YF-22
Encyclopedia
The Lockheed/Boeing/General Dynamics YF-22 was a single-seat, twin-engined prototype fighter aircraft
designed for the United States Air Force
(USAF). The YF-22 was a finalist in the USAF's Advanced Tactical Fighter
competition; two prototypes were built. The YF-22 won the contest against the Northrop YF-23, and entered production as the Lockheed Martin F-22 Raptor. The YF-22 is similar to the F-22, but with differences in the cockpit, tail fins and wings.
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.
(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 Su-27 "Flanker"
-class fighter aircraft. It would take advantage of the new technologies in fighter design on the horizon including composite material
s, lightweight alloy
s, 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. A 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 two prototypes, the YF-22 and the YF-23.
The YF-22 was designed to meet USAF requirements for survivability, supercruise
, stealth, and ease of maintenance. Because Lockheed's design was selected as the winner, the company, through its Skunk Works
division, assumed leadership of the program. 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 counterpart, the YF-22 has a more conventional design – its wings have larger control surfaces, such as full-span trailing edge, and, whereas the YF-23 had two tail surfaces, the YF-22 had four, which made it more maneuverable than its counterpart. Two examples of each prototype 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. Two aircraft were built. The first YF-22 (serial number
87-0700, N22YF), with the GE YF120, was rolled out on 29 August 1990. At the controls of David L. Ferguson, PAV-1 first flew on 29 September 1990, taking off from Palmdale. During the 18-minute flight, PAV-1 reached a maximum speed of 250 knots (136.1 m/s) and a height of 12500 feet (3,810 m), before landing at Edwards AFB. Following the flight, Dave 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), made its maiden flight on 30 October at the hands of Tom Morgenfeld.
(AoA, or high-Alpha) flights were carried out on the YF-22. The aircraft fired AIM-9 Sidewinder
and AIM-120 AMRAAM
missiles from internal weapon bays. The first prototype, PAV-1, achieved Mach 1.58 in supercruise, while PAV-2 reached a maximum supercruise speed of Mach 1.43. Flight testing continued until 28 December 1990, by which time 74 flights were completed and 91.6 airborne hours were accumulated. Following flight testing, the contractor teams submitted proposals for ATF production.
On 23 April 1991, the YF-22 was announced by Secretary of the Air Force
Donald Rice
as the winner of the ATF competition. The YF-23 design was more stealthy and faster, but the YF-22 was more agile. It was speculated in the aviation press that the YF-22 was also seen as more adaptable to the Navy's Navalized Advanced Tactical Fighter (NATF), but the US Navy abandoned NATF by 1992. Instead of being retired, as with the case of PAV-1, PAV-2 subsequently flew sorties following the competition – it amassed another 61.6 flying hours during 39 flights. On 25 April 1991, the aircraft sustained serious damage during a landing attempt as a result of pilot-induced oscillations. It was repaired but never flew again, and instead served as a static test vehicle thereafter. In 1991, it was anticipated that 650 aircraft would be procured.
In many respects, the YF-22s were different from production F-22s. Contrary to the F-117 Nighthawk, which was initially difficult to control because of small vertical stabilizer
s, Lockheed over-specified the fin area on its YF-22. Therefore, the company reduced the size of those on F-22s by 20–30 percent. Lockheed recontoured the shape of the wing and stabilator
trailing edges to improve aerodynamics, strength, and stealth characteristics; the wing sweep was reduced by 6° from 48°. Finally, to improve pilot visibility, the canopy was moved forward 7 inches (178 mm), and the engine intakes were moved rearward 14 inches (356 mm).
Note some specifications are estimated.
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
designed for the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
(USAF). The YF-22 was a finalist in the USAF's Advanced Tactical Fighter
Advanced Tactical Fighter
The Advanced Tactical Fighter was a demonstration and validation program undertaken by the United States Air Force to develop a next-generation air superiority fighter to counter emerging worldwide threats, including Soviet Sukhoi Su-27 and Mikoyan MiG-29 fighters under development in the 1980s...
competition; two prototypes were built. The YF-22 won the contest against the Northrop YF-23, and entered production as the Lockheed Martin F-22 Raptor. The YF-22 is similar to the F-22, but with differences in the cockpit, tail fins and wings.
