane should not be trying to lift anymore fuel because their climb rate is so poor due to the need to run the engines so far below full throttle.
In late 39 three things start to happen. 1. the constant speed prop finally breeches the British costal defenses and they see that a change in climb rate to 20,000ft easily 20% or more is well within reach. 2. tests with 100 octane fuel show that even more performance in emergency situations is possible. countered a bit by 3. Increased protection and/equipment cuts into the new performance capabilities. At least you can climb the planes using 2600rpm and 6lbs of boost or will be able to so soon.
Now in Nov 1939 the Merlin is allowed to use 12lbs of boost but without a CS prop this is not going to help a whole lot.
Using 12lbs of boost increases fuel consumption by about 40% over using 6lbs.
By the BoB all operational squadrons have got CS props of some sort and the old climb limit of 2600rpm and 6.14lbs has been changed to 2850rpm-3000rpm further improving climb.
How soon anybody knew this in order to take advantage of it (like order a long range Spitfire version) is certainly subject to question. 

The Merlin had the highest FTH/critical altitude of any engine in 1938/39. This also means that on 87 octane fuel it had to be throttled down more than most of it's contemporaries which hurt take-off and low altitude climb, even when CS props showed up. 

August 1940 also sees the first Spitfire II's show up. The Merlin XII gets a bit higher FTH with a slightly higher supercharger gear ratio. However with some stronger components and with 100 octane fuel the Take-off rating gets a major boost and the climb rate also gets boosted. Engine is still rated at 12lbs boost though. The British do try to hang a fixed tank under the wing. 
The Spitfire V shows up with the Merin 45 and while the Hooker supercharger increases the FTH by several thousand feet ( and increases the ceiling and climb rates at higher altitudes) it does nothing for the take off rating (about 10HP) and doesn't increase the "normal" climb by much. It takes a while for boost pressures over 12lbs to show up and you don't use the higher boost pressures for take-off or climb. It does provide for better combat ability with a heavier weight for the 5-15 minutes you are using "combat power".
16lbs of boost used up fuel at about 70% higher than 6lbs of boost though. MK V also (mostly) got the 20mm guns and sucked up a few hundred pounds of weight that way rather than carry more fuel. 

Please note that the BF 109F1/2 was about 350lbs lighter than a Spit V depending on guns and the F4 was going into production in the summer of 1941 with a more powerful engine than the F1/2. Adding several hundred pounds to the Spitfire V with the existing engines and having them fight over eastern Belgium or the Dutch-German border may not have worked out well for the British. 

The British 100 octane fuel of 1940 was not quite the same as the 100 octane fuel of 1942. I don't know when it changed but tests of BoB fuel came up as 100/115 to 100/120
I would also note that it took a very long time for the Merlin to be OK'ed for climbing at more than 2850rpm and 9lbs of boost (a 30 minute rating) so there is no help for better climb there. 


Shortround6 said:


> are we going to to turn into the early long range escort? Or several versions with increasing ranges?


I don't doubt that you could cram another 20-30 gallons into a Spitfire with not a big reduction in performance. The question is does that really do anything? 
Or do you need another 20-30 gallon inside and 45-90 gallons outside in order to reach the targets you are interested in?

It is about 260 miles or more depending on airfeilds to fly directly from Ipswich to Cologne. Granted Wellingtons and the like aren't going to fly as high or as fast as the B-17s but it that isn't going to work then you might as well forget the whole idea.

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## Vincenzo (Apr 27, 2022)

Shortround6 said:


> Please note that the BF 109F1/2 was about 350lbs lighter than a Spit V depending on guns and the F4 was going into production in the summer of 1941 with a more powerful engine than the F1/2. Adding several hundred pounds to the Spitfire V with the existing engines and having them fight over eastern Belgium or the Dutch-German border may not have worked out well for the British.


actually delivery of F-4 started in May


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## don4331 (Apr 27, 2022)

Shortround6 said:


> This is the British self inflicted wound. They have the fasted fighter in the world if everything was running right but low altitude speed and climb are both crippled by the crappy propellers.


Per Spitfire: the History, Spitfire with
2 blade wooden propeller - *9.4 minutes from S.L to 20k'*; 363 mph @ 12.5k', 31.9k' ceiling​3 blade metal,2 pitch propeller - 11.4 minutes from S.L to 20k'; *367 mph @ 12.5k'*, 34.4k' ceiling​3 blade metal, CS propeller - 10.7 minutes from S.L to 20k'; 364 mph @ 12.5k', *34.5k' ceiling*​
So, the "performance" numbers say there isn't much to choose between a wooden 2 blade fixed pitch and metal 3 blade CS propeller. If DH and Rotol can only make a limited number of CS propellers, they are better served to be manufacturing them for Battles, Blenheim, etc as the bombers have a critical need for them in takeoff performance.

Now, add 100 octane fuel into the Merlin and suddenly you need to re-equip all your fighters with coarser propellers to take advantage of the power increase. If you are re-propping and your propeller manufacturers now have capacity to deliver the CS unit, it saves you having to re prop again when next power increase comes along. It also improves take off distance, etc.

Similarly, early fighters would have benefit from Merlin X with more power to propeller in MS for take off, then shifting to FS at altitude, but again Halifax, Wellington & Whitley needed it more, just to get off the ground.


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## TonyT (Apr 27, 2022)

Zipper730 said:


> I was curious about two matters
> 
> 1. There was a mention on of an early PR variant that possessed a 20 imperial gallon tank underneath the pilot's seat: I can't seem to find anything specific on this one. I can find mention of a 29 gallon tank that was located behind the pilot (this was also fitted to the Spitfire Mk.V for ferrying), as well as one variant that had a 30 gallon tank in a blister under one wing (it counterbalanced the weight of a cam in the other wing). I'm curious if it existed at all, or was mixed-up with these developments (This keeps getting lost in the discussion, and honestly, it's like trying to nail jello to a wall).
> 
> ...



