Leonardo da Vinci’s aerial screw used a large helical blade intended to rise through the air.
Leonardo drew the design around 1489. It consisted of a linen-covered, cork-supported helical surface mounted on a framework. His notes suggested that if the screw were spun rapidly, the air would be compressed beneath it and the device would climb.
The aerial screw is often described as a conceptual ancestor of the helicopter, but it was not a functioning helicopter. Leonardo had no lightweight engine capable of turning the broad rotor quickly enough, and the proposed machine would have required several people to operate it. Its importance lies in the idea of vertical lift produced by a rotating screw.
The design also illustrates Leonardo’s habit of adapting familiar mechanical principles. Archimedes’ screw was already known as a device for moving water, and Leonardo applied a related helical form to flight. Modern helicopters use powered rotors and aerodynamic lift rather than a solid, cloth-covered screw.