Investigation On Conversion Corridor Analysis Method Of Quad Tilt Rotor Aircraft

Quad Tilt Rotor(QTR)aircraft combines the advantages of vertical take-off and landing,hovering of helicopter and high-speed cruising,strong carrying capacity of propeller airplane.An analysis method was established to investigate the QTR’s conversion corridor between helicopter mode and propeller airplane mode.Firstly,a flight dynamic model of QTR is established,including the rotor,wing,nacelle,and fuselage model specifically.Among them,the rotor model adopts the dynamic inflow model,and the interference between front and rear rotors is considered.The wing model takes into account the effects of upper rotor interference,three-dimensional effect,and aileron maneuvers.The maneuvering redundancy is solved by hybrid-maneuvering.Secondly,aiming at the control way both without and with cyclic pitch,the method calculating conversion corridor of QTR is proposed according to the wing’s lift characteristic limit condition,power limit condition,trimming lift-control travel limit condition,advancing blade compressing and retreating blade stall effect limit condition.Thirdly,in the interior of the conversion corridor,a tilting path with optimal safe cost is determined considering the integrated indicator of attitude cost and the required power cost.A method for determining the weight coefficient between attitude cost and required power cost is proposed.Finally,the impact analysis of the main design parameters is studied so to provide design reference for widening the conversion corridor.This paper analyzes the influence of wing area,initial installation angle,slope of the lift coefficient of the wing on the wing’s lift characteristic limit boundary,the influence of rotor radius,rotor solidity,and fuselage cross-sectional area on the power limit boundary.The influence of the maximum pitch on the trimming lift-control travel limit boundary has also been studied.