AERODYNAMIC AND ACOUSTIC TEST OF A UNITED TECHNOLOGIES MODEL SCALE ROTOR AT DNW

In a major cooperative program between the U.S. Army Aeroflightdynamics Directorate (AFDD), the NASA Ames and Langley Research Centers, the United Technologies Research Center (UTRC), and the Sikorsky Aircraft Division of United Technologies, a geometrically and aeroelastically scaled model of a Sikorsky helicopter rotor was tested in the open-jet anechoic test section of the Duits-Nederlandse Windtunnel (DNW) in the Netherlands. As the fourth entry under the Aerodynamic and Acoustic Testing of Model Rotors (AATMR) Program, comprehensive acoustic, aerodynamic, dynamic, and performance data were obtained for a baseline pressure-instrumented swept tip rotor and for three additional configurations, including a main rotor/tail rotor combination and a main rotor with a BERP-planform tip. The primary objectives were to generate an extensive airload and acoustic data base for the baseline rotor and to examine the relation between the blade pressures and the near- and far-field acoustic radiation. Considering the variety of configurations and measurements, and the number and extent of the sound and pressure measurement locations, this was the most comprehensive model rotor test yet conducted. This paper describes the UTC model scale rotors, the DNW wind tunnel, the AFDD Rotary Wing Test Stand (RWTS), the UTRC and AFDD aerodynamic and acoustic data acquisition systems, and the scope of the test matrices. It also provides an introduction to the test results. The data is expected to improve understanding of rotor aerodynamics, acoustics, and dynamics, and lead to enhanced analytical methodology and design capabilities for the next generation of rotorcraft.