Improve That Design: How Aircraft Could Have Been Made Better

[P-39 Expert]

I make a motion we improve the forum by avioding the P-39 until such time as real-world use and results come into play.

If you look at aerial victories by type and theater, the legacy of the P-39 becomes apparent. First, let's remove the essentially non-participating fighters like the P-26, P-35, P-36, P-43, P-70, F2A, Beaufighter (lend-lease), TBF/TBM, P-61, and the SBD. That leaves the P-38, P-39, P-40, P-47, and P-51 (including F-6 and A-36), F4F/FM-2, F6F, and F4U, and Spitfire (only the MTO) which is most of our fighters.

If we just look at the Pacific, the Spitfire wasn't used by the U.S.A. and it drops out. The Lowest total victories is 288 by the P-39/P-400. Next would be 297 by the P-51 since it got to the Pacific essentially at the end of the war. The FM-2 is next at 422, followed by the P-40 with 661. It continues going up from there.

If we get out of the Pacific only and look at the entire war, the lowest victory tally is 321 by the P-39 / P-400, followed by the Spitfire in the MTO/ETO with 379, and it goes up from there.

The Mosquito, P-26, P-35, P-36, P-43, P-70, F2A, and Beaufighter only scored 58 victories combined, so they don't really count as major fighters in service with the U.S.A. . The TBF/TBM outscored them all combined with 98 victories, but isn't a fighter.

So, we have had 100+ pages and all this "it could have been a great airplane" about the fighter with the lowest score of any major fighter in service with the U.S.A. . The P-51, in all theaters, scored 5,954 victories, followed by the F6F with 5,168. Why we are so concerned with the fighter with the least victories in WWII in U.S. service? It was NOT a good airplane for anything other than short-range, low-altitude missions. We didn't fly many of those except to keep the P-39 drivers current in their airplanes.

P-39 shot down more planes than any other American fighter in Russian service. That was its main combat deployment.

 

[pbehn]

Two things that always puzzle and amuse me about these discussions is that combat lasts 15 minutes, does someone ring a bell and say "time to go home" and that it ends where it starts. 360 MPH is 6 miles per minute , on average pilots may end where they start after 15 minutes but they may be anywhere in a 90 mile radius, that is 90 miles closer to base or 90 miles further away. The Fw 190 that landed in south Wales did so because its pilot didn't have a clue where he was and didn't trust his instruments to tell him. Many accounts I have read say the pilots start to figure out where they were when its over, though they may have some awareness while in combat.

 

[Shortround6]

All AAF fighters had multiple internal tanks and carried external tanks. Procedure was the same on all of them.

Yep and none of them used the procedure you outlined.

 

[Admiral Beez]

Two things that always puzzle and amuse me about these discussions is that combat lasts 15 minutes, does someone ring a bell and say "time to go home" and that it ends where it starts. 360 MPH is 6 miles per minute , on average pilots may end where they start after 15 minutes but they may be anywhere in a 90 mile radius, that is 90 miles closer to base or 90 miles further away. The Fw 190 that landed in south Wales did so because its pilot didn't have a clue where he was and didn't trust his instruments to tell him. Many accounts I have read say the pilots start to figure out where they were when its over, though they may have some awareness while in combat.

I assumed combat ends when one side of the combatants are dead, disabled, out of fuel or out of ammunition.

 

[Shortround6]

P-39 was the second most aerodynamic behind the P-51. Seems
logical it would be the second fastest. BTW why include the P-63?
It had a two stage engine.

The P-51 had the least drag, the P-39M & N next, followed by the P-39Q, the P-63 has a smaller flat plate than the P-40 despite being the largest plane of the group.

As for the P-63, please compare to the P-39N. The P-63 climbs better by 50fpm at 15,000ft. 1.4% better. 30fpm better at 20,000ft 1.3% and 80fpm better at 25,000ft or 4%.
Strange coincidence.

P-39 was the lightest of this group, logical that it had the best climb.

Logic climbed out the window on this one and it was on the 20th floor.

