When the list of greatest American-built fighters of World War II gets tossed around the same names always come up: Mustang, Hellcat, Corsair, Lightning, Thunderbolt. Maybe the P-40 gets honorable mention. Add the Brits to the mix and you’ll get the Spitfire, Hurricane and a few others.
But nobody loves the poor little P-39 Airacobra, which became one of the most successful American made aircraft of the war.
This is the Cinderella story of how the plane nobody wanted came to find its place.
The genesis of the P-39 goes back to a 1937 Army Air Corps (Army Air Forces after 1941) request for a high-altitude interceptor. The specification included heavy cannon armament and a turbo-supercharger for high altitude performance.
The prototype Bell came up with was either innovative or just plain weird depending on your point of view. It incorporated tricycle landing gear, but most oddly had the engine mounted behind the pilot to make room for a 37mm cannon in the nose. Long before the A-10, this was an aircraft literally designed around a gun.
A long driveshaft ran underneath the cockpit to connect the Allison V-12 engine to the propeller. I would have expected the driveshaft to be a high point-of-failure but apparently it was never a problem.
In addition to the 37mm cannon it boasted a mix of .50 caliber and .30 caliber machine guns. The number and placement of the additional guns varied between the different P-39 models.
The P-39D was pretty typical with two .50 caliber guns in the nose and four wing-mounted .30 caliber guns. This sounds like a lot of firepower but the different caliber weapons all had different trajectories so it was unlikely to put all that on the target.
The rear mounted engine allowed for a very sleek, aerodynamic nose. Compare it to something like a P-40 and it has a very clean look about it. I’m surprised the engine didn’t have cooling problems but apparently it didn’t.
Unfortunately this came at a cost. There was no place to mount the turbo-supercharger back there and the P-39 went into production with just a single-stage supercharger.
Why is this important? A turbocharger on an airplane serves a slightly different purpose than the one on my wife’s station wagon. A turbocharger in a car is normally used to get more horsepower out of a smaller engine. That’s how they can make a 2 liter 4-cylinder engine perform like a 60s muscle car.
On an aircraft, the turbocharger lets the engine keep producing its maximum power as altitude increases and the air gets thinner. Without a turbo to cram air into its Allison engine at higher altitudes, the P-39 was a dog about 17,000 feet. Kind of a problem for a plane that was intended to be a high-altitude interceptor.
The unique configuration had some other issues as well. The compact fuselage was crammed full of engine and 37mm cannon. There was no room for gas tanks in there so the P-39 carried its relatively small fuel load in the wings.
Finally the rear mounted engine placed the center-of-gravity relatively far aft and gave the P-39 a nasty reputation for flat-spins and even tumbling end-over-end. Since the P-39 used a car-style door instead of a sliding canopy, bailing out of it was difficult as well. All of this gave it a reputation for being a death-trap.
Don't give me a P-39.
The engine is mounted behind.
They'll tumble and spin and auger you in,
Don't give me a P-39
(from the song “Give me Operations”)
The reputation wasn’t completely deserved. Testing showed that the P-39 was stable as long as it was properly loaded with ammunition in the forward compartment. When empty, the center of gravity would move aft and make the aircraft susceptible to flat spins.
The P-39 proved to be unloved by both the Americans and British. The British ordered 675 of them, equipped with a 20mm cannon in place of the 37mm. The RAF found the P-39 to be a disappointment, with a top speed 30-40 mph slower than what it was supposed to do. Only one RAF squadron was briefly equipped with P-39s and the order was cancelled before all 675 could be delivered.
The remaining 200 British P-39s were renamed as P-400s and served with the Army Air Forces as training aircraft. Some actually went to the Pacific theater, where the joke came to be that a P-400 was a P-40 with a Zero on its tail. Others joked that trucks would have been better, since a truck was faster and better handling than a P-400.
In actuality, the P-39 did about as well against the Zero as anything else did at the time. The Zero was tough to beat in the early years of WWII and the Japanese pilots were at the top of their game at this point. Even the vaunted Spitfire was unable to turn with the Zero, as the British found out.
The P-39 had a roughly even kill ratio against the Zero. Not great, but good by 1941-42 standards against an enemy with numerical advantage and more experienced pilots.Depending on which source you believe the P-39 was either slightly faster than the Zero at low altitude or roughly equal.
Later aircraft like the F6F Hellcat would rack up impressive kill ratios against the A6M, but the Hellcat was designed specifically to beat the Zero. Plus by 1944 the tables had turned and it was the American pilots who were experienced and the Japanese replacements who were the rookies.
Lt. Colonel Boyd Wagner scored three of his eight kills while flying the P-39. He rated the P-39 as 10% better than the P-40 in everything but maneuverability.
The biggest problem for the P-39 in the Pacific was that it simply didn’t have the range for the long distances involved.
The P-39 saw limited service with the Army Air Forces in the Mediterranean theater. Most notably the type was flown by the Tuskegee Airmen, but only for a very short time. They felt it an insult to be relegated to a “2nd rate” aircraft and successfully lobbied for P-51s.
All in all the type just didn’t fit the needs of the Army Air Forces. It didn’t have the legs for high-altitude bomber escort in Europe or Island-hopping in the Pacific.
So what do we do with this plane that the British don’t want and the US doesn’t want? I know, let’s give ‘em to the Russians! Which is what we did, some 4,700 of them.
