When a bird in flight lands, it performs a rapid pitch-up maneuver during the perching process to keep from overshooting the branch or telephone wire. In aerodynamics, that action produces a complex phenomenon known as dynamic stall. Although many fixed-wing aircraft can withstand similar rapid pitch-up maneuvers, a vehicle subject to this dynamic stall process is not reliably controllable. Motivated by the lack of detailed understanding, University of Illinois researchers took a deep dive into the physics of dynamic stall so that it can be used beneficially and reliably by aircraft.