Leonardo da Vinci’s rotating-wing aircraft concept was the aerial screw.
Drawn around 1489, the aerial screw consists of a large helical surface mounted around a central mast. Leonardo reasoned that if the screw were rotated quickly enough, its helical surface might push against the air and lift the structure upward.
The idea resembles a conceptual ancestor of the helicopter, but it was not a working helicopter. The drawing does not provide a practical engine or a sufficiently light structure, and the proposed materials would have made the machine extremely heavy.
Leonardo’s sketch is significant because it recognized that lift could come from a rotating screw rather than from flapping wings. Centuries later, powered helicopter development required lightweight engines, strong materials, and aerodynamic knowledge unavailable during the Renaissance.