Bell P-39 Airacobra & P-63 Kingcobra.

World War II American Military
#61

Please allow me to correct some historical assumptions on the P-39;

  1. EVERY P-39 had a supercharger. Models C thru L had an 8.8:1 internal supercharger, M thru Q had 9.6:1. The Allison V-1710 was an excellent engine, very competitive power/weight and power/frontal area, was produced in hundreds of variants including single speed single stage superchargers (P-39, P-40, P-51A), two stage mechanical superchargers (P-63), and exhaust driven turbochargers (P-38). The Allison was required to pass a 150 hour endurance test when the Merlin would not pass a 100 hour test under the same conditions.

  2. The turbocharger was deleted from the P-39 and P-40 because the Army needed fighter planes in 1941 and the turbo was not sufficiently reliable at that time. The turbocharged P-38 did not enter combat until December 1942, a full year later.

  3. The British rejected the P-400 (same plane as the P-39D) for three reasons:
    A: In mid 1941 the Battle of Britain was over, there was no more threat of invasion, and the British were broke.
    B: Their internal Spitfire and Typhoon production was sufficient for their needs.
    C: Lend-Lease was enacted in March 1941. Why would Britain pay for P-39s ordered in 1940 when they were about to be
    GIVEN free of charge all the planes and other equipment they needed.
    So, Britain specified equipment on the P-400 to make it weigh 7,850 pounds and be too heavy to meet the performance
    guarantees under the production contract. For comparison purposes a 1941 Spitfire V weighed 6,300 pounds.

  4. The Japanese Zero was NOT superior to a P-39. The Zero was more maneuverable and climbed faster but the P-39 was faster at all altitudes, dove much faster, and was equipped with armor and self sealing fuel tanks. The Zero was an unarmored fire trap. Zero pilots WERE superior in mid 1942 (Japanese Navy carrier pilots vs. brand new Army pilots) and the Japanese vastly outnumbered American forces in New Guinea with bases at Lae, Salamalua, Wewak, Hollandia, Finchaven etc. vs. one group (three squadrons) of P-39s split between Port Moresby and Milne Bay. The P-39s held Moresby and Milne Bay despite all the Japanese could throw at them.

  5. The Soviets used the P-39 as an air superiority fighter, not a ground attack fighter. Four of the top five Soviet aces (indeed the top Allied aces of WWII) flew P-39s as did over 40 aces with 20+ victories. They flew the P-39 up as high as the German pilots wanted to go. Their P-39s differed only in that they deleted the wing guns and seldom used drop tanks. Soviets viewed the four .30 caliber wing guns as useless, only good for “damaging German paint”. The remaining P-39 armament of twin .50 caliber machine guns and a 20mm or 37mm cannon was considered devastating by Soviet pilots. The P-39 at around 7,200 pounds (vs. 7,700 pounds as we flew them) was faster and climbed better than the German Me109 and Fw190. This is completely documented by information released after the fall of the Soviet Union. Clearly the P-39 was one of the best planes of WWII.

#62

Whoa… I don’t know about that hgilley.

Air combat is more than just a list of max speeds.

The way one looks at fighter performance, especially before the missile age, is a combination of many factors.

Take speed. The maximum speed of a particular fighter is not just a number. For any altitude the speed is different! One plane may be faster than most at 5000 ft. but slower than others at 20,000 ft.! So one needs to know what their speeds are at several altitude markers. And then, part of speed, is acceleration. A fighter that accelerates faster at 5000 ft. may be slower at 30,000.

Then take turning rates. It’s the same thing. Each fighter as different rates at different altitudes. PLUS, each plane as a different cornering rate (that is, the best speed at THAT altitude to turn in the smallest radius.) And part of turning rate is the roll rate. You will find much differences in roll rate between aircraft as well as between different altitudes.

This also works for dive rates, climb rates (what kind of climb? Vertical? Shallow high speed? Corkscrewing?)

And then there are factors like the ‘legs’, that is how far they can go on what fuel they have. The longer the legs, the better you are.

Plus factors like armor and firepower.

