Bell XP-76

Bell XP-76
Role	Fighter aircraft
Manufacturer	Bell Aircraft Corporation
First flight	1942
Introduction	n/a
Status	Did not enter mass-production
Primary user	United States Air Force
Number built	0
Developed from	P-39 Airacobra

The Bell P-76 was the proposed designation for a production model derivative of the XP-39E, a single-engine United States fighter aircraft prototype of World War II.

Background

On 26 February 1941 the USAAC placed a contract with Bell allowing for the purchase of two XP-39Es (41-19501 and 41-19502) which were envisaged to be a major improvement on the P-39D series. Because of the number of changes proposed the production model was to be called the Bell P-76.

The Bell P-76 was proposed to address the poor high-altitude performance of the P-39 Airacobra by incorporating a new and thicker wing with a symmetrical airfoil; the section chosen was NACA 0018 at the wing-root tapering to an NACA 23009 at the tip. Although the new wing has often been referred to as a laminar flow type, this was not the case.^[1] The wing span was increased to 35 ft 10 in (10.9 m) and the area to 236 ft² (21.9 m²), the thicker wing allowing an increase in the fuel capacity to 150 US gallons (568 l).^[2]

Design of a new Allison V-1710-E9 was also underway. This version, which had the military designation of V-1710-47, used a two-stage mechanical supercharger to increase the engine power at altitude. However, this engine went through so many design changes that it ended up being almost identical to the later V-1710-93 which was fitted in the XP-63A.^[2]

Another change was the engine bay was modified to accept a more powerful engine in lieu of the V-1710. Its origins lie in the 1941 project to equip three P-39D (41-19501, 41-19502 and 42-7164) with the Continental V-1430-1 liquid-cooled supercharged engine. The resultant XP-39E had a symmetrical airfoil wing with square wingtips, an elongated fuselage to accommodate the larger engine, and revised air intakes and radiators. The three prototypes each had a different tailfin. Since the Continental engine was not available at rollout, the prototypes flew with Allison V-1710-47 engines. In 1942, the XP-39E was redesignated XP-76. Although 4,000 aircraft were initially ordered, the order was cancelled to permit the Bell factory to manufacture B-29 Superfortress bomber aircraft under license from Boeing. Many of the lessons learned in the XP-76 were implemented in the subsequent Bell P-63 Kingcobra.

Specifications (XP-76)

General characteristics

Crew: 1
Length: 31 ft 11 in (9.7 m)
Wingspan: 35 ft 10 in (10.9 m)
Height: ft in (m)
Wing area: 236 ft² (21.9 m²)
Empty weight: 6,936 lb (3,150 kg)
Max. takeoff weight: 8,918 lb (4,050 kg)
Powerplant: 1 × Continental I-1430-1, 2,100 hp (1,600 kW)

Performance

Maximum speed: 386 mph (335 knots, 620 km/h) at 21,680 ft (6,600 m)
Rate of climb: 2,150 ft/min (11 m/s)

Armament

Guns:
- 1× 37 mm (1.46 in) Oldsmobile T9 cannon, 30 rounds
- 2× 0.50 in (12.7 mm) M2 Browning machine guns, 200 rounds per gun
- 4× 0.30 in (7.62 mm) M1919 machine guns, 1,000 rounds per gun
Bombs: 500 lb (227 kg) externally

References

Citations

↑ UIUC incomplete guide to Airfoil usage Retrieved: 9 August 2008
1 2 Bowers 1979, pp.21-25.

Bibliography

Bowers, Peter M. "Airborne Cobra Pt.II". Airpower magazine, Vol.9, No.1, January 1979.

USAAS/USAAC/USAAF/USAF fighter designations 1924–1962

Pursuit (pre-1948) Fighter (post-1948)	P-1 P-2 P-3 XP-4 P-5 P-6 XP-7 XP-8 XP-9 XP-10 P-11 P-12 XP-13 XP-14 XP-15 P-16 P-17 YP-18 YP-19 YP-20 P-21 XP-22 P-23 YP-24 P-25 P-26 P-27 P-28 P-29 P-30 XP-31 P-32 P-33 XP-34 P-35 P-36 P-37 P-38 P-39 P-40 XP-41 P-42 P-43 P-44 P-45 XP-46 P-47 XP-48 XP-49 XP-50 P-51 XP-52 P-53 XP-54 XP-55 XP-56 XP-57 XP-58 P-59 P-60 P-61/C XP-62 P-63 P-64 P-65 P-66 XP-67 XP-68 P-69 P-70 XP-71 XP-72 P-73 P-74¹ P-75 XP-76 XP-77 P-78 XP-79 P-80 XP-81 F-82 XP-83 F-84 F-85 F-86/D XF-87 F-88 F-89 XF-90 XF-91 XF-92 YF-93 F-94 F-95 F-96 F-97 F-98 F-99 F-100 F-101 F-102 XF-103 F-104 F-105 F-106 F-107 XF-108 XF-109 F-110 F-111/B

Pursuit, Biplace	PB-1 PB-2 PB-3

Fighter, Multiplace	FM-1 FM-2

¹ Not assigned See also: F-24 • F-117 • P-400 • post-1962 sequence

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