Scaling of helicopter main rotor noise in hover
Abstract
A 2.1-m-diam, one-sixth-scale model helicopter main rotor was tested in hover at the NASA Ames Outdoor Aerodynamic Research Facility. It had previously been tested in hover in the NASA Ames 40- by 80-Foot Wind Tunnel test section. The primary objective of the tests was to obtain acoustic and performance data on a medium-scale rotor at various thrust coefficients and tip Mach numbers to compare to similar existing data on a full-scale helicopter main rotor. Information is presented on the effects of thrust- and tip-speed variation, the effects of boundary-layer trip strips, and the effects of wind conditions. In addition, a preliminary evaluation of the scaling of helicopter main-rotor noise in hover is presented. A secondary objective was to contribute to a data base that will permit the estimation of facility effects on acoustic testing.
- Publication:
-
24th AIAA Aerospace Sciences Meeting
- Pub Date:
- January 1986
- Bibcode:
- 1986aiaa.meetS....K
- Keywords:
-
- Aerodynamic Noise;
- Hovering;
- Rotary Wings;
- Scale Models;
- Wind Tunnel Tests;
- Full Scale Tests;
- Scaling Laws;
- Thrust;
- Tip Speed;
- Wind Effects;
- Acoustics