Multi Jet Induced Forces and Moments on VTOL Aircraft Hovering in and Out of Ground Effect

Abstract

An engineering methodology has been developed for the prediction of propulsive lift system induced aerodynamic effects for multi-lift-jet VTOL aircraft operating in the hover mode in an out of ground effect. The developed methodology takes into account the effects of aircraft geometry, aircraft orientation (pitch, roll) and height above the ground plane, cross-flow, lift- jet vector directions with respect to the airframe, lift-jet exit flow conditions and noncircular nozzle exit geometry for low aspect ratio nozzles.