V-1710 supercharger development potential

[Shortround6]

The P-63 seems more like a case of just being a more advanced airframe overall. It doesn't seem that unrealistic that the engines used in the P-63 series could have been fitted to variants of the P-39 itself. (though maybe some complications due to added length or change in CoG).

only if the variant was 1.5 to 2 ft longer. P-63 also changed wing location.

Good enough to be a reasonable substitute for the Mustang had NA not developed that machine on their own, especially if the merlin engined P-63 project had gone though. (Mustang production started sooner and the USAAF didn't put in massive orders for the P-63, so it's hard to say how well they'd have coped with ramping up production compared to what NA managed historically)

P-63 still had miserable fuel capacity. 126-128US gallons internal.

US pilots might have continued to complain about the 37 mm cannon, but it doesn't seem unreasonable that 20 mm alternative mountings could have been substituted, or even just another .50 cal.

Dropping to a .50 through the prop and the P-39/P-63 loose their reason for being. A 5 machine gun fighter brings what to the table vs the existing 4 and 6 gun fighters?

 

[GregP]

Ho Kool Kitty,

The P-63 as a very good airplane that came along when a few other very good airplanes were in large quantity production.

From your earlier post, the XP-37 DID have troubles and so did the XP-39, but finding solutions to the turbo problem was in sight. Had to be since it WAS successful in the P-38 ... eventually, and also in the P-47 from the start. Had the turbo been allowed to be developed on the P-39 as it was for the P-38, they could have worked out an installation. It would have added weight, but would have also given better high altitude performance.

The powers that be at the time weren't all that convinced that high altitude performance was needed in a fighter, but somehow WERE convinced that high altitude performance WAS needed in a 4-engine bomber. I don't get it, but they reserved the turbos for the bombers ... mostly. It was what it was.

When the mixture and European fuel issue got worked out the V-1710 gave very good performance at altitude in the P-38. Had they pursued the turbocharger in the P-39 and P-40, the war record would certainly have changed ... and they HAD THE TIME to DO it if they only did it. They didn't and the Merlin became the high-altitude engine of choice because of their shortshightedness.

You can make a lot of the same claims for the Edsel automobile ... wrong thing at the wrong time. It could be said of the P-63, too. It looked like a P-39 and there was automatic predisposal to cancel it despite the flight performance. If you improve things, change their looks if the original was a flop.

Think Me 210 / Me 410. The 210 was a killer and the 410 was a good plane that never caught on. VERY similar to the P-39 / P-63 pair of designs.

Then again, the P-51 WAS in quantity production and so was the P-47, both successes if ever there were any for the USA. The F8F had NO chance as a USAAF plane so, despite the potential, it was only looked at by the Navy. The F6F was a great fighter by ANY standards, but was not as good as the P-63 and was ALSO never looked at by the USAAF. The P-63 was a case of too little, too late ... just like the German late-war aircraft (and OTHER weapons) were.

They were advances, but were overshadowed by the hot-shot performers of the current production runs. In the case of the P-63, it really COULD have helped a LOT, but was not needed in the actual event. Uneeded equipment doesn't get much priority, even if it is very good ... MOST of the time. It depends on the reliability of the in-service equipment at the time. In the case of the P-51. it was and IS reliable. Ergo, the P-63 was redundant and no massive retraining was needed for the "new" fighter that no pilot wanted to be assigned to ...

Altogether a self-fulfilling outcome.

 

[tomo pauk]

I don't think that P-63 was that great an aircraft, nor that it was all-around a more capable dsign than Bf-109, let alone Spitfire or Spiteful. The P-63A, in 3 tests available succeeds to beat 400 mph mark in just one (nevermind the projected Bell's performance charts). The Bf 109 was close to 400 mph mark in 1941, beating it in winter or 1941/42, ie. 2 years before the P-63 managed the same. The late war Bf-109 were offering 420-440, or even 450 mph with 2-stage DB 605L
Spitifre was able to average 400 mph in second half of 1942, and got better every year. The Griffon Spitfire was available one year before the P-63E, an aircraft that might equal what Merlin Mustang brought to the table in autumn of 1943 (talking about production dates). The P-63 has either ~70% of fuel as Merlin Mustang, or less than 50%, while the late war Spitfires have had also means to almost double the internal fuel. What P-63 has over 109 or Spit is roll rate, and that's it.

