Numerical and experimental study on flutter characteristics of a wing with drag rudder

The drag rudder serves as an unconventional control surface specifically designed for flying wing aircraft. Positioned near the wingtips, the drag rudder splits to generate drag force and yawing moments, which exhibits significant nonlinear characteristics. This paper introduces a flutter analysis method for drag rudder equipped wing model, which is based on high-precision unsteady aerodynamic force corrections at the flutter frequency domain. Subsequently, a low-speed wind tunnel test for the drag-rudder wing flutter is conducted. The study reveals the flutter patterns of the drag-rudder wing under various split angles by comparing the simulation and wind tunnel test results. Both sets of results indicate that an increase in the split angle leads to a higher flutter speed of the drag-rudder wing. Specificially, a unilateral 20° split angle results in an approximately 8.5% increase in flutter speed compared to the non-split state.