Distribution of aerofoil section lift from section pitching moment applied to a dynamic model for aircraft poststall departure
A method for chordwise redistribution of lift over a wing for poststall flight simulation is investigated. Aerofoil section moment data is used to divide and distribute into two parts the wing lifting line of Prandtl finite wing circulation theory. The method of lift distribution is applied in the aerodynamic package of a six degree-of-freedom flight simulator. The aerodynamic are computed with a nonlinear lifting line method which includes unsteady wake effects due to a discrete, nonplanar vortex system. The fidelity and vortex distribution of the wake is made adjustable under the constraint that the vortex distribution on the surface of the wing provide the same two dimensional angle of attack as did a single bound lifting line. The simulation is that of an actual general aviation aircraft. The wing lifting surface is modeled using the two lifting lines developed here, while the tail lifting surfaces are modeled by a single lifting line and associated control points. The simulation aircraft is “flown” through a prescribed maneuver by integrating the equations of motion.
Results for the two lifting line system showed lateral responses in better agreement, over a single lifting line, with full scale flight tests. A form of the Kutta-Joukowski equation that relates circulation to pitching moment is also presented.