Leonardo da Vinci called his screw-shaped flying machine the aerial screw.
Leonardo drew the design around 1489 in his notebooks. It shows a large helical surface, probably intended to be made from linen stiffened with reeds, wrapped around a central pole. Leonardo reasoned that turning the screw rapidly could make it rise by pushing against the air.
The aerial screw is often described as an early helicopter concept, but it was not a practical helicopter. Leonardo did not provide a complete engine, a workable rotor-control system, or evidence that the machine was ever built and flown. Its proposed lifting principle also differs substantially from that of modern helicopter rotors.
The design belongs to Leonardo’s broader study of flight, which included wings, parachutes, and gliding machines. The word “helicopter” was coined centuries later, so calling the drawing a helicopter is a modern comparison rather than Leonardo’s own terminology.