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The Lockheed/Boeing/General Dynamics YF-22 was an American single-seat, twin-engine fighter aircraft technology demonstrator designed for the United States Air Force (USAF). The design was a finalist in the USAF's Advanced Tactical Fighter competition, and two prototypes were built for the demonstration/validation phase of the competition. The YF-22 won the contest against the Northrop YF-23, and entered production as the Lockheed Martin F-22 Raptor. The YF-22 has similar aerodynamic layout and configuration as the F-22, but with differences in the position and design of the cockpit, tail fins and wings, and in internal structural layout. In the 1980s, the USAF began looking for a replacement for its fighter aircraft, especially to counter the advanced Su-27 and MiG-29. A number of companies, divided into two teams, submitted their proposals. Northrop and McDonnell Douglas submitted the YF-23. Lockheed, Boeing and General Dynamics proposed and built the YF-22, which, although marginally slower and having a larger radar cross-section, was more agile than the YF-23. Primarily for this reason, it was picked by the Air Force as the winner of the ATF in April 1991. Following the selection, the first YF-22 was retired to a museum, while the second prototype continued flying until an accident relegated it to the role of an antenna test vehicle. == Design and development == (詳細はAdvanced Tactical Fighter (ATF) as a new air superiority fighter to replace the F-15 Eagle and F-16 Fighting Falcon. This was made more crucial by the emerging worldwide threats, including development and proliferation of Soviet MiG-29 and Su-27 "Flanker"-class fighter aircraft. It would take advantage of the new technologies in fighter design on the horizon including composite materials, lightweight alloys, advanced flight-control systems, more powerful propulsion systems and stealth technology. In 1985 the Air Force sent out technical requests for proposals to a number of aircraft manufacturing teams. The formal request for proposal (RFP) was issued in July 1986, and two contractor teams, Lockheed, Boeing and General Dynamics, along with Northrop and McDonnell Douglas, were selected on 31 October 1986 to undertake a 50-month demonstration phase, culminating in the flight test of the two teams' prototypes, the YF-22 and the YF-23.〔Miller 2005, pp. 19–20.〕〔Jenkins and Landis 2008, pp. 233–234.〕〔Williams 2002, pp. 5–6.〕 The YF-22 was designed to meet USAF requirements for survivability, supercruise, stealth, and ease of maintenance.〔''Flight International'' 1986, p. 10.〕 Because Lockheed's submission was selected as one of the winners, the company, through its Skunk Works division, assumed leadership of the program partners. It would be responsible for the forward cockpit and fuselage, as well as final assembly at Palmdale, California. Meanwhile, the wings and aft fuselage would be built by Boeing, with the center fuselage, weapons bays, tail and landing gears built by General Dynamics.〔 Compared with its Northrop/McDonnell Douglas counterpart, the YF-22 has a more conventional design – its wings have larger control surfaces, such as full-span trailing edge,〔''Flight International'' 1990, p. 4.〕 and, whereas the YF-23 had two tail surfaces, the YF-22 had four, which made it more maneuverable than its counterpart.〔''Flight International'' 1990, p. 46.〕 Two examples of each PAV were built for the Demonstration-Validation phase: one with General Electric YF120 engines, the other with Pratt & Whitney YF119 engines.〔 The YF-22 was given the unofficial name "''Lightning II''" after Lockheed's World War II-era fighter, the P-38 Lightning, which persisted until the mid-1990s when the USAF officially named the aircraft "''Raptor''". The F-35 later received the ''Lightning II'' name in 2006.〔"〕 The first YF-22 (serial number ''87-0700'', N22YF), with the GE YF120,〔Williams 2002, p. 5.〕〔''Flight International'' 1990, p. 6.〕 was rolled out on 29 August 1990.〔Jenkins and Landis 2008, p. 235.〕〔Bailey 1990, p. 34.〕 PAV-1 first flew on 29 September 1990, taking off from Palmdale piloted by David L. Ferguson.〔〔Goodall 1992, p. 99.〕 During the 18-minute flight, PAV-1 reached a maximum speed of and a height of , before landing at Edwards AFB.〔 Following the flight, Ferguson said that the remainder of the YF-22 test program would be concentrated on "...the manoeuvrability of the aeroplane, both supersonic and subsonic".〔 The second YF-22 (PAV-2, s/n ''87-0701'', N22YX) with the P&W YF119 made its maiden flight on 30 October at the hands of Tom Morgenfeld.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lockheed YF-22」の詳細全文を読む スポンサード リンク
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