Leonardo da Vinci’s spiral-aircraft concept is called the aerial screw.
Leonardo drew the aerial screw in the 1480s, probably in the Manuscript B held by the Institut de France. The design used a large helical structure made from reeds, linen, and wire. Leonardo proposed that if the screw rotated quickly enough, its spiral surface would push against the air and lift the machine.
The idea resembles a helicopter rotor in its use of rotating lift, but it was not a working helicopter. The machine had no practical engine, and human muscles alone could not provide enough power for the proposed scale. Modern historians therefore describe it as an imaginative aerodynamic study rather than a directly buildable aircraft.
Leonardo’s sketch is frequently reproduced as an early helicopter design, but “aerial screw” is the more precise historical name. The helicopter itself required later developments in engines, lightweight materials, and rotor control.