Leonardo da Vinci sketched an aerial screw as an early helicopter-like flying-machine concept.
The drawing appears in the Codex Atlanticus and is generally dated to around 1489. It shows a large helical surface wrapped around a central mast. Leonardo reasoned that if the screw were turned rapidly, its spiral surface might push against the air and lift the machine upward, much as a screw advances through a material.
The proposed machine was far too large and heavy to operate with the materials and power sources available in Renaissance Europe. It was therefore a speculative design, not a successful helicopter. Modern helicopters achieve vertical flight with powered rotor blades, which are aerodynamically different from Leonardo’s continuous helical surface.
The aerial screw remains important because it demonstrates Leonardo’s interest in using rotating motion to generate lift. Historians often describe it as a conceptual forerunner of the helicopter, while emphasizing that no direct mechanical development connects it to modern rotorcraft.