In the 1980s, the USAF began looking for a replacement for its fighter aircraft, especially to counter the advanced Su-27
Sukhoi Su-27
The Sukhoi Su-27 is a twin-engine supermanoeuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the large United States fourth generation fighters, with range, heavy armament, sophisticated avionics and high manoeuvrability...
and MiG-29
Mikoyan MiG-29
The Mikoyan MiG-29 is a fourth-generation jet fighter aircraft designed in the Soviet Union for an air superiority role. Developed in the 1970s by the Mikoyan design bureau, it entered service with the Soviet Air Force in 1983, and remains in use by the Russian Air Force as well as in many other...
. A number of companies, divided into two teams, submitted their proposals. Northrop
Northrop Corporation
Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...
and McDonnell Douglas
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...
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
In 1981, the U.S. Air Force developed a requirement for an Advanced Tactical FighterAdvanced Tactical Fighter
The Advanced Tactical Fighter was a demonstration and validation program undertaken by the United States Air Force to develop a next-generation air superiority fighter to counter emerging worldwide threats, including Soviet Sukhoi Su-27 and Mikoyan MiG-29 fighters under development in the 1980s...
(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 Su-27 "Flanker"
Sukhoi Su-27
The Sukhoi Su-27 is a twin-engine supermanoeuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the large United States fourth generation fighters, with range, heavy armament, sophisticated avionics and high manoeuvrability...
-class fighter aircraft. It would take advantage of the new technologies in fighter design on the horizon including composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
s, lightweight alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
s, advanced flight-control systems, more powerful propulsion systems and stealth technology
Stealth technology
Stealth technology also termed LO technology is a sub-discipline of military tactics and passive electronic countermeasures, which cover a range of techniques used with personnel, aircraft, ships, submarines, and missiles, to make them less visible to radar, infrared, sonar and other detection...
. In 1985 the Air Force sent out technical requests for proposals to a number of aircraft manufacturing teams. A request for proposal
Request for Proposal
A request for proposal is issued at an early stage in a procurement process, where an invitation is presented for suppliers, often through a bidding process, to submit a proposal on a specific commodity or service. The RFP process brings structure to the procurement decision and is meant to...
(RFP) was issued in July 1986, and two contractor teams, Lockheed, Boeing and General Dynamics, along with Northrop
Northrop Corporation
Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...
and McDonnell Douglas
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...
, were selected on 31 October 1986 to undertake a 50-month demonstration phase, culminating in the flight test of two prototypes, the YF-22 and the YF-23.
The YF-22 was designed to meet USAF requirements for survivability, supercruise
Supercruise
Supercruise is sustained supersonic flight of an aircraft with a useful cargo, passenger, or weapons load performed efficiently and without the use of afterburners ....
, stealth, and ease of maintenance. Because Lockheed's design was selected as the winner, the company, through its Skunk Works
Skunk works
Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...
division, assumed leadership of the program. It would be responsible for the forward cockpit and fuselage, as well as final assembly at Palmdale, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. Meanwhile, the wings and aft fuselage would be built by Boeing, with the center fuselage, weapons bays, tail and landing gears
Undercarriage
The undercarriage or landing gear in aviation, is the structure that supports an aircraft on the ground and allows it to taxi, takeoff and land...
built by General Dynamics. Compared with its counterpart, the YF-22 has a more conventional design – its wings have larger control surfaces, such as full-span trailing edge, and, whereas the YF-23 had two tail surfaces, the YF-22 had four, which made it more maneuverable than its counterpart. Two examples of each prototype were built for the Demonstration-Validation phase: one with General Electric YF120
General Electric YF120
|-See also:-References:* Technology News Flight International 23/09/03 .-External links:* . Press release GE Aviation .*...
engines, the other with Pratt & Whitney YF119
Pratt & Whitney F119
|-See also:-External links:* *...
engines.
The YF-22 was given the unofficial name "Lightning II" after Lockheed's World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
-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. Two aircraft were built. The first YF-22 (serial number
United States military aircraft serials
In the United States, all military aircraft display a serial number to identify individual aircraft. Because these numbers are located on the aircraft tail, they are sometimes referred to unofficially as "tail numbers"...
