DARPA has just released this video chronicling the development of a “hummingbird” flyer by Aerovironment from concept to prototype demonstration and introduction to the public.A number of difficult design and engineering challenges were overcome in the course of the programme, particularly in the wing structure, propulsion and control actuators. Numerous complete prototypes were built and tested to assess and improve the performance of the systems shown in the video. The final prototype achieves the noteworthy milestone of 2-wing flapping hovering and fast forward flight with all power sources on the aircraft and all controls implemented through...