P-39 vs P-40

[claidemore]

Like VG-33 said, read Golodnikovs interview. Not only is it informative about the P40 and P39, but gives some interesting insight into what performance criteria were actually most important for air combat.

Conversations with N.Golodnikov

Heres an excerpt pertaining to the P39:

A. S. Nikilay Gerasimovich, could the Cobra really contend with the Bf-109G and FW-190 in aerial combat?

N. G. Yes. The Cobra, especially the Q-5, took second place to no one, and even surpassed all the German fighters.

I flew more than 100 combat sorties in the Cobra, of these 30 in reconnaissance, and fought 17 air combats. The Cobra was not inferior in speed, in acceleration, nor in vertical or horizontal maneuverability. It was a very balanced fighter.

and one pertaining to the P40.

N. G. I say again, the P-40 significantly outclassed the Hurricane, and it was far and away above the I-16.

Personally speaking, the P-40 could contend on an equal footing with all the types of Messerschmitts, almost to the end of 1943. If you take into consideration all the tactical and technical characteristics of the P-40, then the Tomahawk was equal to the Bf-109F and the Kittyhawk was slightly better.

Its speed and vertical and horizontal maneuver were good. It was fully competitive with enemy aircraft.

As for acceleration, the P-40 was a bit heavy, but when one had adjusted to the engine, it was normal.

When the later types Bf-109G and FW-190 appeared, the P-40 Kittyhawk became somewhat dated, but not by much. An experienced pilot could fight an equal fight with it.

I flew somewhere around 50 combat sorties and participated in 10—12 aerial engagements in the P-40. Then the regiment became the next in line to replace its equipment—for the P-39 Airacobra.

Basically Golodnikov says the P40 was a good fighter, but the P39 was better.

 

[Colin1]

There seems to be a fair amount of evidence around that the P-39 was a far more respectable fighter than western allied pilots gave it credit for, within a low-level combat environment even its maximum speed was perfectly acceptable, in fact, in some regimes it was faster than the A6M or Bf109 and was more heavily-armed than the P-51.

I think that the key to the P-39's abilities however was its manoeuvrability. An RAF evaluation document from 1941 stated:

the Bf109 could not compete with the Airacobra in a turn and even if the Bf109 were behind at the start, the Airacobra should be able to out-manoeuvre and get onto the tail of the Bf109 within two complete turns.

On 12Dec41, Col Claire Chennault's AVG went into combat against the Japanese from Mingaladon in Burma using Curtiss P-40B/C variants. Days later, they moved up to Kunming in China to defend the Burma road. For the next six months they would perform well against the likes of the Ki-44 but at least one historian wondered if they might have fared even better had they been equipped with the Bell fighter instead. Rick Mitchell, author of Airacobra Advantage, points out that most aviation experts automatically assume the P-40 to be superior to the P-39. He insists that, on the contrary:

The truth is that no model of the P-40 during its entire service was ever as fast as the slowest version of the P-39. No P-40 was ever armed with the tremendous firepower or knockout punch carried by every P-39. Too many... make the mistake of comparing the P-39, America's earlier modern fighter plane, with much later WWII fighter designs such as the P-47 and the P-51.

So, although the AVG was largely a success, Mitchell believes that their record against the Japanese would have been even higher with Airacobras.

Anecdotally, the P-39 received a mention in a speech from none other than Churchill himself; speaking of the war build-up he promised that Britain would be getting more Spitfires and Airacobras - a curious choice given that the most numerous fighter in the RAF and an aircraft still very much in production, was at the time the Hawker Hurricane.

 

[Colin1]

How so?

Would it really have been?
Is it possible the NACA changes to the XP-39 improved low/medium level performance?
(not making an argument, just a question)

Allison?
Was the Allison supercharger design so out of touch with other contemporary designs?

Later on, yes - but in 1939?

Hi sorry
didn't see these posts
the blame can be placed at the door of both the USAAC and Allison; before 1938, the USAAC was committed to a program of turbocharged powerplants but Allison had committed to a program of integral, mechanical supercharging in order to simplify production. The only way to introduce second-stage supercharging was as a separate, external unit.
Allison joined forces with Curtiss-Wright to persuade the USAAC to accept the V-1710 in this form for the P-40 contract, relegating the Curtiss aircraft to a low-level role even before it had entered service, though this suited the (quickly outmoded) requirements of the time. The integral, mechanical supercharger was not developed any further throughout its service life in the P-40.

