If no P-51, how would the P-40 have evolved?

[drgondog]

Greg - I was really impressed with the restoration facilities at Chino. Looking forward to getting the VIP tour at Wright Pat in October to see what they have and how it compares to Silver Hill.

 

[RpR]

Greg if one would put one of the last much improved Allisons into one of the production P-40s, what performance figure might one get as compared to the WWII figures?

Purely speculation if one would chop and channel a P-40 into a duplicate of the Q with the last best two-stage engine and all simple improvements that occur in building engines with time, what lap speeds, by guess and by gosh, do you thing one might achieve at Reno?

One can only hope that some bucks-up Allison and P-40 aficionado some day builds a full-on Reno racer.

 

[drgondog]

I can't help but think that if the P-51 never existed that USAAF would have been forced to consider F4U in mid 1942 because of the range limitations on P-40/P-47/P-39 and the gestation/cost issues of the P-38. I imagine Curtis still proceeds with P-40 improvements but it had nearly reached its max viability in 1942 compared to adversary competition -

I also imagine that USAAF might consider modifying/building Spit VIII for long range service.

 

[RpR]

Assuming the cluster-f""" that finally destroyed Curtiss was not in play, without the P-51 the Air Corp probably would have used the P-40Q in the Pacific and one of the later P-47 models in Europe.

There would not have been the free-time to dick around with the P-60 sillyness.

Had the Japanese successfuly managed to get the Malay Peninsula I would say the P-40Q and others that were still born would have been in prod. as the Allies would have needed far more aircraft in the Pacific.

I cannot find on the net whent he Q first flew, does anyhone know?

 

[Shortround6]

P-60 sillyness started in 1940-41, Engine for first P-40Q is not delivered until early/mid 1943 and first prototype went through several engine models.

 

[RpR]

As far as every thing goes, as they produced over five thousand N models, even with the existance of the Mustang it would have made far more sense to produce the Q but then with what finally took Curtiss out of aircraft production and the asinine dealing with the Allison by the government, stupidity reigned.

 

[tomo pauk]

deleted

 

[tomo pauk]

Hi, BobR,

Why would it have been much better if they produced the Qs? What was the reason for Curtiss to be out of the business?

 

[Shortround6]

As far as every thing goes, as they produced over five thousand N models, even with the existance of the Mustang it would have made far more sense to produce the Q but then with what finally took Curtiss out of aircraft production and the asinine dealing with the Allison by the government, stupidity reigned.

They should have stopped the last few thousand N models.

Can you be more specific about " the asinine dealing with the Allison by the government"

 

[oldcrowcv63]

Looking over this thread I am astonished at how often the statement is made that P-40s did well against the Japanese, and that the P-40E was an improvement over the P-40B/C/D. As interceptors, from December 1941 through August/September, except in a very few instances IJ aircraft seem to have dominated PTO skies. AFAIK, the P-40E was nominally the toughest opposition IJ faced in any numbers during the early war, but it seems to have been essentially brushed aside throughout the PI, NEI, OZ and early NG campaigns. It seems to me USAAF P-40E pilots were simply unable to confront the air forces of IJ on any thing like its own terms. When opportunity presented, for example, after a bombing raid on Darwin, and the IJ Bombers were descending on egress from the target area, P-40Es could successfully attack retreating IJ raiders. But that's like killing the fox after he's eaten your chickens. Damage done. Am I missing some essential facts that are common knowledge in this forum. It seems to me efforts to improve the P-40 to meet the threat were very slow in evolving (P-40Ks and P-38s for the 49th Pursuit Group arriving late October). It looks like Kiser's Lightweight P-40E (with either 2 or 4 MGs) was used as bait to bring the escorting Zekes into play for his more heavily armed squadron mates flying below about 26-27,000 ft. The suggestion that most PAC combat occurred at low altitude seems to be contradicted by the historical accounts (Bartsch and Ferguson/Pascalis) and appears to be a more complex situation wherein the early, high-altitude raids were not typically countered unless they approached the target below 27,000 ft, which they apparently occasionally did. Once the allies went on offense, the raiding P-40Es escorting P-40E fighter-bombers could then expect to control the terms of combat more easily which would also be more likely to occur at intermediate and low altitude where the P-40E was more in its element. JMO and would be happy to learn why there is this general high opinion of the P-40E.

