Leonardo da Vinci sketched an aerial screw as a rotating-wing machine intended to rise vertically.
The design appears in a manuscript page dated to about 1489. It shows a large helical surface made from reeds, linen, and wire, mounted around a central mast. Leonardo suggested that turning the screw could force air downward and push the machine upward, an idea related to the principle used by helicopter rotors.
The aerial screw was not a working helicopter. The proposed structure was too heavy for the available materials and lacked a practical power source capable of spinning it fast enough. Leonardo’s drawing also did not provide the full modern system of powered rotors, controls, and stabilization.
It is often called a helicopter precursor, but that label should not imply that Leonardo built one. The aerial screw was a conceptual study of vertical flight. Its importance lies in recognizing that a rotating, helical lifting surface might produce upward force.