Uh-2 Helicopter High-Speed Flight Research with Lift and Thrust Augmentation

摘要

The report presents results of a flight test program conducted using a UH-2 helicopter with a fully articulated, servo-flap controlled rotor and provided with a YJ-85 jet engine for thrust augmentation and with wings for lift augmentation. The effect of lift augmentation on airspeed limitations imposed by rotor blade stall or compressibility was investigated, and performance, flying qualities, structural loads, and vibrations were examined. A maximum level-flight speed of 190 knots was achieved. It was determined that the airspeed is limited by power available. Although compressibility effects were encountered at high rotor speed, the airspeed envelope was expanded by reducing rotor speed. Lift augmentation is shown to substantially reduce rotor and airframe loads and vibrations while providing an expanded speed and maneuvering envelope. The suitability of a fixed-wing incidence angle was demonstrated, although it is concluded that further investigation of rotor and aerodynamic surface controls may be required to provide optimum control. Correlation of flight test results and those predicted by analytical study is presented in areas of performance, controllability, and limit flight speeds. In general, analytical methods for predicting these characteristics are shown to be satisfactory. (Author)