87-0700, N22YF), with the GE YF120, was rolled out on 29 August 1990. At the controls of David L. Ferguson, PAV-1 first flew on 29 September 1990, taking off from Palmdale. During the 18-minute flight, PAV-1 reached a maximum speed of 250 knots (136.1 m/s) and a height of 12500 feet (3,810 m), before landing at Edwards AFB. Following the flight, Dave 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), made its maiden flight on 30 October at the hands of Tom Morgenfeld.
Evaluation
During the flight test program, unlike the YF-23, weapon fires and high (60°) angle of attackAngle of attack
Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...
(AoA, or high-Alpha) flights were carried out on the YF-22. The aircraft fired AIM-9 Sidewinder
AIM-9 Sidewinder
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. The missile entered service with United States Air Force in the early 1950s, and variants and upgrades remain in active service with many air forces...
and AIM-120 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...
missiles from internal weapon bays. The first prototype, PAV-1, achieved Mach 1.58 in supercruise, while PAV-2 reached a maximum supercruise speed of Mach 1.43. Flight testing continued until 28 December 1990, by which time 74 flights were completed and 91.6 airborne hours were accumulated. Following flight testing, the contractor teams submitted proposals for ATF production.
On 23 April 1991, the YF-22 was announced by Secretary of the Air Force
United States Secretary of the Air Force
The Secretary of the Air Force is the Head of the Department of the Air Force, a component organization within the Department of Defense of the United States of America. The Secretary of the Air Force is appointed from civilian life by the President, by and with the advice and consent of the Senate...
Donald Rice
Donald Rice
Donald Blessing Rice is a California businessman and senior government official. He has been president and chief executive officer of several large companies including RAND Corporation, and has sat on numerous boards of directors, including Wells Fargo & Company...
as the winner of the ATF competition. The YF-23 design was more stealthy and faster, but the YF-22 was more agile. It was speculated in the aviation press that the YF-22 was also seen as more adaptable to the Navy's Navalized Advanced Tactical Fighter (NATF), but the US Navy abandoned NATF by 1992. Instead of being retired, as with the case of PAV-1, PAV-2 subsequently flew sorties following the competition – it amassed another 61.6 flying hours during 39 flights. On 25 April 1991, the aircraft sustained serious damage during a landing attempt as a result of pilot-induced oscillations. It was repaired but never flew again, and instead served as a static test vehicle thereafter. In 1991, it was anticipated that 650 aircraft would be procured.
F-22 production
As the Lockheed team won the ATF competition, it was awarded the engineering, manufacturing and development (EMD) contract, which would ultimately allow it to proceed with production of operational aircraft. The EMD called for seven single-seat F-22A and two twin-seat F-22Bs. On 9 April 1997, the first of these, Spirit of America, was rolled out. During the ceremony, the F-22 was officially named "Raptor". Due to limited funding, the first flight, which had previously been scheduled for mid-1996, occurred on 7 September. Flight testing for the F-22 continued until 2005. On 15 December 2005 the USAF announced that the Raptor had reached its initial operational capability (IOC).In many respects, the YF-22s were different from production F-22s. Contrary to the F-117 Nighthawk, which was initially difficult to control because of small vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
s, Lockheed over-specified the fin area on its YF-22. Therefore, the company reduced the size of those on F-22s by 20–30 percent. Lockheed recontoured the shape of the wing and stabilator
Stabilator
A stabilator is an aircraft control surface that combines the functions of an elevator and a horizontal stabilizer...
trailing edges to improve aerodynamics, strength, and stealth characteristics; the wing sweep was reduced by 6° from 48°. Finally, to improve pilot visibility, the canopy was moved forward 7 inches (178 mm), and the engine intakes were moved rearward 14 inches (356 mm).
Aircraft on display
- YF-22 Raptor, s/n 87-0700, is on display at the Air Force Flight Test Center Museum, Edwards Air Force BaseEdwards Air Force BaseEdwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
, California.
Specifications (YF-22)