What rotating flight device did Leonardo da Vinci sketch in the 1480s?

Leonardo da Vinci sketched an aerial screw, a rotating flight device, in the 1480s.

The design showed a large helical surface wrapped around a central mast. Leonardo reasoned that if the screw rotated quickly enough, its surface could push against the air and lift the machine. The concept is often described as an early ancestor of the helicopter, although it was not a practical helicopter blueprint.

Leonardo’s drawing used linen, reeds, and wire in its proposed construction. The machine would have required far more power and lighter materials than were available in Renaissance Italy. No evidence shows that Leonardo built or tested a full-scale version.

The aerial screw is commonly mixed up with his ornithopter. The ornithopter flapped wings like a bird, while the aerial screw relied on rotary lift. Modern helicopters use powered rotors, not a giant screw-shaped sail.