A Critical Analysis of the RAF Air Superiority Campaign in India, Burma and Malaya in 1941-45

[Schweik]

The test data showed a 14mph drop in Vmax and a 10mph drop at 20k ft (15mph using lower gear or stage). You've read the data incorrectly as there are dual entries for some altitudes that are close to the supercharger gear and stage changes.

I was reading that directly from Table IV ("Level Speed Without 30 gallon tank ") and Table V ("Level Speed With 30 gallon tank ") here: Spitfire F Mk IX BF274 Test

Spit IX

20k without tank 380 mph
20k with tank 365 mph

That is 15 mph. And more importantly it's 365 mph which ain't fast enough for an escort in NW Europe.[/QUOTE]

 

[PAT303]

I was reading that directly from Table IV ("Level Speed Without 30 gallon tank ") and Table V ("Level Speed With 30 gallon tank ") here: Spitfire F Mk IX BF274 Test

Spit IX

20k without tank 380 mph
20k with tank 365 mph

That is 15 mph. And more importantly it's 365 mph which ain't fast enough for an escort in NW Europe.

[/QUOTE]

Why the hang up on slippers?, put 30 gallons in the rear fuselage, or better yet 66 gallons, problem solved.

 

[Schweik]

Why the hang up on slippers?, put 30 gallons in the rear fuselage, or better yet 66 gallons, problem solved.

The problem is with any external tank, because there is a reason why miliatary airplanes in particular are made aerodynamic. The slipper tank, particularly the big one, decidedly isn't.

The rear fuselage tank would be Ok except that it causes severe stability issues in the Spitfire (and in a P-51)

What they really needed was a wing tank, a real one not that tiny one they used, but that would have required a new wing.

Which is where we started.

 

[RCAFson]

I was reading that directly from Table IV ("Level Speed Without 30 gallon tank ") and Table V ("Level Speed With 30 gallon tank ") here: Spitfire F Mk IX BF274 Test

Spit IX

20k without tank 380 mph
20k with tank 365 mph

That is 15 mph. And more importantly it's 365 mph which ain't fast enough for an escort in NW Europe.

[/QUOTE]

And Vmax is down 14mph and is still 390+mph at 27.4k ft.


This is data from late 42-43 which fits well with our Aug 1943 Schweinfurt scenario, and it shows that even with a 30/45 ST a MkVII/MkVIII/IX HF will be faster than a typical 109G. 20k ft was close to the 109G's Vmax and right at the gear change point for the Merlin, so it's more than a bit misleading. In any event our Spitfire pilot can always choose to dump his ST, assuming he meets a 109G that's done the same, or isn't carrying extra ordnance.

Spitfire Mk IX versus Me 109 G - Flight Testing

Note the performance of the bomber killing 109G6 with gondola guns.
Again, remember that this is not 1945 that we're discussing.

 

[RCAFson]

Why the hang up on slippers?, put 30 gallons in the rear fuselage, or better yet 66 gallons, problem solved.

I'm not hung up on STs but they were a very inexpensive way to give the Spitfire a lot more fuel with only minimal performance loss during combat. Again, over Schweinfurst there were no Allied fighters so any fighter would be huge advantage for the 8th AF.

 

[Schweik]

You are presuming (conveniently) that all LW fighters are going to be configured for taking down B-17s, but that is not what I understand to be the case - some were configured to attack bombers, others were configured to attack the fighter escort. To do otherwise would be suicidal.

So you can't assume that any interceptors are going to be laden down with heavy guns.

If the Spit were escorting Lancasters that would be at 20,000' or lower, not 'vmax'

Depending when in 1943 you will certainly find faster messerschmitts, but the problem for the ~ 360 mph Spit V was the Fw 190, and a Spit IX or VIII with a slipper tank is going to have the same problem, clearly.

 

[RCAFson]

You are presuming (conveniently) that all LW fighters are going to be configured for taking down B-17s, but that is not what I understand to be the case - some were configured to attack bombers, others were configured to attack the fighter escort. To do otherwise would be suicidal.

So you can't assume that any interceptors are going to be laden down with heavy guns.

If the Spit were escorting Lancasters that would be at 20,000' or lower, not 'vmax'

Depending when in 1943 you will certainly find faster messerschmitts, but the problem for the ~ 360 mph Spit V was the Fw 190, and a Spit IX or VIII with a slipper tank is going to have the same problem, clearly.

