Leonardo da Vinci sketched an aerial screw as a rotating device intended to lift into the air.
Leonardo’s aerial-screw drawing appears in the Codex Atlanticus and is generally dated to around 1489. The machine has a large helical surface wrapped around a central mast. Leonardo reasoned that if the screw rotated rapidly, its helical surface could press against the air and rise, an idea resembling the later helicopter rotor.
The design was not a working helicopter. It lacked a practical engine, and the materials and power available in Renaissance Europe could not have produced enough lift. Some reconstructions therefore function mainly as demonstrations of the concept rather than as historically accurate aircraft.
The aerial screw is important because it shows Leonardo thinking about vertical flight separately from bird-like flapping flight. Modern helicopters use powered rotors and aerodynamic blades, not a continuous fabric screw.