Greg,

The F6F was a great fighter by ANY standards, but was not as good as the P-63 and was ALSO never looked at by the USAAF.

If I get this right - the P-63 was one step better than great? What standards are applied in this categorization?

Think Me 210 / Me 410. The 210 was a killer and the 410 was a good plane that never caught on. VERY similar to the P-39 / P-63 pair of designs.

Hate to go further off-topic - but why involve two German aircraft that were not that good? The Me-210 is a killer? Probably against it's early crews.

Ergo, the P-63 was redundant and no massive retraining was needed for the "new" fighter that no pilot wanted to be assigned to

Not just that P-63 did not bring anything new to the table, but it was inferior to the stuff mass produced in 5 American factories (discounting US Navy fighters); it was almost six US factories, had the Curtiss didn't botched their production of P-47s.

The installation may HAVE been heavy, problematic, and appaling, but it was deleted because the War Marriel baords disapproved all turbochargers for US fighters except for the P-38 and P-47. They were saved for the heavy bombers because it was anticipated that Europe would require bombing from high altitude, and turbocharger production was low relative to aircraft and engine production.

About twice of turbochargers can be obtained from each P-38 than from each (X)P-39s. So either someone in the Material Division (or wherever) didn't do their math properly, or they judged that P-38 represented a bird in a hand, while the turboed P-39 represented a bird in the bushes. I'm inclined to the later.
The unarmed XP-39 have had Cd0 of 0.0329, a truly horrendous value for a monoplane with retractable U/C.

Tomo, Allison acq`uired the bearing design by US Government insistence. Of course they for paid. But tyhey would never have given the license if not for government insistence.

Allison? Think you mean that RR acquired license. Nobody in 1920s/1930s was giving away licenses, let alone to foreign companies. In case you don't have a source that backs up that US government somehow twisted the Allison's arm about this, it goes under 'myths' category.

And that's why I said the trade of supercharger for bearings never happened ... precisely because the bearing license was mandaded well before the 2-stage supercharger was operational ... so it wasn't "on the table," so to speak, at the time. You don't seriously think a US company would license a technology that was making their bearings the only game in town ... unless they HAD to, do you?

Then why bringing it up?

If you do, you don't understand US business.

I don't understand many things.
Yet, I do understand this: if I'm to be taken seriously when talking about anything, it is a good practice to back up my talk with sources.

A tidbit on the proposed XP-40H, from Vee's for victory, pg. 184:
The Curtiss P-40H was to have been an Allison powered and turbosupercharged version of the P-40E. At conference at Wright Field on June 10, 1941 Mr. Don Berlin of Curtiss received authority to begin such a project and the Material Division immediately shipped one GE Type B-2 turbosupercharger to Curtiss at Buffalo, New York. By that October the decision has been made to not turbosupercharge the P-40, but instead incorporate the feature into the coming Curtiss P-60. The turbo was to be installed behind pilot in the XP-60.

The excerpt is sourced.
So the Curtiss almost got to build the turbo P-40. But not in March 1938 (when Curtiss submitted the P-36 derivative featuring the V-1710 engine), but more than 3 years after that.

 

[Shortround6]

I would note that decision to drop the turbo from the P-39 was made in 1939.
The War Production Board did not come into existence until Jan 1942 and it's predecessor, the Supply Prioritys and Allocation Board, didn't come into existence until Aug, 1941 and boards/agencies which made up that organization didn't exist or were not even authorized until the summer of 1940.

I would also note that B-17s were being ordered in such low quantities in 1939 and 1940 that Boeing subcontracted and built several hundred A-20s. First B-24s with Turbos aren't built until Nov/Dec of 1941.

Somebody had one check of crystal ball if they took turbos away from P-39s in 1939 to save them for bombers. Army didn't suggest using turbo on B-24s until the summer of 1940, 10-11 months after the Army had ordered 80 P-39Cs.

This is looking like another Furphy.

 

[gjs238]

Well gjs238,

Your assertion above is not quite correct. The Allison DID make it to 2-speed.

The XV-1710-131 was similar to the V-1710-97 except it was fitted with a 2-speed (7.485 : 1 and 9.60 : 1), single stage supercharger and had a different comprression ratio (6.5 : 1).

