Leonardo da Vinci’s 1489 aircraft concept with a helical rotor above a platform was the aerial screw.
Leonardo drew the design in the Codex Atlanticus. It shows a large spiral-shaped linen surface, strengthened with reeds, intended to press against the air as people turned a central mechanism. The idea resembles a helicopter rotor in its use of rotating lift, although the drawing was not a practical powered helicopter.
The aerial screw is often described as an early helicopter concept, but that description needs care. Leonardo had no lightweight engine capable of supplying the required power, and the machine’s structure would have been heavy. Its historical importance lies in recognizing that a rotating helical surface might rise through the air.
The design is also commonly confused with Leonardo’s ornithopter, which used flapping wings. The aerial screw instead depends on rotary motion, making it a distinct invention concept.