Leonardo da Vinci’s rotating aerial-screw concept is called the aerial screw.
Leonardo drew the machine in a manuscript dated to about 1489. The design has a large helical rotor made from a reed-like framework covered with linen. Leonardo reasoned that rotating the screw could cause it to rise by pressing against the air, using an idea broadly comparable to a screw moving through a solid material.
The aerial screw is frequently described as an early helicopter concept, but it was never built or flown by Leonardo. Its proposed rotor was far too large and heavy for the human-powered mechanisms available in Renaissance Italy. Modern reconstructions therefore treat it mainly as a historical experiment in aerodynamic thinking.
It should not be confused with Leonardo’s parachute, which was designed for descent, or with his bird-inspired flapping-wing machines. The aerial screw used rotary motion rather than flapping wings.