| 词条 | Bell P-76 | |||||||||||||||||
| 释义 |
The Bell P-76 was the proposed designation for a production model derivative of the XP-39E, a single-engine American fighter aircraft prototype of World War II. Design and developmentOn 26 February 1941 the United States Army Air Corps (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 P-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 P-76 were implemented in the subsequent Bell P-63 Kingcobra. Specifications (P-76){{aircraft specifications|plane or copter?=plane |jet or prop?=prop |crew=1 |length main=31 ft 11 in |length alt=9.7 m |span main=35 ft 10 in |span alt=10.9 m |height main= ft in |height alt= m |area main=236 ft² |area alt=21.9 m² |empty weight main=6,936 lb |empty weight alt=3,150 kg |loaded weight main= |loaded weight alt= |max takeoff weight main=8,918 lb |max takeoff weight alt=4,050 kg |engine (prop)= |type of prop=Continental I-1430-1 |number of props=1 |power main=2,100 hp |power alt=1,600 kW |max speed main=386 mph |max speed alt=335 knots, 620 km/h |max speed more=at 21,680 ft (6,600 m) |range main= |range alt= |ceiling main= |ceiling alt= |climb rate main=2,150 ft/min |climb rate alt=11 m/s |loading main= |loading alt= |power/mass main= |power/mass alt= |guns=
|bombs=500 lb (227 kg) externally }} See also{{aircontent|related=
|similar aircraft= |lists=
}} ReferencesCitations1. ^UIUC incomplete guide to Airfoil usage Retrieved: 9 August 2008 2. ^1 Bowers 1979, pp.21-25. Bibliography{{refbegin}}
5 : Cancelled military aircraft projects of the United States|Bell aircraft|Mid-engined aircraft|Single-engined tractor aircraft|Low-wing aircraft |
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