Leonardo da Vinci designed an aerial screw as a concept for vertical flight. His drawing shows a helical surface wrapped around a central mast, with a framework intended to rotate the screw and push against the air.
The design appears in Leonardo’s manuscripts from the late fifteenth century. He compared the action of the screw with a screw moving through a solid material, suggesting that a rapidly turning surface could lift a machine. The concept is therefore related to the principle of the modern helicopter, although Leonardo did not build a powered aircraft from it.
The aerial screw was not a helicopter in the modern engineering sense. It lacked a practical engine, suitable lightweight materials, and a proven method for producing enough lift. Scale models can rotate under modern power, but historical reconstructions do not establish that Leonardo’s full-size machine would have flown. The sketch remains important because it identified vertical lift as a distinct flight problem.