Leonardo da Vinci’s rotating-lift flying-machine sketch is commonly called the aerial screw.
Leonardo drew the aerial screw in a notebook usually dated to about 1489. The design has a large helical surface supported by a circular frame. Leonardo reasoned that if the screw rotated rapidly, its surface might push against the air and lift the machine, an idea resembling the principle of a modern helicopter rotor.
The drawing is one of Leonardo’s best-known studies of flight, but it was not a working helicopter. The proposed structure was heavy, and the design included no engine capable of producing the necessary rotation. A modern rotorcraft uses aerodynamic rotor blades, an engine, and controls that are fundamentally more practical than Leonardo’s cloth-covered helix.
The aerial screw is often casually called Leonardo’s helicopter, but that label can mislead. Leonardo did not build a powered helicopter, and the sketch was a theoretical machine rather than a tested aircraft. It is also separate from his flapping-wing ornithopter designs.