XP-39 II - The Groundhog Day Thread

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A standard P-39 would climb with an A6M2 at military power (3000rpm). I was talking about a lighter P-39 without wing guns and nose armor in the 7200lb range which would outclimb an A6M2.
 
Here's a photo of the arrangement. Don't think the 37mm horsecollar magazine fits in there, but a 20mm belt feed might.
 

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A standard P-39 would climb with an A6M2 at military power (3000rpm). I was talking about a lighter P-39 without wing guns and nose armor in the 7200lb range which would outclimb an A6M2.
Which P39, even the dog D1? Even your hot rod custom P39, which may measure a steady state climb rate higher than Koga's (90%) Zero, isn't going to pop up from level cruise into its best climb fast enough to get out of range without being hit. Lighter weight, lower wing loading, and a better L/D are going to give a 100% Zero quicker initial response. Sure, the P39 may eventually pull away, if it's still intact, but Saburo will get in a good long burst before it does.
 
Are we already in gun range? Did we not detect each other visually before we are close enough to start shooting?
 
If the P-39 would climb with a Zero, it might not have been such a dud in the Pacific Theater. Early encounters with the zero certainly don't support that.

Actual war performance makes your statement a bit suspect, P-39 Expert. Granted we had novice pilots, but we had abysmal sucess early-on, and it didn't get a lot better until after we had some experience, and that was with other types of airplanes. The P-39's success never DID get good in US hands. It only had success in Soviet hands.

In U.S. service, for the entire war, the P-39 had 32 kills (14 air, 18 ground) against 107 combat losses in the ETO. I don't have numbers for other theaters. The Statistical Digest of WWII gives enemy ariplanes destroyed by fighters for all threaters, but does not show the model of airplane that achieved the victories. So, we know how many were destroyed by all fightrers, but not by the P-39 or any other model alone.

In any case, the P-39 was NOT a favorite combat airplane of anybody on the US military in any theater. It probably represented the highest-performance airplane that a new pilot in training ever flew the first time he flew one, but that didn't mean it remained his favorite when he went operational overseas.
 
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Biff, those teste were conducted at Wright Field by AAF staff whose only job was to test those planes under very strict testing standards and criteria. If some guys on a message board try to invalidate a test done 70 years ago then we have no basis for evaluating the differences in those planes. We must assume that the tests were conducted properly and the information is accurate. Otherwise, what's the point if we're making the rules up as we go along?
 
P-39 Expert, I am with you on respecting the tests as run at the time. But, in this case, we have one test that is markedly different from all the OTHER tests.

The basic differences between the P-39C and P-39D were armor, 2 more guns and ammunition (with an existing two relocated to the wings), and self-sealing tanks. The weight difference you keep harping on, "836 pounds," WILL NOT result in an extra 1,000 feet per minute climb difference. Period. A 12% reduction in weight does NOT give you a 37% increase in climb rate.

So, either the P-39C was operated at higher MAP than reported or the other P-39s were operated at lower power. There is no third option. If I'm going to say a test is recorded incorrectly, it makes a LOT more sense to me that ONE test (the P-39C) is misreported than all the rest of them (P-39D, et al) being incorrect. For all I know, the Allison in the P-39C test was "hot-rodded" by being ported and polished to give more power than normal. I DOUBT that, but there is SOMETHING wrong for sure. I hesitate to even question ONE test, but we have this wide discrepancy in climb rate that only shows up in the P-39C test.

Saying that 836 pounds accounts for it just isn't going to cut it because it doesn't account for it. The LEAST history-disturbing conclusion is that the P-39C test was run in some non-standard manner.
 

For that time period, absolutely, but it's quite evident, looking in hindsight, there's room to dispel some data based on what we now know about these aircraft and some of the methodology used to collect data.
 
In any case, the P-39 was NOT a favorite combat airplane of anybody on the US military in any theater.

Really good pilots loved the P-39 because it was very responsive, with a gearing between the stick and the control surfaces that meant that it required very small movements to get a lot of results. They did not love it because it was easy to fly but rather because it was hard.

Chuck Yeager loved it. "Winkle" Brown loved it. A friend of mine who had flown in WWII delivered an airplane to a museum back in the 90's and found they were distraught because they completed restoration of a P-39 but had no one checked out in it. He told them he was, took it up, and had a ball.

But that does not mean that they would want to fly it in combat.
 
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