In this paper, nonlinear aeroelastic characteristics of a wing with control surface
freeplay were investigated. The transonic small disturbance equation was applied
to calculate unsteady aerodynamic forces in subsonic/transonic region. The
fictitious mass method was used to apply a modal approach to nonlinear structural
models. Nonlinear aeroelastic time responses were calculated by the coupled time
integrationmethod. In this study, it was found that aerodynamic nonlinearity, initial
flap angle and freeplay angle affect aeroelastic characteristics.