Development of Theoretical Models for Jet-Induced Effects on V/STOL Aircraft

Abstract

Successful design and development of V/STOL aircraft requires an understanding and accurate prediction of aircraft forces and moments caused by jet-induced phenomena. Several computerized analytic procedures have been developed using potential flow theoretical solutions to model the entrainment and displacement effects of a propulsion system efflux. The various flow regimes and theoretical models will be described for out-of-ground effect and in-ground effect, where multijet interactions with the ground plane cause significantly increased entrainment and fountain forces. These jet models are coupled with a panel method for calculating the aerodynamic forces and moments. Excellent agreement between calculated and model test data is displayed.