Leonardo da Vinci's spiral rotor concept was called the aerial screw. He sketched it around 1489, showing a helical sail wrapped around a light frame that he believed could lift itself by rotating.
The drawing appears in Leonardo's manuscripts and is usually interpreted as an attempt to apply the screw principle to air. Leonardo may have been inspired by Chinese flying toys and by the way a screw moves through water. His proposed machine was roughly 4.8 metres in diameter, with a reed-and-canvas helical surface.
The aerial screw could not have flown as designed because human muscle power was insufficient to spin its large rotor rapidly, and the structure was too heavy. Nevertheless, its rotating-lift idea resembles the principle later used by helicopters. Modern helicopters use powered rotors and aerodynamic blades, not a continuous linen spiral.