Why the fudge are you talking about Lancasters? We're discussing adding Spitfire escort fighters in time to cover the 8th AF raid on Schweinfurt.

There were no Allied fighters at Schweinfurt so the Luftwaffe was free to use TE night fighters and rocket lobbing JU-88s, along with underwing cannon 109Gs. These would have been slaughtered by the Spitfires, even with STs attached. To get above the escort fighters and gain advantage the Luftwaffe fighters needed to climb well above 25K ft, and even their best fighters are at a disadvantage at that altitude and above.

 

[Schweik]

I guess it's a circular argument - they were using all the heavy cumbersome stuff at Schweinfurt because there were no escorts, but would they still send them in, without any normally configured fighters if they didn't? I think that is a bit unlikely.

If your aim though is to be able to handle Ju 88s though then fine, you are probably safe there lol... just watch out for those Fw 190s

 

[RCAFson]

I guess it's a circular argument - they were using all the heavy cumbersome stuff at Schweinfurt because there were no escorts, but would they still send them in, without any normally configured fighters if they didn't? I think that is a bit unlikely.

If your aim though is to be able to handle Ju 88s though then fine, you are probably safe there lol... just watch out for those Fw 190s

So the mere presence of the Spitfires has severely curtailed the Luftwaffe's firepower....thanks for pointing that out.

Again, if we trade Spitfire losses for B-17 losses, it's still a big win for the 8th AF.

 

[Shortround6]

You really need to stop reading the history of WW II by M. A. Larkey

Much like the Watch Maker Rolls Royce Merlin's...and a lousy engine as far as durability.

The Merlin was not a watchmaker engine, or else Packard and Ford of Englane would not have been able to turn them out by the 10s of thousands.
If fact the Men from Ford of England complained that the tolerances were too loose.
Durability is relative, The Merlin being much more durable than any German, Italian, French, Russian or Japanese engines.
It is also evolving, a 1945 Merlin had about 40-50% more life than a 1939 Merlin despite making much more power.

IMHO should have developed the A and B/C/D Mustangs at the same time.

Would have been a real great idea, had they access to a time machine to get a 2 stage Merlin engine in 1940 or 1941, of course they would also have needed the 1942/43 fuel in 1940.early 1941 to get the two stage Merlin to work like it did in 1943.

 

[Airframes]

It's worth noting that the slipper tank (and other types) were normally jettisoned after crossing the coast of Europe, the tank being used first, during form-up, and subsequent RV with the bomber formation.
If Spitfires were on a fighter sweep ( i.e. not escorting), the tank may have been retained until empty, but either way, any external tank would be jettisoned before encountering enemy aircraft, and would certainly not be retained during combat.

 

[Kevin J]

Big question. Why the Schweinfurt raid in August 1943? Wait until September 1943, then you have 3 squadrons of P-38H in ETO, 8 squadrons of Spitfire VIII in MTO, and 2 squadrons of Spitfire VII in ETO. So providing you redeploy the Spitfire VIII from the MTO should give you your 150 fighters to escort the Schweinfurt mission. Problem solved.

Want to do it again, don't do it in October, wait for the P-38J to arrive. Do it in December. Problem solved.

So the second big question is, were the VIII Air Force trying to prove that 'the bomber will always get through' before the arrival of suitable escorts?

Anyway, back to the CBI. Spitfire IX / XVI with wing and rear fuselage tanks would have come in very handy in 1945 in Burma. The degradation of performance carrying ST insignificant as these Spitfires significantly outclassed the Ki-43. Instead of flying over contested airspaces they would have been flying over trees so better ranges could have been achieved.

N.B. The Spitfire XVIII with strengthened wing, and both wing and rear fuselage tanks was only used in the Far East, albeit post-war.

Forget the Spitfire V/IX with rear fuselage tanks. It wasn't going to happen at that stage of the Spitfires development life cycle. The best you could hope for in 1943 would be allowing the fitment of the 29 IG rear fuselage tank giving IMO a combat radius of 312.5 miles over hostile territory for the Spitfire VII/VIII, 270 miles for the Spitfire IX carrying the 90 IG ST.

So you could have either P-47D and / or Spitfire IX escort to Aachen, Spitfire VII, Aachen to Koblenz, P-38H from Koblenz to Schweinfurt.