The Mk21 had the tank under the seats, enclosed is the drawing from the original pilots notes

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## Shortround6 (Apr 27, 2022)

Vincenzo said:


> actually delivery of F-4 started in May


thank you.


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## Shortround6 (Apr 27, 2022)

don4331 said:


> Per Spitfire: the History, Spitfire with
> 2 blade wooden propeller - *9.4 minutes from S.L to 20k'*; 363 mph @ 12.5k', 31.9k' ceiling​3 blade metal,2 pitch propeller - 11.4 minutes from S.L to 20k'; *367 mph @ 12.5k'*, 34.4k' ceiling​3 blade metal, CS propeller - 10.7 minutes from S.L to 20k'; 364 mph @ 12.5k', *34.5k' ceiling*​
> So, the "performance" numbers say there isn't much to choose between a wooden 2 blade fixed pitch and metal 3 blade CS propeller. If DH and Rotol can only make a limited number of CS propellers, they are better served to be manufacturing them for Battles, Blenheim, etc as the bombers have a critical need for them in takeoff performance.
> 
> ...


That is not what the the results say. While the 2 blade wood and the 2 pitch metal agree with your numbers the 3 blade Rotol propeller has 7.7min to 20,000ft, 354mph at 18,900ft and a service ceiling 34,700ft. What is a bit puzzling is why the plane with the 2 blade wooden propeller has a max speed of 363mph at 12,500ft. There should have been few, if any, Spitfires using wooden props when 100 octane fuel was approved and allowed the 12lbs of boost at that altitude. 
There was a test of a plane that armed with two 20mm and four .303 guns that has the same climb to 20,000ft and the same ceiling that you post but it was using a 2 pitch prop and not a CS prop. It speed of 364mph was done at 18,600ft instead of 12,500ft. 






Spitfire Mk I N.3171 Trials Report


Spitfire Performance Testing, wartime flight trials and reports of Spitfire aircraft. Spitfire Mk I data.



www.spitfireperformance.com





Some (or at least one) of the early tests seem to have propellers that were not set up for optimum engine performance. 

Unfortunately the Blenheim's were saddled with two pitch propellers until the MK V model. 

I believe you are wrong about the need to re-pitch propellers with the use of 100 octane fuel. The speed of the aircraft didn't change much, or at least the top speed.
So the same pitch propeller should have given you the same speed at the same propeller rpm at the same altitude. 
The problem with the fixed pitch and the 2 speed props was that they could NOT open the throttle in parts of the flight envelope without over speeding the prop for the air they were going through, like a boat cavitating it's propeller at slow speed. 
A CS prop would keep the angle of the prop at a good angle for the speed of the airplane and increase the angle of attack of the blades as the speed increased until the max speed of the airplane was reached. It would allow for much improved acceleration to reach the top speed. 
Few of the early Spitfires were faster at low level even with 12lbs of boost than they were at 18-19,000ft using 6lbs of boost so the need to re-pitch the props should have been minimal. The test of the cannon armed Spit with the two speed prop shows the ASI of the plane only changed from 289.5mph at 13,000ft to 285mph at 18,600ft while the true airspeed changed from 339mph to 364mph. Engine rpm on the fixed pitch prop went from 2860rpm to 3045rpm with the boost staying at 6.3lbs the whole or for each test.

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## ThomasP (Apr 27, 2022)

Hey Don4331,

I think Spitfire: The History has the numbers you posted mixed up, or misrepresented (accidentally).

Do the ROCs the Spitfire book mention include the weights of the aircraft during the tests?

According to the actual results of testing done by A&AEE at Boscombe Down:

Rotol CS____ 6050 lbs_____+6.4 lb or FT______7.7 min to 20,000 ft
DH 2P______ 5930 lbs_____+6.4 lb or FT_____11.4 min to 20,000 ft
Wood FP____5820 lbs_____+6.4 lb or FT _____ 9.4 min to 20,000 ft

Whoops!  I see Shortround6 beat me to it.

All I can add is that there used to be a report (I think on the "WWII Aircraft Performance" website but I am not seeing it now) that gave the Spitfire Mk I ROC with different props and the different weights in a single table in the report. It seems to have disappeared.

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## EwenS (Apr 28, 2022)

In relation to the introduction of 100 octane fuel you might be interested in this.





100-Octane







soc.history.war.world-war-ii.narkive.com


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## tomo pauk (Apr 28, 2022)

TonyT said:


> The Mk21 had the tank under the seats, enclosed is the drawing from the original pilots notes
> 
> View attachment 666065


That is Spiteful. Note the wing shape and layout, as well as undecarriage.

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## EwenS (Apr 28, 2022)

Does anyone have the dates when the various Spitfire drop tanks entered service? 

I believe the 30 & 45 gallon slipper tanks were on the Mk.V in 1941 (but when?) and the 90 gallon slipper tank by the time the first aircraft were being delivered to Malta in Feb 1942. The 170 gallon ferry tank was first used in Oct 1942. And there was a 50 gallon "torpedo" tank from shortly before D-Day.

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## EwenS (Apr 28, 2022)

This whole discussion about turning the Spitfire into an escort fighter kind of reminds me of the tourist asking the Irishman for directions and the reply "Well sir, if I were you, I wouldn't start from here".🤣

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## Shortround6 (Apr 28, 2022)

EwenS said:


> In relation to the introduction of 100 octane fuel you might be interested in this.
> 
> 
> 
> ...



That thread has a bit of good info and some rather dubious info.

_"What the high octane did do for the engine was allow the Rolls Royce
engineers to introduce a more efficient supercharger for the Merlin
that forced more air and fuel into the intake manifold than the
version used in the Mk1's._"

RR (see Hooker) did develop a more efficient supercharger but it was in addition to the high "octane" fuel.
Using 87 octane fuel the Merlin was limited to about 6-6.5lbs of boost in a Merlin III using the supercharger gears the Merlin III used. A few other early Merlins used a different boost limit depending on the supercharger gear ratios involved.
Using 100 octane fuel the Merlin III could handle 12lbs of boost from the start and could handle 16lbs of boost if they didn't really care about engine life.
However the "old" supercharger would only give 16lbs of boost at 5500ft and would only supply 6 1/4lbs at 16,250ft.
The "new" supercharger would supply 16lbs of boost at 11-12,000ft which shows some of the efficiency. This supercharger was used on the Merlin 45 and it's decedents and was also used on the Merlin XX and it's decedents.

