Comparison of ground and flight test results using a modified F106B aircraft

Abstract

Two aft underwing nacelles housing afterburning J85 engines were added to an F106 to study exhaust nozzles in flight at Mach numbers up to 1.3. Installation effects were determined for several nozzles by comparing flight data to data from an isolated wind tunnel model. Reynolds number effects were studied at subsonic flight speeds for nozzles intended for use with afterburning turbofan engines. A wide range of Reynolds number was obtained by flying the F106 over a range of altitude and by using 5 and 22% wind tunnel models of the F106. A contoured nozzle had a boattail drag as low as that of a longer circular arc nozzle over the Reynolds number range studied.Take-off flight velocity (Mg = 0.4) effects on noise suppression and thrust of supersonic cruise type nozzles and several noise suppression nozzles were studied by comparing flyover data with static data. Peak noise levels measured in flyover were generally higher than predicted from static data. Thrust performance of noise suppression nozzles was degraded in flyover. When data were scaled to full size engines and a sideline distance of 2128 ft noise suppression effectiveness of 14.5 EPNdb was obtained with 14.3% loss in thrust.