Leonardo da Vinci’s spiral flying-machine design is called the aerial screw.
Drawn around 1489, the aerial screw shows a large helical surface wrapped around a central mast. Leonardo proposed that turning the structure would force it upward through the air, in a way resembling a screw moving through wood or water. The design is one of his best-known studies of vertical flight.
The aerial screw is often described as a helicopter precursor, but it was not a working helicopter. Leonardo did not have an engine, rotor controls, or sufficiently light materials capable of making the concept practical. The drawing is therefore best understood as a mechanical investigation rather than a tested aircraft.
Its historical importance lies in identifying the screw or rotor principle for lift. Modern helicopters use powered rotors and aerodynamic blades, not a continuous fabric-covered spiral. The visual similarity can make the two designs seem closer than their engineering principles actually are.