Leonardo da Vinci’s rotating aerial-screw design, sketched around 1489, is called the aerial screw. The drawing shows a helical sail wrapped around a central mast, with a platform and supporting structure beneath it.
Leonardo believed the device could rise if the helical surface were spun quickly enough. His notes compare the action to a screw moving through a solid medium, although air does not provide the same resistance as wood or water. The concept is therefore an important early study of vertical flight, not a functioning helicopter.
The aerial screw had no engine capable of supplying the required power. It also lacked the controls and rotor arrangement needed for stable flight. Modern helicopters use powered rotors that generate lift, while Leonardo’s design was a broad spiral surface.
The sketch is often described as a helicopter ancestor. That comparison is useful historically, but it should not imply that Leonardo built or flew a helicopter. His contribution was the early visual exploration of a rotary-wing flight principle.