Aerodynamic Design Optimization of Helicopter Rotor Blades Including Airfoil Shape

This study proposes a process to get optimal helicopter rotor blade shape regarding aerodynamic performance discipline. This optimization process is constructed by integrating several programs which were developed by Department of Aerospace Information Engineering at Konkuk University. Design variables include blade twist, taper ratio, point of taper initiation, blade root chord, and airfoil shape. Airfoil shape is considered as design variables by using a new geometry representation algorithm which uses both the Class Function/Shape Function Transformation (CST). Aerodynamic constraints consist of limits on available power in hover and forward flight, thickness of blade, aerodynamic requirements (lift, drag, and moment coefficients). The trim condition must be attainable in any flight conditions. Objective function is chosen as combination expression of nondimensional required power in hover and forward flight. The objective function reduced 8% in case of optimum rotor blade shape.