Lift Superposition and Aerodynamic Twist Optimization for Achieving Desired Lift Distributions

A method for achieving an arbitrary lift distribution with an arbitrary planform is presented. This is accomplished through optimizing aerodynamic twist for a given number of either known airfoils or airfoils to be designed. The spanwise locations of these airfoils are optimized to get as close to the desired lift distribution as possible. Airfoils are linearly interpolated between these points. After aerodynamic twist, the planform is twisted geometrically using radial basis functions to model the twist distribution. The aerodynamic influence of each twist distribution is determined and all are superimposed to determine the function weights of each twist function, yielding the optimal twist to match the given lift. This method has been shown to match both an elliptical and a triangular lift distribution for an arbitrary planform. This method can also be used with any fidelity model, creating a powerful design tool.