Propeller Effects on the Response of High-Altitude Long-Endurance Aircraft

An enhanced nonlinear aeroelastic-coupled-flight dynamics framework that enables the investigation of propeller aerodynamics and inertial effects on the response of a very flexible aircraft is presented, verified and used to investigate the propeller effects on the aeroelastic response of a very flexible aircraft. The developed framework couples a geometrically nonlinear structural solver with an unsteady vortex lattice method for lifting surfaces and a viscous vortex particle for propeller slipstream. Propeller gyroscopic moment and viscous drag estimation for unsteady vortex lattice method are also included. For the study case considered, the University of Michigan's X-HALE unmanned aerial vehicle model, results indicate that the influence of propeller is more pronounced for free-flight cases and in clamped cases involving torsional excitation.