Leonardo da Vinci sketched an aerial screw as a flying-machine concept with a rotating helical rotor above a platform.
Leonardo drew the design around 1489–1490 in his notebooks. The machine resembles a large screw or auger, with a linen-covered helical surface wound around a central reed-and-wire framework. His idea was that turning the screw would make it “screw” upward through the air, although the drawing does not provide a workable engine or complete mechanism for continuous rotation.
The aerial screw is often called an early helicopter concept, but it was not a helicopter in the modern engineering sense. Modern helicopters use powered rotor blades that generate lift through aerodynamic airfoils. Leonardo’s design is historically important because it shows him reasoning about vertical flight centuries before practical powered aircraft. It is also distinct from his ornithopter, which depended on flapping wings rather than a rotor.