It is a persistent myth in the West that the Soviets used the P-39 as a tank-buster. This is simply not the case. The Russians never had armor-piercing ammunition for the 37mm T-9 cannon.
The myth comes from an incorrect translation of the Russian term “ground support” to mean “close air support”. The Russian meaning is actually closer to the western term “air superiority”.
The Soviet P-39 missions in order of priority were:
Protect ground units from enemy aircraft
Escort bombers
Suppress AAA in the area of bomber targets
Reconnaissance
Free hunt
Attack soft targets
Protect high-value friendly targets
Ground attack was strictly a secondary mission for P-39s in Russian service. It was primarily used in an air to air role. I’m sure that at some point a Russian P-39 shot at a German tank but this was not its normal mission. The high explosive rounds fitted to the T-9 cannon could not pierce even the thinner top armor of most German tanks.
The Russians usually removed the wing-mounted machine guns from their P-39s to improve the aircraft’s roll rate. Some Russian accounts, however, mention using the wing-mounted guns in combat so this may not have been done across the board. In general the Russians didn’t like putting guns in the wing. Most of their designs kept the guns in the nose.
The Kobrushka “little cobra” proved well suited to the type of encountered on the Eastern Front. Most air combat there took place at low to medium altitudes where the P-39 was in its element.
Soviet pilots found the type to be sturdy, maneuverable at low altitude and possessing better firepower than early Soviet types. Plus it had instruments and a radio that actually worked at a time when many Russian-built aircraft didn’t even have radios.
Some other qualities of the P-39 included good cockpit visibility, and decent armor protection for the pilot (but not the engine which was vulnerable).
At low altitude the Airacobra was roughly equal to the mid-war Bf-109 and superior to the FW-190.
The 37mm cannon could destroy an enemy aircraft with a single hit, assuming you could achieve a hit with it. It had a slow rate of fire (3 rounds per second) and only carried 30 rounds of ammunition.
The Airacobra was the best Russian fighter at the time...a close match for our Bf 109's.
Luftwaffe Ace Helmut Lipfert (203 victories)
The top P-39 ace of any country was Alexander Pokryshkin, who scored 47 (some say 48) of his 65 kills while flying the Airacobra. He may have had more than 65 total kills since he had several that were unconfirmed because they took place over German territory. Some sources claim as many as 100 total. This also makes him the highest scoring person ever flying an American aircraft.
Pokryshkin was also the mastermind behind Soviet air tactics in WWII. In 1941, Soviet air tactics were way behind the times. Pokryshkin threw out the rule book, came up with his own tactics and most importantly taught them to other pilots in his regiment.
Pretty gutsy thing to do in Stalinist Russia. They weren’t big on “initiative”. His disregard for orders nearly got him court-martialed (and probably executed) early on. Fortunately, in a story right out of the movies, some higher-ups liked the results he was getting and promoted him instead.
Pokryshkin’s love for the P-39 also got him in hot water with the powers that be. He stuck with the type long after Soviet-produced aircraft became available. This got him labeled as unpatriotic. After the war he was passed over for promotion several times, and only finally promoted after Stalin’s death.
Several of the top Russian aces scored most of their victories in the P-39. Note that these numbers are approximate as sources vary.
Pilot |
Kills |
Kills in P-39 |
Aleksandr I. Pokryshkin |
65 |
47 |
Nikolai Gulayev |
57 |
41 |
Grigori A. Rechkalov |
56 |
50 |
Dimitriy B. Glinka |
50 |
41 |
The top 10 Russian Airacobra aces had a combined total of 300 kills while flying the P-39.
Some sources claim that the P-39 had the most kills of any American produced fighter but I can’t find any good data to confirm this. Soviet data from the time of Stalin needs to be taken with a grain of salt as it had a heavy dose of propaganda. Soviet P-39s would have had to shoot down 5,163 Axis aircraft to match the record of the F6F Hellcat in the Pacific.
Still, the unloved little Airacobra shot down a lot of German aircraft and had the highest kill rate per-person of any American type. Most importantly it was there when the Russians desperately needed fighters. At one point Joseph Stalin personally wrote to Franklin D. Roosevelt asking for more P-39s.
Always intended to be an “interim fighter”, by 1944 the P-39 starts to be eclipsed by Soviet types like the La-7 and Yak-3 as Russian production really got cranking.
Bell fixed most of the P-39’s flaws with the improved P-63 Kingcobra. Most notably an improved two-stage supercharger gave it the high altitude performance that the Airacobra lacked. It actually beat the P-51 in roll rate, but overall the USAAF preferred the P-51.
Russian input figured heavily in the development of the Kingcobra and most of the production went to Russia. By lend lease agreement the Russians weren’t suppose to use the P-63s against Germany. They were to be saved for the eventual attack on Japan. The Russians seem to have disregarded that and some late-war Russian units may have secretly converted to P-63s while still officially being listed as “P-39” units.
I can’t say I blame them. “Hey Ivan! The Americans gave us these shiny new airplanes but they don’t want us to use them? Screw that!”
Ultimately the Soviet P-63s did officially see action against the Japanese during the 1945 invasion of Manchuria.
Today the Airacobra remains largely unloved in the West. Unlike other WWII fighters, there is no “P-39 Pilots Association”. There is no P-39 monument at the Air Force Academy.
My search for “P-39 Monument” turned up exactly one. It is fittingly, in Russia.