Some fixed-wing micro air vehicles have high levels of structural flexibility, a property which is known to improve gust rejection qualities and delay stall. However, the exact level of flexibility is typically the result of a trial-and-error approach instead of being part of a rigorous design framework and may result in unknown aeroelastic effects on the flight dynamics. The current research investigates the nature of these aeroelastic effects. Using a generic MAV configuration, bending and torsional stiffness of the wing are independently varied from 1.0 Nm~2 to 0.07 Nm~2 while the trim conditions, flight dynamics, and structural dynamics are analyzed. Stiffness is found to have a significant, nonlinear effect on the rigid-body flight dynamics. The bending stiffness has the largest effect, which comes through changes in the dihedral angle of the deformed wing. Large changes are seen in structural frequencies, which affect the rigid-body modes due to their frequency separation. The effects of torsional stiffness are minimal due to the close proximity of the elastic axis and the center of pressure.
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