Leonardo da Vinci sketched an aerial screw as a possible machine for vertical flight.
His drawing, generally dated to around 1489, shows a large helical surface wrapped around a central shaft. Leonardo proposed that rotating the screw would make it rise by pressing against the air, in a way that resembles a screw advancing through a solid material. The design is therefore often described as a helicopter precursor.
The aerial screw was not a practical aircraft. Leonardo had no engine light enough to power it, and the proposed linen-covered reed frame would have been too heavy and inefficient for human flight. The sketch nevertheless shows his interest in translating mechanical principles into airborne machines.
Modern helicopters use rotating blades that generate lift aerodynamically, not a single large spiral rotor. The resemblance is historical and conceptual rather than evidence that Leonardo built a working helicopter.