Edit,' Hooker was working on the "new" supercharger (actual just a modified cover and inlet for the existing supercharger, same impeller, same volute, same rear case and same exit to manifold) in 1939, it just took a while to finalize things and assign production priorities.' 

_"But this did not necessarily give it a higher ceiling than the Bf109,
nor did it give it a better performance at extremely high altitude."_

Actually the Merlin III did have better perform in the Spitfire than to 109E had, at least most of the 109s in the BoB.
It may not have been a lot but it was there.
However the same engine in the Hurricane did NOT have superior performance. The larger Hurricane used up more of it's power in drag and had less for climb.
The slower Hurricane also had a bit less RAM in the intake duct which also hurt the altitude performance. When a Spitfire I was operating at around 28,000ft it was no "boost" to the engine. This is not correct, it was providing no "boost" on the gauge which was refenced to sea level. If the gauge was reading -0.5lbs it shows the supercharger was compressing the air to almost 3 times what the air entering the intake was.
109 was about 300-400lbs lighter than a Spitfire I so it had about a 5% advantage in power to weight if the engines in both planes were making the same power.
There are often a lot of things affecting performance. We have to be sure we are weighing in all the factors we can.
109s in the BoB were getting a small sprinkling of the DB610N engine.

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## PAT303 (May 1, 2022)

EwenS said:


> This whole discussion about turning the Spitfire into an escort fighter kind of reminds me of the tourist asking the Irishman for directions and the reply "Well sir, if I were you, I wouldn't start from here".🤣


We aren't turning the Spit into an escort fighter, we are just giving it longer legs, it's biggest Achilles heal.


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## PAT303 (May 1, 2022)

drgondog said:


> Initial P-47C/D Combat Radius in May 1943 through June 1943 was 125mi +. 350mi CR wasn't attained until Jan 1944.


There we go, all the more reason to add fuel to the Spit wouldn't you say?.


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## PAT303 (May 1, 2022)

Shortround6 said:


> What I find interesting is idea that because something was doable in 1942 then they should have been doing it in 1939 or 1940.


Having 20 more gallons of fuel in an under seat/rear tank allows Spitfires to be climbing before the Luftwaffe crosses the channel in 1940 instead of waiting until the last minute and climb up from underneath, in 1941 extra fuel allows MkV's to maintain higher speeds over France to negate to a degree being bounced so easily, in 1942-43 MkIX's could have been doing deep raids into France supporting the daylight bombers, more fuel allows more flexibility, it's that simple.

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## Shortround6 (May 1, 2022)

PAT303 said:


> Having 20 more gallons of fuel in an under seat/rear tank allows Spitfires to be climbing before the Luftwaffe crosses the channel in 1940 instead of waiting until the last minute and climb up from underneath, in 1941 extra fuel allows MkV's to maintain higher speeds over France to negate to a degree being bounced so easily, in 1942-43 MkIX's could have been doing deep raids into France supporting the daylight bombers, more fuel allows more flexibility, it's that simple.



For a little bit of perspective a Spitfire I could climb to 25,000ft 4.9 minutes faster using the Rotol Prop than using the DH 2 pitch prop. 
Adding 20 gallons of fuel to the Spitfire I would add another couple of minutes to the climb of the plane with the 2 pitch prop.
The British just squeaked by getting CS props.

Now the idea transforming the BoB by putting in 20 gallon tanks may need a bit of looking at. 
You have to KNOW when the Germans are coming. Not guess when they are coming. 
Depending on your cruise speed at over 20,000ft the extra 20 gallons may only give you around 30 minutes. 

Map of Chain home.





Things got slightly better between 1938 and 1940. 
Planes flying higher than 15,000 gave extra warning. Planes flying lower gave less. 
Warning over land got worse. That is to say that German planes coming from the Southeast are going to give less warning than planes coming from Holland or Cherbourg may be just a few minutes. 

I have no idea of how accurate the Germans knew the radar was but trying to standing patrols with just 20-30 gallons extra means the Germans can try feints. They fly 1/2 dozen plans just close enough to the get the British to scramble, British don't have a good count of the aircraft, Germans turn around and launch real raid 30 minutes later.
Reasons for the British doing late launches means radar operators could "guesstimate" size of the formations better. They could Guess the coarse a bit better (trying to judge if the incoming formation is going to do a dog leg) and they guesstimate or try to get a visual estimate of the height. Now you can do allof that stuff with larger fuel tanks but the delayed scrambles weren't entirely the result of short endurance of the Spitfires. 

Now once you start sending Spitfires over Europe you need an external tank AND the internal tank. 

Plus how far are your "deep" raids into France? 200 miles, 250 miles, 300 miles?

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## drgondog (May 2, 2022)

PAT303 said:


> There we go, all the more reason to add fuel to the Spit wouldn't you say?.


Adding enough internal fuel to compete with Mustang range would have rendered the Spitfire into a fat waddling fuel truck suitable for soon to be needed mid air refueler role.

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## Geoffrey Sinclair (May 2, 2022)

PAT303 said:


> Having 20 more gallons of fuel in an under seat/rear tank allows Spitfires to be climbing before the Luftwaffe crosses the channel in 1940 instead of waiting until the last minute and climb up from underneath, in 1941 extra fuel allows MkV's to maintain higher speeds over France to negate to a degree being bounced so easily, in 1942-43 MkIX's could have been doing deep raids into France supporting the daylight bombers, more fuel allows more flexibility, it's that simple.


