Leonardo da Vinci designed an aerial screw, a spiral flying machine often described as an early helicopter concept.
His drawing, usually dated to around 1489, shows a large helical surface made from linen stretched over a reed or cane framework. Leonardo reasoned that turning the screw could make the spiral surface “screw” upward through the air, much as a screw moves through a solid material.
The design was not built or flown in Renaissance Italy. Its proposed size and the lack of a sufficiently powerful, lightweight engine made practical flight impossible. Modern historians therefore describe it as an influential conceptual ancestor of the helicopter rather than a helicopter itself.
Leonardo’s aerial screw belongs to a group of flight studies that also included a parachute and an ornithopter. The helicopter would not become a practical aircraft until much later, after engines, rotors, and control systems had developed.