Leonardo da Vinci drew an aerial screw as a possible vertical-flight machine.
The design, created around 1489, has a large helical rotor made from reed, linen, and wire. Leonardo proposed that the rotating screw could “screw” itself upward through the air, an idea that gives the concept its name. The drawing is commonly associated with the history of helicopter development.
However, the aerial screw was not a helicopter in the modern engineering sense. Leonardo did not provide a complete power system capable of turning the rotor fast enough, and the proposed structure would have been too heavy for the available materials and human power. Its value was conceptual: it explored vertical lift rather than ordinary forward flight.
Modern helicopters use powered rotors and carefully designed aerodynamic blades. Leonardo’s aerial screw and his flapping-wing ornithopters represent different approaches to flight. Calling the sketch simply a “helicopter” is understandable, but “aerial screw” is the more precise name for Leonardo’s device.