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

[wuzak]

Would those engines work properly with just an aftercooler or did they need an intercooler too?

I believe they had an intercooler, but not an aftercooler.

I cannot confirm at the moment, as I am away from my books.

Just looked at Dan Whitney's Vee's for Victory and can confirm that I was mistaken and that it was an aftercooler, not an intercooler.

There really wasn't enough space for an intercooler and an aftercooler in the Allison design.

 

[Shortround6]

It's late so just three quick points.

• P-60 development may have started in 1941 but it continued until 1944. The P-60A flew on Nov 1942, the P60C flew on January 1943, and the P-60E flew in January 1944, and the complete version not until July 1944. Even Curtiss thought that was a waste of time and asked the War Dept to be let out of their contract.
• You mentioned the P-40Q weight was 9,000 lbs and you try to nudge it up from there, but the P-60Chad a gross weight of 11,835 lbs! With four .50 cal guns.
• It also had a 41' wingspan, vs. the 35' span of the P-40Q. (the latter was heading in the right direction)

P-60E, they all looked radically different

It may have been impossible to have gotten it working early enough to matter due to the trouble with the two stage Allison, but I think you can look at that, and compare it to the P-40Q I posted, and tell which one was a more viable design.

So what I mean by saying they shouldn't have wasted their time with it is they should have gone in that design direction (longer, slimmer, more streamlined, shorter wings, and yes a two stage or at least two speed supercharger but not a turbo) earlier instead of wasting their time for three years with the P-60.

XP-60 (Merlin 28, first flight September 1941)
XP-60A (V-1710 + turbo, first flight November 1942)
XP-60B (V-1710 + different turbo - completed as XP-60E)
XP-60C (originally to be Chrysler IV-2220 but ended up with R-2800 and contra-props, first flight January 1943)
XP-60D (XP-60 was changed to fit the V-1650-3) - this crashed in May 1943, still before the XP-40Q was a thing.
XP-60E (XP-60B airframe completed with R-2800 and single rotation propeller, first flight May 1943).

The wing and landing gear had been designed for the P-53 and carried on pretty much unchanged through the whole series. The original armament of the P-53 and early P-60s was (or supposed to be) eight .50 cal machine guns, ammo load unknown (at least to me). Army requirement or Curtiss suggestion?

Say what you will about Curtiss management, they were not dumb enough to think they could sell the P-36/P-40 airframe forever. Seversky/Republic had been a main competitor since the P-35 days. Once they are building an eight .50 cal fighter can Curtiss do less? So you get the 45ft wing of 275sq ft. at which point the Allison, regardless of supercharger is too small, the Merlin is too small, the wonderful (sarcasm) IV-1430 is too small (even if it had worked) and the search was on the bigger engine. The Chrysler IV-2220 was wonderfully streamlined but would never be available time. Leaving the P & W R-2800 and sticking an R-2800 into a P-40 fuselage was going to take a lot of work

Curtiss had been a main supplier of Army fighters since the late 20s, if it wanted to remain in that position it could not offer fighters almost as good as the other companies, they had to better, more innovative.

The P-40Q was not a change in design in direction, it was a last desperate gasp to keep Curtiss in the game while they worked on something better than the P-60 (making P-47s under licence might have been profitable but it was no way to ensure the future of the company). Cutting a few feet of wing tip off the old P-36 wing was not an example of innovation or modern thinking.

Unfortunately for Curtiss the basic design talent seemed to be lacking, the P-60 series dropped to six guns and then to four guns in an attempt to get the planes lighter to keep the performance up even as they got the more powerful engine (the R-2800).

You also have to compare the military power of the engines, not the WEP power (which didn't officially exist until late 1942 and some engines got it sooner than others).
The high performance of the P-40Q was using 75in manifold pressure and water injection. Please compare to P-51 using 150 octane fuel.

 

[Shortround6]

To add or modify the above post, the US Air Material Command was also pushing for the P-40Q in Dec of 1943 to help with an anticipated shortage of fighters in 1944.
It was seen as a way to keep numbers up and keep the P-40 in production at higher numbers than earlier plans called for (at least 200 planes per month).