Of course if all that's being said is that ETO air combat occurred more regularly above 27,000 ft. Than that's a fair observation except that the ETO aircraft involved appear to have been operating at or near their operational ceiling as were those in the PTO, except that operational ceiling just happened to be a bit lower (especially for one combatant) than that of the major types in the ETO (Hurricanes, Spitfires, Me-109s and FW-190s, not counting the bombers which were probably flying at altitudes not too dissimilar to that of the IJ bombers.) If P-40Bs or Hurricanes had been employed instead of P-40Es would there have been more generally widespread higher altitude combat?

 

[tomo pauk]

Paging JoeB

 

[Shortround6]

There is a BIG problem in using average combat heights as a criteria, and that is just the nature of "averages". One fight at 27,000ft and one fight at 7,000ft equal an average height of 17,000. Gee, that is within the capability of the P-40, right?

Very few fights that started with one side or the other at 27,000 ft STAYED at 27,000ft. Almost all ended up at a lower altitude. What altitude is used to "report" that combat? If the enemy comes in at 26,000ft and bounces then P-40s flying at 20-22,000ft What is the height of the engagement?

The P-40s poor altitude performance meant that more often than not the initiative would be with the enemy aircraft. The P-40s could contest part of the sky but could NOT deny or contest the higher altitudes no matter what the average heights of the combats were.

 

[oldcrowcv63]

There is a BIG problem in using average combat heights as a criteria, and that is just the nature of "averages". One fight at 27,000ft and one fight at 7,000ft equal an average height of 17,000. Gee, that is within the capability of the P-40, right?

Very few fights that started with one side or the other at 27,000 ft STAYED at 27,000ft. Almost all ended up at a lower altitude. What altitude is used to "report" that combat? If the enemy comes in at 26,000ft and bounces then P-40s flying at 20-22,000ft What is the height of the engagement?

The P-40s poor altitude performance meant that more often than not the initiative would be with the enemy aircraft. The P-40s could contest part of the sky but could NOT deny or contest the higher altitudes no matter what the average heights of the combats were.

I appreciate and understand that distinction. I wasn't talking/posting about average altitudes, or the altitude of the escort air battle with defending interceptors that often followed a raid and typically descended to lower altitude as P-40s dove for the deck in a favored tactic to counter the A6M and stay alive. I was looking at the large number of raids that were reported to approach at altitudes in excess of 26,000 ft. and the inability of the P-40E to forestall them. That appears (in what I've read) to be the standard early IJ tactic to soften a target and achieve air superiority in preparation for an invasion or a ground advance. Of course, excepting the case of Darwin where IJ appeared to just want to minimize its use as a base covering the westward sea approach to Southern New Guinea.

 

[Shortround6]

I am sorry if you thought my comment was directed at you, Oldcrow, it wasn't. It was meant to forestall one or more other posters who keep wanting to reduce things to "averages".

I admire the amount of effort and thought you put into your posts and the amount of research that you do.

 

[oldcrowcv63]

I admire the amount of effort and thought you put into your posts and the amount of research that you do.

Well, it's easy for me to say the admiration is reciprocated.

 

[RpR]

They should have stopped the last few thousand N models.

Can you be more specific about " the asinine dealing with the Allison by the government"

The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e

This is quoted from the Allison home page but has been written about for decades:
Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited.

The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature. All 14,000 P-40s got gear-driven superchargers, and as a result, were never first-class fighter planes. Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era. This may be to some extent the bias of a proud parent, but there is no doubt that the deletion of the turbo-supercharger ruined the P-39 .

