Leonardo da Vinci sketched an aerial screw as a flying-machine concept driven by people turning a large helical rotor.
The drawing appears in the Codex Atlanticus and is usually dated to about 1489. Its linen-covered reed-and-wire screw was intended to push against the air and rise, an idea that resembles the principle of a modern helicopter rotor. Leonardo proposed a machine roughly 5 metres across, with a central mast and a platform for operators.
The design could not realistically have lifted itself with Renaissance materials and human muscle. Its rotor would have needed more power and a lighter structure than the period could provide. For that reason, historians generally treat it as an imaginative precursor to vertical-flight machines rather than the first helicopter.
It is also often called Leonardo’s helicopter, but “aerial screw” is the more precise name for the historical drawing.