As I've said before, planning and allocation of resources often occurred months or year before the production planes rolled out the door.
Unfortunately Allison's two stage engine was not quite ready for service use, the 2nd P-40Q prototype was out of service for about 40 days out of the 70 days it was under test in the summer of 1944.

ammo capacity of the P-40Q is given as 1208 rounds for 4 guns,

Ammo capacity for the P-53 was given as 2000 rounds for eight guns.

 

[Schweik]

Curtiss had been a main supplier of Army fighters since the late 20s, if it wanted to remain in that position it could not offer fighters almost as good as the other companies, they had to better, more innovative.

The P-40Q was not a change in design in direction... Cutting a few feet of wing tip off the old P-36 wing was not an example of innovation or modern thinking.

Unfortunately for Curtiss the basic design talent seemed to be lacking, the P-60 series dropped to six guns and then to four guns in an attempt to get the planes lighter to keep the performance up even as they got the more powerful engine (the R-2800).

Thanks, you articulated exactly the point I've been making about US weapon procurement for years. But I would rephrase your statement above slightly.

They didn't want an incremental improvement, they wanted a quantum leap.

This is a frequent pattern, the desire to make a quantum leap past what was already available and into something truly new and innovative. Like the B-70 Valkyrie, or the F-102, or the P-55 Acender (another zany project that Curtiss wasted time with) it could easily become a costly failure. Or like the ultimately successful P-38 and P-47, it might struggle through years of teething problems and issues with over-ambitious systems (turbo comes to mind).

Sometimes all the ambition for greatness builds up pressure that dooms a new design. A lot of times the best new designs started out as cheap alternatives mean to buy time until the next great idea came along. The Mosquito was made mainly to save on strategic materials. The F-16 was supposed to be a cheap stop gap. Yet these were some of the best new designs of their eras.

Any real quantum leap to make in 1944 or even 1943 was obviously going to be jet powered. So any more or less conventional pro driven fighter design was incremental, the only question was how far of an improvement would it be - two steps, three or four? And if Allison really couldn't get the two stage supercharger working then P-40Q was dead in the water regardless. That is probably what in fact happened.

However, if they could, perhaps with a bit more effort (putting a few more engineers on the project, whatever) have gotten the V-1710-101 working reliably by some time in 1942, I think that aircraft would have been more viable than the P-46, P-53, and P-60 series among other wasted efforts.

The P-40 itself was just a simple incremental upgrade over the P-36, as you have pointed out, basically just adding a better engine. And yet it proved to be vastly more capable and useful, extending the operational use of the P-36 to the end of the war. The P-51B was, similarly, an incremental update of a promising but not really viable fighter in the P-51A. The B model basically just put in a new, much better engine and fixed a problem with the ailerons. The Tempest was originally just an incremental improvement of the Typhoon, and yet it turned out to be vastly more useful.

Of the aircraft available in 1943 or 1944, the Mustang to me is the one that clearly was far above and beyond the P-40. It was the ideal escort fighter. It could contend with the Bf 109 at altitude and Fw 190 in terms of speed. But the Mustang wasn't great at everything. It's closest competitors, the P-38 and P-47, having lost out in the prestige battle for the escort role, were often used as low altitude fighters and fighter-bombers. But neither was ideal for that.

The P-38 was a very innovative design (certainly a quantum leap) but did not come into it's own until the late J and L models in 1944 when the dive flaps fixed the compressibility problems, boosted ailerons improved maneuverability, they had a second generator, cockpit heating, and most of the turbo issues were resolved. But even then it wasn't an ideal low altitude fighter or fighter bomber, size alone made it vulnerable to ground fire. The earlier P-38s were still very useful in the Pacific, and the P-38L could have rivaled the P-51 as an escort but that decision had already been made. The P-47 went through similar teething problems though for not quite as long. It's main issue was ultimately just range, due largely to the thirsty engine with the huge turbo (which was a circular problem in that the big turbo contributed to the huge overall size of the plane which meant it needed more power to drag it through the sky drinking more fuel etc.). It too got relegated largely to ground attack, and while it is celebrated in that role and the radial engine helped it survive being hit, it's large size and the fact that it was generally speaking, draggy down low and designed to be a high altitude fighter meant that it really wasn't ideal for that role.

The reality is that the P-40 soldiered on longer than it should have of course. To wit:

You do know that P-51s were being licence built in Australia from 1943 or 1944?