I think you are trying to solve a problem the RAF did not have in 1940. The limiting factor for RAF fighter responses during the Battle of Britain was not range, but how good they thought they knew what the Luftwaffe was going do to over the next hour or two. Given the ranges involved the Luftwaffe bombers could stay in a holding pattern over France, fake setting course for England before returning to the holding pattern and still have the fuel to conduct a raid. The Luftwaffe could run feints, try saturation of an area, timing multiple raids to catch RAF aircraft on the ground, make course changes and so on, with a limited fighter defence it was always a judgement call about when to put fighters into the air, too early and they could be reacting to a decoy or be left behind by a course change. A main point of the system was to minimise flying hours and so strain on pilots and ground crew.

On an individual level having more fuel is a good thing. For the RAF as an Air Force in 1941 and into 1942 the Spitfire range was not much of a missed opportunity, it was in the second half of 1941 for the draw down of Luftwaffe day defences in France, the Germans had little in France etc. they were worried about and if they did the RAF lacked the bomber force to do much to them, even counting all of Bomber Command. Malta had the enemy coming to them, overseas Spitfire fighters elsewhere were a second half of 1942 event and most such day operations were happening within Spitfire V range. Getting working drop tanks was enough at the air force level of things but agreed more internal fuel was more efficient, though the mark V was not matching the performance of the German fighters.

The mark VIII helped solve the range issue and it arrived at the end of 1942, plus there was a build up of allied day bomber strength. My opinion of the optimal 1943 and beyond Spitfire change schedule, given what the RAF did, would be make wing tank kits available for earlier Spitfires, switch Castle Bromwich to the mark VIII, not IX (or at least the IX being built has the VIII internal fuel), by or in Q4 of 1943 enable the mark VIII to fight with a full 33 gallon rear fuselage tank, this would enable the Spitfire to keep matching the P-47 range for operations from England into 1944, in early 1944 enable a 1,000 pound bomb load, ideally with the rear fuselage tank full, to allow longer range fighter bomber operations, again mostly from England, then in the second half of 1944 put in the larger rear fuselage tanks to enable Spitfire escort from England of Bomber Command raids on the Ruhr. That matches the historical operations available for the Spitfires to do in quantity, plus the opportunity to enable longer range RAF day bomber raids in 1943 and fill the gaps escorting 8th Air Force bombers in the second half of 1943, but also note the limits at the time on the bomber strength in terms of size and weather as well as doctrine. In the period January to May 1943 while still under Bomber Command the RAF day bomber force dropped 1,230 long tons of bombs, the US medium and light bomber operations essentially started in July 1943, managed 8,179 short tons of bombs for the year, all up the 8th and 9th Air Force bombers dropped 22,440 tons on France and 767 tons on the low countries in 1943. There were still few targets in France, Belgium and the Netherlands the Germans needed to defend though, defence was more about attritioning the allied bomber force. The US heavies dropped 47,452 short tons of bombs in 1943, over half in the final quarter of the year. Not a lot of point having long range escort fighters and few bombers available.

Look at the RAF Merlin P-51 operations in late 1943 and early 1944 when considering what the longer range Spitfire would have done out of England, the RAF P-51 units certainly did operations in support of the 8th Air Force raids, but as far as I know that was only a part of their work, Operation Overlord was more the priority. The same would apply to any long range Spitfires in the same time period. In any case these P-51 were a better choice to replace long range Spitfires in the escort role as soon as the P-51 were operational.

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## tomo pauk (May 2, 2022)

drgondog said:


> Adding enough internal fuel to compete with Mustang range would have rendered the Spitfire into a fat waddling fuel truck suitable for soon to be needed mid air refueler role.



Why should a long-range Spitfire compete with Mustang?

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## SaparotRob (May 2, 2022)

Lucrative endorsements?

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## drgondog (May 2, 2022)

tomo pauk said:


> Why should a long-range Spitfire compete with Mustang?


Why should so much discussion lead to making design decisions for the Spitfire that did not have much value in 1944-1945?

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## tomo pauk (May 2, 2022)

drgondog said:


> Why should so much discussion lead to making design decisions for the Spitfire that did not have much value in 1944-1945?



Because a long-range Spitfire would've been an asset from 1940-43, as well as in 1944-45. Even in 1939, if the RAF is allowed to bomb Germany.

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## GregP (May 2, 2022)

PAT303 said:


> Having 20 more gallons of fuel in an under seat/rear tank allows Spitfires to be climbing before the Luftwaffe crosses the channel in 1940 instead of waiting until the last minute and climb up from underneath, in 1941 extra fuel allows MkV's to maintain higher speeds over France to negate to a degree being bounced so easily, in 1942-43 MkIX's could have been doing deep raids into France supporting the daylight bombers, more fuel allows more flexibility, it's that simple.



And exactly how are the Spitfires supposed to know "Better" when to take off in 1940? They had Chain Home and already knew from where the Germans were coming, and they took off accordingly. They even had Chain Home Low to see the low-flying raids. Your extra 20 gallons might allow them, say, 10 minutes of extra climb time, but they already were doing quite well in the BOB at being to altitude for their attacks.

And nobody wanted the extra weight at the expense of less armament. If the people at the time had the chance to vote for more fuel (they didn't), they might have or might not have. The Spitfire was already a pretty darned good fighter, and adding fuel might or might not make it better in their eyes. Tough to ask at this juncture.

We can all see it needs the fuel in your eyes, perhaps not without some justification. I'm just wondering if anyone at the time tries to make that happen.


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## drgondog (May 2, 2022)

tomo pauk said:


> Because a long-range Spitfire would've been an asset from 1940-43, as well as in 1944-45. Even in 1939, if the RAF is allowed to bomb Germany.


Of course it would have. The same can be said for Bf 109 and Fw 190 in 1940. Ditto for instant access and design integration into the Mustang with Rolls engine hierarchy. But having a plausible, sellable solution approach to make it happen was impossible, technically and politically.

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## PAT303 (May 2, 2022)

Shortround6 said:


> Depending on your cruise speed at over 20,000ft the extra 20 gallons may only give you around 30 minutes.


