Leonardo da Vinci’s screw-shaped aerial machine was the aerial screw, a design often described as a conceptual precursor to the helicopter.
Leonardo drew the aerial screw in a manuscript generally dated to about 1489. The device has a large helical surface made from reeds, linen, and wire, supported by a circular frame. His notes suggest that rotating the screw could make it rise by pushing against the air, an idea analogous to the action of a modern rotor.
The machine was not an operational helicopter. Its proposed materials and human-powered mechanism would not have produced enough thrust to lift the structure and pilot. The design also lacks the powered rotor, control system, and lightweight construction essential to helicopter flight.
The aerial screw remains significant because it shows Leonardo reasoning about vertical flight. The word “helicopter” itself was coined much later, and modern helicopters use rotating blades rather than one continuous fabric-covered spiral.