Wind Tunnel Test of an Active Flap Rotor: BVI Noise and Vibration Reduction

This paper describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14 × 22 Foot Subsonic Wind Tunnel. The primary purpose of the test was to examine the reduction of blade vortex interaction (BVI) noise. Vibration reduction and performance improvements with the active flap were also examined. This paper is intended as a record of the program, its conduct, and results. The design of the model rotor and flap actuation profiles is described. The conduct of the test program is detailed. Examples of performance, aerodynamic and acoustic data are presented and discussed.