Parametric Analysis of Rotor Orientation and Location for a Highly Efficient Winged Quadcopter

Winged Quadcopters are an increasingly popular UAS configuration due to their mechanical simplicity and high degree of aerodynamic efficiency, but this efficiency is highly sensitive to the chosen blade pitch and rotor orientation. In this study, a rotor-wing system representative of a winged quadcopter is simulated and a parametric sweep of blade pitch, rotor tilt, cruise speed, and weight is conducted. At the baseline 30 kts cruise speed and 3 lb vehicle weight, the optimal configuration (blade pitch: 10° - 20°, rotor tilt: 30° - 40°) is 4.4 times more efficient than the baseline Quadrotor Biplane Tailsitter (blade pitch: 0°, rotor tilt: 0°). Even if flight speed and weight is increased (up to 50 kts and 9 lb), combinations of blade pitch and rotor tilt can offer improved efficiency; and at the optimal condition, 12.5° blade pitch and 35° rotor tilt is 5.3 times more efficient than the baseline QBiT. The rotor-wing system is also simulated using CFD with the rotor at 58 different positions around the wing. Rotors mounted directly in front of the wing leading edge near the wing tip operate at the lowest power, but if the rotors are located laterally inboard on the wing, directly below or above is more favorable. While the effect of rotor position is somewhat small compared to that of blade pitch or rotor tilt, all are viable means for improving winged quadcopter aerodynamic efficiency. Proper selection of these parameters can dramatically transform the aerodynamic efficiency of these UAS, enabling profound enhancements to range, endurance, and payload capacity.