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Aviation History
1991
1991 - 2523.PDF
X The YF-22 has thrust-vectoring The ATF competition was judged in three areas, with technical and programme issues rated equal in priority but ahead of cost in importance. The Lockheed/P&W combina tion was judged to have significant strengths, including the F-22's well- balanced design and the F119's margin for growth. Equally important were the F-22 team's programme to mature the design and its plans to integrate development of airframe, avionics, engine and training and support systems. An example cited by the Air Force itself was the decision to co-locate and overlap avionics and training-system devel opment so that software would transport easily from aircraft to simulator. OFFERING VALUE Because of this, and other factors, the USAF decided that the probable life-cycle cost of the F-22/FH9 combination was the lowest of all the proposals. The P&W-powered Lockheed fighter was judged, therefore, to offer the best overall value. Value is important to an Air Force which plans to spend around $65 billion buying 648 F-22s. Projected flyaway cost in 1991 dollars is $59.4 million, says Fain, who reveals that the service has already spent five years and $5 billion on its replacement for the F-15. . The service awarded cost-plus EMD con tracts, worth $9.55 billion and $1,375 billion, to Lockheed and P&W respectively on 1 August. That money buys the USAF 11 F-22 flying prototypes — nine single-seat and two tandem-seat — and 33 F119s. Fabrication of the first EMD F-22 will begin in December 1992. Assembly will begin in mid-1993 for a mid-1994 first flight which launches a four-year flight-test programme. Under current plans, a contract for four pre-production verification F-22s will be awarded in 1997. Low-rate initial production will begin in 1998 and the peak production rate of 48 aircraft a year will be reached in 2002. The F-22 is scheduled to achieve initial operating capability in 2002, when 48 aircraft will be in service. That is almost 30 years after the F-15 entered service and some 15 years after the Air Force launched its search for a new air-superiority fighter with the award of $690 million ATF dem/ val contracts to Lockheed and Northrop. By the end of the 54-month programme in December 1990, the F-22 team-members had invested another $675 million, and their suppliers a further $408 million, in dem/val. Lockheed was late in freezing the shape of its YF-22 prototype but came from behind and pulled ahead of Northrop in an eventful three-month flight-test programme. Two aircraft, one powered by GE YF120s and one by P&W YF119s, logged more than 91h in 74 sorties. In flight-testing between 29 September and 28 December, 1990, the YF-22 exceeded Mach 1.8 with afterburner and "supercruised" without afterburner at speeds in excess of Ml.4. It demonstrated thrust-vectoring, reached an angle of attack of 62°, and launched both A1M-9 and AIM-120 air-to-air missiles from internal weapon bays. Continued testing of the YF119-pow- ered prototype will play a key role in further F-22 develop ment. The aircraft will resume flying in November and 100 sorties are planned. Additional flight-test data on conditions within avionics and weapons bays will im prove reliability, says Fain, while Blackwell says precise measure ment of flight loads is essential to achieving minimum weight. Although the target take-off gross weight was 22,700kg, the F- 22 will be a 27,200kg-class air craft, says Fain, not seeming overly con cerned. "We had to give designers some thing to aim for," he says. Lockheed hopes to finalise the F-22's shape by October, says Blackwell, but completion of inter nal design is at least two years away. This is because the inter nal structure will be refined through three design cycles. Iterative design of the internal structure is an integral part of Lockheed's F-22 de velopment concept. Blackwell says the con cept promises to eliminate design changes almost completely once fabrication begins, avoiding schedule slips and cost increases that have plagued many other programmes. Where previous fighters have been de signed for manoeuvrability, with attention being paid more recently to reliability and maintainability, Fains says the F-22 team will "... design in all the 'ilities' to get it right first time". That includes stealth, which is a key feature of the F-22. Its stealthiness has already been tested "... at all frequencies and all angles" using a full-scale model, says Fain. Stealth testing was part of a dem/val effort which included demonstrating the F-22's avionics architecture in both ground-based and airborne laboratories. Demonstration of prototype avionics hardware and software, including some 800,000 lines of Ada code, involved 16 subcontractors and was "very successful", says Fain. Avionics were dem onstrated first in Boeing's ground laboratory YF-22 launches missiles from internal weapons bays FLIGHT INTERNATIONAL 25 September - 1 October, 1991 33
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