Spitfire Combat Radius (range) evolution, limitations?

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.

Click to expand...

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.

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).

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 .

Click to expand...

The F-8* could have quite long range!


Not very useful as a fighter, though.

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

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.

Click to expand...

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.

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).

Click to expand...

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?

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.

Click to expand...

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)

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.

Click to expand...

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.

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.

Click to expand...

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.

Click to expand...

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.

Click to expand...

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.

Part 2

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

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.

Click to expand...

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.

Click to expand...

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?

Click to expand...

"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?

Click to expand...

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?

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.

Click to expand...

Denied permission because GM owned Allison and NAA?

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?

Click to expand...

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.

Click to expand...

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.

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.

Click to expand...

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.

drgondog said:

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

Click to expand...

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.

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.

Click to expand...

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.

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.

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.

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?

Click to expand...

No.

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.

GregP said:

No.

Click to expand...

Well I disagree.

Wild_Bill_Kelso said:

Well I disagree.

Click to expand...

I like your moxie, kid!