Leonardo da Vinci’s spiral rotor concept for vertical flight is commonly called the aerial screw.
Leonardo drew the aerial screw around 1489, showing a large helical surface mounted on a central frame. His idea was that the spiral would “screw” upward through the air if rapidly rotated. The drawing resembles a helicopter rotor in broad concept, but it does not use the modern helicopter’s powered rotor, tail rotor, controls, or lightweight materials.
The aerial screw was a theoretical machine, not a demonstrated aircraft. Its proposed structure was too heavy and its human-powered mechanism too weak for practical takeoff. The design is still historically significant because it anticipated the idea of vertical lift centuries before powered helicopters became possible. It is also sometimes casually called a helicopter, although “aerial screw” is the more precise historical name.