A Wind Tunnel Investigation on the Aerodynamics of the Propulsion Wing for a Novel eVTOL Vehicle

With increasing interest in the urban air traffic market for electric Vertical Take-Off and Landing (eVTOL) vehicles, there are opportunities to enhance flight performance through new technologies and control methods. One such concept is the propulsion wing, which incorporates a cross-flow fan (CFF) at the wing's trailing edge to drive the vehicle's flight. This article presents a wind tunnel experiment aimed at analyzing the aerodynamic characteristics of the propulsive wing for the novel eVTOL vehicle. The experiment encompasses variations in angels of attack, free stream velocities and fan rotational speeds. The result verifies that cross-flow fans offer unique flow control capabilities, achieving a tested maximum lift coefficient exceeding 7.6. Since flow from the suction surface is ingested into the CFF, the flow separation at large angle of attack (up to 40°) is effectively eliminated. The aerodynamic performance of the propulsive wing depends on the advance ratio and angle of attack. Generally, with a high advance ratio and sufficient CFF power for flow control, the airfoil's lift coefficient increases with angle of attack, while drag coefficient decreases with higher fan rotational speeds. Additionally, this study identifies improved flow control capability with the presence of a vortex cavity. The propulsion wing shows promising application prospects for eVTOL vehicle.