Aerodynamic Interaction Analysis of a Tiltrotor Electric Vertical Takeoff and Landing Aircraft: A Comparative Study of Tiltrotor and Tiltwing Configurations

Although electric vertical takeoff and landing (eVTOL) aircraft are considered a viable solution for urban air mobility, rotor–airframe aerodynamic interference remains a critical challenge as it affects hover and cruise performance. This study investigates the aerodynamic interaction mechanisms of tiltrotor and tiltwing eVTOL configurations across cruise and hover flight modes using a computational framework coupling steady Reynolds-averaged Navier–Stokes equations with the virtual blade model. During cruise, rotor slipstream improves aerodynamic efficiency by increasing the effective angle of attack and accelerating the upper-surface airflow on the wing, yielding a 28.18% increase in the lift coefficient at an angle of attack of 3°. During hover, the horizontal wing in the tiltrotor configuration acts as an aerodynamic obstruction, inducing a partial ground effect that reduces local induced velocity and generates an asymmetric high-thrust region. Meanwhile, the impinging downwash causes a fountain effect, producing a download force equivalent to 14.69% of rotor thrust. A parametric analysis of five tiltwing schemes revealed tilting the 0.3R-0.9R wing segment as the critical design intervention because it alleviates downwash blockage, suppresses the fountain effect, and reduces download forces by 81.79%. Although the relief of the partial ground effect marginally reduces rotor thrust by 5.34%, it improves the net hover aerodynamic efficiency. This study reveals mechanisms of rotor wake enhancement and download interference in eVTOL multimode flight, which indicates that suppressing fountain effects is a key factor for improving hover efficiency.