What was the name of Leonardo da Vinci’s 1480s rotating aircraft concept?

Leonardo da Vinci’s 1480s rotating aircraft concept was called the aerial screw.

The design appears in Leonardo’s notebooks, including the Codex Atlanticus. It shows a large helical surface, or screw, intended to rotate rapidly and push against the air. Leonardo compared its action to a screw moving through a solid material, suggesting that air could support a machine if the screw turned quickly enough.

The aerial screw is frequently described as a forerunner of the modern helicopter, but it was not a functioning helicopter. Its proposed materials and human-powered mechanism could not have produced enough power for sustained flight. The design also lacked the control systems required for stable hovering.

The term matters because Leonardo was exploring vertical flight rather than simply gliding. His separate ornithopter studies copied the flapping motion of birds, while the aerial screw imagined lift from continuous rotation.