Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Christopher Shearer, PhD.


Recent events, such as the crash of NASA's 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's 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's 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.

AFIT Designator


DTIC Accession Number