Aerodynamic Interactions of Quadrotor Configurations

Abstract

An advanced potential flow method is used to study the aerodynamic interactions between small rotors of quadrotor configurations and the impact on the overall flight performance. The aerodynamic analysis method is validated by comparing the thrust and power predictions of isolated rotors in hover and forward flight with experimental results. The aerodynamic model was next extended to consider the interactions of several rotors of various quadrotor configurations. Compared with an independent rotor, the interaction of multiple, closely located rotors increases the power requirements of the vehicle and causes a loss of thrust. For diamond configurations, the rotation direction of the lead rotors impacts the thrusts of the midrotors and, subsequently, the overall vehicle rolling moment. For square configurations, slightly higher total thrusts and slightly greater tendencies to pitch up are observed when the retreating blades of the lead rotors move back along the vehicle centerline than for the reversed rotational orientations. The diamond configuration exhibits up to 3.5% higher rotor efficiency and a lesser tendency to pitch up with increasing forward speed than the square configuration.