New transition method of a ducted-fan unmanned aerial vehicle

In this research, a winged version of the ISTAR (from "intelligence, surveillance, target acquisition, and reconnaissance") unmanned aerial vehicle is modeled first, and then a new transition method is proposed, which enables the vehicle to fly sideways at low speed for drag reduction.Anonlinear trajectory-following logic is adopted to correct altitude loss and horizontal drift during the transition. By simulation, the proposed transition method shows better acceleration performance. The comparison of the induced drag shows that the vehicle should roll to resume fixed-wing lift as soon as its minimum level-flight speed is achieved to optimize its acceleration performance.