Load alleviation of feather-inspired compliant airfoils for instantaneous flow control.

Birds morph their wing shape to adjust to changing environments through muscle-activated morphing of the skeletal structure and passive morphing of the flexible skin and feathers. The role of feather morphing has not been well studied and its impact on aerodynamics is largely unknown. Here we investigate the aero-structural response of a flexible airfoil, designed with biologically accurate structural and material data from feathers, and compared the results to an equivalent rigid airfoil.

A tale of two tails: developing an avian inspired morphing actuator for yaw control and stability.

Motivated by the lack of research in tailless morphing aircraft in addition to the current inability to measure the resultant aerodynamic forces and moments of bird control maneuvers, this work aims to develop and test a multi-functional morphing control surface based on the horizontal tail of birds for a low-radar-signature unmanned aerial vehicle. Customized macro fiber composite actuators were designed to achieve yaw control across a range of sideslip angles by inducing 3D curvature as a result of bending-twisting coupling, a well-known phenomenon in classical fiber composite theory. This allows for yaw control, pitch control, and limited air break control.