Leonardo da Vinci designed an aerial screw, a screw-shaped rotor intended to lift a machine into the air.
The concept appears in a famous drawing from around 1489. Leonardo imagined a large helical surface wrapped around a central frame. If the screw rotated rapidly, he reasoned, it might press against the air and rise, in a way comparable to a screw moving through a solid material.
The aerial screw is frequently described as a forerunner of the helicopter, but the comparison has limits. Leonardo’s drawing does not provide a practical engine, a workable control system, or a demonstrated method for producing enough power. The machine was not built and flown by Leonardo.
The design is also easy to confuse with a parachute or an ornithopter. A parachute slows descent, an ornithopter uses flapping wings, and the aerial screw depends on a rotating helical surface. Its historical importance lies in the attempt to apply mechanical principles to vertical flight.