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Rockwell International's XFV-12A was a supersonic fighter/attack "Thrust Augmenter Wing" concept. The design used a modified 30,000 lb thrust (in afterburner) Pratt & Whitney F401 engine (a larger Navy cousin of the F100 which was canceled before production). For vertical lift, a diverter valve in the engine exhaust system blocked the nozzle and directed the gases through ducts to ejector nozzles in the wings and canards for vertical lift. The thrust of the spanwise ejectors could be modulated by varying the diffuser angle: pitch and roll were controlled by differential variation of the four ejectors from fore to aft and left to right; yaw was controlled by differential ejector vectoring. An auxiliary engine inlet for use in vertical flight was located immediately behind the cockpit. The prototype aircraft used parts from the A-4 and F-4; the fuselage was 44 ft long with a 28.5 ft wingspan and a 12 ft canard span. Operational vertical take-off weight was expected to be 19,500 lb, with a maximum speed of over Mach 2 anticipated by Rockwell.
Engine rig testing began testing in 1974, aircraft ground testing in July 1977, and suspended tether trials conducted in 1978. Only one of two contracted aircraft were completed in order to curtail increasing costs. Lab tests were interpreted to show that 55% augmentation could be anticipated, but differences from the lab models to the full scale system caused the actual augmentation to be onlu 19% for the wing and 6% for the canard. Lift improvement testing and plans to modify the ejector/augmentor system were discontinued in 1981 due to cost overruns and waning Navy V/STOL interest.
Source: AHS V/STOL Wheel
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