Leonardo da Vinci dated his aerial-screw design to 1489.
The aerial screw appears in Leonardo’s notebooks as a large rotating device intended to rise through the air. Its helical surface was compared with the action of a screw moving through wood or a corkscrew moving through material. Leonardo’s drawing is one of the best-known early concepts for vertical flight.
The design was not a working helicopter. It required a large crew to turn the structure, and the available materials and power sources could not have produced enough lift. Modern historians therefore describe it as a conceptual precursor rather than a successful aircraft.
The aerial screw is also sometimes incorrectly called Leonardo’s helicopter. The word helicopter was coined centuries later, and modern helicopters use powered rotors, not a fabric-covered spiral rotor like Leonardo’s proposal.