This is from a book written on the collapse of Curtiss as an aircraft company. Get the book--: Curtiss-Wright. The only American manufacturer capable of immediately meeting the demands of the Allied aviation programs of 1938-43, the corporation concentrated on the quantity production of aircraft that were soon obsolete in light of the rapid pace of technological change. Instead of cross-licensing designs and subcontracting other producers for component parts, the corporation overextended its managerial and engineering resources to expand its own production facilities.
Consequently, when Curtiss-Wright attempted to introduce new designs, such as the C-46 transport or the R-3350 radial engine, there were significant developmental problems. Curtiss-Wright's promise of untested technologies in large quantities and the failure to deliver them resulted in a considerable loss of prestige and the scrutiny of congressional investigators.

The P-60 started as an improved P-40 but turned into a pathetic malaise of untested engines, cancelled engines etc.
The YP-60E did not fly till mid 1944, while the Q, which out performed any model of the 60, including the E which was not a bad plane but was not needed, was flying already by mid 1943.
I do not have the book here and cannot find it on the net but if I remember correctly it was Curtiss management that killed the Q, not the Army Air Corp.
they could have been producing the much improved Q bbefore the beggining of 1944 instead of producing a still poorly engined N model. Hell they could have simply put the Q engine into the N and had improvement.

 

[rinkol]

The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e

This is quoted from the Allison home page but has been written about for decades:
Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited.

The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature. All 14,000 P-40s got gear-driven superchargers, and as a result, were never first-class fighter planes. Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era. This may be to some extent the bias of a proud parent, but there is no doubt that the deletion of the turbo-supercharger ruined the P-39 .

I've never seen any evidence of a P-40 with a turbocharger. Such a device is not trivial to add to a conventional fighter with a V-12 engine. The only examples that come to mind are the XP-37, XP-60A and B and FW-190C, none of which were especially successful.

Aside from this, my undestanding is that the original XP-39 was actually a disappointment and could not have come close to the reputed performance figures. I'm sure that, if it would have been an easy thing to effect a good installation in the P39 airframe, the turbosupercharger would have been reinstated at some point. The later P-63 was never fitted with a turbo and used the Allison with a two stage mechanically driven supercharger.

 

[RpR]

I've never seen any evidence of a P-40 with a turbocharger. Such a device is not trivial to add to a conventional fighter with a V-12 engine. The only examples that come to mind are the XP-37, XP-60A and B and FW-190C, none of which were especially successful.

Aside from this, my undestanding is that the original XP-39 was actually a disappointment and could not have come close to the reputed performance figures. I'm sure that, if it would have been an easy thing to effect a good installation in the P39 airframe, the turbosupercharger would have been reinstated at some point. The later P-63 was never fitted with a turbo and used the Allison with a two stage mechanically driven supercharger.

The original XP-39 was built with a V-1710 augmented by a Type B-5 turbosupercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers, NACA aerodynamicists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie. The production P-39 was thus stuck with poor high-altitude performance and proved unsuitable for the air war in Western Europe which was largely conducted at high altitudes. The P-39 was rejected by the British, but used by the U.S. in the Mediterranean and the early Pacific air war, as well as shipped to the Soviet Union in large numbers under the Lend Lease program. The Soviets wer e able to make good use of P-39s because of its excellent maneuverability and because the air war on the Eastern Front in Europe was primarily short ranged, tactical, and conducted at lower altitudes. In the P-39, Soviet pilots scored the highest number of individual kills made on any American, or British fighter type.

The P-40, which also had only the single-stage, single-speed-supercharged V-1710, had similar problems with high-altitude performance.