I strongly suggest you take this site in for reading and understand just what factors are needed to evaluate fighters.

http://www.wwiiaircraftperformance.org/

In particular look at:

http://www.wwiiaircraftperformance.org/mustang//p-51-37320-chart.jpg

and

http://www.wwiiaircraftperformance.org/japan/p5016.pdf

Deaf

#63

Which were very inadequate superchargers and barely counted the aircraft as being ‘supercharged.’ The Allison was an excellent engine in the right circumstances, but it wasn’t well suited to high level combat and the problem couldn’t be easily technically solved as there were problems with enhancing the supercharger IIRC. By the time the P-39 series was modernized, there were already P-51Ds and P-47s in full production. So why bother?..

…
4. The Japanese Zero was NOT superior to a P-39. The Zero was more maneuverable and climbed faster but the P-39 was faster at all altitudes, dove much faster, and was equipped with armor and self sealing fuel tanks. The Zero was an unarmored fire trap. Zero pilots WERE superior in mid 1942 (Japanese Navy carrier pilots vs. brand new Army pilots) and the Japanese vastly outnumbered American forces in New Guinea with bases at Lae, Salamalua, Wewak, Hollandia, Finchaven etc. vs. one group (three squadrons) of P-39s split between Port Moresby and Milne Bay. The P-39s held Moresby and Milne Bay despite all the Japanese could throw at them.

If you’re trying to say the P-39/63/400 series was an effective, underrated and much maligned aircraft by snobby U.S. and British pilots: you’re preaching to the choir. But it was certainly not as effective as the Zero and was nearly useless at high level as an interceptor as the USAAF found out in Australia IIRC. On Guadalcanal, they struggled to keep up with the F4 Wildcats and could only hang back in a support and ground attack role…

With some improvements, and there was an excellent final prototype version that was on par with the P-51, it certainly could have been one of the marquee fighters in Asia and the Western Front…

  1. The Soviets used the P-39 as an air superiority fighter, not a ground attack fighter. Four of the top five Soviet aces (indeed the top Allied aces of WWII) flew P-39s as did over 40 aces with 20+ victories. They flew the P-39 up as high as the German pilots wanted to go. Their P-39s differed only in that they deleted the wing guns and seldom used drop tanks. Soviets viewed the four .30 caliber wing guns as useless, only good for “damaging German paint”. The remaining P-39 armament of twin .50 caliber machine guns and a 20mm or 37mm cannon was considered devastating by Soviet pilots. The P-39 at around 7,200 pounds (vs. 7,700 pounds as we flew them) was faster and climbed better than the German Me109 and Fw190. This is completely documented by information released after the fall of the Soviet Union. Clearly the P-39 was one of the best planes of WWII.

This isn’t anything ground breaking as it was said here years ago that the Soviets loved the fighter because, like the P-40, it was more than a match for the Me109 at the lower level and the altitudes typical of the heavy tactical air support nature of the Eastern Front air war. It was certainly one of the best planes of the Great Patriotic War!

#64

Please keep in mind what I said in the last paragraph. At 7,200 pounds the P-39s as the Soviets used them were a match for any German planes in 1942-43. As for wwiiaircraftperformance.org, love that site, have it practiclly memorized. The chart you mentioned shows the P-39D-1 at 7,700#. The Soviets deleted the worthless .30 caliber machine guns and a few other unneeded items and used that same plane at 7,200#. Huge difference in performance and altitude. The japan paper you referenced compares the Zero with a P-40K weighing 8,400#. The P-40K had the same engine and propeller as the P-39 but the P-39 only weighed 7,700# and equipped properly would have weighed only 7,200#. Huge difference in performance. The Zero was a 330mph plane. The P-39 and P-40 were faster. Don’t turn with a Zero and you had no problems.

#65

Allison internal supercharger produced the same horsepower at the same altitudes as the German engines RELATIVE TO THE DISPLACEMENT OF THE ENGINES. German engines were substantially larger thus more powerful. German engines were single stage engines just like the Allison. Allison’s problem was the planes that it powered were substantially heavier RELATIVE TO THE DISPLACEMENT OF THE ENGINES. At the lower weights used by the Soviets the P-39 was comparable to the German fighters at all altitudes.

