OT: Piece of Junk? Why the P-39 Was So Hated

[RangerJoe]

A nice video with comparisons with the P-40D and the A6M2/3. Included is a little from the Soviets use.

https://www.youtube.com/watch?v=db0pBdBzhXc

[Ian R]

1 -It was a novel design with the engine in the middle, and tricycle landing gear. People often don't like new things.
2-The power plant was no good above a few thousand feet. Even with the turbo charger. As the aircraft was built to meet a 1937 specification (X-609) for a high altitude interceptor, this was should have been fatal to series production.
3- I have seen it alleged that Bell only received such large procurement contracts as a result of buying political patronage, and this was resented by the AAF.


The Soviets used them at low altitudes. They were quite good down low with or without the turbocharger, and air/air combat on that front was generally at lower levels. As a result about 50% of production was shipped to the USSR as lend lease.

[Denniss]

No Turbo on P-39 despite initial planning for it, just supercharger good for performance up to 15k feet.
Soviets loved them but they also lightened them for better performance

[fcooke]

It is interesting how different Air Forces got very different service from airframes thought to be inferior in the West. The Finns use of Buffaloes also comes to mind. And you have to wonder what the P-39 could have been with a proper supercharger set-up.

[Ian R]

ORIGINAL: Denniss

No Turbo on P-39 despite initial planning for it, just supercharger good for performance up to 15k feet.
Soviets loved them but they also lightened them for better performance

Including deleting the wing mounted 30 cals to improve the roll rate.

[Rusty1961]

ORIGINAL: Ian R


3- I have seen it alleged that Bell only received such large procurement contracts as a result of buying political patronage, and this was resented by the AAF.

The more things change....

[bomccarthy]

ORIGINAL: fcooke

And you have to wonder what the P-39 could have been with a proper supercharger set-up.

No need to wonder - it was called the P-63, which first flew in December 1942. The auxiliary stage supercharger was driven through a fluid coupling, somewhat similar to the arrangement in the DB600 series used in the BF-109. However, by the time it was ready for operational service, the P-47 and P-51B had already proved faster at altitude. Worse, it's internal fuel capacity was only 6 gallons greater than that of the P-39.

This was the main shortcoming of a mid-engine fighter in the 1940s - fuel tanks need to be near the center of lift (within 1/4 of the mean aerodynamic chord), otherwise the center of gravity shifts beyond this midpoint as fuel is consumed and instability in handling results. With the engine occupying the center space in the fuselage, the only midpoint space left is the wing root, which is where the fuel tanks were located in both the P-39 and P-63.

Pilots strongly criticized the unstable handling of the P-39 in combat ("Don't give me a P-39 / It will tumble and spin and soon auger in / Don't give me a P-39"). Testing showed that as the cannon ammo stored in the nose was expended, the c.g. shifted reward, beyond 1/4 of the mean aerodynamic chord, causing the plane to become unstable in maneuvers.

Incidentally, the turbocharger installation was never really tested in the P-39 prototype, so it is unclear that it would have worked as intended. Given the critical aspects of turbo plumbing layout (the P-47's turbo plumbing was designed first for optimal placement and flow, and the fuselage was then designed around it), it seems unlikely that P-39's small airframe would have been a good fit for a turbo installation.

[Sardaukar]

Did P-400 fare any better? I'd think 20mm cannon would have been more sensible for the plane than 37mm.

[Sardaukar]

*double tap*

[Chickenboy]

ORIGINAL: Sardaukar

Did P-400 fare any better? I'd think 20mm cannon would have been more sensible for the plane than 37mm.

No. The P-400 was even worse. Good reason for the flyboys to say that the plane was a P-40 with a "Zero" on its tail.

[PaxMondo]

I found the video to be a pretty fair assessment. Was the P39 suited for the SE theatre? Nope. Nor was the P40, in fact the the P39 was the better performer except in the 12,000-18,000 environment which would take the P40 days to get to with its abysmal climb rate. So why did the P40 have the better rep? Simple. Chennault. He had devised better tactics for the P40 to use against the IJA. The P40 had a pretty good rep because of it. But the P39 got thrown into the fray at Port Moresby, replacing a completely eliminated AUS unit flying P40's (I believe my memory is accurate here) against a crack A6M2 unit. So average USAAF flyers with an average plane using WWI doctrine (USAAF wouldn't really listen to Chennault despite his success) against a crack unit at altitudes that were unfavorable ... Here's the real catch .. .if the units had been equipped with P40's, the result would have been the same BUT maybe someone would have started listening to Chennault 6 months earlier ... someone might have said: "how the heck are the P40's doing so well in China and sucking so bad in the DEI?"

The truth is the in early '42, the US and its allies didn't have a competitive plane against the A6M2 at 15,000. Worse, they were using WWI tactics. Updated ones could have gotten them from the Brits, but just like Chennault, they weren't going to ask were they?.

Anyway, the P39 was the best fighter that the US had in early 42 which isn't saying much. It's major issue was that the pilot height was limited ... 5'8" I believe. Other than that, better than the P40 in almost all aspects. Far better than the F4F which was more than 10% slower ... yeah, the cupboards were pretty bare until the F4U/P51/P47/P38 started to show up. The Spitfires were better than any of these except in range (brutally short, but fine for point defense), but production was not able to meet local UK defense needs yet, let alone be sent to the Pacific.

[RangerJoe]

That Australian P-40 unit was mentioned in the video. They fought with the A6M2 until both had to withdraw, replenish, and rest.

The 37mm could have used a larger ammo belt as was used on the P-63 which would have improved things. Think if a modern 25mm chain gun was installed. [X(]

[CaptBeefheart]

The P-400 had a French oxygen system, which USAAF had no way of connecting to, so they were limited to 12,000 feet. That was a bit of a problem. There's a book on the Cactus Air Force I just read and the P-39 and P-400 were truly best used for ground support at Guadalcanal. F4Fs handled most of the air defense duties there.

Cheers,
CB