Jet/intake interference in short take off, vertical landing aircraft

An experimental programme was conducted to investigate the aerodynamic interference effects between the jet-and intake-induced flows and the lifting surfaces of a generic jet-lift short take-off and vertical landing aircraft in transitional flight, out of ground effect. The tests were carried out in an open-jet wind tunnel, and the model was equipped with a single, variable position, vectored lift-jet and powered intakes. Static pressure measurements were made on the wing and intake lips from which airloads were inferred. The effect of jet to intake mass flow ratio on jet/intake aerodynamic interactions was investigated. The experiments conclude that a mutual interference exists between the jet and intake flows, which generates nonlinearly additive loads on the airframe. The combined jet- and intake-induced interference on the wing increased with increasing jet to intake mass flow ratio. Ignoring jet/intake interference effects gave a consistently lower overall wing root lift loss, which was equivalent to up to 0.75 deg of incidence.