Leonardo da Vinci’s 1485 concept for a rotating-wing aircraft is called the aerial screw.
Leonardo sketched the aerial screw in the Codex Atlanticus. Its broad helical surface was intended to push against air as four men turned a central shaft. The design is often described as an early helicopter concept, although it was never built or tested by Leonardo.
The aerial screw was based on the idea that a screw could rise through air in the same way that a screw advances through a solid material. That analogy was imaginative, but the proposed human-powered mechanism could not produce enough lift with the materials and engines available in Renaissance Italy.
It is sometimes called a “helicopter,” but that modern label describes its general purpose rather than its exact engineering. Leonardo’s sketch did not include a practical powered rotor system, and later aircraft designers solved the lift and control problems in very different ways.