 

[Shortround6]

How far do they need to go?, no one is saying the Spit can match the P51 but if set up like this http://www.spitfireperformance.com/spitfire9-fuelsystem-lr.jpg they could cover a lot of territory.

I don't know how far they needed to go but someone in this thread is talking about escorting the Schweinfurt mission/s which is over 400 miles one way,
Even using relays so one fighter group doesn't have to fly the whole way that is a fair distance, a distance that P-51s would have needed a pair of 75 gallon drop tanks and no rear fuselage tank (334 US gallons) to do ( and that barely allows for a dog leg or two) or P-47s with 305 gallons inside and 300 gallons outside.

Set up in the drawing is 220 Imp gallons or 264 US gallons. This is a considerable increase over normal Spit MK 9s but if the Spit needs 10% more fuel (?) to go the same distance at the same speed then the Spit needs over 50 Imp gallons more than the drawing shown for a radius of 450-475 miles.

And once again, it is not the total amount of fuel, it is the fuel left after what ever external tanks were used are punched off, and the internal fuel drawn down to acceptable flying characteristics (33 gallons?), figured against 15-20 minutes of combat power (5 minutes WEP and 10-15 minutes at military or rated power) and then the trip from Schweinfurt (or other similar distance target) to the channel at about 210mph IAS at over 20,000ft, at the channel they can start descending and slowing down. You still need 20-30 minutes fuel at most economic after reaching the English coast. a bit more if the fighter base is not right on the coast.

 

[Shortround6]

Instead of flying over contested airspaces they would have been flying over trees so better ranges could have been achieved.

This is one of the big differences between ranges/radius in the CBI (or south pacific ) and NW Europe. If they weren't flying over trees they were flying over water, altitudes did not have to be nearly as high and ingress and egress speeds could be much lower at distances around 50-75 miles from the target instead of high cruise speed being maintained for hundreds of miles.

 

[Stig1207]

Three Hurricanes will shoot down one Spitfire in combat.

That very much depends on the situation.

Wait until September 1943, then you have 3 squadrons of P-38H in ETO

Have to wait longer than that; the 55th FG were only operational from mid-October, and they weren't called on to provide escort for even the 2nd Schweinfurt raid.

 

[Dan Fahey]

You really need to stop reading the history of WW II by M. A. Larkey



The Merlin was not a watchmaker engine, or else Packard and Ford of Englane would not have been able to turn them out by the 10s of thousands.
If fact the Men from Ford of England complained that the tolerances were too loose.
Durability is relative, The Merlin being much more durable than any German, Italian, French, Russian or Japanese engines.
It is also evolving, a 1945 Merlin had about 40-50% more life than a 1939 Merlin despite making much more power.




Would have been a real great idea, had they access to a time machine to get a 2 stage Merlin engine in 1940 or 1941, of course they would also have needed the 1942/43 fuel in 1940.early 1941 to get the two stage Merlin to work like it did in 1943.

I read a ton on the Merlin Engine...it was coined the Watch Makers Engine.
Because it had so many little parts and before Packard engines were handmade.
You could not easily interchange parts from one engine to another.

Was not until Ford and Packard shut down the arrogance of Merlin.
Who thought their engines were built with high tolerances.
Packard redesigned the drawings so it could be manufactured and made identically.
Did their best not to redesign the engine and oil and cooling system.
Though made many improvements, used better materials especially the horrible bearings.
Packard double the life of the Merlin yet would never be an Allison.

The Allison was key making the venerable P40 into a great aircraft.
Did not have need all the work arounds.
Allison was just a much tighter engine platform and took half as long to rebuild.
Because it had half the parts and progressed to be a better platform as the war progressed.

D

 

[Dan Fahey]

I don't agree about the Spitfire, there was a need in the war for different combat types. Not every aircraft could be a generalist. You needed escort planes and fighter-bombers and carrier fighters and you definitely needed interceptors especially early in the war. The Spitfire was the only fighter in the Allied arsenal through 1943 that could reasonably be claimed to be as good as, or arguably better than the German fighters. That mattered. And for the Battle of Britain I think you did need a purpose-built interceptor. Casualties were high enough as it is, the British could not have afforded three times more casualties.

The Rolls Royce Merlin was probably the best inline engine of the war, in my book. Only close comparison was the DB 600 series.

After all, it was the engine in the Mustang right?

