Leonardo da Vinci sketched a rotating aircraft concept called the aerial screw as a possible way to rise into the air.
The aerial screw appears in a manuscript drawing usually dated to around 1489. Leonardo proposed a large helical structure made from reeds, linen, and wire, with the surface intended to screw through the air as it rotated. His concept resembles the principle of a modern helicopter rotor, but it did not include the powered rotor system, controls, or lightweight engineering needed for practical flight.
The aerial screw is often described as a helicopter ancestor, although that comparison must be made carefully. Leonardo did not build a working aircraft, and the drawing’s exact operation is open to interpretation. The idea is distinct from his ornithopter, which depended on flapping wings. Its historical importance lies in recognizing that lift might be produced by a rotating or helical surface rather than by imitation of a bird.