Leonardo da Vinci’s rotating helical flying-machine concept is called the aerial screw.
Leonardo drew the aerial screw in a manuscript usually dated to around 1489. The design shows a large spiral structure made from reeds, linen, and wire, supported by a circular frame. Leonardo proposed that the spiral could “screw” upward through the air if turned rapidly enough.
The idea resembles a modern helicopter rotor in its use of rotating lift, but it was not a helicopter in the modern engineering sense. Leonardo did not provide a workable engine or a complete method for producing the necessary power. The proposed materials and scale would also have created serious structural and aerodynamic problems.
The aerial screw is often described as a helicopter predecessor, not as the first helicopter. Its importance lies in the early recognition that rotary motion could provide vertical lift, a principle later developed with powered rotors and modern aerodynamic theory.