P-39 Airacobra
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| P-39 Airacobra | ||
|---|---|---|
| Missing image P-39.jpg Bell P-39 Airacobra | ||
| Description | ||
| Role | Fighter | |
| Crew | 1 | |
| First flight | April 1939 | |
| First variants entered service in | Early 1941 | |
| Manufacturer | ||
| Dimensions | ||
| Length | 30 ft 2 in | 9.2 m |
| Wingspan | 34 ft 0 in | 10.4 m |
| Height | 12 ft 5 in | 3.8 m |
| Wing area | 213 ft² | 19.8 m² |
| Weights | ||
| Empty | 5,347 lb | 2,420 kg |
| Loaded | 7,379 lb | 3,350 kg |
| Maximum takeoff | lb | kg |
| Powerplant | ||
| Engine | Allison V-1710 | |
| Power | 1,200 hp | 895 kW |
| Performance | ||
| Maximum speed | 376 mph | 605 km/h |
| Combat range | 1,098 miles | 1,770 km |
| Ferry range | miles | km |
| Service ceiling | 35,000 ft | 10,700 m |
| Rate of climb | 3,750 ft/min | 1,140 m/min |
| Armament (P-39Q) | ||
| Guns | 1 × 37 mm T9 cannon (propeller hub) 4 × 0.50 in (12.7 mm) machine guns (most P-39 variants armed with 1 37 mm T9 cannon, 4 0.30 in [7.62 mm], 2 0.50 in machine guns) | |
| Bombs | 500 pounds (230 kg) of bombs externally | |
The Bell P-39 Airacobra was one of the principal fighter aircraft in service with American forces at the start of World War II. (The P-39 was at first for a short time designated XP-45.)
The aircraft's unusual design featured its Allison engine mounted in the middle of the fuselage, just behind the pilot, driving the propeller through a driveshaft passing between the pilot's feet. The purpose of this was to free up space for the heavy main armament, a 37 mm T9 cannon firing through the center of the propeller hub for optimum accuracy and stability when firing. The weight distribution necessitated a tricycle undercarriage, a first among American fighters. Entry to the cockpit was through a side door rather than a moving canopy. The weight distribution of the P-39 supposedly is the reason for its tendency to enter a dangerous spin - a characteristic Soviet tests proved to the then-sceptical manufacturer who had been unable to reproduce them.
The P-39's Allison V-1710 engine had a single-speed, single-stage supercharger, which brought about a decrease of performance compared to the promising prototype which had been fitted with an an exhaust-driven turbo-supercharger. Due to the high weight of the P-39 and the poor high-altitude power of the mechanically supercharged Allison, the P-39's performance was markedly inferior to the contemporary European fighters, and as a result the first USAAF fighter units in the ETO were equipped with the Spitfire V (which ironically featured a single-speed, single-stage supercharger, too).
Above the V-1710's full throttle height of about 17,000 ft (5,000 m), the P-39's performance dropped off rapidly. This limited its usefulness in traditional fighter missions, in Europe as well as in the Pacific where it was not uncommon for Japanese bombers to attack at altitudes above the P-39's operational ceiling (which in the tropical hot air inevitably was lower than in moderate climates).
It is mistakenly believed that the Airacobra was used as a ground-attack airplane by the Soviet Union; the lack of a turbo-supercharger restricting it to low-altitude combat. In fact, it appears that the Soviets did not use it for ground-attack, but instead to provide top cover. The tactical environment of the Eastern Front did not demand the high-altitude operations that the RAF and USAAF used with their big bombers. In the relatively low-altitude operations in the East the lack of a supercharger was not as bad a handicap. The second-highest scoring Allied ace, Pokryshkin, flew the P-39 until 1944 before finally converting to Lavochkin fighters.
9,584 were produced, with over half being sent to the Soviet Union under the Lend-Lease program.
A number are still in existence of which three are still flying.
The mid-engine, gun-through-hub concept was developed further in the Bell P-63 Kingcobra.
Sources: Template:Web reference - Aerodotus 19:18, 3 Jan 2005 (UTC)
Variants
- XP-39
- YP-39
- YP-39A
- XP-39B
- P-39C
- P-39D
- P-39D-1
- P-39D-2
- XP-39E
- P-39E
- P-39F-1
- P-39F-2
- P-39G
- P-39H
- P-39J
- P-39K
- P-39L
- P-39M
- P-39N
- P-39P
- P-39Q
| Related content | |
|---|---|
| Related development | P-63 Kingcobra |
| Similar aircraft | |
| Designation series | |
| Related lists | List of military aircraft of the United States - List of fighter aircraft |
Reference
- William Green (1961). War Planes of the Second World War - Fighters, (Vol 4). London: MacDonald
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