  The operation of drones in cluttered environments and over extended areas
demands adaptive flight capabilities to meet the opposing aerodynamic
requirements of agile and fast cruise flight. High agility and maneuverability
are required to aggressively navigate around obstacles and to perform
instantaneous takeoffs or landings, while high energy efficiency is desired
when covering large distances. In nature, these requirements are met by some
birds by synergistic adaptation of wings and tail, such as the northern
goshawk, which displays high agility and maneuverability when flying through
forests and fast steady flight capabilities when ambushing prey in the open
field. In this article, we experimentally study the effects of bio-inspired
wing and tail morphing on flight performance by means of a novel morphing
drone. We show that the combined morphing of wing and tail can improve agility,
maneuverability, stability, flight velocity range, and energy efficiency of a
winged drone. The drone's flight performance is validated in wind tunnel tests,
shape optimization studies and outdoor flight tests.
