An experimental benchmark of a very flexible wing

The paper presents an experimental benchmark of a very flexible wing that is aimed at validation of analytical aeroelastic models of large deformations. For that goal, a wind tunnel wing model was designed for large deformations and manufactured. Wind-tunnel experiments include static and dynamic tests in which the wing deformations were tracked by a Motion Recovery System, the strains over the wingspan were recorded with a Bragg-grating fiber-optics system, and the aerodynamic loads were recorded by a force balance. The paper presents the wing design, linear and nonlinear dynamic and static aeroelastic analyses, calibration ground vibration tests and static loading tests, and the wind tunnel tests. The largest wingtip static deformation recorded in test was of 50% span. In the dynamic velocity-sweep tests, the wing became unstable at a velocity at which the wingtip deformation was approximately 25% of the span, and became stable again at higher speeds.