EXPERIMENTAL AERODYNAMIC AND AEROACOUSTIC INVESTIGATION OF A SCALED TILT ROTOR IN HOVER

A study of tilt rotor hover aerodynamics and aeroacoustics is made using a 0.08 scale model of the XV-15 tilt rotor research vehicle. Important dimensionless parameters describing the rotor downwash/airframe interaction flows and the rotor noise they influence are identified, and compared in the model and full scale. Scaling laws are developed to relate the model measurements to prototype. These scales are used to analyze some flow visualization, hot wire measurements and acoustic measurements recently made using the scale model. It is shown that the model can be used to estimate the aeroacoustic effects of configuration changes on the prototype aircraft. The results of some add-on devices intended to control the rotor downwash interference flows are discussed. It is shown that a flat plate positioned between the rotors is effective at blocking some transport of turbulent fluctuations back into the rotor disks.