Yet when the V-1710 entered service in the P-38 it was equipped with turbochargers.

Your second post, I don't think so, there seems to be enough existing data to support the notion that NACA had indeed found lift and drag issues with the P-39's airframe and any modifications were designed to overcome that.
The decision to remove the turbocharger seems to have been made without any real controversy; I would guess that the current USAAC thinking of the time that there would be no high-altitude combat between opposing fighters was well embedded enough to negate any panic. Secondly, Bell lauded the financial relief from removing an unfamiliar, unreliable (at the time) unit that was likely to be fraught with expensive developmental problems.

Your third post, similar to an earlier observation you made, I think you have that the wrong way around too; the early V-1710s were hamstrung performance-wise by the management decision to use the integral mechanical power section, it really handicapped the unit development-wise vs the Merlin say. Later versions of the V-1710, the -143/145s, were as good as anything and were used in all versions of the P-82 bar the B (which used Merlins).

 

[Colin1]

Did they ever try to fit a Merlin engine into the P39. The low level rated Merlin 24 engine with 1600 hp could have made it into a pretty rapid fighter.

http://www.ww2aircraft.net/forum/aviation/has-merlin-ever-been-put-into-p-39-a-16729.html

 

[MikeGazdik]

An over simplified summation of varous posts if you will:
1) USAAC envisioned their Bomber force not needing escort, hence no "escort fighters" by design.

2) USAAC wanted the high speed high altitude pursuit to intercept enemy bombers attacking the U.S. homeland , which brought the P-38 with turbocharging ONLY to get to bomber altitude.

3) USAAC also believed that the regular pursuits (not the bomber interceptor) would operate at low or medium altitudes and would not need the turbo installation. Hence the P-36 / P-40 designs, and the turbo removed from the P-39 design.

4) Though the USAAC played with other pursuits with turbo installations, mainly Republic P-43 and such, I believe those were nothing more than fleets of working test beds. They didn't really push for a true full scale production pursuit with the turbo installation, until the P-47. Which was at the dawn of , the Battle of Brittain. USAAC by then had much more info coming back from the European conflicts showing they were wrong in the pursuits not needing high altitude abilities. Then it obviously would take a few more years to learn they were wrong in believing their heavy bombers did not need high altitude escort fighters.

5) All that being said, the P-39 is still awesome to my eyes. Nothing looks sexier on the ramp than that slick nosed, tricycle geared beauty with the snappy Allison exhaust blowing out the middle of the fuselage! And seriously, Airacobra! Not a better name for a fighter has been created. (except maybe Spitfire!)

 

[michaelmaltby]

By all accounts, the Soviets preferred the P-39 to the P-40 ... and preferred the P-40 to the Hurricane.

The Airacobra was a slick, well-built fighter with lots of problems ... but unlike the P-40 and Hurricane it had THIS gun. And if you liked to work at close quarters - and the Reds did - the gun was very effective.

MM

 

[VG-33]

By all accounts, the Soviets preferred the P-39 to the P-40 ... and preferred the P-40 to the Hurricane.

The Airacobra was a slick, well-built fighter with lots of problems ... but unlike the P-40 and Hurricane it had THIS gun. And if you liked to work at close quarters - and the Reds did - the gun was very effective.

MM

Considering soviet datas, P-39 was about 20 mph faster than P-40, climbed better but turned a little worse.
Obviously it's acceleration was better too, and respunse time to commands, since the engine was close to GC.

As for P-39, soviets reduced the extra large weight of the P-40, but couldn't do nothing with it's extra large size.

Regards

 

[Colin1]

3) USAAC also believed that the regular pursuits (not the bomber interceptor) would operate at low or medium altitudes and would not need the turbo installation. Hence the P-36 / P-40 designs, and the turbo removed from the P-39 design

I believe the reason for its removal was:

i. doctrinal with the USAAC
ii. aerodynamic with NACA and
iii. financial with Bell

a collaboration of misguided ideals that relegated the P-39, quite undeservedly, to the second-tier.

 

[gjs238]

I believe the reason for its removal was:

i. doctrinal with the USAAC
ii. aerodynamic with NACA and
iii. financial with Bell

a collaboration of misguided ideals that relegated the P-39, quite undeservedly, to the second-tier.

A nice summation of this thread.
Now that we've separated the wheat from the chaff (the turbocharged planes from the non-turbo planes), I'm still interested in why the disparity between the P-39 P-40.

