Leonardo da Vinci designed an aerial screw with a helical linen sail intended to rise by rotating through the air.
The drawing appears in the Codex Atlanticus and is usually dated to about 1489. Leonardo described a structure roughly 5 metres across, with a reed frame covered in linen. His idea was that the spiral surface would “screw” into the air when turned.
The aerial screw is often called a helicopter precursor because its central concept resembles a rotorcraft. However, Leonardo did not have a practical lightweight engine, and the machine could not supply enough power for sustained flight. The drawing therefore represents an important conceptual experiment, not a functioning helicopter.
The design also differs from an ornithopter, which uses flapping wings, and from a parachute, which descends by creating drag. Modern helicopters use powered rotors, aerodynamic blades, and control systems that were unavailable to Leonardo.