Leonardo da Vinci’s 1489 sketch for a helical-rotor vertical-flight machine is called the aerial screw.
Leonardo drew the design in the Codex Atlanticus. It shows a large spiral-shaped linen surface, supported by a reed framework and coated with starch, intended to screw upward through the air when rotated. The drawing is often described as an early helicopter concept, although it was not a working helicopter and Leonardo did not build a full-scale version.
The design is easy to confuse with Leonardo’s ornithopter, which was based on flapping wings. The aerial screw instead used rotary motion. Modern engineers generally regard it as an imaginative precursor rather than a practical aircraft, because the proposed materials and human power would not have supplied enough lift.
Leonardo’s notes on flight included several other ideas, including parachutes, gliders, and birdlike machines. Together, they show that he studied air resistance, balance, and lift long before powered aviation became possible.