Leonardo da Vinci sketched an aerial screw with a helical rotor intended to lift into the air.
The design appears in a manuscript from around 1489 and resembles a large screw or propeller wrapped in a helical surface. Leonardo reasoned that if the screw-like structure rotated rapidly, its surface might push against the air and raise the machine. The idea is often compared with the modern helicopter, although Leonardo’s sketch did not provide a practical engine or a complete control system.
The aerial screw was a theoretical machine rather than a documented flying aircraft. Its proposed rotor was made from materials such as reed, linen, and wire, and the design would have been far too heavy for the available power sources.
Despite those limitations, the sketch is historically important because it anticipates the basic idea of vertical lift from a rotating airfoil. It is separate from Leonardo’s bird-winged ornithopter and pyramid parachute.