This engine flew in the XC-114 and the YC-116. It didn't make it intoa US fighter, but it flew.

It also isn't much known, so probably almost everyone else thought so, too.

It also made it to 2-stage with the auxiliary stage. It wasn't an integral 2-stage, but was 2-stage.

Nice - would love to see prints for the 2-speed engines.

 

[GregP]

Hi Tomo,

The F6F was a great fighter for the Pacific Theater of Operations. It could outclimb a Zero and hit hard enough to do damage when it did so. It wouldn't turn with a Zero but could stay in there for about 3/4 of a turn, enough to get off a shot. The acceleration was MUCH better than a Zero. It was the right package at the right time. The P-63 climbed better, was faster (cruised significantly faster), and hit harder ... ergo my statement.

About the P-39 and the turbo, Ben Kelsey was a huge advocate of the turbocharger. He was in the UK in 1939 when Larry Bell proposed to the USAAC and NACA to produce a variant of the P-39 without the turbo. They agreed and the prototype, which was a ton lighter than a production bird was built and verified the perforamcne gains predicted. Kelsey was NOT a happy camper and when the armor and armament and ammunition, etc. was added, the production plane suffered in performance relative to the prototype. But ... production got started.

Meanwhile, President Roosevelt created the The Office of Production Management and the Supply Priorities and Allocation Board in Jan 1941. They had exactly the same function as the 1-year later War Production Board (official title) and they determined where the turbochargers went. In one if their earliest decisions, they allocated turbochargers to only ONE front-line US fighter, the P-38. Had the P-39 been using a turbo at the time, it would have been removed anyway.

In later years, Ben Kelsey lamented not being present when Larry Bell made his sales pitch becuase he felt like the P-39 turbo issues could have been worked out. He said that because they started production without the turbo did not mean it could not have been added back in at any time. All it would take is the turbos and some development work at Bell. They never got the turbos again, even for the P-63, so they went to the auxiliary stage supercharder on the Allison.

Another often-repeated rumor about the P-39 was that it would tumble end-over-end. In fact, NACA and Bell and the USAAC tested P-39 models both in wind tunnels and in 86 test flights and were never able to get them to tumble. Then, in the 1970's in an attempt to see the real truth, an informal study of the spinning characteristics of the P-39 was done. It might never have been done except they found the original spin test model in storage and decided to test it.

When balanced at full ammunition load, it spun normally and would not tumble. When balanced at a no-ammunition load, it tumbled rather often and easily while spinning.

Just goes to show that if testing is not done at the CG envelope extremes, then you really don't KNOW what a palne will do at the extremes of the envelope when pushed hard.

Having spoken with several people associated with WWII aircraft development and procurement over the years, including Ben Kelsey (he visited Purdue University when I was in the aeronautical engineering department and we had a round table with him, our professor, and 20 students), I have concluded that had both the P-38 and P-39 been equipped with turbos, one or the other would have been directed to stop using them. Bell was a small-time outfit compared with Lockheed, and I have great difficulty believing the P-38 would have been the one so ordered. In fact, Kelsey said they could never get the turbos back even when the combat operformance of the P-39 shouted out the need for them. The War Production Board just said no.

Kelsey liked the P-39, but he also liked the P-38. I don't know which one would have been ultimately better, but I suspect that, if for no other reason, the range would have dictated staying with the P-38. According to Ben and to Pete Law (Skunk Works), the turbos were considered difficult items to make enough of, and were rather jealously apportioned out when they were in "short" supply. Remember, a B-17 or B-24 took four each, so a couple hundred turbos would only produce 50 bombers. That made then even MORE hard to get.

The P-38 was a case of throwing all the eggs in one basket, so to speak. It did not turn out badly as the P-38 was the mount of our top two aces for the entire war.

Now, I suppose it is possible I have concluded incorrectly. I feel that a LOT of modern looks at the past come to very incorrect conclusions because modern people have no concept of the attitudes and feelings of the people in charge at the time. Modern young people look at the world in a wholely different way than some who grew up and was about 18 - 25 years old when war broke out does. Some things that modern people feel should have been done would NEVER have even been considered and the person(s) proposing them would have been ejected from the neetings.

