Leonardo da Vinci proposed an aerial screw as a rotating machine for lifting people into the air.
Leonardo drew the aerial screw in the Codex Atlanticus, probably around 1489. The design shows a large helical rotor made from reeds, linen, and wire, supported by a circular platform. Leonardo suggested that the screw might rise by “screwing” into the air, an idea that resembles the principle of a modern helicopter rotor.
The machine was never built by Leonardo and could not have lifted its proposed weight with the materials and power available in the fifteenth century. Its importance lies in the early recognition that a rotating airfoil could create lift.
The aerial screw is often called a helicopter prototype, but that label can be misleading. It did not include an engine, a practical control system, or a separate rotor for balancing torque. It was a conceptual study of vertical flight, not a functioning helicopter.