Wind Tunnel Data from a Rotor Wake/Airframe Interaction Study.

Abstract : Accurate prediction and understanding of the aerodynamic interactions between a rotor and airframe are essential to the improvement of future rotorcraft. Large amounts of energy are added by the lifting rotor to an otherwise uniform free stream. The resulting wake flow interaction with the airframe has led to problems in dynamics, performance, acoustics and handling qualities. The interaction phenomena associated with a rotor/airframe in forward flight are currently under study as part of a research effort in the Rotary Wing Technology Center sponsored by the U.S. Army at Georgia Tech. The objective of this program is the systematic measurement of interaction effects and the validation of prediction codes using these measurements. This report presents the aerodynamic interaction data base that has been generated in experiments conducted in the John J. Harper 7x9-foot wind tunnel at Georgia Tech. It is hoped that these results will be useful as a guide in the development of prediction codes as well as providing a test for their validity. (Author)