Leonardo da Vinci’s spiral machine is commonly called the aerial screw.
Leonardo sketched the aerial screw around 1489 in his notebooks. The design shows a large helical surface wrapped around a vertical framework. He reasoned that if the screw rotated rapidly enough, its spiral surface might “screw” upward through the air, in a way broadly analogous to a screw entering wood.
The aerial screw is often described as a helicopter precursor, but it was not a working helicopter. Its proposed materials and human-powered mechanism could not supply enough thrust, and the sketch lacks a complete practical propulsion system. Modern helicopters use powered rotors that generate lift through rotating blades, whereas Leonardo’s concept depended on a continuous helical sail-like surface.