Be that as it may, if you look at the Australian victory claims for 1944, you'll notice that the majority of their victory claims were still by P-40s. I don't see any by Mustangs. By my count it's 17 from P-40s, 4 from Beaufighters, and 9 from Spitfires. So clearly there was still a need and a role for the P-40s.

If you accept the idea however that the Mustang should have been the only American made fighter in use after Jan 43, which I could agree with provisionally except for the problem of production, then the notion that there is no need for a P-40Q is valid. But since the production capacity for P-51s and their engines was limited, and other fighter types could compliment the mission, the P-40Q seems viable. P-40s were more maneuverable than Mustangs and seemed to hold up better to battle damage. The P-40Q was just a P-40 that had less drag, a much higher operational ceiling (39,000 ft vs. 31,000 for the P-40N) was 44 mph faster and had 300 miles more range. Four guns to me is also not a problem, does anyone doubt that a P-51B with four .50 cal guns was a better fighter than a Hurricane IIC with four 20mm cannon?

 

[wuzak]

Be that as it may, if you look at the Australian victory claims for 1944, you'll notice that the majority of their victory claims were still by P-40s. I don't see any by Mustangs. By my count it's 17 from P-40s, 4 from Beaufighters, and 9 from Spitfires. So clearly there was still a need and a role for the P-40s.

The point is they were going to get P-51s from Australian production before they got P-40Qs.

 

[Schweik]

The point is they were going to get P-51s from Australian production before they got P-40Qs.

The genuine usefulness of the Q hinges entirely on it's being available earlier. I agree (and stipulated from the beginning of this segue) that by 1944 there wasn't much of a market for it. I think the War Dept might have accepted it anyway if not for the prototype crashes (the first one may have happened in 1943, but there were three more in March, April and July of 44) which don't bode well for production aircraft, but sometimes are just purely accidents.

But to reiterate, the plane was at least a year too late. The only way it could have been viable is if Allison had been able to sort out the two-stage engine by late 42 or early 43, that way it could have been (arguably) in the field by mid 1944. If so it probably could have played a useful role in Burma and Italy among other places.

 

[Kevin J]

The genuine usefulness of the Q hinges entirely on it's being available earlier. I agree (and stipulated from the beginning of this segue) that by 1944 there wasn't much of a market for it. I think the War Dept might have accepted it anyway if not for the prototype crashes (the first one may have happened in 1943, but there were three more in March, April and July of 44) which don't bode well for production aircraft, but sometimes are just purely accidents.

But to reiterate, the plane was at least a year too late. The only way it could have been viable is if Allison had been able to sort out the two-stage engine by late 42 or early 43, that way it could have been (arguably) in the field by mid 1944. If so it probably could have played a useful role in Burma and Italy among other places.

Not even Italy, especially not Burma as its range that everyone wants. It's only the USSR that's uninterested in range.

 

[Schweik]

Not even Italy, especially not Burma as its range that everyone wants. It's only the USSR that's uninterested in range.

I've seen various estimates for the P-40Q range but with an external tank it appears to be 994 miles. Not as good as a Mustang but considerably better than any Spitfire (most marks around 430 miles, VIII seems to have been best at about 660 miles), Tempest (420 miles - with an extra fuel tank), or P-47 (best I've seen is 800 miles, most were realistically more like 500*) all of which were still in use in 1944 and 1945.

The main point though is that they were using P-40K, M and N from 1943 through early 1945 in many places including Italy and Burma, and also in the South Pacific. P-40s were still scoring victories in late 1944. If you had replaced those aging P-40N with P-40Q in say, early or mid 1944, that probably would have been a useful improvement. Given A) there aren't enough P-51s and B) there aren't enough P-38s either, the latter still experiencing teething problems into 1944... and the P-47 never really excelled in the CBI where the P-40 scored more victories than all other US types combined. For that matter P-40 units scored more than twice as many victories in the MTO as P-47s did too.

You could make the same argument for the Hurricane - an incrementally improved (say clip winged, two stage supercharger) Hurricane would have been very helpful in 1943 or 1944, IMO. If you could improve the top level speed to over 350 or 360 mph and increase the maximum dive speed and acceleration by about 20% each you would have put it back into a viable place.

*The special long range P-47N with an extra 100 gallons of gas in the wings, apparently could fly 2,300 miles ferry range, but it didn't see action until 1945 as far as I could determine googling it just now.