I choose to believe Ben Kelsey and Pete Law and the guys who were around and who grew up at the time and who KNOW why things were done the way they were done. Logic has nothing to do with some decisions that were made. They were made for very specific reasons that were never laid down in meeting minutes.

I have debated the P-63 in here before and do not propose to replicate that in here. Suffice to say I think it could have been a real asset anywhere it was deployed. If you think otherwise, you are free to do so without comment from me. We all know what happened in the end, and what-ifs are unwinnable by either side of an argument.

 

[Balljoint]

Greg, I pretty much agree. I view the P-39 and P-40 as very successful designs in that, save for the late-recognized need for high altitude, long range escorts, most combat was at lower altitudes, the Desert Air Force, The Cactus Air Force (P-400 CAS), AVG, Soviets etc., all low altitude conflicts served well by these aircraft. In time their weakness in the vertical may have been exploited. But these aircraft held their own during some of the more critical times.

The high altitude Alison P-51 was, to me, a galling missed opportunity. But, given the history during the 1930s and early 1940s, understandable.

 

[tomo pauk]

Greg, thanks for that overview. At any rate, the historic P-39 went in the mass production to fulfill a current need, that being bulking up the numbers of 1st line USAF fighters (even though the European designs moved the goal post in the meantime), along with P-40 and P-38.
Re. deleting turos from aircraft: the brass have had no objections for the production of P-43 and slightly improved P-43A, Republic also started designing the XP-44 that got replaced by P-47B. The brass shortly authorized the XP-40H, the P-60A almost got into production, Curtiss get to produce the P-47 under license instead of (X)P-53 and (X)P-60, the Evansville factory for the P-47s was to be built - all for the turboed fighters. So you'd excuse me that I don't believe that P-39 lost turbo because someone thought there would not be enough of those, while I also don't believe that someone would've started deleting turbos from fighters other than P-38 in 1941.

 

[gjs238]

I have debated the P-63 in here before and do not propose to replicate that in here. Suffice to say I think it could have been a real asset anywhere it was deployed. If you think otherwise, you are free to do so without comment from me. We all know what happened in the end, and what-ifs are unwinnable by either side of an argument.

Or would one just be better off with more P-51's?

 

[gjs238]

Hi Tomo,

The F6F was a great fighter for the Pacific Theater of Operations. It could outclimb a Zero and hit hard enough to do damage when it did so. It wouldn't turn with a Zero but could stay in there for about 3/4 of a turn, enough to get off a shot. The acceleration was MUCH better than a Zero. It was the right package at the right time. The P-63 climbed better, was faster (cruised significantly faster), and hit harder ... ergo my statement.

About the P-39 and the turbo, Ben Kelsey was a huge advocate of the turbocharger. He was in the UK in 1939 when Larry Bell proposed to the USAAC and NACA to produce a variant of the P-39 without the turbo. They agreed and the prototype, which was a ton lighter than a production bird was built and verified the perforamcne gains predicted. Kelsey was NOT a happy camper and when the armor and armament and ammunition, etc. was added, the production plane suffered in performance relative to the prototype. But ... production got started.

Meanwhile, President Roosevelt created the The Office of Production Management and the Supply Priorities and Allocation Board in Jan 1941. They had exactly the same function as the 1-year later War Production Board (official title) and they determined where the turbochargers went. In one if their earliest decisions, they allocated turbochargers to only ONE front-line US fighter, the P-38. Had the P-39 been using a turbo at the time, it would have been removed anyway.

In later years, Ben Kelsey lamented not being present when Larry Bell made his sales pitch becuase he felt like the P-39 turbo issues could have been worked out. He said that because they started production without the turbo did not mean it could not have been added back in at any time. All it would take is the turbos and some development work at Bell. They never got the turbos again, even for the P-63, so they went to the auxiliary stage supercharder on the Allison.

Another often-repeated rumor about the P-39 was that it would tumble end-over-end. In fact, NACA and Bell and the USAAC tested P-39 models both in wind tunnels and in 86 test flights and were never able to get them to tumble. Then, in the 1970's in an attempt to see the real truth, an informal study of the spinning characteristics of the P-39 was done. It might never have been done except they found the original spin test model in storage and decided to test it.

When balanced at full ammunition load, it spun normally and would not tumble. When balanced at a no-ammunition load, it tumbled rather often and easily while spinning.

