Aerodynamic Results of a Pressure-Instrumented Model Rotor Test at the DNW

Extensive airload measurements have been obtained during wind tunnel testing of a pressure-instrumented model of the UH-60A Black Hawk helicopter main rotor. The test included level flight, descent and hover conditions, and was conducted at the Duits Nederlands Windtunnel as part of a joint acoustics and aerodynamics program by the Army Aeroflightdynamics Directorate, NASA, United Technologies Research Center and Sikorsky Aircraft. The combination of the variety of measurements (blade pressures, acoustics, dynamics, and performance), the density of measurement stations, and the number and range of test conditions resulted in the most comprehensive model rotor test yet conducted. This paper describes the model and discusses the aerodynamic results. The blade pressures and integrated airloads are examined to identify regions of wake interaction, supersonic flow, negative loading, and flow separation. For descent conditions, the radial and azimuthal locations of impulsive loading events related to blade-vortex interaction noise are determined and compared with predictions. Supersonic flow regions are examined in terms of their potential for generating high speed impulsive noise.