Your totally missing my point, the radar operators tracked incoming raids and Hurricane and Spitfires were launched only after they were certain what the target was, the reason being that they lacked endurance, an extra 20G of fuel gives them the freedom to launch earlier to get above the bombers and more importantly the fighters, it even allows the radar operators to direct them to the optimum position for an attack.


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## PAT303 (May 2, 2022)

drgondog said:


> Adding enough internal fuel to compete with Mustang range would have rendered the Spitfire into a fat waddling fuel truck suitable for soon to be needed mid air refueler role


Just to be clear, I'm not trying to make the Spitfire into a Mustang, I'm just trying to get more than 85G of fuel into it.


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## PAT303 (May 2, 2022)

tomo pauk said:


> Why should a long-range Spitfire compete with Mustang?


No idea, apparently if a fighter can't carry enough fuel to fly to Berlin and back it's not worth perusing.

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## PAT303 (May 2, 2022)

Geoffrey Sinclair said:


> I think you are trying to solve a problem the RAF did not have in 1940


I think you should read and understand what I am saying, more fuel allows more flexibility, flying feints and bogus raids is part of warfare, flexibility gives you options to deal with it instead of guessing your enemy's intensions.


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## PAT303 (May 2, 2022)

GregP said:


> And nobody wanted the extra weight at the expense of less armament.


Why does more fuel mean less armament?, the fuel is going in behind the seat, not in the wings.


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## PAT303 (May 2, 2022)

GregP said:


> The Spitfire was already a pretty darned good fighter, and adding fuel might or might not make it better in their eyes


What front line fighter didn't have it's fuel capacity increased throughout the war?.


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## PAT303 (May 2, 2022)

drgondog said:


> Of course it would have. The same can be said for Bf 109 and Fw 190 in 1940. Ditto for instant access and design integration into the Mustang with Rolls engine hierarchy. But having a plausible, sellable solution approach to make it happen was impossible, technically and politically.


Spitfires had 85G because they started with two bladed props, then two speed props with less than 1000hp, by 1939 they had constant speed props, 100 octane fuel and 1200hp, the reason for weight saving was no longer there as it's performance increased, and kept on improving.


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## Shortround6 (May 2, 2022)

PAT303 said:


> Why does more fuel mean less armament?, the fuel is going in behind the seat, not in the wings.


Why didn't we realize this before ????????????
Weight added to the fuselage doesn't count when fighting gravity, ONLY WEIGHT IN WINGS counts for Gravity.  


PAT303 said:


> What front line fighter didn't have it's fuel capacity increased throughout the war?.


Hmmmm,
Bf 109,
P-40?
P-39?
Both of them actually had versions with their fuel capacity reduced to gain performance.
F6F.
F4U
And that is off the top of my head, no research.
Granted they all had total fuel capacity increased but internal fuel stayed the same or was reduced.


PAT303 said:


> Spitfires had 85G because they started with two bladed props, then two speed props with less than 1000hp, by 1939 they had constant speed props, 100 octane fuel and 1200hp, the reason for weight saving was no longer there as it's performance increased, and kept on improving.


The British had tested the better propellers 1939 (other countries had bee using them for 3 years or so) but it wasn't until 1940 that they were in production unless you have dates?
The frantic scramble to retro fit DH two position props _between_ the BoF and the BoB shows the difference between testing something and producing it.
The Spitfire had "_constant speed props, 100 octane fuel and 1200hp_" but it was in 1940 and not 1939. They were called Spitfire IIs.

The Spitfire Is, even with CS props and 100 octane fuel were not cleared for 1200hp _for take-off or climb. _
Until you get the CS props you are dealing with around 600-700hp for take-off and climb. In fact you can't even use the rated 880hp for low level high speed level flight.

BTW, since in the real world weight added to the fuselage does affect climb/performance the some of the hoped for gain in performance in MK II was canceled out by the weight gain in extra equipment like IFF, different armor etc.
Add, as has been pointed out before. They did make about 50 MK IIs with extra fuel. it wasn't done well but it was done and we can see see the difference performance and make estimates based off of it.

Edit, The P-40 and P-39 both took out guns and ammo to improve climb and their guns and ammo were in the wings. P-39 had it's fuel in the wings. P-40 took out the forward 'wing tank' which was actually underneath the cockpit.

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## tomo pauk (May 3, 2022)

drgondog said:


> Of course it would have. The same can be said for Bf 109 and Fw 190 in 1940. Ditto for instant access and design integration into the Mustang with Rolls engine hierarchy. But having a plausible, sellable solution approach to make it happen was impossible, technically and politically.



We know that it was technically possible to have a longer ranged Spitfire via increase of internal fuel and realization of the idea of a drop tank, since it was done. 
Politics - not having a doctrine covering a LR fighter and later the open disparaging of the idea by the RAF brass - stood in the way well into 1944.

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## GregP (May 3, 2022)

OK, Pat. The Spitfire WOULD have been better with more fuel. You win.

But, in real life, they didn't pursue it except for the PR variants late in the life of the airplane.

Now, what has changed that actually happened? Nothing. We're stuck with Spitfires as they were actually built, like we were before you started this. So, we might as well praise and enjoy their successes and lament their failures, like we do for all the other piston fighters.

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## drgondog (May 3, 2022)

PAT303 said:


> What front line fighter didn't have it's fuel capacity increased throughout the war?.


F4U-4 from F4U-1 removed the wing fuel tanks, as an example. P-39Q from P-39D reduced internal fuel. F6F-3 same as F6F-6.

Perhaps the over-riding reason nobody in authority was willing to compromise scarce design resources and disrupted production to introduce a version of a Spitfire for which there was no compelling national interest. There was no RAF mission for long range daylight bombing escort. There was no RAF mission for long range fighter bomber (short range compare to bomber escort) role that US didn't fill nicely with P-47 and P-51 and P-38. The long range low level recon/interdiction role was filled by Mustang, Ditto for RN ops for which USN types fit nicely.

The RAF/RN didn't have the clout to demand types for aircraft that the US designed, produced and delivered that met roles that RAF/RN would 'like to have', but didn't fill 'must have' niche.

