Leonardo da Vinci’s 1489 helical rotor design is called the aerial screw.
The drawing appears in Leonardo’s notes and shows a large spiral structure supported by a circular frame. Leonardo reasoned that a screw-shaped surface could push against the air, much as a water screw moves through water. His design is often described as an early conceptual ancestor of the helicopter.
The aerial screw was not a working aircraft. Renaissance materials, power sources, and engineering methods could not provide the necessary lift or reliable control. Modern helicopters use powered rotors with carefully shaped blades rather than Leonardo’s continuous helical sail.
A common mix-up is calling the sketch a helicopter. That word and the practical aircraft came centuries later. Leonardo’s drawing is important because it shows an early attempt to explain vertical flight through a rotating lifting device.