Leonardo da Vinci’s rotating-aircraft concept around a central vertical shaft was the aerial screw.
Leonardo drew the aerial screw in a manuscript dated to about 1489. The design shows a helical, screw-shaped surface wrapped around a vertical framework. Leonardo reasoned that if the screw were turned rapidly, it might push against the air and rise, an idea that resembles the operating principle of a modern helicopter rotor.
The drawing is important as an early conceptual study, but it was not a working helicopter. The proposed structure was large, heavy, and dependent on a power source that did not exist in Renaissance technology. It also did not include the aerodynamic control systems, lightweight materials, or engine needed for practical vertical flight.
The aerial screw is often called a helicopter precursor, not the first helicopter. Modern helicopters use rotating airfoils that create lift, while Leonardo’s drawing used a continuous helical surface. The design shows his ability to reason from familiar mechanical devices, especially the screw, toward a new form of transport.