Regarding Guadalcanal, the few P-400’s had British oxygen systems not compatible with Navy/Marine systems so those P-400’s had NO oxygen. They could not climb over 15,000’ or the pilots would pass out. And they weighed 7,700#. Still at that weight the P-400 would certainly climb to 18-22,000’ where the Japanese Bettys flew and would climb to that altitude faster than any F4F. But not without oxygen.

And please don’t compare the P-39 to a Merlin P-51. P-39 performance peaked from November 1942 when the “N” began production and lasted through 1943. The P-51B didn’t get into combat until 1944 (a few in Dec. '43). P-51B was superior but was not available in 1943. Can’t fight with a plane you don’t have.

#66

I love the P-39/400 and P-63, I currently have 10 models of them completed and will surely do more.
But maybe we should give Lend Lease and their use by the Russians some perspective.
Around 7,000 P-39 and P-63’s (at least 10% were lost in transit or in accidents) were provided to Russia, by far the largest number of any type of West. aircraft; Russian aircraft industry produced close to 160,000 of its own aircraft from 1942-45, a ratio of nearly 23 to 1. It would appear that US and British aid was very important, especially in 1942/43, but far from what W. propaganda made it out to be.
Nor, as we were led to believe, were the Russian aircraft inferior. I’ve read that late model La and Yak series fighters tested at the end of the War by US and Brit pilots were judged equal or superior to anything flown by the West.; Pe-2 and Tu-2 were outstanding and we had nothing to compare with the Il-2.
I’ve read that Russian’s were not always truthful when dealing with the West, they needed all the help they could get and weren’t likely to speak poorly of the equipment they received (doing so may have resulted in repercussions from their own people). So I have to wonder about comments and evaluations by their pilots.
I’ve also read that in the heat and humidity of the Pacific the ammunition of the early model 37mm cannons often failed.
All its failings aside I still love the Airacobra and Kingcobra and would love to have flown one, although maybe not in combat.

#67

Gen. Chuck Yegar wrote that he liked the P-39. He trained in it before going to the P-51 (and of course Yeager knew a thing about airplanes!)

Deaf

#68

Enjoy the debate, P-39 was way undervalued by AAF, properly used by Russians.

#69

The P-39 had it’s uses hgilley. It was not a good one for 1 .vs. 1 with the Zero, but that was mainly cause it could not reach the normal fighting altitude in the Pacific and still function well (20,000) and thus very often at a disadvantage to the A6M and Ki-43.

Now on the Russian front, with BF-109s and FW-190s at below 15000, where most of the fighting was, it was a fine and dandy plane.

And it could not do much of an escourt job in the ETO due to it’s short legs and no way to do much at 30,000 ft!

Still it did it’s job. They even asked for more of then in the Pacfic in 44 as it was a good light ground attack machine.

Deaf

#70

I enjoy this debate. You have certainly read your history on the P-39. Trouble is, most of it doesn’t consider Soviet records which became available after the fall of the Soviet Union. Soviet pilots maintain their P-39s would compete with the German fighters up as high as they wanted to go, usually not over 25,000’. Otherwise, if the P-39 was no good over 15,000’ then the Germans would have simply stayed at 20,000’ and bounced the Russians all day long. Russians held a 4-1 victory ratio over the Germans with their P-39s and could not have maintained that if the Germans had an altitude advantage. I agree most of the air fighting was tactical below 15,000’ but the Russians used a “flying bookshelf” formation with four planes at 15,000’, four more at 20,000’, and the last four at up to 25,000’ to fill out a squadron of 12.

Too bad the AAF was so far behind the learning curve when they began using the P-39 in combat in New Guinea in April 1942. Their P-39s were just too heavy at 7600-7800# plus the ever present 110 gal drop tank adding another 700#. The Russians discarded the useless .30 caliber wing guns (.50 cal in the Q model) and fought their P-39s at about 7100# and seldom required a drop tank. The P-39Ds and P-400s in New Guinea in the last 8 months of 1942 could have easily weighed 7000# including proper armor plate and self sealing fuel tanks and even with a drop tank would have maintained a healthy performance advantage over the Zero at any altitude (after dropping the tank for combat of course). But at 8400# with drop tank they struggled to get above 18,000’ and the Japanese Bettys operated at 18,000-22,000’. The P-39 shot down plenty of Bettys when they had adequate radar warning to take off and climb above them (or happened to be on patrol) but radar was very new then and notoriously unreliable. No plane on earth could intercept bombers at 20,000’+ without early warning via radar or forward observers. But the AAF slogged along with their overweight P-39s and their green pilots fighting experienced Japanese carrier pilots stationed on land bases in northern New Guinea. Those brave kids still managed a 1:1 victory ratio against the numerically superior Japanese.

