What name is given to Leonardo da Vinci's propeller-like flying-machine design?

Leonardo da Vinci's propeller-like flying-machine design is called the aerial screw.

Leonardo drew the aerial screw in a manuscript usually dated to about 1489. The machine featured a large helical sail, or screw, mounted around a central shaft. His notes suggest that rotating the screw could make it rise through the air, an idea that resembles the lifting principle of a modern helicopter rotor.

The aerial screw was never built and tested by Leonardo, and the original concept would not have had enough power to lift its own structure. It is therefore better understood as a pioneering aerodynamic thought experiment than as a practical helicopter.

The design is sometimes casually called a helicopter, but that is a modern comparison, not Leonardo's name. It also differs from his ornithopter sketches, which sought lift through flapping wings modeled on birds.