Rotor--Rotor Aerodynamic Interactions --- Moment Effects on Efficiency in Forward Flight

This study examines the aerodynamic interactions between rotors in quadrotor vehicles and their impact on forward-flight stability and performance. Through wind tunnel testing of plus and cross configurations, individual rotor forces and moments were measured across varying hub spacings and advance ratios. Results indicate that rotor-rotor interference significantly alters thrust distribution, inducing unintended rolling and pitching moments. Furthermore, Particle Image Velocimetry (PIV) identified asymmetrical inflow distributions as the primary physical driver of these interactions. While increased hub spacing was found to mitigate aerodynamic coupling. These findings highlight the importance of accounting for aerodynamic interactions in multirotor vehicle design and control, particularly for trimming and optimizing forward-flight performance.