HARP MODEL ROTOR TEST AT THE DNW

A dynamically scaled model of the Hughes Advanced Rotor Program (HARP) bearingless model main rotor and the 369K tail rotor were tested at the Duits Nederlands Windtunnel (DNW) in the fall of 1987. This cooperative wind tunnel test program between the Army Aeroflightdynamics Directorate (AFDD), McDonnell Douglas Helicopter Company (MDHC), and NASA Ames Research Center (ARC), was the third DNW tunnel entry in the Aerodynamic and Acoustic Testing of Model Rotor (AATMR) Program. The objectives of this test were to; 1) obtain far field acoustic data over a wide range of testing conditions, 2) obtain high quality performance data for this dynamically scaled bearingless rotor, 3) investigate the effects of a shear layer on the acoustic transmission of low frequency rotorcraft noise, 4) study near field/far field rotorcraft acoustics, and 5) study main rotor/tail rotor interactions. This paper describes the HARP model rotor, DNW wind tunnel, AFDD Rotary Wing Test Stand (RWTS), methods and instrumentation used to acquire the data, conduct of the wind tunnel test, and the scope of the test matrix. An introduction is presented to the acoustic, performance, dynamics and blade loads data acquired during the wind tunnel test. This paper is meant to document and serve as an introduction to data from this test, which when reduced, will prove essential to validating the computational methods necessary to the design of the next generation of advanced rotorcraft.