The Lockheed–Boeing–General Dynamics YF-22 is an American single-seat, twin-engine, stealth fighter prototype technology demonstrator designed for the United States Air Force (USAF). The design team, with Lockheed as the prime contractor, was a finalist in the USAF's Advanced Tactical Fighter (ATF) competition, and two prototypes were built for the demonstration and validation phase. The YF-22 team won the contest against the Northrop-led YF-23 team for full-scale development and the design was developed into the Lockheed Martin F-22. The YF-22 has a similar aerodynamic layout and configuration as the F-22, but with notable differences in the overall shaping such as 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 to counter emerging threats such as the advanced Soviet Su-27 and MiG-29. A number of companies submitted their proposals, with the competition narrowing down to Lockheed and Northrop as the two finalists for demonstration/validation. Northrop teamed with McDonnell Douglas to develop the YF-23; Lockheed teamed with Boeing and General Dynamics to develop the YF-22, which, although marginally slower and having a larger radar cross-section, was more agile than the YF-23. The Lockheed team was picked by the Air Force as the winner of the ATF competition in April 1991. The U.S. Navy considered adopting a naval version of the ATF, but these plans were later canceled due to cost. Following the selection, the first prototype was retired as an exhibit at the Air Force Flight Test Museum, while the second continued flight testing until an accident relegated it to the role of an antenna test vehicle and it was later stored.
Development
Concept definition In 1981, the U.S. Air Force (USAF) began exploring concepts and developing requirements for an Advanced Tactical Fighter (ATF) that would eventually become 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 in the late Cold War, including development and proliferation of Soviet MiG-29 "Fulcrum" and Su-27 "Flanker"-class fighter aircraft, A-50 "Mainstay" airborne warning and control system (AWACS), and more advanced surface-to-air missile systems. The ATF would take advantage of the new technologies in fighter design on the horizon including composite materials, lightweight alloys, advanced avionics and flight-control systems, more powerful propulsion systems and stealth technology.
The USAF sent out the ATF request for information (RFI) to the aerospace industry in May 1981 to explore what the future fighter aircraft could look like, and subsequently established a Concept Development Team (CDT) to analyze the results. Eventually code-named "Senior Sky", the ATF at this time was still in the midst of requirements definition with both air-to-air and air-to-ground missions in consideration, and consequently there was substantial variety in the responses from the industry. Lockheed's initial concept was a particularly large aircraft called CL-2016, weighing over 110,000 lb (50,000 kg) at takeoff and nicknamed "battlecruiser" for its size, that resembled its SR-71/YF-12 with large delta wings and engines mounted in nacelles spaced away from the fuselage and would have had similarly high operating speed and altitude as a missile platform (or "missileer" per Lockheed). In 1983, the ATF Concept Development Team became the System Program Office (SPO) at Wright-Patterson Air Force Base. After discussions with aerospace companies and Tactical Air Command (TAC), the CDT/SPO narrowed the requirements to an air superiority fighter with outstanding kinematic performance, i.e. excellent speed and maneuverability, to replace the F-15. Additionally, the SPO began to increasingly emphasize stealth for survivability, while still requiring fighter-like speed and maneuverability, due to the Air Force's experience from "black world" projects such as the Have Blue/F-117 ("Senior Trend") and the Advanced Technology Bomber (ATB) program (which would result in the B-2, or "Senior Ice"). With stealth becoming a core requirement, Lockheed's design team, led by Bart Osborne from its Skunk Works division at Burbank, California, migrated away from its initial SR-71-like "battlecruiser" concept and instead began drafting a design that resembled the company's F-117 stealth attack aircraft. However, the faceted shape, resulting from Lockheed using the same "Echo" computer program that it had used to design the F-117, gave the design very poor aerodynamic performance that would be unsuitable for a fighter. Lockheed would perform poorly throughout the concept exploration phase, placing among the bottom of the competing contractors.
Demonstration and validation
By November 1984, the SPO had further narrowed the requirements and released the Statement of Operational Need (SON), with requirements calling for a 50,000 lb (22,700 kg) takeoff weight fighter that places strong emphasis on stealth, maneuverability, and supersonic cruise without afterburners, or supercruise; mission radius was expected to be 500 nautical miles (580 mi; 930 km) mixed subsonic/supersonic or 700–800 nautical miles (806–921 mi; 1,300–1,480 km) subsonic. In September 1985, the Air Force sent out technical request for proposals (RFP) to a number of aircraft manufacturing teams for demonstration and validation (Dem/Val). In addition to the ATF's demanding technical requirements, Dem/Val also placed a great deal of importance on systems engineering, technology development plans, and risk mitigation. The top four proposals, later reduced to two to reduce program costs, would proceed with Dem/Val as finalists; there was initially no requirement for prototype air vehicles. At the time, the Air Force anticipated procuring 750 ATFs at a unit flyaway cost (or the unit production cost for delivery) of $35 million in fiscal year (FY) 1985 dollars (~$86.4 million in 2024). Furthermore, under Congressional pressure to combine efforts with the Air Force to reduce costs, the U.S. Navy joined the ATF program initially as an observer and eventually announced in 1988 that it would use a variant/derivative of the winning design to replace its F-14 Tomcat as the Navy Advanced Tactical Fighter (NATF); the service called for the procurement of 546 aircraft.
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