🛩️ This day in the history of aviation – April 6, 1938 – First flight of the Bell P-39 Airacobra
The Bell P-39 Airacobra was one of the principal American fighter aircraft in service when the United States entered World War II. The P-39 was used by the Soviet Air Force, and enabled individual Soviet pilots to collect the highest number of kills attributed to any U.S. fighter type flown by any air force in any conflict.
Designed by Bell Aircraft, it had an innovative layout, with the engine installed in the center fuselage, behind the pilot, and driving a tractor propeller with a long shaft. It was also the first fighter fitted with a tricycle undercarriage. Although its mid-engine placement was innovative, the P-39 design was handicapped by the absence of an efficient turbo-supercharger, preventing it from performing high-altitude work. For this reason it was rejected by the RAF for use over western Europe but adopted by the USSR, where most air combat took place at medium and lower altitudes.
Together with the derivative P-63 Kingcobra, the P-39 was one of the most successful fixed-wing aircraft manufactured by Bell.
The XP-39 made its maiden flight on 6 April 1938.at Wright Field, Ohio, achieving 390 mph (630 km/h) at 20,000 ft (6,100 m), reaching this altitude in only five minutes. However, the XP-39 was found to be short on performance at altitude. Flight testing had found its top speed at 20,000 feet to be lower than the 400 mph claimed in the original proposal.
The P-39 was an all-metal, low-wing, single-engine fighter, with a tricycle undercarriage and an Allison V-1710 liquid-cooled V-12 engine mounted in the central fuselage, directly behind the cockpit.
The Airacobra was one of the first production fighters to be conceived as a “weapons system”; in this case the aircraft (known originally as the Bell Model 4) was designed to provide a platform for the 37 mm T9 cannon. This weapon, which was designed in 1934 by the American Armament Corporation, a division of Oldsmobile, fired a 1.3 lb (590 g) projectile capable of piercing .8 in (2.0 cm) of armor at 500 yd (460 m) with armor-piercing rounds. The 90 in (230 cm)-long, 200 lb (91 kg) weapon had to be rigidly mounted and fire parallel to and close to the centerline of the new fighter.
The complete armament fit consisted of the T9 cannon with a pair of Browning M2 .50 caliber (12.7 mm) machine guns mounted in the nose. This changed to two .50 in (12.7 mm) and two .30 in (7.62 mm) guns in the XP-39B (P-39C, Model 13, the first 20 delivered) and two .50 in (12.7 mm) and four .30 in (7.62 mm) (all four in the wings) in the P-39D (Model 15), which also introduced self-sealing tanks and shackles (and piping) for a 500 lb (230 kg) bomb or drop tank.
The most successful and numerous use of the P-39 was by the Red Air Force (Военно-воздушные силы, Voenno-Vozdushnye Sily, VVS). They received the considerably improved N and Q models via the Alaska-Siberia ferry route. The tactical environment of the Eastern Front did not demand the high-altitude performance the RAF and AAF did. The comparatively low-speed, low-altitude nature of most air combat on the Soviet Front suited the P-39’s strengths: sturdy construction, reliable radio gear, and adequate firepower.
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Soviet pilots appreciated the cannon-armed P-39 primarily for its air-to-air capability. A common Western misconception is that the Bell fighters were used as ground attack aircraft. This is because the Soviet term for the mission of the P-39, prikrytiye sukhoputnykh voysk (coverage of ground forces) is commonly translated ground support, which is often taken to mean close air support. In Soviet usage, it has a broader meaning. Soviet-operated P-39s did make strafing attacks, but it was “never a primary mission or strong suit for this aircraft”.The Soviets developed successful group aerial fighting tactics for the Bell fighters and scored a surprising number of aerial victories over a variety of German aircraft. Soviet P-39s had no trouble dispatching Junkers Ju 87 Stukas or German twin-engine bombers and matched, and in some areas surpassed, early and mid-war Messerschmitt Bf 109s.
- Crew: 1
- Length: 30 ft 2 in (9.19 m)
- Wingspan: 34 ft 0 in (10.36 m)
- Height: 12 ft 5 in (3.78 m)
- Wing area: 213 sq ft (19.8 m2)
- Empty weight: 6,516 lb (2,956 kg)
- Gross weight: 7,570 lb (3,434 kg)
- Max takeoff weight: 8,400 lb (3,810 kg)
- Powerplant: × Allison V-1710-85 V-12 liquid-cooled piston engine, 1,200 hp (890 kW) at 9,000 ft (2,743 m) (using emergency power)
- Propellers: 3-bladed constant-speed propeller
- Stall speed: 95 mph (153 km/h, 83 kn) power off, Flaps & undercarriage down
- Never exceed speed: 525 mph (845 km/h, 456 kn)
- Range: 525 mi (845 km, 456 nmi) on internal fuel
- Service ceiling: 35,000 ft (11,000 m)
- Rate of climb: 3,805 ft/min (19.33 m/s) at 7,400 ft (2,256 m) (using emergency power)
- Time to altitude: 15,000 ft (4,572 m) in 4 minutes 30 seconds, at 160 mph (260 km/h)
- Wing loading: 34.6 lb/sq ft (169 kg/m2)
- Bombs: Up to 500 lb (230 kg) of bombs underwings and belly
The above text was copied from Wikipedia
Read more about the Airacobra’s history in the book Airacobra Advantage: The Flying Cannon, The Complete Story of Bell Aircraft Corporation’s P-39 Pursuit Fighter Plane