The P-38 was the only fighter to make it into combat during World War II with turbosupercharged V-1710s. The operating conditions of the Western European air war – flying for long hours in intensely cold weather at 30,000 feet (9,100 m) – revealed several problems with the turbosupercharged V-1710. These had a poor manifold fuel-air distribution and poor temperature regulation of the turbosupercharger air, which resulted in frequent engine failures (detonation occurred in certain cylinders as the result of persistent uneven fuel-air mixture across the cylinders caused by the poor manifold design). The turbosupercharger had additional problems with getting stuck in the freezing air in either high or low boost mode; the high boost mode could cause detonation in the engine, while the low boost mode would be manifested as power loss in one engine, resulting in sudden fishtailing in flight. These problems were aggravated by suboptimal engine management techniques taught to many pilots duri ng the first part of WWII, including a cruise setting that involves running the engine at a high RPM and low manifold pressure with a rich mixture. These settings can contribute to overcooling of the engine, fuel condensation problems, accelerated mechanical wear, and the likelihood of components binding or "freezing up." Details of the failure patterns were described in a report by General Doolittle to General Spatz in January 1944.

 

[Shortround6]

Oh boy, where to start.

The government told Allison not to develope the multi-staged geared supercharger they were going to as they had a fetish for exhaust driven super-chargers but due to the exotic heat resistent metal necessary that resulted abandoning a standard that worked more easily and cheaply for one that was more time consuming and more difficult to mass produce.e

The "government" did not have fetish for the turbo-charger, the ARMY may have. The NAVY did not. The Navy was funding mechanical two stage superchargers (or at least ones from P&W). Allison in 1938 was a very small company in 1938, only 25 employees in the engineering section including the guys that ran the blueprint machine/s. Allison had earlier turned down an Army request/contract to develop a fuel injection system, saying they had too little engineering staff to work on the fuel injection and the other Army contracts at the same time. There were TWO aircraft at the 1939 Army fighter trials using P&W two stage superchargers, the Army was less than impressed.

Had Allison's engineers been able to put the effort into gear-driven superchargers that Pratt and Whitney and Rolls-Royce did, it might have been a different story. As it was, there can be little doubt that the V-1710 had more potential than was actually exploited.

This statement is quite true. but be careful of company web site Histories. they may be written by PR people with little knowledge of the actual history and with goal of making the company look good. and with that we are off to:

The few turbo-supercharged Allisons that were made, were allocated to P-38s, making the high-altitude performance of that plane its best feature.

There were over 10,000 P-38s made meaning over 20,000 Allisons were run with turbo-chargers, not including replacement engines. While that is fewer than the non-turbo Allison numbers it is not what most people think of when told that there were few turbo-supercharged Allisons made.

Donaldson R. Berlin, the P-40's designer, has said that P-40s experimentally equipped with turbo-superchargers outperformed Spitfires and Messerschmitts and that if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era. This may be to some extent the bias of a proud parent,

I would hesitate or dislike to say he was lying as he cannot defend himself at this point. Mistaken perhaps? In the 67 years since the end of WW II NOBODY (to my knowledge) has been able to come up with a photograph of a turbo equipped P-40, a good drawing, a factory work order or assembly print/drawing, a test report of even date of a test flight let alone name of the test pilot. Yet there are photos of prototype P-40s with different radiator installations and other modifications. I also wonder about this part "....if it had been given the engine it was designed for, the P-40 would have been the greatest fighter of its era." The XP-40 was the 10th P-36 of the production line re-engined from the firewall forward. Work on the Curtiss Model 75 (which became the P-36 ) started in November 1934. Which engine was the XP-40 originally designed for? This statement also tends to overlook ( or perhaps Mr. Berlin was referring to this aircraft and NOT the P40?) the XP-37 and 13 YP-37 which used the Curtiss airframe with Turbo-charged Allisons. By 1940 -41 the Army had a pretty good idea of what to expect from a Single engined turbo-charged Curtiss airframe.

but there is no doubt that the deletion of the turbo-supercharger ruined the P-39 .

Actually there is quite a bit of doubt. In fact there is a school of thought that says deleting the turbo saved the P-39.

