Sharp turning maneuvers with avian-inspired wing and tail morphing

Flight in dense environments, such as forests and cities requires drones to perform sharp turns. Although fixed-wing drones are aerodynamically and energetically more efficient than multicopters, they require a comparatively larger area to turn and thus are not suitable for fast flight in confined spaces. To improve the turning performance of winged drones, here we propose to adopt an avian-inspired strategy of wing folding and pitching combined with a folding and deflecting tail. We experiment in wind tunnel and flight tests how such morphing capabilities increase the roll rate and decrease the turn radius - two measures used for assessing turn performance. Our results indicate that asymmetric wing pitching outperforms asymmetric folding when rolling during cruise flight. Furthermore, the ability to symmetrically morph the wing and tail increases the lift force, which notably decreases the turn radius. These findings pave the way for a new generation of drones that use bird-like morphing strategies combined with a conventional propeller-driven thrust to enable aerodynamic efficient and agile flight in open and confined spaces. Fixed wing drone flight in dense (urban or forest) environments is challenging due to a need for a large area to turn. Inspired by the avian wing morphing, Enrico Ajanic and colleagues proposed and tested a drone with wings capable of folding and pitching, and a tail capable of folding and deflecting as a strategy to increase the roll moment, lift force, and reduce the turn radius. This finding enables agile drone flight within limited space.