Leonardo da Vinci’s helical flying-machine design is called the aerial screw.
Leonardo drew the aerial screw around 1489, probably while investigating how air might support a rotating or spiraling surface. The sketch shows a large helical structure made from reeds, linen, and wire, mounted on a circular platform. Leonardo proposed that the screw could rise if turned rapidly, because the surface would press against the air.
The machine was never built or tested by Leonardo, and it could not have lifted itself with the materials and human power available at the time. Modern historians usually describe it as an imaginative flight concept rather than a practical helicopter prototype. Modern helicopters rely on powered rotor blades that generate lift through aerodynamic rotation, not a continuous linen-covered helix.
The aerial screw is frequently linked to helicopter history because of its shape. It should not be confused with Leonardo’s parachute, which was designed to slow descent rather than produce powered lift.