Fig. 3: Active electrostatic adhesion (EA) improved efficiency at higher speeds.
From: Electrostatic adhesion mitigates aerodynamic losses from gap formations in feathered wings

A The lift-to-drag ratio (L/D) measures the efficiency of a wing (N ~ 31,000) by comparing orthogonal aerodynamic forces responsible for balancing the weight and thrust requirements of an aircraft. B At low flow velocities (11.5 m/s), the baseline wing (black) was more efficient than the feathered wings (passive: blue; EA: orange); however, the rigid wings (baseline: black; plate: gray) lost efficiency as flow velocity increased, whereas the more compliant feathered wings became more efficient. C Electrostatic adhesion improved feathered wing efficiency at nearly twice the rate of the passive feathers (198%).