Leonardo da Vinci called his proposed vertical-flight machine the aerial screw.
Leonardo sketched the aerial screw around 1489. The design used a large helical rotor made from a framework covered with a sail-like material. His notes suggested that, if the rotor could be made to turn rapidly, the screw might rise through the air in the same way that a screw advances through a material.
The machine was not a helicopter and was never demonstrated as a working aircraft. Human muscle power available in the Renaissance could not provide the thrust required for its large rotor. Modern historians therefore treat it as an influential conceptual study rather than a successful flying invention.
The aerial screw is frequently called a helicopter precursor because it explores vertical lift. That description is useful but should not imply that Leonardo solved powered flight. His drawing captures a mechanical idea that became practical only after engines, lightweight materials, and aerodynamic knowledge developed centuries later.