The Americans and British seemingly vilified the plane.
The Soviets seemingly loved it.

Perhaps the P-39 was a tricky bird to fly.
Like the B-26 Marauder, green pilots and those with closed minds didn't fare well in this plane.

Perhaps it was it's short legs.

Perhaps it was just it's unconventional layout.

Oh yeah, and the spinning problem.
But that didn't seem to dampen Soviet enthusiasm.

 

[gjs238]

Production numbers according to Wikipedia (I know, take it with a grain of salt)

P-39: 9,584
P-63: 3,303
=======
12,887

P-38: 10,037 (thought this number would be lower)
P-40: 13,738 (thought this number would be higher)
P-47: 15,686
P-51: 15,875 (nice, esp considering how "late" this plane got in the program)

For those always arguing in favor of the P-51, it is amazing how many were cranked out for a plane that entered the game late.

But back to the P-39...
The P-39/P-63 family also churned out a decent amount, all of which did not go to the Soviets.
It seems someone was putting them to use.

 

[Demetrious]

I've been waiting for this thread.

I never thought of the P-39 much till I started playing it in Il-2. It's easy to look at the raw performance stats of a fighter and write it off, but once you use it in a (reasonably accurate) simulator, you start to notice and appreciate features and aspects of the aircraft that are otherwise not mentioned. For instance, it has been said in this thread that the P-39 is 20mph faster then the P-40 (a solid, but not tremendous, advantage,) but while flying the P-39 in that game, having spent the last few weeks in P-40s, I soon developed the impression that the P-39 was a "hot ship."

As often happens, I look backwards from my simulator experience to real-world information to see why that is, and I realized that the P-39 is a much cleaner ship then any iteration of the P-40. The P-40 has been discussed at length in these past months on this forum, and many times it's overly draggy nature has been commented on. At a glance, one can see that the P-39 doesn't have that problem. The most difficult thing for any simulator to emulate is drag modeling, but even the rudimentary implementation afforded by this simulator shows me that the P-39 spent far more of it's time in it's upper speed ranges, unlike the P-40. The P-39 doesn't accelerate spectacularly, but it's at least decent, unlike the P-40.

The consequences of that, of course, is that the P-39 often has more energy then the P-40 to throw itself into vertical maneuvers. It's also fortunate because the P-39 was often observed to have poor low-speed handling (in contrast to the P-40, which was oft described as having no vices.) It's stall behavior in vertical maneuvers was also distressing, but only if one attempted such manuvering at lower energy states (which was never a good idea in a plane with an unimpressive power/weight ratio anyway.)

However, it could easily turn with a P-40 (the documents on the Mustang II over at WWIIaircraftperformance.net observe that there is "almost no difference between the P-39, P-40, and P-51 in a turn,) and it had a decent roll rate, giving it a net speed/energy/vertical advantage over the P-40, at the cost of some quirky handling, with nearly identical manuverability.

It's pretty easy to see why the Russians loved the P-39. It was, indeed, a dangerous aircraft.

 

[michaelmaltby]

I keep hoping that a Soviet WW2 veteran will turn up who flew both the P-39 and P-63 in combat. I'd like to learn his views.

" ... It seems someone was putting them to use." Exactly.

MM

 

[claidemore]

I keep hoping that a Soviet WW2 veteran will turn up who flew both the P-39 and P-63 in combat. I'd like to learn his views.

" ... It seems someone was putting them to use." Exactly.

MM

His views: Conversations with N.Golodnikov
Read Part 3 and Part 4 specifically.

 

[michaelmaltby]

Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan. But that interview with G is a treasure in terms of details.

Thanks

MM

 

[VG-33]

Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan. But that interview with G is a treasure in terms of details.

Thanks

MM

Hello,

Soviets never flew P-63 against German on front line units*. All planes served in the PVO (anti-aircraft defence) far in the rear. Maybe one air victory or two against Japan, nothing more.

By 1944 soviets standards it was to slow at low altitude (515 km/h), against 567, 583, 612-630 at SL for serial Yak-3, La 5FN, La-7, and much heavier than other soviet frontal fighters. On the other side it's high altitude capabilities were appreciated.

Regards

Vg-33

*Avions magazine, 3-4 years ago....

 

[JoeB]

Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan.