 

[Kevin J]

I've seen various estimates for the P-40Q range but with an external tank it appears to be 994 miles. Not as good as a Mustang but considerably better than any Spitfire (most marks around 430 miles, VIII seems to have been best at about 660 miles), Tempest (420 miles - with an extra fuel tank), or P-47 (best I've seen is 800 miles, most were realistically more like 500*) all of which were still in use in 1944 and 1945.

The main point though is that they were using P-40K, M and N from 1943 through early 1945 in many places including Italy and Burma, and also in the South Pacific. P-40s were still scoring victories in late 1944. If you had replaced those aging P-40N with P-40Q in say, early or mid 1944, that probably would have been a useful improvement. Given A) there aren't enough P-51s and B) there aren't enough P-38s either, the latter still experiencing teething problems into 1944... and the P-47 never really excelled in the CBI where the P-40 scored more victories than all other US types combined. For that matter P-40 units scored more than twice as many victories in the MTO as P-47s did too.

You could make the same argument for the Hurricane - an incrementally improved (say clip winged, two stage supercharger) Hurricane would have been very helpful in 1943 or 1944, IMO. If you could improve the top level speed to over 350 or 360 mph and increase the maximum dive speed and acceleration by about 20% each you would have put it back into a viable place.

*The special long range P-47N with an extra 100 gallons of gas in the wings, apparently could fly 2,300 miles ferry range, but it didn't see action until 1945 as far as I could determine googling it just now.

The Kiwis opted for the Corsair, the Aussies the Mustang, the Brits Mustangs and Thunderbolts, CBI USAAF the Mustang, USAAF Europe Mustang and Thunderbolts, Soviet VVS Kingcobra, USAAF Pacific Thunderbolts and Mustangs, Soviet PVO Spitfire and Thunderbolts, so maybe just maybe Soviet Naval Aviation to back up their Thunderbolts and P-40N's.

By late 1944, Spitfires also have rear fuselage fuel tanks. So what would you choose for the UK and USSR, Spitfire LXVI or P-40Q? When will it enter service, late 44 or early 1945?

I only see one potential customer for it, Soviet Naval Aviation.

 

[Schweik]

The Kiwis opted for the Corsair, the Aussies the Mustang, the Brits Mustangs and Thunderbolts, CBI USAAF the Mustang, USAAF Europe Mustang and Thunderbolts, Soviet VVS Kingcobra, USAAF Pacific Thunderbolts and Mustangs, Soviet PVO Spitfire and Thunderbolts, so maybe just maybe Soviet Naval Aviation to back up their Thunderbolts and P-40N's.

By late 1944, Spitfires also have rear fuselage fuel tanks. So what would you choose for the UK and USSR, Spitfire LXVI or P-40Q? When will it enter service, late 44 or early 1945?

I only see one potential customer for it, Soviet Naval Aviation.

Those picks were based on what was available, we are speculating about another plane that wasn't - presumably if it was it may have been part of the mix.

By the time the Kiwi's got their Corsairs (I think this was basically decided by the US) they weren't encountering Japanese planes. As you can see yourself their last 20 victory claims were all with P-40.

I already pointed out that similarly, the Australians got all their final victories with P-40s, Spitfires and Beaufighters. They did not seem to have any claims with the P-51 so I would say it's a safe bet they got them into combat too late. As CAS / fighter-bombers they were not ideal (they would have been better with Corsairs probably).

VVS did accept some Kingcobras but the P-40Q would have been better (fast enough to keep up with Fw 190s but also much longer range which did actually matter even to the VVS). The Soviets definitely did not care for the P-47 which they declared "not a fighter" and I believe would certainly have used P-40Q for PVO as well as VVS if available. They were still using P-40N in Naval aviation by the end of the war as you probably know.

The Brits would have accepted P-40Q in 1944 I think since they were still using Hurricanes (!) in the CBI and P-40N's in Italy, and didn't have enough Mustangs. I don't think they ever particularly loved the Thunderbolt.

USAAF was still using P-40s in the CBI into November 1944 (23rd and 51st FG). The 80th FG for example actually switched from the P-47 to the P-40 before rotating to the Theater.

