Leonardo da Vinci’s aerial screw used a helical screw to suggest a vertical-flying machine.
Leonardo drew the design around 1489–1490, during his studies of flight and the movement of air. The sketch shows a large spiral-shaped linen surface wound around a central mast. Leonardo reasoned that, if the screw were turned rapidly, its surface might push against the air and lift the structure.
The aerial screw was a concept, not a demonstrated aircraft. Its heavy frame and the limited power available in Renaissance machinery would have made practical flight impossible. It is often called an early helicopter concept, although modern helicopters use powered rotors rather than a single helical screw. Leonardo also studied wings, parachutes, and flapping machines separately.