P-39 was 98.7% as heavy as the P-39M and yet this just over 2% decrease in weight is supposed to be responsible for a 26.5% increase in climb at 15,000ft, 31.5% increase in climb at 20,000ft and a whopping 38.6% increase in climb at 25,000ft.
If you believe that I have vacation land for sale in Florida, usable 1/2 the year (every 12 hours)

The change in reduction gear and different prop might be worth something but the poor P-39Q-5 was faster climbing on the same power (or very slight changes) while being over 400lbs heavier than the P-39M. But compared to the N????? N is only 92.4 percent as heavy but the increase in climb is for the N is 17.6%, at 15,000, 19.5% at 20,000, 23.5% at 25,000 a lot of improvement for a 7.6% change in weight.

The P-40, P-39M and P-51A actually track pretty well. small differences in climb with small differences in power and weight.

Climb is pretty much dependent on power to weight after you subtract out the power needed to fly at the best climbing speed (usually a bit faster than the lowest drag speed.)
The P-40 climb speeds were the slowest of the group by about 10-20mph depending on altitude. The P-39N was actually flying a couple mph faster than the P-51A, strangely the P-39M and P-39Q, despite being a bit heavier flew just a bit slower than the P-39N.

. So, we have another bad test? Those Wright Field test pilots could test every plane in the AAF inventory, but somehow all their P-39 tests were wrong?

There are a number of typos, moved rows/columns and mislabeled headings in some of the tests and pilots manuals and data sheets. I have no idea why the P-39N numbers are so far off but something doesn't seem right.
BTW check out the manual for the P-39Q, max cruise is labeled IAS for the clean aircraft while the chart with drop tank says true airspeed in the max cruise column.
Not a biggy but the clean airplane is supposed to do 330mph IAS at 25,000ft.
cruise at 2600rpm is 495mph true?????
Sometimes the error is easy to spot, sometimes it is not.
In this case a number of other charts for other airplanes give the max cruise in true airspeed and all the other columns are IAS so it was really easy to pick up on.

 

[Shortround6]

I assumed combat ends when one side of the combatants are dead, disabled, out of fuel or out of ammunition.

This assumes the pilot/s who are at the disadvantage have enough speed, or climb, or altitude or distance between them and their opponents to disengage without winding up first in your list.

Pilots did push their planes past the artificial time limits, there was no clockwork mechanism (except on some 109s) that would automatically reduced power.
However pushing the plane/engine increases the likelihood of the engine breaking down at worst and used up the fuel needed to get home at best.

 

[GregP]

It didn't HAVE that climb rate uless they ran extra MAP. Use the POH climb rates for U.S. sevice airplanes abd service MAP levels. It sure isn't even 3,000 fpm in climb, especially at 44" MAP, and P-39s typically took off at about 8,000 lbs, not 7,500 lbs.

The statement was made that the P-39 shot down more enemy aircraft than any other American fighter in Soviet service. So, how many did it shoot down and what is the source for that statement. I have certainly seen the statement in print, have repeated it myself, but have also seen no victory figures with sources to back it up. So, its basically an unsupported statement.

Enough round words of greatness, what are the figures? I hope they imclude sorties, too. including action and non-action sorties.

 

[GrauGeist]

And there was only one USAAF pilot who made ace while flying a P-39.

One...

 

[pbehn]

I assumed combat ends when one side of the combatants are dead, disabled, out of fuel or out of ammunition.

Only if you have a plane good enough to break off, that was the issue with a Spitfire MkV against the Fw 190. There is the other scenario, when you are relieved as an escort it is then your choice how much fuel and ammunition you use on targets of opportunity.

 

[Juha3]

...The statement was made that the P-39 shot down more enemy aircraft than any other American fighter in Soviet service. So, how many did it shoot down and what is the source for that statement. I have certainly seen the statement in print, have repeated it myself, but have also seen no victory figures with sources to back it up. So, its basically an unsupported statement.

Enough round words of greatness, what are the figures? I hope they imclude sorties, too. including action and non-action sorties.

