Leonardo da Vinci’s aerial screw used a large screw-shaped rotor to suggest vertical flight.
Leonardo drew the design around 1489–1490 in his Paris Manuscript. It shows a helical surface made from linen stretched over a reed framework, with a platform and people turning a central shaft. Leonardo reasoned that the rotating screw would “screw” itself upward through the air, much as a screw moves through wood.
The aerial screw is often called a helicopter or helicopter prototype, but it was not a working helicopter. Its materials, human power, and lack of a practical engine would not have produced enough lift. Modern helicopters use powered rotors and aerodynamic blades rather than a continuous linen helix.
The sketch is important because it shows Leonardo applying mechanical reasoning to flight. It was one of several studies in which he explored air resistance, lift, and human flight, alongside winged machines and parachute designs.