Just goes to show that if testing is not done at the CG envelope extremes, then you really don't KNOW what a palne will do at the extremes of the envelope when pushed hard.

Having spoken with several people associated with WWII aircraft development and procurement over the years, including Ben Kelsey (he visited Purdue University when I was in the aeronautical engineering department and we had a round table with him, our professor, and 20 students), I have concluded that had both the P-38 and P-39 been equipped with turbos, one or the other would have been directed to stop using them. Bell was a small-time outfit compared with Lockheed, and I have great difficulty believing the P-38 would have been the one so ordered. In fact, Kelsey said they could never get the turbos back even when the combat operformance of the P-39 shouted out the need for them. The War Production Board just said no.

Kelsey liked the P-39, but he also liked the P-38. I don't know which one would have been ultimately better, but I suspect that, if for no other reason, the range would have dictated staying with the P-38. According to Ben and to Pete Law (Skunk Works), the turbos were considered difficult items to make enough of, and were rather jealously apportioned out when they were in "short" supply. Remember, a B-17 or B-24 took four each, so a couple hundred turbos would only produce 50 bombers. That made then even MORE hard to get.

The P-38 was a case of throwing all the eggs in one basket, so to speak. It did not turn out badly as the P-38 was the mount of our top two aces for the entire war.

Now, I suppose it is possible I have concluded incorrectly. I feel that a LOT of modern looks at the past come to very incorrect conclusions becauise modern people have no comcept of the attitudes and feelings of the people in charge at the time. Modern young people look at the world in a wholely different way than some who grew up and was about 18 - 25 years old when war broke out does. Some things that modern people feel should have been done would NEVER have even been considered and the person(s) proposing them would have been ejected from the neetings.

I choose to believe Ben Kelsey and Pete Law and the guys who were around and who grew up at the time and who KNOW why things were done the way they were done. Logic has nothing to do with some decisions that were made. They were made for very specific reasons that were never laid down in meeting minutes.

I have debated the P-63 in here before and do not propose to replicate that in here. Suffice to say I think it could have been a real asset anywhere it was deployed. If you think otherwise, you are free to do so without comment from me. We all know what happened in the end, and what-ifs are unwinnable by either side of an argument.

How does the P-47 with it's turbo fit in here?

 

[wuzak]

A tidbit on the proposed XP-40H, from Vee's for victory, pg. 184:
The Curtiss P-40H was to have been an Allison powered and turbosupercharged version of the P-40E. At conference at Wright Field on June 10, 1941 Mr. Don Berlin of Curtiss received authority to begin such a project and the Material Division immediately shipped one GE Type B-2 turbosupercharger to Curtiss at Buffalo, New York. By that October the decision has been made to not turbosupercharge the P-40, but instead incorporate the feature into the coming Curtiss P-60. The turbo was to be installed behind pilot in the XP-60.

The excerpt is sourced.
So the Curtiss almost got to build the turbo P-40. But not in March 1938 (when Curtiss submitted the P-36 derivative featuring the V-1710 engine), but more than 3 years after that.

Thanks for that Tomo.

I forgot (or didn't know) about that specific proposed variant.

It doesn't change the fact that the P-40 was not intended to use a turbo from the start.

 

[tomo pauk]

It doesn't change the fact that the P-40 was not intended to use a turbo from the start.

Indeed - 3 years of difference between XP-40 and XP-40H proposals.

 

[GregP]

Hi guuys,

The P-47 and P-38 were the high altitude fighters we produced with turbochargers. As it turned out, the P-47 was excellent at high altitude and better than most at low altitude, but was at a disadvantage at mid-altitudes. The P-51's was made into a winner almost be accident. It slipped under the radar because it was designed to a British request. When the Brits got some allison-powered units, they decided they were rather good ... at elast better than other American fighters, but lacked an altitue capability. The Brits then proceeded with the Mustang X while the foks at North American proceeded with the P-51B/C. Either one could have been a winner.

Had the P-51 had to go through the War Production Board's review, I do not pretend to know if it would have made it or not, but we know it survived and thrived. Many decisions weree made to give much-needed work to specific areas of the country. There were aircraft plants on the east coast, midwest, and west coast, and they ALL got some work in the end, even Brewster ... who arguably shouldn't have.

