An Analysis of Rotor-Induced Vibration on Winged eVTOL Aircraft

This study investigates the vibratory loads and stresses on an electric vertical takeoff and landing (eVTOL) aircraft featuring internal batteries and four rotors mounted on underwing booms on a semi-span wing. During low-speed forward flight (20 kts), the rotor excitation frequency is closest to the wing's second torsional mode, resulting in dominant vibratory torsional moments at the wing root. A full rotor phasing sweep reveals that relative phasing has a critical effect on peak-to-peak (P2P) wing root loads and stress levels. Selected phasing configurations are shown to reduce maximum wing root P2P principal and shear stress resultants by over 70% and 60%, respectively, compared to their mean peak-to-peak values over the phase sweep. Sensitivity analysis further indicates that increasing rotor speed shifts the dominant vibratory response from torsional to flapwise bending modes.