Leonardo da Vinci’s 1485 conical flying-machine design is called the aerial screw.
Leonardo drew the aerial screw in the Codex Atlanticus, describing a large helical surface wrapped around a frame. His concept appears to have been based on the idea that a rotating spiral could “screw” itself upward through the air, somewhat as a screw moves through wood.
The design is often called an early helicopter concept, but it was not a helicopter in the modern engineering sense. It had no workable engine, and the materials and human power available in the Renaissance could not have generated enough lift to make it rise.
The aerial screw is important because it anticipated a central idea of vertical flight: a rotating surface can produce upward force. Centuries later, powered helicopters used carefully shaped rotor blades and engines rather than Leonardo’s continuous helical sail.