Aerodynamic performance of a non-planar multi-rotor air-craft in hover

An experimental investigation of the noise and forces generated by tandem eVTOL rotors in simulated forward flight was performed in the University of Florida Anechoic Wind Tunnel. The campaign consisted of 48 test conditions sweeping through the tip Mach numbers and freestream velocity to cover a range of realistic eVTOL flight conditions for two rotors. The mean rotor forces and noise at 90 microphone locations below the rotor plane were measured for each test condition. The results showed that the noise and forces of the rear rotor were effected by the wake of the front rotor. Additionally, the inclusion of a wing and boom reduced overall noise levels and increased the rear rotor thrust coefficient. The results emphasize the importance of rotor-rotor and rotor-airframe interactions on eVTOL noise. 

Acoustics and forces from isolated and installed tandem eVTOL rotor configurations

This paper investigates the transient aerodynamic interference of rotors imposed on fuselage for a quadcopter through Computational Fluid Dynamics (CFD) simulations. The numerical study of transient effects due to rotor rotation is enabled by sliding mesh which defines the rotation domains encompassing rotor blades. The results show that the interference effects of rotor change the aerodynamic forces of the fuselage, causing about 67% in-crease in lift, 13% increase in drag, and 90% increase in pitching up moment on average. The variations of fuselage lift are associated with the pressure distribution changes due to rotors rotation, the high-pressure areas and low-pressure areas over the rotor projects on the arms of the quadcopter causing periodical abrupt changes on the lift, drag and pitching moment.

Li Mo

Papers

Numerical Study of the Aerodynamic Interference of Rotors Imposed on Fuselage for a Quadcopter