Leonardo da Vinci sketched an aerial screw, a rotating flying-machine concept often viewed as an early ancestor of the helicopter.
His famous drawing, dated around 1489, shows a large helical surface wrapped around a central mast. Leonardo proposed that rapid rotation could make the screw bite into the air and rise, in a way broadly analogous to a screw moving through a solid material.
The machine was never built and tested by Leonardo, and the proposed human-powered mechanism could not have supplied enough energy for practical flight. Nevertheless, the sketch is historically important because it presents vertical lift through rotating blades rather than through flapping wings.
The aerial screw is commonly called a helicopter precursor, but it was not a working helicopter. Modern helicopters depend on powered rotors, carefully shaped airfoils, and control systems that Leonardo’s paper design did not possess.