Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained) (3 Viewers)

GregP said:

Of course he did. It was likely his first high-performance fighter aircraft out of training. It was WAY more fun than an AT-6.

But, then again, he hadn't flown many other fighters yet.

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There was a lady who flew a P-39 at air shows in the late 40's. I remember Chuck talked her into letting him taking the P-39 up for the air show instead of her. He supposedly wrung the airplane out in front of the crowd without them knowing who was flying.

GregP said:

Of course he did. It was likely his first high-performance fighter aircraft out of training. It was WAY more fun than an AT-6.

But, then again, he hadn't flown many other fighters yet.

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Didn't he write that preference later, in one of his books?

warbird51 said:

Look at the climb improvement the P-47 had when going to the paddle blade propeller. A better propeller would have helped the P-39's also.

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The Ns and Qs got a bigger propeller. They changed the gear ratio in the reduction gear and put 11ft 7in props on them.

These helped but what really helped was running the engines at 57in boost (about 13.5lbs boost) in the lower part of the climb.

Which meant the P-39Q could climb with or stay close to the Spitfire V with it's little 3 blade prop using lots of boost and ballasted to simulate a plane carrying four 20mm cannon.
Basically the P-39Q was year too late.

warbird51 said:

There was a lady who flew a P-39 at air shows in the late 40's. I remember Chuck talked her into letting him taking the P-39 up for the air show instead of her. He supposedly wrung the airplane out in front of the crowd without them knowing who was flying.

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That was in the USSR as I recall. Perhaps I misremember.

I've read at least one book by Chuck Yeager, maybe two.
In one of those books or a U-Tube video, he stated he would take on anybody with a P-39, BELOW 5000 feet.
That last part is usually ignored by P-39 fanboys.

GregP said:

That was in the USSR as I recall. Perhaps I misremember.

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Nope, it was here in the US. Off the top of my head, it was Betty Skelton who owned and flew the P-39. I think is was called JUBA and I saw it at Silver Hill in the 2000's

MiTasol said:

From the -1 for the model - K had more internal fuel than the Spit and Q had less.

P-39K
View attachment 761776

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Normal fuel was about the same as a Spitfire V.

104 USG = 86.6 Imp G.

Spitfire V had 85 Imp G.


In Expert discussions it was asserted that most P-39s had 120 USG, which is ~100 Imp G.

That chart lists 16 gallons as overload.

Was this carried in the same fuel tank, and it was normal just to fill up with 104 USG, or was there a separate overload tank?

drgondog said:

A 1940 P-39, Hurricane and Spitfire were not far apart

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P-39 had Spitfire performance at lower altitudes and Hurricane performance at higher altitudes?

Thumpalumpacus said:

Didn't he write that preference later, in one of his books?

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Yes, but - the 357th was tasked with TAC resposibility when they trained in P-39. Yeager liked flying the P-39 very much, but in no way was implying that he would favor the P-39 over the P-51B/D when the fight took him over 15000 feet.

A P-51B/D driver would have his hands full vs a P-40 and P-39 on the deck if he chose to fight in the horizontal.

His two favorite airplanes were P-51B/D and F-86.

wuzak said:

That chart lists 16 gallons as overload.

Was this carried in the same fuel tank, and it was normal just to fill up with 104 USG, or was there a separate overload tank?

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It was carried in the same tank/s.
My own opinion is that there is confusion in the manuals.
The P-40s are often listed as holding 120 gallons for gross weight. Anything over 120 gallons is listed as overload. P-40s could hold (at least most of them) around 140+ gallons. They just didn't fill the tanks.
The P-39, P-40, P-47 and P-51 (and others) use two fuel taps in one of the tanks, much like motorcycles. In "normal" you can't use all the fuel. You have to switch to "reserve" to use the last XX number of gallons depending on plane.
From the manuals I have read (and I could be wrong) it seems that the P-39s "reserve" was 16 gallons. Coincidence or confusion? The reserve was in the left hand tank.
P-40s used (mostly) the forward tank as the reserve. P-40s (not Fs or Ls or 2 tank versions) took off using the forward tank and the rotated through the other tanks until, if needed, going back to the forward tank if running low and needing the reserve to get home/land. P-51s and P-39s just used the 2nd fuel tap in the left tank. P-47s used two taps in the main tank.

Most of the time the reserve "capacity" does not match the difference between normal fuel for "normal" Gross weight.
A P-39 with the small tanks (87 gallons) may still have the 16 gallons of reserve but that comes out of the 87 gallon tanks, not an addition to it. They took out 3 fuel cells on each side.

I could be wrong, it just seems strange that on the P-39 the "overload" matches the "reserve" capacity.

warbird51 said:

Nope, it was here in the US. Off the top of my head, it was Betty Skelton who owned and flew the P-39. I think is was called JUBA and I saw it at Silver Hill in the 2000's

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Here's the excerpt from Yeager' book about the incident of flying the P-39 mentioned above

Removing all technical issues from the discussion, much discussion about the P-39 involves the P-39N and P-39Q. What happened to the rest of the freakin alphabet while the war was going on? It first flew in April1938 which makes it after the Spitfire and Hurricane Mk Is but is before the P-40 and everything else. As a sorted aircraft it was a contemporary of planes like the P-47, Spitfire Mk IX and Mustang Mk I Typhoon etc which were all either in service and proven or offered much more potential.

A bit of nit picking here.

pbehn said:

What happened to the rest of the freakin alphabet while the war was going on?

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What happened was that the US was using complete letters for minor changes. Like the difference between a P-39K and a P-39L was the prop.
You could put 5-7 letters on on the Spitfire MK V here.
MK VA Merlin 45 with DH Prop
MK VB Merlin 45 with Rotol Prop
MK VC Merlin 46 with DH Prop
MK VD Merlin 46 with Rotol Prop
MK VE Merlin 45 cropped impeller with DH Prop
MK VF Merlin 45 cropped impeller with Rotol Prop
Etc, etc.
It took a while for the US to smarten up and use dash numbers.
In the P-39 many of the "missing" letters were for one-off experiments.

pbehn said:

but is before the P-40 and everything else

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Not quite, any refrences to the P-39 flying in 1938 are false, it did not fly until April 1939, about 6 months after the P-40 and since the XP-40 was the 10th P-36 airframe pulled off the production line and given a new engine the rest of the airplane was pretty well sorted out. The P-40 was low risk, quick build option.

pbehn said:

As a sorted aircraft it was a contemporary of planes like the P-47,

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Depends what is meant by "sorted" Britain was getting P-39s delivered to England in the fall of 1941, granted they needed sorting out
XP-47 flew in April 1941 the 2nd one showed up in March 1942.
By April 1941 Bell had built 21 P-39s, Curtiss had built almost 1400 P-40s
By end of Feb 1942 Bell had built 1331 P-39s and Curtiss had built over 3600 P-40s total.
End of Dec 1942 saw 533 P-47 since the start. 2871 P-39s since start and 6883 P-40s since start of production.
The P-39 was NOT a contemporary of the P-47.