Aerodynamic study of dihedral angle configurations on a hexacopter during horizontal airflow disturbances

Multi-rotor Unmanned Aerial Vehicles (UAVs) often experience horizontal incoming flow disturbances during hovering, which can compromise both mission accuracy and stability. This study investigates the aerodynamic performance of a hexacopter with dihedral angle configurations, which is capable of resisting interference from horizontal flows, unlike planar hexacopters. The effects of four yaw angles and three rotor dihedral angles were systematically examined using both test bench experiments and computational fluid dynamics simulations under varied operating conditions. The aerodynamic performance of the propellers was analyzed in terms of upwash, downwash flow, and rotor angle of attack. Results demonstrate that the direction of rotation of the front rotor significantly influences the thrust distribution of adjacent rotors in the presence of incoming flow. Among the yaw angles studied, a yaw angle of 60° generated higher lift and pitching moments compared to a yaw angle of 0°, while yaw angles of 30° and 90° induced additional rolling moments. The study also reveals that differences in the rotor dihedral angle significantly affect the pitching moment and positional drift of the hexacopter, respectively. These findings provide insights into optimizing the performance of multi-rotor UAVs under wind disturbances.