What was the name of Leonardo da Vinci’s rotating aerial-screw design?

Leonardo da Vinci’s rotating aerial-screw design was called the aerial screw.

Leonardo drew the aerial screw in the Codex Atlanticus, probably around 1489. The sketch shows a helical linen surface wrapped around a frame. Leonardo appears to have imagined that rotating the screw would force air downward and lift the machine upward, an idea that resembles the operating principle of a helicopter rotor.

The aerial screw was not a powered helicopter and there is no evidence that Leonardo built or flew a full-size version. Its proposed motion also differs from the controlled lift produced by modern rotors. The design is important primarily as an early recorded study of vertical flight.

The shape may have been inspired by Leonardo’s observation of seeds, screws, and other spiral forms. Modern historians usually describe it as a conceptual ancestor of helicopter technology rather than the first helicopter itself. That distinction avoids confusing a Renaissance drawing with a tested aircraft.