Leonardo da Vinci’s aerial screw is widely regarded as an early helicopter concept.
Leonardo sketched the design around 1489 in the Codex Atlanticus. It showed a large helical sail made from reed, linen, and wire, mounted on a circular platform. Leonardo reasoned that turning the screw could make it rise through the air, much as a screw advances through wood.
The machine was never built or tested by Leonardo, and its proposed human-powered mechanism could not have generated enough lift. Modern historians therefore describe it as a conceptual precursor, not a working helicopter. The design also differs from a modern helicopter, whose rotor blades generate lift by aerodynamic rotation.
The aerial screw is often confused with Leonardo’s ornithopter, which attempted to imitate the flapping motion of bird wings. Both belonged to his studies of flight, but the aerial screw used a rotating helical surface rather than wings.