The Soviets used a few P-63's in action in Germany, by 67th GIAP, according to "Red Stars Vol 4" by Geust and Petrov. Also a number of other early units that received them were air defense (PVO) units in the Moscow district, some of those units were later used in the August campaign against Japan along with VVS (and Fleet Air Arm) units. What source says the Soviets were only supposed to use P-63's in the Far East under LL? That seems a little odd given the general situation where the Soviets, while they eventually took advantage of joining the war against Japan (to help the Chinese Communists, establish a friendly regime in NK, etc) at least played the part of if being something of a favor they were doing for the Western Allies.

Joe

 

[FLYBOYJ]

"As mentioned above, most P-63s were delivered to the Soviet Union via Alaska/Siberia as soon as they had left the factory. One of the routes used led from Niagara Falls to Selfridge Field (Michigan) and on to Truax Field near Madison (Wisconsin). There the Bell fighters were picked up by (mostly) female Russian pilots who flew them via Anchorage (Alaska) to the Soviet Union. Another route went from Great Falls (Montana) to Fairbanks (Alaska) and on to Siberia. One source states that there were 2,397 P-63As and Cs sent to the USSR, of which only 21 were lost en route. Another source records 2,456, of which 2,421 reached their destination. Deliveries commenced in September 1944 and until May 1945 only 51 P-63As had been received by the Soviet Union. They were assigned to PVO units. This makes any significant use against German tanks or aircraft very unlikely. So the often read statements about the successful Soviet use of the P-63 against German armor seem to have been "extrapolated" from the P-39 Airacobra.

Re-equipment of Soviet Air Force units with the Kingcobra continued after the end of the war in Europe. The type was used in combat against Japan at the Far East and Trans-Baikal Fronts. The 12th Air Army of the latter Front had its 245th (940th and 781th IAPs) and 190th (17th and 21 IAPs) IADs equipped with Kingcobras. On August 15, 1945 Captain Vyacheslav Sirotin of the 17th IAP, a 21-victory ace and Hero of the Soviet Union, scored the only aerial victory of the P-63 Kingcobra when he shot down a Japanese Ki-27 or Ki-43. Other Soviet P-63-equipped units in the Far East in the summer of 1945 were the Kamtschatka-based 128th SAD (888th and 410th IAPs - the latter having been equipped with Il-2s before as the 410th ShAP) and parts of the 7th IAD of the Pacific Ocean Fleet. In July 1945 the 128th SAD supported the Soviet landings on Shimushu (Kuriles). Soviet Kingcobras normally had their underwing gun gondolas removed.

After the war re-equipment of new units with the P-63 continued at an accelerated pace. These included the 5th GvIAD in the Baltic District, the 269th IAD in Armenia, the 6th GvIAD in the Ukraine and the 1st GvIAD at Neuhausen in Germany. There were also P-63-equipped units based in Austria and China. About 25 aircraft seem to have been converted into P-63U two-seat trainers in the USSR at that time. The 307th and 308th IAPs in the Kuriles flew the P-63 until as late as 1951. Due to its post-war use in Russia the P-63 even received a NATO code name: "Fred". One of the last incidents involving Soviet P-63s happened in 1952 when USAF jets mistakenly strafed the Soviet airfield of Sukhaya Rechka outside Vladivostok and destroyed 8 (albeit already de-commissioned) P-63s."

P-63 Kingcobra by Bell

 

[Soundbreaker Welch?]

I didn't realize the P-63 was almost an unused fighter of WWII. I thought the Reds killed a few Germans with it. The P-63 did have good manuverability, but it was too little to late I guess.

I think like Mike said the P-38 was the main fighter the US was planning to use in shooting down attacking bombers, thus the only one allowed to have a supercharger. Sadly for the P-38, it's high altitude performance was still not steller, even with the supercharger. But it was a better energy fighter than the P-39.

 

[MikeGazdik]

Be careful with the term Supercharger. It is an often ( at least in many of the older books ) used but incorrect term applied to WWII fighter engines. Maybe because I am a gearhead, but it matters greatly. The P-38 was Turbocharged. All Allison engines have an intregal single stage Supercharger. So the most correct word to use on the P-38 is actually Turbo-Supercharged. You can look up the technical aspects of each on your own, don't want to get too long winded and sound like a know it all. So in reality, the P-40 and P-39 were Supercharged.

 

[gjs238]

I think like Mike said the P-38 was the main fighter the US was planning to use in shooting down attacking bombers, thus the only one allowed to have a supercharger.

I would much prefer to see a scan of original documentation stating this policy. Otherwise this is speculation.