Leonardo da Vinci’s spiral device intended for vertical lift is commonly called the aerial screw.
Drawn in a notebook around 1489, the aerial screw featured a large helical structure supported by a framework. Leonardo reasoned that if the spiral surface were driven rapidly enough, it might screw upward through the air. The idea resembles the operating principle of a modern helicopter rotor, although the proposed machine lacked a practical engine and suitable lightweight materials.
The design was not a working helicopter. It was a theoretical engineering study showing Leonardo’s interest in translating familiar mechanical ideas into the air. He also considered how the structure could be assembled and operated by several people.
The term “aerial screw” is more precise than “helicopter.” Leonardo never built a powered helicopter, and the modern helicopter developed much later through advances in engines, aerodynamics, and rotor design.