Consideration of V/STOL Downwash and the Ground Environment

Effective mission capability of future V/STOL transport aircraft in military and civil operations demands a thorough understanding of the downwash environment surrounding the aircraft.

Over the last decade, studies and experimental tests by aerospace industry and government agencies have resulted in empirical data and theoretical equations for predicting downwash. Only recently has a systematic test approach with full size vehicles been accomplished. A series of tests with theXC-142A tilt wing V/STOL aircraft and the HH-3C and HH-53B helicopters examined the downwash velocity in the ground environment associated with these VTOL vehicles. This paper reviews these tests with respect to a comparison of the downwash values between the vehicles.