A piloted simulator study of a jet VTOL aircraft in partially jet-borne flight

Abstract

A simulation of a small jet VTOL aircraft has been used to examine the principles of controlling such aircraft in the partly jet-borne regime. An investigation of three alternative techniques for control at constant speed was made, from which the pilots were able to select a single control technique that was effective from the lowest speed simulated (40 kt) to the highest (150 kt). The preferred technique was to use thrust to control flight path and thrust vector angle to control airspeed while using attitude (controlled by the elevator) to make fine adjustments to both flight path and airspeed. A preliminary study of techniques for performing the transition between wing-borne and jet-borne flight was then made. Although computation limitations precluded transitions to speeds below 40 kt, some valuable information was gained. In particular, a number of transitions were performed successfully, and without great difficulty, while following an I.L.S. beam. As a result of these tests, it is believed that jet VTOL aircraft with adequate stability may have a greater potential than had been anticipated for operating in poor weather, without the complicated flight-director systems and automatic controls that have generally been thought to be necessary.