Over the course of the war 20k Spitfires were built.
The plane that got to fight the most was the Hurricane.
As an engine foundation the Merlin was and expensive time consuming engine to build.
What made the Merlin was one thing..
....some brilliant person designed a 2 speed 2 stage Supercharger that was fault free.
Allison built a better single speed SC and coulda should had a British one adopted.
Except for NIMBY and other reluctance for other reasons to to make one.

Once the TurboCharger issues were solved on the P38.
Then the reliability of the airframe come on to its own with an improved combat record.

Spitfire took a back seat to the Mustang.
In fact every fighter plane eventually did.
Few counties after WW2 bought Spitfires up.
The Italian Fighters and British Fury were more desired.
The French liked the P63 and Grumman Aircraft
The late Spitfire marks were Spitfire in name only.
Mk22 in Korea was a horrible carrier plane.

To give you some Boxing terms...
The Spitfire was a 4 round fighter..done and gassed out in 5th round!
The Mustang a 12 round fighter.and venerable for another round if necessary.

 

[wuzak]

I read a ton on the Merlin Engine...it was coined the Watch Makers Engine.

By people who did not understand how it was made.

Because it had so many little parts and before Packard engines were handmade.
You could not easily interchange parts from one engine to another.

Not true.

Ford UK was one of the contractors to build the Merlin, and it is true they tightened the tolerances for manufacture.

The only engines that were hand made were in Rolls-Royce's own experimental department.

Was not until Ford and Packard shut down the arrogance of Merlin.
Who thought their engines were built with high tolerances.

The story is that Rolls-Royce thought Ford UK could not make the Merlin because the tolerances were too tight, but Ford said they were too loose.

This was before Packard was involved (or Ford US, who the BPC first approached).

Packard redesigned the drawings so it could be manufactured and made identically.

Packard redrew the drawings to US standards so their fitters could make the parts.

Rolls-Royce drawings were in 1st angle, US standard was 3rd angle.

Did their best not to redesign the engine and oil and cooling system.

Huh?

As they were contracted to manufacture the engine and not design them, they would not have been allowed to redesign the engine without permission.

As it was, Packard was the first to introduce the two piece block, Rolls-Royce having to delay their changeover due to production and, you know, trying to win the fucking war.

Packard introduced their own system for connecting the block cooling passages to the cooling passages in the head. But they changed back to the definitive Rolls-Royce solution later.

Though made many improvements, used better materials especially the horrible bearings.

The improvements they made weren't that many.

The materials were, mostly, the same. Except where they couldn't get the same as what Rolls-Royce used.

They used some US parts, because it was convenient - such as the carburettor.

The two stage engines used a different supercharger drive system - but Packard did not design it. From what I understand, it was done by Wright. (Rolls-Royce Merlins and the single stage V-1650-1 used a Farman type gear drive, for which a royalty had to be paid to Farman. Maybe this is why it was ditched in US production.)

That the bearing material that Packard used was better than the one Rolls-Royce used, does not make the original bearings "horrible".

Packard double the life of the Merlin yet would never be an Allison.

No, they really didn't.

The Allison was key making the venerable P40 into a great aircraft.
Did not have need all the work arounds.
Allison was just a much tighter engine platform and took half as long to rebuild.
Because it had half the parts and progressed to be a better platform as the war progressed.
D

The parts count may be not as big an advantage for the Allison as you think. Many of the extra parts in a Merlin were fasteners, used to secure covers, such as the cam covers.

The Allison never did get on the same performance terms as the Merlin, mainly because the supercharger wasn't as good.

 

[Kevin J]

If only the Air Ministry had told Rolls-Royce to put the Merlin 61 into the Miles M20 and ordered mass production. The Merlin powered Mustang would have been unnecessary and the RAF could have provided escorts for the US VIII from the start.

 

[Kevin J]

If only the Air Ministry had told Rolls-Royce to put the Merlin 61 into the Miles M20 and ordered mass production. The Merlin powered Mustang would have been unnecessary and the RAF could have provided escorts for the US VIII from the start.

Actually, I was being half serious, if you look at that power egg on the M20, it doesn't provide much extra boost from the engine exhaust. So, replace it with a Merlin 61 with individual exhausts and put a Mustang style radiator underneath to take advantage of the Meridith effect. Now would we then have a fighter with twice the internal fuel of a Hurricane and the speed of a Spitfire? Any takers on this idea?