And gjs, we could have used more P-51's instead of P-63's. In the end, that's exactly what we got. It worked out fine. I like the P-63, but would not change hsitory just to have some built for the U.S.A. ... it was an almost-made-it that didn't make it in US service. But it DID get produced for Lend-Lease to the Soviet Union, so at least SOME got into the fray somehow. According the Soviets, they acquitted themselves well and were liked by their pilots. I suspect one of the features they liked best was a good cockpit heater! ... and maybe a few creature comforts not usually seen on Soviet fighters.

Ah well, at least there are a few flyable planes about, and we have one locally at Palm Springs that flies in our airshow every year.

Tomo, I won't try to convince you of anything in US WWII politics. Since it is decades old news, it doesn't much matter anyway. Heck, the Falklands conflict is old news. WWII is interesting only because it interests ME. I don't see many young people out there helping to restore the old planes ... it is mostly guys 55 and older. When we're gone, I doubt seriously if many of the flying WWII planes today will continue to fly all that much longer as the skills needed to sustain them die off with us and the ability to fabricate spare parts goes away, too.

 

[gjs238]

I don't see many young people out there helping to restore the old planes ... it is mostly guys 55 and older. When we're gone, I doubt seriously if many of the flying WWII planes today will continue to fly all that much longer as the skills needed to sustain them die off with us and the ability to fabricate spare parts goes away, too.

The youngsters will just 3D print everything

 

[GregP]

I hope that turns out to be TRUE!

 

[kool kitty89]

P-63 still had miserable fuel capacity. 126-128US gallons internal.

This really is an odd issue and more puzzling since most of the range figures on internal fuel seem relatively high for such a limited fuel capacity. (more so given the range is signigicantly longer than the P-39 in spite of being larger and heavier ... and limited range/fuel capacity was one of the biggest shortcomings of the P-39, so failing to address that seems particularly strange)

But beyond that, the P-63 had larger area wings and a thicker airfoil than the P-51, yet carried less fuel AND was unable to mount guns inside the wings? The radiators took up some of the space and wheel placement may not have been as efficient as the P-51, but that still seems really limited. (more so since the P-39 itself carried nearly as much fuel in its wing cells)

Dropping to a .50 through the prop and the P-39/P-63 loose their reason for being. A 5 machine gun fighter brings what to the table vs the existing 4 and 6 gun fighters?

Centerline armament (and considerably higher RoF than the synchronized guns), same as the P-38s that were field modified to 5 .50s. (still a 20 mm would make the most sense so long as it had an in-flight cocking mechanism to clear stoppages like the P-38 -given the problems with the US Hispanos )

And regardless, for pilots that found the 37 mm gun more or less useless in fighter vs fighter combat, an added .50 would have still been better. (a conversion like that on the P-39 would have been more problematic given the CoG issues there with the stall/spin made much worse as the nose was lightened ... unless ballast was fitted)

From your earlier post, the XP-37 DID have troubles and so did the XP-39, but finding solutions to the turbo problem was in sight. Had to be since it WAS successful in the P-38 ... eventually, and also in the P-47 from the start. Had the turbo been allowed to be developed on the P-39 as it was for the P-38, they could have worked out an installation. It would have added weight, but would have also given better high altitude performance.

The poor cockpit placement on the XP-37 also would have had to been dealt with. (maybe possible to move the turbo to the rear like the P-60/P-47/P-43, but managing that while keeping fuel tankage decent seems like it may have been a mess)

And on that note, the P-43 should be on the list of USAAF fighters allowed to have turbos. (on top of numerous prototype projects, including Grumman's XP-50)

You can make a lot of the same claims for the Edsel automobile ... wrong thing at the wrong time. It could be said of the P-63, too. It looked like a P-39 and there was automatic predisposal to cancel it despite the flight performance. If you improve things, change their looks if the original was a flop.

The P-39 being that looked-down upon still confuses me somewhat. Aside from the unpleasant stall/spin characteristics, the P-39 seemed to be in a similar class as the early (single stage) Spitfire or 109 and significantly better performing than the P-40, let alone Hurricane. (shorter range than the P-40 but longer than the Spit or 109 -aside from the stripped-down P-39N with reduced internal fuel)

For that matter, it had better overall low/mid alt performance than the contemporary early model P-38 or P-47 (especially with over-boosting taken into account), albeit limited range was even more dramatically obvious there, though (still not as bad as the 109/Spit/Hurricane -or most Soviet fighters).

