NASA F-18 High Alpha Research Vehicle

The F-18 High Alpha Research Vehicle was a heavily modified Hornet used to study control at very high angles of attack. NASA’s three flight-research phases ran from April 1987 through September 1996. Initial flow visualisation and aerodynamic measurements were followed by exhaust-deflecting thrust-vector vanes and a research flight-control system, then actuated forebody strakes. Across 385 research flights, the aircraft demonstrated stabilised flight at angles of attack of 65–70 degrees. The thrust-vector installation removed the divergent nozzle sections and prevented supersonic flight in that configuration. Flight measurements helped validate wind-tunnel results and computational fluid-dynamics predictions.