Leonardo da Vinci’s aerial screw used a spiral sail to suggest a machine that could rise into the air.
Leonardo drew the design around 1489. It resembles a large helical rotor mounted on a circular platform. His notes proposed that the spiral surface could grip the air if it were made from reeds, linen, and wire, producing upward movement as it rotated.
The aerial screw is often described as an ancestor of the helicopter, but it was not a functioning helicopter. The sketch does not provide a practical engine or a complete method for generating enough sustained power. Its importance lies in Leonardo’s early attempt to apply screw-like geometry to vertical flight.