Optimm Design of Airfoil Stiffeners of CFRP Wing for a Small UAV

Abstract

In recent years，a UAV for emergency assistance of disaster and observation has attracted strong attention especially in Japan. A wing of large UAVs has usually the same structure as typical manned aircraft. On the other hand, in case of small UAV, more simple structure composed of CFRP spars and skins are often introduced due to the easy and low cost manufacturing. However in order to operate small UAVs in tough environment such as typhoon, more strong and stiffened skin structures are necessary and then ribs should be introduced to withstand the large lift force and moment. This design increase manufacturing cost of the UAVs calculation. In the present paper, idea of designing light and high-strength wings by introducing airfoil stiffeners integrated into a CFRP skin. In this design, a number of the parts of the wing can be reduced comparing to traditional wing structures. Optimization of number, size and placement of the airfoil stiffeners were conducted by CFD and FEM analysis.