Performance of a dual-controlled rotor in level flight

Abstract

Feasibility of a "level flight" multi-rotor aircraft, a concept for a high-speed multi-rotor aircraft characterized by a horizontal attitude during forward flight, using a separately placed propeller for propulsion is investigated. The performance of a single rotor used in this aircraft at forward flight is evaluated through numerical simulations. Also, a dual-controlled rotor whose control parameters are rotational speed and blade pitch angle was investigated. The numerical results show that the effective lift-to-drag ratio of the horizontal rotor is higher than that of the forward-tilted rotor. Adding control of the blade pitch angle improves the effective lift-to-drag ratio compared to rotors that can only be controlled by rotation speed. The optimal value of the effective drag is determined by the relationship between the power and the drag. The rotational speed changes the rotor power, and the drag reduction depends on the blade pitch angle. In addition, the untwisted blade shows a higher effective lift-to-drag ratio than the twisted blade. The blade twist significantly affects the drag of the rotor.