Leonardo da Vinci sketched an aerial screw around 1489 as a proposed rotating flight machine.
The design had a large helical surface made from reed, linen, and wire, supported by a circular frame. Leonardo reasoned that turning the screw could force air downward and lift the machine upward. The drawing appears in his notebooks and is widely recognized as an early conceptual ancestor of the helicopter.
It would not have flown as drawn. The proposed human-powered mechanism could not provide enough energy to rotate such a large rotor, and the structure would have been too heavy. The design therefore belongs to the history of imaginative engineering rather than practical aviation.
Leonardo’s aerial screw is sometimes incorrectly called the first helicopter. Helicopters require powered rotors and controllable lift; workable examples appeared only after advances in engines, materials, and aerodynamics in the 20th century.