The Effect of Thrust Vectoring on Aeroelastic Stability of Electric Aircraft

In this paper, the effect of thrust vectoring of propulsors on the aeroelastic stability of an electric aircraft wing power up with electric propulsors is investigated. The electric aircraft is composed of six high-lift and one cruise propulsors. The developed model resembles the NASA X-57 electric aircraft. It is assumed that the rotor disc of propulsors is able to be tilted in two directions (e.g. pitch and yaw) to change the thrust vector. Three aeroelastic models are developed and compared to verify the aeroelastic results. In the first method, the wing has been modelled using a linear beam combined with an unsteady compressible source and doublet panel method. In the second method, a linear beam and the 2D unsteady incompressible Theoderson theory are combine. While the third method is based on coupling a geometrically exact beam formulation with the 2D incompressible unsteady Peters' aerodynamic model. The comparison between these three methods results in a fairly good agreement with the unsteady source and doublet panel method predicting slightly higher flutter speed than the other two methods. This could be due to the effects of tips that has not been included in the other two methods. Furthermore, the propulsors are modelled using a follower force that acts directly on the centre of gravity of it. It is highlightd that by vectoring the thrust it is possible to enhance the aeroelastic stability of the wing. But the amount of change is dependent on the pitch or yaw angle of thrust vector, thrust value and mass of the propulsors. Also, it is obtained that yawing the thrust has more effect on the stability of the wing than pitching the vector. Finally, the effect of wing bending to torsion stiffness ratio on the effectiveness of the proposed concept is investigated. It is observed that the thrust vectoring mechanism is more effective for higher stiffness ratios.