Manufacturing Method of the Morphing Wing Structure for UAV by CFRP with Applying the Electroformed Resin Molding Method

Aircraft flight control usually requires driving flaps and ailerons. However, the air drags increase significantly due to the corners of flaps and aileron. Especially, the gap between mother wing and flap / aileron causes a drag increase. Therefore, studies are being conducted on morphing wings that smoothly and greatly deform the wing surface. For aircraft wing, it is needless to say that strength is important to sustain lift and drag for the aircraft during the flight. For morphing wings, in addition, actuators must be mounted inside the wing to enable the morphing deformation. Moreover, for the aircraft wing, weight is quite important. Therefore, carbon fiber reinforced plastic (CFRP) is currently most suitable for aircraft wing structural materials. However, it is difficult to mold CFRP so that it has sufficient strength and can be morphed. In this study, by using CFRP, the morphing wing structure was prototyped with targeting a small unmanned aerial vehicle (UAV) weighing 3 kg. The CFRP lattice structure that enables morphing deformation was designed and manufactured by applying the electrodeposition resin molding (ERM) method which was developed by the authors. In the ERM method, firstly, the carbon fiber was fixed with a jig according to the designed morphing wing structure, and immersed in the electrodeposition solution. Secondly, the epoxy polymer particle in the solution were electrophoresed and impregnated between carbon fibers. After thermal curing, the morphing wing structure was fabricated. Further, the loading-unloading torsion and bending tests of the morphing wing structure were carried out. Smooth morphing deformation and sufficient strength were confirmed.