Leonardo da Vinci’s aerial screw used a helical sail to suggest vertical flight.
Leonardo drew the aerial screw in the 1480s, probably in a notebook now associated with his studies of flight. The machine had a large spiral surface made from linen, with a framework of reeds. Leonardo reasoned that rotating the screw could make the spiral “screw” itself upward through the air.
The sketch is often called a helicopter precursor, but it was not a practical helicopter. The proposed linen surface would have been too heavy, and the design supplied no workable engine or lightweight rotor system. Human muscles alone could not have powered it.
Its importance lies in the underlying idea of vertical lift from a rotating helical surface. Modern helicopters use rotating blades rather than a continuous screw, but both concepts use aerodynamic lift generated by rotation. Leonardo’s drawing therefore belongs to the history of vertical-flight ideas rather than completed aircraft.