Leonardo da Vinci designed an ornithopter, a bird-inspired flying machine whose wings were intended to move by mechanical flapping.
Leonardo studied bird anatomy and flight in notebooks such as the Codex on the Flight of Birds, completed around 1505. His ornithopter concepts used large wings connected to systems of levers, pedals, and hand controls. The pilot’s muscular effort was supposed to drive the wings, imitating the action of a bird.
The designs were not successful aircraft. A human cannot generate enough power to flap wings of the proposed scale, and the machines lacked an engine or a reliable method of controlling sustained flight. Leonardo’s studies nevertheless advanced the observation of airflow, balance, wing structure, and the relationship between weight and lift.
An ornithopter differs from Leonardo’s other flying-machine concepts because its defining feature is flapping flight. Modern experimental ornithopters can fly with engines or lightweight mechanisms, but they do not validate the feasibility of Leonardo’s human-powered plans.