Leonardo da Vinci’s four-wing, human-powered flying-machine design is an ornithopter.
An ornithopter is an aircraft intended to fly by flapping wings, imitating birds, bats, or insects. Leonardo studied bird anatomy and flight in several notebooks and proposed mechanisms in which a pilot’s movements would drive large wings. His drawings show that he understood the importance of lift, balance, and wing structure, even though the proposed human power was not sufficient for practical flight.
Leonardo did not build a successful full-size ornithopter. The design belongs to his broader investigations of air, birds, and mechanical motion during the late fifteenth and early sixteenth centuries. Modern ornithopters can fly as small radio-controlled models, but they use lightweight materials and motors rather than a person’s muscles.
The design is sometimes confused with Leonardo’s aerial screw, which used a helical rotor concept rather than flapping wings. The ornithopter’s defining feature is repeated wing movement.