Wing and tail morphing in birds and drones

To aid humans in civilian tasks, future drones will have to operate in large cities that abound with difficult flight conditions such as confined spaces, obstacles, and turbulent air. Such drones must cruise efficiently to cover vast distances fast and also fly aggressively to avoid obstacles and negotiate complex environments. Today's most common drone designs still struggle at this feat. While multi-copters are highly agile and maneuverable, they require much energy to stay aloft, limiting their endurance and range. Instead, winged drones need comparatively little energy for the same weight to stay aloft but cannot change their flight path rapidly, and are sensitive to turbulent air, which limits their application to open obstacle-free terrain.We propose to bypass these limitations through large morphological changes displayed by birds to adapt their aerodynamic surfaces to different flight conditions, thus achieving outstanding flight capabilities. In the first part of this thesis, inspired by gliding birds of prey we develop and test two novel drone designs with a morphing wing and tail made from artificial feathers. We show how adapting such morphing surfaces can improve the flight performance of drones in longitudinal and lateral flight. Morphological changes during flapping flight could further increase the adaptability of drones to different flight conditions. However, there are still many open questions why birds apply specific wing morphologies. Thus, in the second part of this thesis, we develop and test a biohybrid flapping wing robot made from real jackdaw feathers, which can be used in wind tunnel studies to simulate and better understand the bird's complex flapping aerodynamics.