I guess nobody knows, same goes to any widely used fighter, claims, even accepted claims are not the same as the real figures. But
-Stalin asked more P-39s and Spitfires, not P-40s and Hurricanes
-Three of the five top Soviet aces (Grigori Rechkalov, Nikolai Gulaev and Dmitri Glinka) got most of their kills while flying P-39s and Rechkalov and D. Glinka ended the war in May 1945 still flying P-39s with Guards units operating inside Germany. Gulaev was badly wounded in Aug 44, while still flying P-39 with 129 GIAP
The two other aces being Kozhedub (1st) (La-5, -5FN, -7) and Yevstigneyev (4th) (La-5, -5FN). 6th was Vorozheikin, I-16 and Yaks, 7th Pokryshkin
Soviets did not have high regard on the few P-51s they got and did not understand P-47, to them it was far too big and heavy to be a good fighter, and there were not many of them to be used, they were used mainly as fighter bombers IIRC.

So there are clear indicators that P-39 clearly was the most successful US fighter in the VVS service.

 

[GregP]

Hi Juha3,

Yes, I agree. There are clear indications the P-39 did rather well in Soviet service. Just not numbers. It surely shot down more than U.S.-operated P-39's did, but there seems to be no real way to tell how many. So, that being the case, there is no real way to compare its perofrmance in Soviet hands with aircraft in U.S. service in an apples-to-apples manner.

So, any arguments are sort of based on opinions, not combat statistics. Personally, I LIKE the P-39. But 100+ pages of gushing about its virtues leaves me with a very sour opinion of the subject in general. If it was so good, why doesn't is show up in the war record? And ... we don't HAVE the Soviet war record for any of the aircraft they operated as far as I can tell.

Opinions can only really stand up for a post or two. Not 100+ pages, especially when using flight manual seems to make no dent in the performance claimed. Except for the WER tests, there is no other evidence the P-39 could climb so well in combat reports. They tested the P-40 at 75" MAP, too, but I do not claiming it generally flew at those numbers. If youa re going to take the highest numbers you can find and claim all of them were that good, the argument falls on its face all by itself.

 

[Milosh]

Lend-Lease aircraft supplied to the Red Air Force 1942-1944

US aircraft Total
Curtiss P-40 2,097
Bell P-39 Airacobra 4,746
Bell P-63 Kingcobra 2,400
P-47 Thunderbolt 195
B-25 Mitchell 862
Douglas A-20 Boston 2,908
US total 13,208

British aircraft Total
Curtiss Tomahawks, Kittyhawks 270
Hawker Hurricane 2,952
Spitfire Mk V 143
Spitfire Mk IX 1,188
Handley Page Hampden 46
Armstong Albemarle 14
British total 4,613
OVERALL 17,821

 

[GrauGeist]

The British gave the Soviet Union many of their Airacobras, too.

 

[SaparotRob]

The British gave the Soviet Union many of their Airacobras, too.

.. and happily.

 

[TheMadPenguin]

All the helicopter installations used cooling fans.

Umm... you DO KNOW that "cooling fan" is what keeps the helicopter airborne, yes?

 

[GrauGeist]

Umm... you DO KNOW that "cooling fan" is what keeps the helicopter airborne, yes?

Early Sikorsky's had their radial engines encased in the nose - plus on most helos, the prop-wash is minimal at the hub.

 

[TheMadPenguin]

Early Sikorsky's had their radial engines encased in the nose - plus on most helos, the prop-wash is minimal at the hub.

There you go, spoiling the joke...

 

[SaparotRob]

There you go, spoiling the joke...

I know, right?

 

[Admiral Beez]

The British gave the Soviet Union many of their Airacobras, too.

The Soviets can have them, but I'd preferred that the British had kept their Canadian-made Valentines and Hurricanes. Those two should have gone to North Africa and/or Malaya.

 

[pbehn]

The Soviets can have them, but I'd preferred that the British had kept their Canadian-made Valentines and Hurricanes. Those two should have gone to North Africa and/or Malaya.

At what time? In the early days of the war between Germany and Russia it was a conflict that the allies couldn't afford to lose.