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## drgondog (May 3, 2022)

PAT303 said:


> Spitfires had 85G because they started with two bladed props, then two speed props with less than 1000hp, by 1939 they had constant speed props, 100 octane fuel and 1200hp, the reason for weight saving was no longer there as it's performance increased, and kept on improving.


The reason Spits had 85 gal is that the intended fuel fraction, combined with other design attributes such as low drag wing, design gross weight, landing gear design and armament led to all fuselage internal fuel decision. The technology improvements led to better performance, but the specification under which it was designed controlled the decision for original fuel location and future changes were limited by CG and space considerations.

The Mustang and Lightning were originally designed to specifications that emphasized range as an attribute and had the happy circumstance of relaxed GW parameters based on initial projections of the original available Allison/prop capability of the time. In the airframe business, 'do overs' on original design generally cause extended design and production insertion schedules. The P-47D-25 was a good example. When the P-51B 85 gallon tank was ordered by Materiel Command in early July, and the P-38J 110 gal LE tanks, the two fighters were able to increase internal fuel by 46% and 36% respectively and deliver both into combat ops within 6 mo. The P-47D, however only increased internal fuel by 23% and took nearly 11 months to enter combat ops due to the very significant structural changes in the middle airframe. 

As to 'no longer having a 'reason for weight saving', any increase in GW is detrimental to all the other performance features of the design, ranging from landing speed, top speed, climb rate and acceleration - in comparison with the adversary - in order to push the combat radius. The AAF-HQ (and 8th, 15th, 5th AF) had the missions and determination to accept the consequences and order the change

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## Geoffrey Sinclair (May 3, 2022)

PAT303 said:


> I think you should read and understand what I am saying, more fuel allows more flexibility, flying feints and bogus raids is part of warfare, flexibility gives you options to deal with it instead of guessing your enemy's intensions.


Guessing the intentions, or at least the target, is important, stern chases are often a waste of time. In 1940 the RAF was not worried about fighter range. Scrambling according to the estimates of distances to a target and time for the interceptors to take off and climb. Which references report delayed take offs due to range limitations in 1940? Versus the known uncertainties, radar could do range quite well, size was an estimate, height was a problem and it took a visual sighting to confirm composition, behind the coast the raids were plotted visually and slight errors in the measurements made the raids appear to zig zag. The system was meant to reduce flying hours.

The Luftwaffe fighters defending Germany began using drop tanks, but they had more warning, longer tracks of the raids and a bigger area to defend.

RAF contract cards say 174 Spitfires from the first order had Merlin II, with Merlin III from K9961, aircraft number 175 of the order, which would mean a change over in May 1939, the online Spitfire histories say the first 194 had Merlin II, which would mean a change over at K9980 in June. Contract card notes against individual aircraft at times have the words wooden airscrew while the first variable pitch notation is K9855 (aircraft 69) but that is over written by wood airscrew, K9860 has the note V.P., it would appear for a time wooden airscrews were fitted to aircraft meant as replacements for squadrons still using wooden propeller versions, until those units were upgraded to variable pitch. While the notation Rotol Airscrew starts appearing against some aircraft starting with N3096 and N3097 in October 1939 (these two under contract B10783/39 or B10983/39). The June 1939 publicity photographs at Hornchurch all show 3 bladed two pitch propellers, with the two identified serials delivered in March 1939, N9910 and N9912, aircraft 126 and 128 of the order.

The first 363 Hurricanes had Merlin II, change over in April 1939 at L1909, the first variable pitch propeller production aircraft was number 435, L1980, in June 1939.

The crash program in mid 1940 was the change from variable pitch to constant speed.

According to the RAF the Spitfire I with Merlin III engine rated at 1,030 HP at 16,250 feet could reach 15,000 feet in 6.2 minutes, tare weight 4,795 pounds, 84 gallons of fuel weight 630 pounds. Spitfire II with Merlin XII engine rated at 1,150 HP at 14,000 feet could reach 15,000 feet in 4.9 minutes, tare weight 4,738 pounds, 84 gallons of fuel weight 605 pounds.

The Hurricane I fitted with a DH propeller could reach 15,000 feet in 7.25 minutes, with a Rotol propeller 6.3 minutes.

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## drgondog (May 3, 2022)

PAT303 said:


> No idea, apparently if a fighter can't carry enough fuel to fly to Berlin and back it's not worth perusing.


YOU miss the point. There was no reason, doctrine or mission important enough to greatly extend combat radius - based on an unfilled need.

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## FLYBOYJ (May 3, 2022)

PAT303 said:


> No idea, apparently if a fighter can't carry enough fuel to fly to Berlin and back it's not worth perusing.


And that requirement would be known in 1936?

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## Shortround6 (May 3, 2022)

drgondog said:


> As to 'no longer having a 'reason for weight saving', any increase in GW is detrimental to all the other performance features of the design, ranging from landing speed, top speed, climb rate and acceleration - in comparison with the adversary - in order to push the combat radius


In fact the increase in weight may have the least effect on top speed. 

Many of us have been indoctrinated of many years (around 60 for me) of reading about aircraft were the overly simplistic explanation of using increased weight to show a decrease in speed from prototype or early version to later versions was used. 
It was never explained that a lot of the weight increases were accompanied by changes to the external envelope that caused drag (extra machine gun ports, extra cartridge case ejector slots, BP glass wind screens, wear view mirrors, radio antennas. etc) and the loss of performance was all reduced to a single sentence. And that sentence usually made no reference to
" landing speed, turning rate, climb rate and acceleration"

The people that worked in aviation knew the difference but many of us amateur historians took quite a while to pick up the difference.

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## drgondog (May 3, 2022)

Shortround6 said:


> In fact the increase in weight may have the least effect on top speed.
> 
> Many of us have been indoctrinated of many years (around 60 for me) of reading about aircraft were the overly simplistic explanation of using increased weight to show a decrease in speed from prototype or early version to later versions was used.
> It was never explained that a lot of the weight increases were accompanied by changes to the external envelope that caused drag (extra machine gun ports, extra cartridge case ejector slots, BP glass wind screens, wear view mirrors, radio antennas. etc) and the loss of performance was all reduced to a single sentence. And that sentence usually made no reference to
> ...


