Leonardo da Vinci designed an aerial screw with a large helical rotor intended to lift people into the air.
The drawing appears in Leonardo's notebooks from around 1489. It shows a large spiral surface, often described as linen stretched over a framework, with a platform and supports beneath it. Leonardo reasoned that if the screw turned rapidly enough, its spiral surface might bite into the air and rise.
The aerial screw is often called a helicopter ancestor, but it was not a helicopter in the modern engineering sense. It had no engine, and the human-powered mechanism shown would not have supplied enough energy for sustained flight. The design therefore remained a theoretical machine rather than a demonstrated aircraft.
It is also easy to confuse this concept with Archimedes' screw. The two share helical geometry, but Leonardo's aerial screw was intended for air and flight, while Archimedes' screw lifts water.