Bell P-39 Airacobra: WWII’s Most Controversial Low-Altitude Fighter

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A substantial portion of combat during WWII occurred in the skies, as countries developed their aerospace technology. That included the United States, which developed more effective fighter planes. However, there’s one that’s been subject to ridicule for over 70 years: the Bell P-39 Airacobra.

A new fighter plane is requested

In 1937, Captain Gordon P. Saville of the Air Corps Tactical School and Lieutenant Benjamin S. Kelsey of the U.S. Army Air Corps issued a request for a new fighter plane. The Circular Proposal X-609 asked for a single-engine, high-altitude interceptor able to conduct the “tactical mission of interception attack of hostile aircraft at high altitude.”

They wished for the plane to have numerous features, including a liquid-cooled Allison engine with a General Electric turbo-supercharger, tricycle landing gear, the ability to carry 1,000 pounds of armaments, and a cannon. It had to reach a top speed of at least 360 miles per hour and a height of 20,000 feet.

Fleet of Bell P-39 Airacobras on the ground
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Bell Aircraft, an aerospace manufacturer based in New York, presented its own design. Called the “XP-39,” the prototype reached 390 mph in only five minutes, but it was unable to reach its top stated altitude. The National Advisory Committee for Aeronautics (NACA) evaluated the aircraft and listed recommendations to allow it to reach the necessary requirements.

However, the P-39 Airacobra never turned out to be the fighter plane Bell Aircraft made it out to be. After applying the NACA’s suggestions, there was no room within the craft to fit the turbo-supercharger. In its place was a single-stage, single-speed fighter plane with a top altitude of 12,000 feet. This meant it was easier to produce and maintain, but it took away the opportunity to serve as an effective high-altitude fighter.

An intricate design

Despite its perceived failings, the Bell P-39 Airacobra featured a sleek design that was unlike anything seen before. Its all-metal design was not only the first to feature tricycle landing gear, but to also seat its engine in the center of the fuselage, as opposed to the nose. This was done to fit its 37mm T9 cannon through the propeller hub.

The resulting design meant the pilot sat in front of the engine and higher in the fuselage, allowing for a better view of their surroundings. While the rear position of the engine protected it from ground attacks, it made it susceptible to those in the air.

Assembly plant in Wheatfield, New York
Bell P-39 assembly plant in New York. (Photo Credit: Unknown Author / Wikimedia Commons)

Different from other fighter planes was the P-39’s wing size. Smaller than normal, they allowed the plane to turn quickly but also hurt its ability to reach higher altitudes. Its small size also affected the amount of fuel it held, meaning it couldn’t conduct long-range flights.

However, what it lacked in altitude it made up for in armament. Along with its cannon, it also featured a pair of .30-caliber machine guns on top of the nose, which were synchronized to fire between the propellor blades. Later designs would see the addition of six .50-caliber machine guns: two on each wing and two on the nose. Hardpoints were also added to allow it to carry bombs onboard.

Fighting high in the skies

By the time the production of the P-39 Airacobra was underway, the war in Europe had begun to escalate. To help build up their fleet, Britain’s Royal Air Force (RAF) placed an order for the fighter planes. They received a special export version called the P-400, which had been initially meant for France. However, given that Germany invaded the country early in the war, Bell Aircraft was unable to deliver.

RAF armorers with the 601 Royal Auxiliary Air Force load a Bell P-39 with ammunition
RAF armorers load a Bell P-39 Airacobra with ammunition. (Photo Credit: Fox Photos / Getty Images)

The P-400 was different than the P-39 in that modifications were made to reduce drag. This included the installation of new exhaust stacks and modifications to the tail, amongst others. It was also lightly armored, with fewer weapon implements. The .30-caliber machine guns were on the wings, as opposed to the nose, and the cannon was smaller, at only 20mm.

The No. 601 Squadron with the RAF was the only British unit to allow the P-39 to see operational use. In October 1941, four planes arrived at Dunkirk, but the pilots found issues with the lack of altitude, as it was becoming increasingly clear that air combat would regularly occur at 30,000 feet, over the P-39’s maximum.

