Leonardo da Vinci designed an aerial screw with four spiral-shaped wings.
Leonardo sketched the aerial screw in about 1489. The machine had a central mast and a helical surface made from reeds, linen, and wire. His notes suggested that if the screw rotated rapidly, its spiral surface might press against the air and lift the structure upward.
The concept is frequently described as an ancestor of the helicopter because it uses a rotating lifting surface. However, it was not a helicopter: Leonardo's drawing does not show a practical engine, and the proposed materials and human power could not provide enough energy for sustained flight.
The aerial screw is also distinct from Leonardo's ornithopter. An ornithopter flaps wings like a bird, while the aerial screw depends on rotation. Modern helicopters use powered rotors with carefully designed blades, control systems, and engines, all of which were absent from Leonardo's 15th-century concept.