Leonardo da Vinci’s spiral device designed to rise through the air was called the aerial screw.
Leonardo drew the design around 1489 in the Codex Atlanticus. It consists of a large helical surface wrapped around a central mast, supported by a circular frame. Leonardo reasoned that if the screw rotated quickly enough, its spiral surface would “screw” into the air and lift the machine. The concept is therefore often described as an ancestor of the modern helicopter, although it was not a functioning helicopter.
The design probably could not have flown as drawn because human muscle power would not have provided enough energy to rotate its large rotor. It also lacked several features required for controlled vertical flight, including a practical counter-rotating rotor or an effective anti-torque system. Modern replicas are generally used to illustrate the idea rather than to prove that the original design was airworthy.
The aerial screw is distinct from Leonardo’s ornithopter studies, which imitate the flapping motion of bird wings. Its significance lies in using a rotating helical surface to create lift.