What name is commonly given to Leonardo da Vinci's screw-shaped aerial machine?

Leonardo da Vinci's screw-shaped aerial machine is commonly called the aerial screw.

Leonardo drew the device in the Codex Atlanticus, probably in the late 15th century. Its design features a large helical surface made from linen stiffened with reeds and supported by a framework. Leonardo reasoned that rotating the screw could make it rise by pressing against the air, an idea that resembles the principle of a screw advancing through a fluid.

The aerial screw was never built by Leonardo and could not have lifted a person with the materials and power available in Renaissance Italy. It is therefore better described as a visionary flight concept than as a working helicopter. Modern helicopters generate lift with powered rotor blades, which are aerodynamically different from Leonardo's continuous spiral surface.

The drawing is still historically important because it identifies a rotating lifting device more than four centuries before powered helicopters became practical. The name “helicopter” is sometimes applied informally, but “aerial screw” is the standard name for Leonardo's specific design.