SR, while the loss in top speed is in low % due strictly to increased weight, Induced drag IS a detrimental factor in the entire performance envelope and increases with the square of lift coefficient CL. CL grows in direct proportion to increase in GW.

Further, Induced Drag dominates total drag from takeoff into cruise speed envelope.

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## Shortround6 (May 3, 2022)

drgondog said:


> SR, while the loss in top speed is in low % due strictly to increased weight, Induced drag IS a detrimental factor in the entire performance envelope and increases with the square of lift coefficient CL. CL grows in direct proportion to increase in GW.
> 
> Further, Induced Drag dominates total drag from takeoff into cruise speed envelope.


It does but most popular books over simplified things a lot. 
Like the Curtiss XP-46 that went from a claimed 400 (or 403) mph to 355mph when operational equipment was fitted and the difference was usually simply attributed to weight. 
Probably unknown but the climb rate was never mention? 

In some cases the author would write something like "Bomber XX had it's top speed drop from 313mph to 287mph due to increased weight in the later versions"
While the increased weight covered new, higher drag gun mounts, or external gun pods or some other rather large lumps and bumps on the aircraft (new air intakes with bulky air filters or larger oil cooler intakes or??????) 

They didn't have to spell everything out but just adding the words ".....and drag....." after the word "weight" might have encouraged some of us to try and find out more.


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## drgondog (May 3, 2022)

Shortround6 said:


> It does but most popular books over simplified things a lot.
> Like the Curtiss XP-46 that went from a claimed 400 (or 403) mph to 355mph when operational equipment was fitted and the difference was usually simply attributed to weight.
> Probably unknown but the climb rate was never mention?
> 
> ...


Ah, yes. You might note that very few Aero engineers write books. Kit Carson is one that comes to mind and he injected several technical pearls of wisdom regarding the P-51. I duly noted the lack of serious discussion regarding the technical features and devoted most of the Appendices toward explaining the "Why and "How' of superb qualities of the Mustang design - some unintelligible to the math/aero 'challenged' but I felt important enough to try.

Your point regarding post prototype changes is dead on when pointing finger at most performance changes implemented (good and bad) after the airframe entered service. Most every physical change resulted in Parasite drag, often overcome with more horsepower. But even high performance aircraft like P-51, Spitfire (and bomber/cargo aircraft) live in low speed (land), climb, and medium speeds cruise range where Gross Weight and Drag (like take off and climb) duke it out - .

At high speed for a given altitude and air density, the CL will be at minimum (and CDi will be minimum). The drag reduction methodology is always focused on reducing parasite drag (turrets/enclosed gun positions, complete landing gear cover, retracting tail wheel, better butt joints, flush rivets, flap/aileron seal, etc) influencing better airflow properties. 

What many technical but non-aero types do not understand going into a drag discussion surrounding Induced Drag, is that there are TWO components of Lift Coefficient related phenomena. The commonly understood component is Induced drag due to Lift (and GW). The second component, and not insignificant, is the increased Lift Coefficient (and increased Pressure/Parasite drag) on the wing when flying at increased altitudes. Due to decreased density, the aircraft has to Increase CL for same GW and airspeed in order to maintain level flight. At high altitude/high speed, that CL contribution to parasite drag on a Mustang is about the same magnitude as the exhaust stacks or gun ports.

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## wuzak (May 5, 2022)

drgondog said:


> YOU miss the point. There was no reason, doctrine or mission important enough to greatly extend combat radius - based on an unfilled need.



"Leaning into France"?

Though I am not sure that longer range/endurance would be a good thing.

It may lead to more Spitfire pilots being lost, as it gives the Luftwaffe more opportunity.

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## tomo pauk (May 5, 2022)

wuzak said:


> "Leaning into France"?
> 
> Though I am not sure that longer range/endurance would be a good thing.
> 
> It may lead to more Spitfire pilots being lost, as it gives the Luftwaffe more opportunity.



What were the numbers' odds during the 'leaning into France', RAF Spitfires vs. LW Fighters?


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## Shortround6 (May 5, 2022)

It rather depends on how far you want to lean into France. 

As 45-60 gallon drop tank get you well past the coast.

Around a 90 gallon drop tank is where you run into trouble, Will 90 gallons outside get you further into France than you can get back out with 85 gallons inside? 

Merlin 45 burns 2.5 gallons an hour so 15 minutes of combat power costs 37 gallons. You need about 15 gallons for 30 minute reserve once you are back in England leaving you with about 33 gallons for the trip home. A Spitfire V will do 281mph true at 42 gallon an hour so just over 90 miles will cost you 14 gallons (over the channel) and at 331mph the plane burns about 70 gallons an hour. At the 331mph speed you are good for about 100 miles in 18.5 minutes. 

So you are good for about 100 miles inland with a 90 mile crossing with 30 minutes once you are over land with a 15 minute combat duration.
With a XX gallon drop tank and 85 gallons internal. 
A lot of things can wrong but again, how far do you want to push into France? 
Every minute in combat is worth over 10 miles of getting home at 331mph. and 5 minutes at an economical speed of just over 200mph when trying to find the home airfield.

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## GregP (May 5, 2022)

Shortround6 said:


> It rather depends on how far you want to lean into France.
> 
> As 45-60 gallon drop tank get you well past the coast.
> 
> ...



Hi Shortround, I'd change that 2.5 gph to 25 gph and, are you sure. That seems might low compared with real-life Merlins today. Most of them run 50 - 55 gph at cruise. You can cruise at less fuel flow, but the spark plugs just don't like it much, and the engine stays much cooler at slightly higher fuel flow.


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## pbehn (May 5, 2022)

tomo pauk said:


> What were the numbers' odds during the 'leaning into France', RAF Spitfires vs. LW Fighters?


