What name is given to Leonardo da Vinci’s screw-shaped aircraft concept?

Leonardo da Vinci’s screw-shaped aircraft concept is called the aerial screw.

Leonardo drew the aerial screw around 1489–1490 in the Codex Atlanticus. The design shows a large helical surface mounted around a central mast. Leonardo appears to have imagined that rotating the spiral could make it rise by pressing against the air, an idea often compared with the operating principle of a modern helicopter rotor.

The aerial screw was never demonstrated as a working aircraft. Its proposed structure was too heavy and its power system was not adequate for real flight. Modern historians therefore describe it as an important conceptual precursor rather than an actual helicopter.

The design is sometimes called a “helicopter” in popular accounts, but that label can be misleading. The modern helicopter depends on powered rotating blades and aerodynamic lift, while Leonardo’s drawing uses a continuous spiral sail-like surface. The distinction helps separate Leonardo’s original idea from later rotorcraft engineering.