It should have made a better fighter-bomber than the spit/109, though weaker than the P-40 in that role. (or A-36 ... hurrcane had shorter range but larger wings to cope with varied bomb/rocket loads, same for the Typhoon)

Then again, the P-51 WAS in quantity production and so was the P-47, both successes if ever there were any for the USA. The F8F had NO chance as a USAAF plane so, despite the potential, it was only looked at by the Navy. The F6F was a great fighter by ANY standards, but was not as good as the P-63 and was ALSO never looked at by the USAAF. The P-63 was a case of too little, too late ... just like the German late-war aircraft (and OTHER weapons) were.

The F4U would have been most interesting to the USAAF of anything USN/USMC specific. (let alone with it having more trouble fitting as a carrier capable fighter)

But on the P-63, with the Mustang already in the picture, it was the all-around better aircraft for nearly any purpose. (P-63 might have had an edge in bomber interception with that 37 mm ... but the US really didn't need a plane in that role at the time) If it came down to engine vs airframe allocation, puting those 2-stage Allisons into P-51s would almost certainly have been the wiser move.

 

[GregP]

The P-43 was a stop-gap at BEST and was a very small production run that was tried to see how the systems would perform in the real field.

The USAAC considered the P-43 and its variants obsolete from the start and used them only for training purposes. In fall 1942, all surviving USAAF (transitioned from USAAC in June 1941) P-43s were redesignated RP-43 indicating they were unfit for combat. Most of the aircraft that were not sent to China were modified for photo-reconnaissance duties and used for training. Eight P-43s were loaned to the Royal Australian Air Force in 1942 and served with No. 1 Photo Reconnaissance Unit, based at Coomlie, Northern Territory. The RAAF flew many long range, high-altitude photo reconnaissance missions before the six survivors were returned to the USAAF in 1943.

With only 272 built, the P-43 was a sort of non-event ... we made 10 - 15 thousand front line fighters and the 272 P-43 were not first-line aircraft when they rolled off the lines.

 

[tomo pauk]

The reason why the P-63 have had more range than P-39 was the ability to carry 3 drop tanks, rather than just one on P-39. Great for ferrying, not so much for combat on long ranges, where the internal fuel capacity is a major factor. The P-63 did not carried any fuel in front of the main spar, there was enough space to almost double up the internal fuel capacity.
As for armament, I'd propose deleting gun pods, while chaning the 37mm for belt-fed 20mm. Should give more chances vs. fighters, while giving some speed due to lack of gun pods.

 

[kool kitty89]

The reason why the P-63 have had more range than P-39 was the ability to carry 3 drop tanks, rather than just one on P-39. Great for ferrying, not so much for combat on long ranges, where the internal fuel capacity is a major factor.

I was actually speaking more for the normal/clean ranges being compared, but I suppose I might also be seeing apples and oranges figures (ie good/ideal cruising for the P-63 vs more average/faster/low alt cruising for P-39). I knoe the ferry range figures are MUCH longer for the P-63, but I'm thinking more in terms of 600-700 miles vs 950 miles. Though on second look, that 950 mile figure is specifically for the P-63D. Not sure if that model had expanded internal tankage compared to others.

That and the figures I'm seeing for the P-39 are mostly for mid-speed cruise, nothing minimal/long range optimized, granted, few things actually point out range using optimimal/minimal cruise. (some tactical planning charts do, but I've only seen those for a handful of aircraft) This is somewhat significant given the V-1710 had particularly good qualities for low RPM very lean cruising.

The P-63 did not carried any fuel in front of the main spar, there was enough space to almost double up the internal fuel capacity. [.quote]
Interesting so, had the requirement been pressed to Bell for extending long-range capability, the existing airframe should have been fairly straighforward to adapt for this purpose? (given the Russian operations, the limited fuel capacity wouldn't have been much of a concern)

As for armament, I'd propose deleting gun pods, while chaning the 37mm for belt-fed 20mm. Should give more chances vs. fighters, while giving some speed due to lack of gun pods.

