Abstract
We propose a new morphing wing concept for wing twist using a specially designed spar consisting of two pipes. One pipe is a thick closed-section member that carries bending moments. The other pipe is the shape variable member and has open and closed sections. The combination of open and closed sections is designed to achieve an objective disribution of twist angles. The ends of the two pipes are connected at the wing tip side and the other ends are connected to the airplane body or motor, providing a torque at the wing root side. According to this mechanism, the wing tip side has a larger twist angle than the wing root side. We established a theoretical formula describing the twist angle of the spar that combines the open and closed section members. The feasibility of the theoretical formula was demonstrated thorough numerical simulations using finite element analyses.