So again, all I believe candidates to use any available P-40s with 40 mph faster speed, 5,000 higher ceiling, 300 miles better range, and double the rate of climb if it was available really any time in 1944.

 

[Kevin J]

Those picks were based on what was available, we are speculating about another plane that wasn't - presumably if it was it may have been part of the mix.

By the time the Kiwi's got their Corsairs (I think this was basically decided by the US) they weren't encountering Japanese planes. As you can see yourself their last 20 victory claims were all with P-40.

I already pointed out that similarly, the Australians got all their final victories with P-40s, Spitfires and Beaufighters. They did not seem to have any claims with the P-51 so I would say it's a safe bet they got them into combat too late. As CAS / fighter-bombers they were not ideal (they would have been better with Corsairs probably).

VVS did accept some Kingcobras but the P-40Q would have been better (fast enough to keep up with Fw 190s but also much longer range which did actually matter even to the VVS). The Soviets definitely did not care for the P-47 which they declared "not a fighter" and I believe would certainly have used P-40Q for PVO as well as VVS if available. They were still using P-40N in Naval aviation by the end of the war as you probably know.

The Brits would have accepted P-40Q in 1944 I think since they were still using Hurricanes (!) in the CBI and P-40N's in Italy, and didn't have enough Mustangs. I don't think they ever particularly loved the Thunderbolt.

USAAF was still using P-40s in the CBI into November 1944 (23rd and 51st FG). The 80th FG for example actually switched from the P-47 to the P-40 before rotating to the Theater.

So again, all I believe candidates to use any available P-40s with 40 mph faster speed, 5,000 higher ceiling, 300 miles better range, and double the rate of climb if it was available really any time in 1944.

Us Brits has better fighters to deploy in all our theatres. There's no need for the P-40Q, likewise our Commonwealth, and if we gave them to the Soviets then maybe they wouldn't have stopped in the Kuriles but marched into Hokkaido too, so not a good idea.

 

[Schweik]

Us Brits has better fighters to deploy in all our theatres. There's no need for the P-40Q, likewise our Commonwealth, and if we gave them to the Soviets then maybe they wouldn't have stopped in the Kuriles but marched into Hokkaido too, so not a good idea.

If that were true they wouldn't have been using P-51s and P-47s

 

[Kevin J]

If that were true they wouldn't have been using P-51s and P-47s

The later Spitfire IXe's and L XVI's had 66 Imp gals more fuel than the VIII's so are a much better option.

 

[Schweik]

The later Spitfire IXe's and L XVI's had 66 Imp gals more fuel than the VIII's so are a much better option.

What was their range with and without external tanks?

 

[Kevin J]

What was their range with and without external tanks?

Don't know mate, can't exactly remember, somewhere around 1000/1200 on full internal IIRC, but if you add external you can't add a centre line bomb or 2 rockets under each wing and you can only fill all the rear tanks for ferrying, otherwise it's half fill only. Would have been useful in 1945 for liberating Malaya. It's certainly better than the P-40Q.

 

[Schweik]

Lol I find that doubtful, I'd really need to see some data on that. 1,000 miles range on internal fuel? Combat radius, combat range or ferry range?

This seems to be devolving yet again into one of those patriotic type debates.

• The Spit was the best medium to high altitude interceptor and short range air superiority fighter on the Allied side, maybe for any side of the war (with the only real rival being the Bf 109). Once LF variants became available in 1941 it was also an excellent low altitude interceptor / air superiority fighter, though it would be challenged for supremacy in this role by the Yak-3 and some of the other Soviet types, as well as by the Fw 190. By continuous upgrading, the Spitfire stayed in dominant role in the interceptor niche through the end of the war, but it was never a good escort fighter or fighter-bomber. At best the VIII and other extended range variants seem to have given medium range.
• The P-51B and later marks, once they arrived, were the ultimate escort fighter of the late war with not long but very long range and good outcomes in air to air combat. The mantle was probably owned by the A6M for the early war and maybe the P-38 for the mid-war, at least in the Pacific. But P-51s were never particularly good interceptors or ground attack planes. Neither were P-38s.
• P-47s were contenders as arguably the best high altitude fighter on the Allied side and did well in the FB role in spite of massive drag and large target size. The rare Fw 190D and even rarer Ta-152 were probably the best for the Axis.
• The A6M was the best carrier fighter of the early war, the F6F Hellcat was hands down the best carrier fighter of the late war, followed by the F4U.
• The Soviets, as I said already, probably had the best short range, low altitude fighters of the war, chief among with was probably the Yak 3, but only once they were fully shaken out and developed, with the earliest really good ones probably not really making their presence felt until Spring of 1943. Before that the general purpose Bf 109, seemingly good at all altitudes, was clearly dominant. By the end of the war the Tempest is also highly competitive in this specific role.

