Leonardo da Vinci’s aerial screw is a helicopter precursor designed to rise by rotating a helical rotor.
Leonardo sketched the design around 1489–1490 in the manuscript known as the Codex Atlanticus. The machine shows a large spiral-shaped linen surface mounted around a central mast. Leonardo reasoned that, if the spiral were rotated quickly, it could “screw” itself upward through the air.
The design was never built and tested by Leonardo, and its linen helix would not have produced enough lift with the materials and power available in Renaissance Italy. Modern historians therefore treat it as an influential conceptual study rather than a working helicopter.
The aerial screw is often called a helicopter ancestor, but it was not the first practical helicopter. Powered vertical flight became possible only centuries later, after engines, lightweight structures, and controllable rotors had developed.