This is from a book written on the collapse of Curtiss as an aircraft company. Get the book--: Curtiss-Wright. The only American manufacturer capable of immediately meeting the demands of the Allied aviation programs of 1938-43, the corporation concentrated on the quantity production of aircraft that were soon obsolete in light of the rapid pace of technological change. Instead of cross-licensing designs and subcontracting other producers for component parts, the corporation overextended its managerial and engineering resources to expand its own production facilities.
Consequently, when Curtiss-Wright attempted to introduce new designs, such as the C-46 transport or the R-3350 radial engine, there were significant developmental problems. Curtiss-Wright's promise of untested technologies in large quantities and the failure to deliver them resulted in a considerable loss of prestige and the scrutiny of congressional investigators.

All quite true but it has little bearing on the P-40 or a turbo P-40.

The P-60 started as an improved P-40 but turned into a pathetic malaise of untested engines, cancelled engines etc.
The YP-60E did not fly till mid 1944, while the Q, which out performed any model of the 60, including the E which was not a bad plane but was not needed, was flying already by mid 1943.
I do not have the book here and cannot find it on the net but if I remember correctly it was Curtiss management that killed the Q, not the Army Air Corp.
they could have been producing the much improved Q bbefore the beggining of 1944 instead of producing a still poorly engined N model. Hell they could have simply put the Q engine into the N and had improvement.

The P-60 started as the P-53. The first flight of a P-60 (with a Merlin engine) was 18th September 1941. One reason the P-40Q could out perform the XP-60 aircraft was that it carried a rather pathetic armament and the P-60s had been designed around a somewhat too ambitious armament which resulted in a substantially larger aircraft than the P-40 series.

Curtiss (or any other manufacturer) cannot change the product in mid contract, especially considering that the engines were GFE ( Government Furnished Equipment). The Army contracted with Allison of XXX number of model YYY engines and shipped them to the airframe makers. Many of these contracts were placed months (if not a over a year) in advance and while contracts were canceled, modified and changed it could take weeks or months to have any effect.

 

[Shortround6]

We are back to one of the greatest WW II aviation myths>

The original XP-39 was built with a V-1710 augmented by a Type B-5 turbosupercharger as specified by Fighter Projects Officer Lieutenant Benjamin S. Kelsey and his colleague Gordon P. Saville. Numerous changes were made to the design during a period of time when Kelsey's attention was focused elsewhere, and Bell engineers, NACA aerodynamicists and the substitute fighter project officer determined that dropping the turbocharger would be among the drag reduction measures indicated by borderline wind tunnel test results; an unnecessary step, according to aviation engineer and historian Warren M. Bodie.

Borderline Windtunnel tests? Please explain that one.

There is no evidence what so ever that the XP-39 ever came close to the performance numbers claimed for it in any number of books or websites. And quite a bit of information that makes it look extremely unlikely.

1.The XP-39 flew for 20 minutes or just under on the it's first flight/day of flying. Which is rather normal for first flight and testing but hardly enough time to gather any performance numbers.
2. The XP-39 was plagued with both coolant and oil over heating problems even in ground running/taxi tests making high speed runs or climb to altitude tests rather unlikely.
3. The XP-39 had the coolant and oil cooler ducts worked on several times between the first flight and being shipped off for the wind tunnel tests meaning that there were also a number of days when it wasn't available for flying.
4. Calculations had predicted an vibration problem with the original drive shaft in the event of one or more cylinders miss-firing. A bigger diameter drive shaft with heavier walls had been designed/ built but not fitted until AFTER the wind tunnel tests were done. Engine was limited to 2600rpm until the new drive shaft was fitted which also means that any maximum performance tests were extremely unlikely.
5. the XP-39 first flew on April 6th 1939. On April 21st 1939 Gen. Arnold was issuing orders for the XP-39 to be sent to Langley Field and the NACA wind tunnel. The ONLY full sized tunnel in the US at the time. DO aircraft that are successfully meeting their performance goals need help form the NACA?