Fig. 1: Electrostatic adhesion fastens engineered feathers together for avian-informed wing design. | Communications Engineering

Fig. 1: Electrostatic adhesion fastens engineered feathers together for avian-informed wing design.

From: Electrostatic adhesion mitigates aerodynamic losses from gap formations in feathered wings

Fig. 1

A Bird wings incorporate a series of overlapping feathers that slide over one another to maintain contact and produce a smooth, unified lifting surface during flight (Red-tailed hawk at the California Raptor Center Credit: Alfonso Martínez, BIRD Lab, UC Davis). B The ability to exhibit large shape changes to their primary lifting surfaces has inspired small uncrewed aerial system designs to incorporate feathered structures to achieve similar degrees of freedom during flight. C On a bird’s wing, this effect is achieved by incorporating both a ligament structure connecting the hollow shaft at the base of the feathers, as well as hook and barbule structures that act as directional probabilistic fasteners (figure adapted from refs. 16,25). D We used electrostatic adhesion to achieve a similar effect for an engineered wing with a feathered trailing edge. E This system used a low power voltage (~0.72 mW) to create two adhesive forces, including coulombic (\({F}_{{\rm {C}}}\)) and Johnsen–Rahbek (\({F}_{{{\rm {JR}}}}\)), allowing the wing to toggle between a continuous trailing edge structure when activated, and low traction movement when inactive. F The bond between feathers increased with voltage, requiring greater force to create separation. Shaded regions represent 95% confidence intervals (1.96\(\,\times\) standard deviation, N = 5).

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