As I remember the loss ratio was about 5 to 1 in the LW favour at worst and operations were cut back and suspended or curtailed because of that. The Spitfire had nothing to escort and no spare Spitfires were available in 1940. In 1941 to 42 the Spitfire was not better than the f 109 and Fw 190 so increasing range would only increase losses. When the Mk IX appeared in mid 1942 what could be done with it, more than what was done they escorted USA bombers at Dieppe, but there were only 6 squadrons of them at Dieppe.. In Big Week early 1944, the USA had 800 P-47s 100 P-38s and 100 P-51Bs that is 1000 aircraft and pilots and they were hard pressed to protect their bomber force AND they were assisted by the RAF with some Spitfires. 1,000 pilots and aircraft is pretty much the normal RAF front line strength, so to run regular daylight bomber operations you need another "RAF fighter Command"

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## tomo pauk (May 6, 2022)

pbehn said:


> As I remember the loss ratio was about 5 to 1 in the LW favour at worst and operations were cut back and suspended or curtailed because of that. The Spitfire had nothing to escort and no spare Spitfires were available in 1940. In 1941 to 42 the Spitfire was not better than the f 109 and Fw 190 so increasing range would only increase losses. When the Mk IX appeared in mid 1942 what could be done with it, more than what was done they escorted USA bombers at Dieppe, but there were only 6 squadrons of them at Dieppe.. In Big Week early 1944, the USA had 800 P-47s 100 P-38s and 100 P-51Bs that is 1000 aircraft and pilots and they were hard pressed to protect their bomber force AND they were assisted by the RAF with some Spitfires. 1,000 pilots and aircraft is pretty much the normal RAF front line strength, so to run regular daylight bomber operations you need another "RAF fighter Command"



5:1 odds?? Luftwaffe had 5000 fighters to call during the 'leaning into France' vs. 1000 Spitfires?

700-odd RAF BC bombers in mid-1941 would be called by someone as 'substantial number', not 'nothing to escort'.


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## pbehn (May 6, 2022)

tomo pauk said:


> 5:1 odds?? Luftwaffe had 5000 fighters to call during the 'leaning into France' vs. 1000 Spitfires?
> 
> 700-odd RAF BC bombers in mid-1941 would be called by someone as 'substantial number', not 'nothing to escort'.


Sorry that is the loss rate.


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## Milosh (May 6, 2022)

Didn't I read in this thread that a 90gal dt would give the Spitfire a 500 mile combat range?


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## Shortround6 (May 6, 2022)

Milosh said:


> Didn't I read in this thread that a 90gal dt would give the Spitfire a 500 mile combat range?


Range or radius?


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## drgondog (May 6, 2022)

Shortround6 said:


> Range or radius?


The only way a spitfire reaches Berlin in escort role is to have ~ 300 gal internal coupled with 90gal combat tank


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## Vincenzo (May 6, 2022)

or take off from Hamburg

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## pbehn (May 6, 2022)

PAT303 said:


> I think you should read and understand what I am saying, more fuel allows more flexibility, flying feints and bogus raids is part of warfare, flexibility gives you options to deal with it instead of guessing your enemy's intensions.


In the Battle of Britain 1940 Park used his fighters to put up a screen to cover possibilities as an attack developed. The RAF would always have more fuel in their fighters than the LW because the LW had to form up and cross the channel, the LW also had to go back whereas an RAF plane could force land in a field if out of fuel. There were many cases where the RAF were taken by surprise and had to scramble to altitude, in that case you cannot take the additional fuel out and all it does is increase your take off run and decrease your rate of climb.


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## pbehn (May 6, 2022)

tomo pauk said:


> What were the numbers' odds during the 'leaning into France', RAF Spitfires vs. LW Fighters?


If you are asking how many on each side of the Channel the actual numbers changed a lot especially after Barbarossa, but they didnt really matter. The area of France across the Channel from England didnt have a huge number of targets that would damage Germany if destroyed. After a few initial successes bouncing German interceptors the L/W got wise to what the RAF were doing, and only engaged on their terms. Most of the time if they bombed something the Germans told the French to repair it. If you wreck a port it is a French port that discounts it from any invasion plan like Dieppe etc.


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## Milosh (May 6, 2022)

Shortround6 said:


> Range or radius?


radius
To lazy to go looking for the post by PAT303.


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## Shortround6 (May 6, 2022)

A lot of times operational radius was less than even the hasty numbers I gave which worked out to over 250 miles of radius.
I didn't figure in dogleg courses or flak detours or try to estimate prevailing winds out of the west. Or try to figure in forming up at the end of combat. It also assumes that the planes will be exactly on course and the proper distance from home at the end of 15 minutes of combat flying.


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## pbehn (May 6, 2022)

Shortround6 said:


> A lot of times operational radius was less than even the hasty numbers I gave which worked out to over 250 miles of radius.
> I didn't figure in dogleg courses or flak detours or try to estimate prevailing winds out of the west. Or try to figure in forming up at the end of combat. It also assumes that the planes will be exactly on course and the proper distance from home at the end of 15 minutes of combat flying.


There are many ways to calculate things. I was surprised to read that the Mustang Mk I used on tactical recon didnt have a radius as as such, they did their missions in a different way and generally it boiled down to 90 miles in from the enemy coast. The actual plane could of course go much further but not the way those missions were conducted.

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## Zipper730 (Dec 5, 2022)

don4331 said:


> Per Spitfire: the History, Spitfire with
> 2 blade wooden propeller - *9.4 minutes from S.L to 20k'*; 363 mph @ 12.5k', 31.9k' ceiling
> 3 blade metal,2 pitch propeller - 11.4 minutes from S.L to 20k'; *367 mph @ 12.5k'*, 34.4k' ceiling
> 3 blade metal, CS propeller - 10.7 minutes from S.L to 20k'; 364 mph @ 12.5k', *34.5k' ceiling*​


Wait, those numbers don't look right. There's a site called WWII Aircraft Performance which indicates for the Supermarine Spitfires full-throttle heights were a bit higher...


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