Leonardo da Vinci’s 1489 design for a vertically rising, screw-driven flying machine is called the aerial screw.
Leonardo drew the concept in a manuscript now associated with the Codex Atlanticus. Its large helical sail was intended to rotate and push against the air, using an idea compared with the action of a screw moving through a solid material. The drawing is one of the best-known images connected with Leonardo’s studies of flight.
The aerial screw is often described as an early helicopter concept, but it was not a working helicopter. Leonardo did not build a full-scale version, and the materials and power sources available in Renaissance Italy could not have supplied enough lift for the proposed structure. Modern reconstructions therefore test the principle rather than demonstrate a practical aircraft.
A common mix-up is calling the design an ornithopter. An ornithopter uses flapping wings, whereas the aerial screw depends on rotary motion. Leonardo also studied gliders, parachutes, and birdlike flying machines separately.