Bell P-39 Airacobra in flight
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Pilots also found the plane had a tendency to enter a flat spin. They began to report it would tumble “end over end” during certain maneuvers, often at the maximum altitude with a considerable amount of power.

While the RAF continued to train with the P-39 throughout the winter of 1941, it was eventually replaced by the higher-altitude flying Supermarine Spitfire. This, combined with pilot distrust over the plane, was the start of the P-39’s degrading reputation on the front.

War in the Pacific

The Japanese attack on Pearl Harbor was America’s entrance into WWII. To fight their Pacific neighbors, the U.S. Army took over the British contract for the Bell P-39 Airacobras and immediately dispatched squadrons to Australia. These units received support from those stationed in the Philippines, as the 35th Pursuit Group had set sail for Manila just two days before the bombing.

American soldiers working on the plane's fuselage in Brisbane
American soldiers working on the fuselage of a P-39. (Photo Credit: State Library of Queensland, Australia / Wikimedia Commons)

By mid-March 1942, 90 P-39s and over 100 P-40s were shipped to Australia, while additional squadrons were distributed to Fiji, Canton, Christmas Island, Palmyra, and New Caledonia. Various fighting groups were created from these squadrons, with the goal of protecting major Pacific entities from Japanese invasion.

P-39s were also sent to Alaska and North Africa. From September to November 1942, pilots with the 57th Fighter Squadron flew them, along with P-38s, when attacking invading Japanese forces on Alaska’s Attu and Kiska Islands.

Three Bell P-39 Airacobras in flight
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The 99th Fighter Squadron trained in the U.S. with P-39s before being deployed to North Africa and the Mediterranean. However, they only flew the planes for a few weeks before transitioning to the P-40.

The P-39 Airacobra’s one shining moment

The Bell P-39 Airacobra officially entered combat while the U.S. Army was stationed in New Guinea. The mission for Allied troops was to defend Australia, and General Douglas MacArthur drew the battle line across New Guinea. The move was contradictory to the original plan to draw the line across central Australia, with MacArthur on the offensive after the loss of the Philippines.

The 8th Fighter Group moved its P-39s to Port Morseby, located on the south coast of Papua New Guinea. They were led by Lieutenant Colonel Boyd “Buzz” Wagner, who was well-versed in the flying techniques employed by the Japanese. His knowledge would be invaluable to the fight in the Pacific.

Aviators with the Royal Australian Air Force plan attacks in front of the plane
The Royal Australian Air Force (RAAF) 8th Squadron flew the P-39 in New Guinea. (Photo Credit: John Thomas Harrison / Wikimedia Commons)

On April 20, 1942, Wagner led 26 P-39 pilots on their first combat mission, where they strafed Japanese airfields and fuel dumps in Salamaua and Lae. While they lost four planes, they experienced no human casualties. The mission would be the planes’ first in over two months of fighting, during which the 39th Squadron shot down 12 Japanese planes and knocked out supply sites.

Despite the success, they were only able to intercept the Japanese four out of nine times. They made up for this when the combat dropped to lower altitudes. It was also learned that a better strategy was to attack the fleet on the ground with the P-39s’ cannons and bombs.

The Bell P-39 Airacobra: Disliked by many, loved by the Soviets

While the P-39 Airacobra was disliked by many, they were actually beneficial to the Soviet Union’s Red Army. The tactical environment of the Eastern Front meant air combat was largely conducted at lower altitudes, and Soviet airfields tended to be closer to the front lines. Therefore, the plane’s inability to fly high and its short flight range weren’t an issue.

Russian soldiers sitting around a Bell P-39 Airacobra
Russian aviators with a P-39. (Photo Credit: Keystone-France / Getty Images)

The Red Army received planes from the U.S. and the U.K. via the Alaska-Siberia ferry route. They were able to create an effective aerial fighting group that saw a number of victories against the Germans. The Red Air Force was such a big fan that they gave the P-39 an affectionate nickname, Kobruksha, or “Little Cobra.”

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The Russians kept the P-39 in service until 1949. Its effectiveness on the Eastern Front is an example that, while the plane may not have been ideal for all methods of air combat, it did accomplish a lot when circumstances allowed.