Bell P-39 Airacobra

Specifications

1st Flight 1938

Crew: one

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: 1 × Allison V-1710-85 V-12 liquid-cooled piston engine, 1,200 hp (890 kW) at 9,000 ft (2,743 m) (emergency power)

Propellers: 3-bladed constant-speed propeller

Performance

Maximum speed: 389 mph (626 km/h, 338 kn)

Stall speed: 95 mph (153 km/h, 83 kn) power off, flaps and 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 (2,300 m) (using emergency power)

Time to altitude: 15,000 ft (4,600 m) in 4 minutes 30 seconds, at 160 mph (260 km/h)

Wing loading: 34.6 lb/sq ft (169 kg/m2)

Power/mass: 0.16 hp/lb (0.26 kW/kg)

 

 

Variants

XP-39-BE – Bell Model 11, one prototype 38–326 first flown 6 April 1938. Powered by an Allison V-1710-17 (E2) engine (1,150 hp/858 kW), the aircraft was fitted with a General Electric B-5 turbo supercharger, creating a two stage supercharging system similar to the P-38 (engine-mounted mechanical supercharger, remote exhaust-driven turbo-supercharger as a second stage for high-altitude). Provision was made for two .50 in (12.7 mm) machine guns in the forward fuselage and one 25 mm (.98 in) cannon but aircraft remained unarmed. Later converted to XP-39B.

XP-39B – One conversion first flown 25 November 1939. Streamlined XP-39 based on NACA wind tunnel testing resulting in revised canopy and wheel door shape, oil cooler/ engine coolant radiator intakes moved from right fuselage to wing roots, fuselage increased length (by 1 ft 1 in, to 29 ft 9 in) and decreased wingspan (by 1 ft 10 in, to 34 ft). The turbo supercharger was removed, and the single-stage, single speed, supercharged Allison V-1710-37 engine (1,090 hp/813 kW) was left in place. The carburettor air intake was moved behind canopy, just above the carburettor.

YP-39 – Bell Model 12, service test version, V-1710-37 (E5) engine (1,090 hp/813 kW). First two aircraft delivered with armament, the remained with a M4 37 mm (1.46 in) auto cannon with 15 rounds, 2 × .50 in (12.7 mm) machine guns with 200 rpg, and 2 × .30 in (7.62 in) machine guns with 500 rpg in the nose. wider vertical tail than XP-39B. 12 completed with the first flying 13 September 1940.

YP-39A – One intended to have a high-altitude V-1710-31 engine (1,150 hp/858 kW), but was delivered as a regular YP-39.

P-39C – Bell Model 13, first flown in January 1941 it was the first production version, identical to YP-39 except for V-1710-35 engine (1,150 hp/858 kW). Armed with 1 × 37 mm (1.46 in) cannon, 2 × .50 in (12.7 mm) & 2 × .30 in (7.62 mm) machine guns in the nose. Aircraft lacked armor and self-sealing fuel tanks. Twenty produced out of an order of 80 the remainder were redesignated P-39D

P-39D-BE – Bell Model 13, production variant based on the P-39C with 245 lb (111 kg) of additional armor, self-sealing fuel tanks. Armament increased to 1 × 37 mm/1.46 in cannon (30 rounds), 2 × .50 in/12.7 mm (200 rpg) and 4 × wing mounted .30 in/7.62 mm (1,000 rpg) machine guns; 60 Produced.

P-39D-1 – Bell Model 14A, production variant fitted with a 20 mm (.79 in) M1 cannon. Specifically ordered for delivery under Lend-Lease; 336 produced:1 sent to Soviet Union and used in combat alongside P-39D-2s.

P-39D-2 – Bell Model 14A-1, production variant with a V-1710-63 (E6) engine (1,325 hp/988 kW) restored the 37 mm (1.46 in) cannon, provisions for a single 145 gal (549 l) drop tank or maximum 500 lb (227 kg) bomb under the fuselage; 158 produced. Some 50 at least sent to USSR and used in combat, some 15–20 used by 16th Guards Fighter Regiment.

P-39D-3 – 26 conversions from P-39D-1 to Photo Reconnaissance Configuration; K-24 and K-25 camera in rear fuselage, extra armor for oil coolers

P-39D-4 – 11 conversions from P-39D-2 to Photo Reconnaissance Configuration. Same modifications as D-3 aircraft.

XP-39E – Bell Model 23. three P-39Ds modified for ground and flight testing first flown 21 February 1942. Intended for Continental I-1430-1 engine with (2,100 hp/1,566 kW) actually flown with Allison V-1710-47 (1,325 hp/988 kW) engine. Airframes were used to test various wing and different vertical tail surfaces. Fuselage was lengthened by 1 ft 9 in (53 cm). Used in the development of the P-63. The production variant, with the Continental engines was to be redesignated P-76; there was no Bell XP-76 as such.

P-39F – P-39F-1 – Bell Model 15B, production variant with three-bladed Aeroproducts constant speed propeller, 12 exhaust stacks; 229 built.

TP-39F-1 – One P-39F converted as a two-seat training version with additional cockpit added in nose— no armament.

P-39F-2 – 27 conversions from P-39F-1 with additional belly armor and cameras in rear fuselage.

P-39G – Bell Model 26, 1800 ordered, intended to be a P-39D-2 with an Aeroproducts propeller. Due to modifications during production no P-39G were actually delivered. Instead, these aircraft were re-designated P-39K, L, M and N.

P-39J – Bell Model 15B, P-39F with V-1710-59 (1,100 hp/820 kW) engine with automatic boost control,; 25 built.

