Leonardo da Vinci sketched an aerial screw as a rotating-wing machine in the 1480s. Its large helical surface was intended to press against the air and lift the device upward.
The design appears in Leonardo’s notes and is often described as an early helicopter concept. It was not a working helicopter: the drawing gives no practical engine, and the proposed human power would not have been sufficient for sustained flight. The idea nevertheless shows Leonardo’s interest in translating the action of a screw into an aerial machine.
The aerial screw is commonly confused with Leonardo’s ornithopter, whose wings were supposed to flap like a bird’s. The screw instead uses rotary motion. It also differs from a modern helicopter, which uses powered rotor blades and aerodynamic lift rather than a continuous fabric-covered helix.
Leonardo’s sketch was part of a broader set of experiments with flight, including parachutes, wings, and mechanical transmission systems. Later inventors developed rotary-wing aircraft only after lightweight engines and suitable materials became available.