Leonardo da Vinci’s aerial screw used a rotating helical blade to create lift through the air.
Leonardo drew the design around 1489, describing a large screw-shaped linen surface stretched over a framework of reeds. He reasoned that rotating the surface could push against the air and make the machine rise. The concept is frequently called a forerunner of the modern helicopter because both use rotating lifting surfaces, although Leonardo’s machine had no practical engine and could not have lifted its proposed structure with human power.
The aerial screw should not be confused with Leonardo’s ornithopter. An ornithopter depends on flapping wings, whereas the aerial screw depends on rotation. It also differs from a parachute, which slows descent rather than producing powered ascent. Modern helicopters use powered rotors with carefully shaped blades, an aerodynamic solution much more efficient than the broad helical canvas surface in Leonardo’s sketch.