Simulations for the Test Flight of an Experimental HALE Aircraft

Recent events, such as the crash of NASA\u27s Helios aircraft during a test flight, show that more must be known about the nonlinear control of HALE aircraft. Shearer, Cesnik and their co-workers have developed a code that is a practical solution to the coupled nonlinear aeroelasticity and flight dynamics of very flexible aircraft called the University of Michigan\u27s Nonlinear Aeroelastic Simulation Toolbox (UM/NAST). They are also in the process of developing a model HALE aircraft called X-HALE which will be used to validate this code experimentally. This research performs flight simulations with UM/NAST so as to make predictions about X-HALE\u27s future test flights and subsequently uncover the strengths and weaknesses of UM/NAST when X-HALE is finally flown. These simulations include simulations of straight and level flight and rolling flight. Rolling simulations involve periodic changes in the angle of the ailerons. Both the 6 meter and the 8 meter models of X-HALE are studied. Two control models are compared. These include the linear and non-linear models of UM/NAST