Extended Nonlinear Lifting-Line Method for Aerodynamic Modeling of Reconfigurable Aircraft

An iterative extension of a modified Weissinger's method for curved wings enables viscous flow effects to be introduced into the sectional aerodynamics. The algorithm derived uses the single-step, modified Weissinger's method to establish the initial point of the iterative process that attempts to minimize the difference in the circulation distribution calculated by this method and that given by the sectional aerodynamic data. Three wing shapes are examined using this algorithm and compared with low-speed wind-tunnel results. The results of this comparison indicate that this method corroborates the experimental results well in the attached flow regime and is able to predict the onset of stall over the wings. This method provides a low-order method for aerodynamic calculations, suitable for design or trajectory optimization applications, that nevertheless is able to incorporate nonlinear effects efficiently.