P-39K – P-39K-1 – Bell Model 26A, a P-39D-2 with Aeroproducts propeller and V-1710-63 (E6) (1,325 hp/988 kW) engine. Vents added to nose; 210 built. Some 50 sent to USSR and used in combat – 16th Guards Fighter Regiment were initially issued 11, 1 of, which was Pokryshkin’s first Airacobra.

P-39K-2 – Six conversion from P-39K-1 with additional belly armor and cameras in rear fuselage.

P-39K-5 – One conversion with a V-1710-85 (E19) engine to serve as a P-39N prototype

P-39L-1BE 44-4673 – Lend-Lease to USSR

P-39L – P-39L-1 – Bell Model 26C, a P-39K with Curtiss Electric propeller, revised nose gear for reduced drag, provision for under wing rockets; 250 built.

P-39L-2 – Eleven conversions from P-39L-1 with additional belly armor and cameras in rear fuselage.

P-39M – P-39M-1 – Bell Model 26D, variant with an 11 ft 1 in Aeroproducts propeller, V-1710-67 (E8) (1,200 hp/895 kW) engine with improved high-altitude performance at the expense of low-altitude performance, 10 mph (16 km/h) faster than P-39L at 15,000 ft (4,600 m). Note: some P-39M-1BE were delivered with the V-1710-83 (E18) engine; 240 built.

P-39N – Bell Model 26N, originally part of the P-39G order. V-1710-85 (E19) (1,325 hp/988 kW) engine. Aeroproducts propeller (10 ft 4 in diameter) & different propeller reduction gear ratio. Starting with the 167th aircraft, propeller increased to 11 ft 7 in & internal fuel reduced from 120 gal (454 l) to 87 gal (329 l); 500 built.

P-39N-1 – Variant with internal changes to adjust center of gravity when nose guns were fired; 900 built.

P-39N-2 – 128 P-39N-1 converted with additional belly armor and cameras in rear fuselage.

P-39N-3B – 35 P-39N converted with additional belly armor and cameras in rear fuselage.

P-39N-5 – Variant with armor reduced from 231 lb (105 kg) to 193 lb (88 kg), Armor plate replaced the bulletproof glass behind the pilot, SCR-695 radio was fitted, and a new oxygen system was installed; 695 built.

P-39N-6 – 84 P-39N-5 converted with additional belly armor and cameras in rear fuselage.

P-39Q – The final production variant last one built in August 1944.

P-39Q-1 – Bell Model 26Q, variant with wing-mounted 0.30 in (7.62 mm) machine guns replaced with a single 0.50 in (12.7 mm) with 300 rounds of ammunition in a pod under each wing. Armor increased to the original 231 lb (105 kg) of armor of the P-39N-1BE; 150 built.

P-39Q-2 – Five P-39Q-1s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.

P-39Q-5 – Production variant with reduced armor (193 lb/88 kg), fuel capacity increased (110 gal/416 l). Type A-1 bombsight adapters added; 950 built.

TP-39Q-5 – One conversion to a two-seat training variant with additional cockpit added in nose – no armament. Enlarged tail fillet and a shallow ventral fin added.

P-39Q-6 – 148 P-39Q-5s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.

P-39Q-10 – Variant with increased armor (228 lb/103 kg), fuel capacity increased (120 gal/454 l). Automatic Boost controls added and Throttle & RPM controls were coordinated. Winterization of oil systems and rubber mounts added to the engines; 705 built.

P-39Q-11 – Eight P-39Q-10s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.

P-39Q-15 – Production variant with reinforced inclined deck to prevent .50 in (12.7 mm) machine gun tripod mounting cracking, bulkhead reinforcements to prevent rudder pedal wall cracking, a reinforced reduction gearbox bulkhead to prevent cowling former cracking, and repositioning of the battery solenoid. Oxygen system reduced from four bottle to only two; 1,000 built.

P-39Q-20 – Production variant with minor equipment changes. The under-wing 0.50 in (12.7 mm) machine gun pods were sometimes omitted in this version; 1,000 built.

P-39Q-21 – 109 P-39Q-20 fitted with a four-bladed Aeroproducts propeller.

RP-39Q-22 – 12 P-39Q-20s converted to two-seat trainers .

P-39Q-25 – Production variant similar to the P-39Q-21 but with a reinforced aft-fuselage and horizontal stabilizer structure; 700 built.

P-39Q-30 – Production variant that reverted to the three-bladed propellor; 400 built.

ZF-39 – Remaining examples in service, re-designated in June 1948.

P-45 – The P-45 was the initial designation of the P-39C or Model 13.

XFL-1 Airabonita – One prototype tail-wheel undercarriage carrier fighter for the USN.

XTDL-1 – United States Navy (USN) designation for two P-39Qs used as target drones. Assigned to NAS Cape May for test work. Later redesignated F2L-1K.

F2L-1K – XTDL-1 drones re-designated

P-400 – An export model of the P-39 with a less powerful cannon, using a 20 mm Hispano cannon rather than the standard 37 mm cannon. It also had 2 .50 caliber machine guns in the nose, and 2 .30 caliber machine guns in each wing.

Airacobra I – Bell Model 13, Royal Air Force (RAF) designation for three P-39Cs delivered to the A&AEE Boscombe Down for testing.

Airacobra IA – Bell Model 14. Briefly named ‘Caribou’. V-1710-E4 (1,150 hp/858 kW) engine, 1 × 20 mm (.79 in) cannon with 60 rounds & 2 × 0.50 in (12.7 mm) machine guns were mounted nose and four 0.303 in (7.7 mm) machine guns were mounted in the wings. IFF set removed from behind pilot.

note: the designation IA indicates direct purchase aircraft (as opposed to Lend-Lease); 675 built. The USAAF operated 128 former RAF aircraft with the designation P-400.

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