Leonardo da Vinci sketched an aerial screw, a rotating-lift device with a helical sail intended to rise into the air.
The drawing appears in the Codex Atlanticus and is usually dated to around 1489. Leonardo proposed a large spiral surface made from reed, linen, and wire. His idea was that the rotating helical surface would “screw” upward through the air, much as a screw moves through a solid material.
The concept is often described as an early ancestor of the helicopter, but it was not a workable helicopter. Leonardo did not have a lightweight engine capable of spinning the structure fast enough, and the design lacked the modern rotor and control systems needed for stable flight.
The aerial screw is distinct from Leonardo’s flapping-wing ornithopter. One relies on rotary motion, while the other attempts to imitate the wing beats of birds.