Leonardo da Vinci studied an ornithopter, a bird-inspired machine designed to fly by flapping wings.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo investigated several versions during the late fifteenth and early sixteenth centuries, studying bird anatomy, wing motion, balance, and the forces acting on airfoils.
His sketches generally place a human operator inside or beneath a winged framework, with pedals, levers, or other mechanisms intended to drive the wings. These machines were not practical aircraft: human muscles cannot supply enough continuous power for a machine of the proposed scale, and flapping-wing flight requires complex control.
Leonardo’s work nevertheless helped connect careful observation of animals with mechanical design. An ornithopter differs from a glider, which relies on fixed wings, and from an aerial screw, which uses rotary motion rather than flapping wings.