In other words there were different niches that different aircraft were good at. No one aircraft was good at doing everything - those with the greatest versatility perhaps had the most applications, but not necessarily the most important applications. The Mustang was never as important as the Spitfire because the Spitfire defended the homeland and that was the priority mission of the war.

 

[Kevin J]

Lol I find that doubtful, I'd really need to see some data on that. 1,000 miles range on internal fuel? Combat radius, combat range or ferry range?

This seems to be devolving yet again into one of those patriotic type debates.

The Spit was the best medium to high altitude interceptor and short range air superiority fighter on the Allied side, maybe for any side of the war (with the only real rival being the Bf 109). Once LF variants became available in 1941 it was also an excellent low altitude interceptor / air superioritiy fighter, though it would be challenged for supremacy in this role by the Yak-3 and some of the other Soviet types, as well as by the Fw 190. By continuous upgrading, the Spitfire stayed in dominant role in the interceptor niche through the end of the war, but it was never a good escort fighter. At best the VIII and other extended range variants seem to have given medium range.

The P-51B and later marks, once they arrived, were the ultimate escort fighter of the late war with not long but very long range and good outcomes in air to air combat. The mantle was probably owned by the A6M for the early war and maybe the P-38 for the mid-war, at least in the Pacific. But P-51s were never particularly good interceptors or ground attack planes. Neither were P-38s.

P-47s were contenders as arguably the best high altitude fighter on the Allied side. The rare Fw 190D and even rarer Ta-152 were probably the best for the Axis.

The A6M was the best carrier fighter of the early war, the F6F Hellcat was hands down the best carrier fighter of the late war, followed by the F4U.

The Soviets, as I said already, probably had the best short range, low altitude fighters of the war, but only once they were fully shaken out and developed, probably not until 1943. Before that the general purpose Bf 109, seemingly pretty good at all altitudes, was clearly dominant. By the end of the war the Tempest is also highly competitive in this specific role.

In other words there were different niches that different aircraft were good at. No one aircraft was good at doing everything - those with the greatest versatility perhaps had the most applications, but not necessarily the most important applications. The Mustang was never as important as the Spitfire because the Spitfire defended the homeland and that was the priority mission of the war.

Best I've seen in an old book I have is Spitfire IX tested in states. 284 Imp gal total with 2 X 62 Imp gal drop tanks so 160 Imp internal so slightly more than original Mustang. You need to Google Spitfires range.

 

[Schweik]

I have, needless to say. Extraordinary claims require extraordinary evidence Kevin.

 

[Kevin J]

I have, needless to say. Extraordinary claims require extraordinary evidence Kevin.

It's out there. The Spitfire Story' by Alfred Price. Revised 2nd Edition 2002. I think it was about 160 gal max for combat for later marks. So 95 front fuselage, 33 wing, 66 rear. Rockets never used operationally in WW2. Don't think they ever used them in Burma though. War ended.

 

[Schweik]

It's out there. The Spitfire Story' by Alfred Price. Revised 2nd Edition 2002. I think it was about 160 gal max for combat for later marks. So 95 front fuselage, 33 wing, 66 rear. Rockets never used operationally in WW2. Don't think they ever used them in Burma though. War ended.

I don't doubt you are referring to something real, but I don't buy your interpretation. I think you are referring to either ferry range or to untenable fuel loads they could barely fly with or both. 160 gallon isn't even that much fuel if you are including external tanks, Mustang carried 184 internal + 150 external for long range flights.

If they had a Spit IXe or XVI with a 1,200 miles range I would think P-51 production would rapidly wind down and Spitfires would immediately take over all escort missions to Germany. Hell Lancasters could start flying during the day. The Spit was a much better dogfighter than a P-51 so if it had the same range I think maybe you switch NA production to the P-82 or P-80 or something.