Agree. My comments on the .50 were mostly as an interim/stop-gap option for cases where the 37 mm was unattractive and 20 mm was not functioning properly. (without the ability to re-**** M2 Hispano cannons, they were generally too unreliable to service -the Navy got away with that by using excessive amounts of librication wax and grease on the amunition ... not fool proof, but enough to alleviate some of the issues with chamber size and firing pin position -most stoppages were due to lightly struck primers)




Come to think of it, with the heavy cannon and machine guns and boost limits raised, the P-39D-L should have made pretty good low-altitude interceptors along the lines of the Spitfire L.F. Mk.Vb or even better if they pushed the boost as high as common overboosting on the P-40. (much higher power output than the Merlin 50)
The P-39N was more along the lines of the standard Spit Mk.Vb, the M would be slightly worse there. (the tropicalized versions would have given a bigger performance advantages to the P-39 though ... )

Should have been good for the MTO ... and some PTO operations. I know it DID see some successes in those theaters, but it seems to get much more of a negative reputation than the P-40 for some reason. (if the P-40 was much more often tweaked to raise boost limits on the engine, that alone would have been a huge difference)

The single-stage V-1710 did compare rather favorably with the Merlin 45/50 series on the whole.

 

[tomo pauk]

I was actually speaking more for the normal/clean ranges being compared, but I suppose I might also be seeing apples and oranges figures (ie good/ideal cruising for the P-63 vs more average/faster/low alt cruising for P-39). I knoe the ferry range figures are MUCH longer for the P-63, but I'm thinking more in terms of 600-700 miles vs 950 miles. Though on second look, that 950 mile figure is specifically for the P-63D. Not sure if that model had expanded internal tankage compared to others.

The one-off P-63D was indeed provided by increased fuel tankage vs. the rest of P-63 line, even vs. P-63E that would be coming after it. 'America's hundred thousand' states 168 gals of fuel, vs. 126-128 for -A, -C and -D.
A curiosity on the P-63 was that a 64 US gal tank (self-sealing, slipper flush fitting), was a posibility on belly rack; ie. an extra fuel that was to be carried in combat. Not sure how big was the performance penalty, though. During e war the P-47 was also tested with a similar tank of 75 gals.

Interesting so, had the requirement been pressed to Bell for extending long-range capability, the existing airframe should have been fairly straighforward to adapt for this purpose? (given the Russian operations, the limited fuel capacity wouldn't have been much of a concern)

My understanding is that P-63 was envisioned as an aircraft that would be able to outclimb the Fw-190 and Zero, or at least there is a line in the 'Vee's' about that. Small (for non-European measuring sticks) fuel tankage should contribute to that, the P-63 was a good climber. However in late 1943, when the P-63 entered production, the long range was a requirement for the USAF fighters, not the great RoC. For Bell to install greater fuel tanks would mean further delays to the production, since it would mean different ribs.
The Soviets needed range. They went ahead with Yak-9D and -9DD, that provided increase in fuel tankage, at the cost of performance. The appeal of foreign fighters, among other features, was that they were able to mount drop tanks, a feature seldom seen on Soviet-made fighters.

Agree. My comments on the .50 were mostly as an interim/stop-gap option for cases where the 37 mm was unattractive and 20 mm was not functioning properly. (without the ability to re-**** M2 Hispano cannons, they were generally too unreliable to service -the Navy got away with that by using excessive amounts of librication wax and grease on the amunition ... not fool proof, but enough to alleviate some of the issues with chamber size and firing pin position -most stoppages were due to lightly struck primers)

The Hispano worked okay aboard the P-38 - rigid fuselage mount benefits a bit? The ability to re-c0ck the Hispano would be a safety feture, of course.

The single-stage V-1710 did compare rather favorably with the Merlin 45/50 series on the whole.

I will politely disagree with that. At 20000 ft, the better V-1710 (ie. 9.60:1 S/C gear) it with give around 950 HP, vs. ~1130HP of Merlin 45. It will enter production some 15-18 months later than Merlin 45. It will compare favorably under 10000 ft, though, not a great thing in a fighter aircraft.
What the V-1710 will have against early Merlin 45 might be the better carb (pressure injection vs. float-type) and use of 6-per-side exhaust stacks rather than 3-per-side; those are engine add-ons, though. The Merlins also received better carbs not long after the 9.60:1 V-1710s were introduced.