Now the later P-39N and Q could have escorted bombers over Europe with minor midifications but I’ve bored you enough already. If you would like to read some of the Soviet information I’ll be happy to furnish it to you.

#71

hgilley,

The Russian front was a tactical war front with very few strategic bombers on either side. And as a result most of the efforts of the Soviets and Germans were in tactical support. And that is why aerial combat was usually well below 20,000 ft.

And since German fighters were similar to the American, British, and Russians (that is they were not stunt planes, which in reality the Japanese planes were) they all had similar performance envelops. The P-39 did to up to its practical ceiling. That practical ceiling was around 15,000 ft and that was great for the Russian Front but not so good for the ETO or PTO.

And that is why we tended to use it as a light attack plane and not as a fighter.

Deaf

#72

Agree with you on combat on the Russian front being well below 20,000’ and the Japanese planes were basically stunt planes, but disagree on P-39’s practical ceiling being 15,000’. I know that is what has been printed for decades, but fairly recent Russian accounts say the plane was competitive with German fighters at all altitudes. Otherwise the Germans would have come in at 20,000’ and bounced the P-39s with virtual impunity. If you are interested I’ll furnish numerous sources.

#73

Reading this thread about how pilots from different countries have different opinions about the P-39 brings to mind something I read about Finland’s views re the B-239 (export version of the infamous Buffalo).
They loved this airplane so much they produced it themselves, yet American, Dutch and British pilots were easy meat for the Jap’s. I once read a claim by a Fin pilot that the “Sky Pearl” (as they named it) had the highest kill to loss ratio of any fighter they used.

#74

I haven’t a copy of Frank’s seminal Guadalcanal so I cannot readily dispute your first part of this post. But I believe there were more problems relitive to high level permorance than oxygen systems on the P-400’s.

But you’re wrong on the P-51. The Merlin powered XP-51B first flew in November of 1942, not 1943 if Wiki is to be trusted, and production was started in early 1943…

#75

It should be noted that many of the Soviet P-39’s victories came over tactical bombers. So, yes, the Germans could have attempted to jump the Red Aircobras from above. But their tactical support aircraft would have been left unattended and been mincemeat…

#76

Maybe this will helps guys.

http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=140

http://www.aviation-history.com/bell/p39.html

http://www.wwiiaircraftperformance.org/

http://www.wwiiaircraftperformance.org/mustang//p-51-37320-chart.jpg

(notice the climb rates of the XP-51/P-40/P-39D)

http://www.acepilots.com/planes/specs.html

This is Specs of Fighter Planes by model and type (WW2). Quite a few here!

If I was to really want to research this I’d use:

Report of Joint Fighter Conf.

NAS Patuxent River, MD 16-23 Oct. 1944.

And I’d read carefully:

http://yarchive.net/mil/p39.html

Deaf

#77

I’ve found that if you read five articles you’ll get five sets of numbers. I prefer to use figures from the official WWII pilot manuals for each plane. P-39N manual says it will climb to 25,000’ in 8.7 minutes, faster than comtemporary P-38, P-47 and P-51. Compare that with 109, 190 and Zero. P-39 was much better plane than American history says.

#78

Sounds crazy, doesn’t it? Fins must have had better pilots or tactics, or maybe the Buffalo was the best plane the Fins had at the time.

#79

P-51B first appeared in combat in December 1943. First flight and production must occur prior to combat.

#80

Yes, many P-39 victories came over Stukas and other tactical bombers. And yes, the German escorts could not abandon their bombers, but they could (and did) station a portion of their fighters at higher altitudes. If German escorts had a performance advantage at altitude they would have exploited that advantage. Soviet pilots maintain their P-39s were competitive with German fighters at any altitude. I’m not making this up, proof is available.