The Bell P-39 Airacobra was a single-seat fighter used by the United States and her allies during World War II.
The first production model of the series was the P-39C model, originally designated P-45. Unlike most fighters of the time, the P-39 had a tricycle undercarriage, due to the fact that it was powered by an Allison V-1710 liquid cooled engine located behind the cockpit. The engine was mounted in this position, directly over the center of gravity, in order to allow the aircraft to carry a 37mm M4 cannon that fired through the middle of the propeller. The P-39 also had an additional two 12.7mm MGs mounted in the nose and two 7.62mm MGs mounted in the wings.
The P-39 also differed by having a side opening car style door for the cockpit instead of a sliding hood.
The P-39 Airacobra was developed by R. J. Woods and O. L. Woodson in 1938, and the first prototype - the XP-39 - made its initial flight in April 1939, with the first models entering service soon afterwards. A British order in 1940 led to the P-39D based Aircobra I, which had the 15 round M4 cannon replaced by a 60 round Hispano Auto-cannon. Arriving in June 1941, these underwent RAF tests, which revealed that production P-39s had an overall performance that did not match contemporary British fighters, prompting British rejection of the type. Apart from one example retained by the Royal Navy for experimental work, the P-39s intended for the RAF were either returned to US service as the P-400, or passed to the Soviet Union.[N 2]
A total of 9,588 examples were built, with the final batch, comprising the last of over 4,900 of the P-39Q version, being delivered in May 1944.
Bell also developed a naval fighter based on the P-39 design. Delivered as Navy No. 1588, and known as the XFL-1 Airabonita, this aircraft was first flown on 13 May 1940, and primarily differed from the land-based aircraft by having tailwheel undercarriage and underwing radiators. Further development was abandoned at the beginning of 1942, after the type failed its carrier qualification trials.
- As well as being operated by the Free French, the Italian Co-Belligerent Air Force, Portugal (Interned aircraft), the Soviet Union and - briefly - the Royal Air Force, the type was also flown in limited numbers by the air arms of Australia (type code A-53), Canada (one example tested late November 1941), Germany (captured example flown with fuselage code GE+DV) and Poland (P-39Q of the 2nd Special Air Regiment, Polish Air Force, serving as the personal aircraft of Russian General Fyodor Polynin, Commander of the Polish Air Force in 1944 - 1947).
- A number of these retained the 20 mm Hispano cannon and original British serial.
- Gunston, Bill. Illustrated Directory of Fighting Aircraft of World War II. Salamander Books. 1988. ISBN 0-86101-390-5 Page 98
- "Aircraft of the World Card Collection (Group 11 Card 21).
- Gunston, Bill. St Michael Aircraft of World War 2. Octopus Books. 1982. ISBN 0-86273-014-7 Page 20
- Green, William and Gordon Swanborough. Complete Book of Fighters. Salamander Books. 2001. ISBN 1-84065-269-1 Page 57
- "Aircraft of the World card collection (Group 11 Card 30).