Leonardo da Vinci studied a rotating-wing aircraft concept called the aerial screw in a drawing dated 1489.
The design shows a large helical rotor made from a framework covered with reed and linen. Leonardo reasoned that if the screw turned rapidly enough, its helical surface might press against the air and lift the machine. The concept is often described as an ancestor of the helicopter, although it was not a practical helicopter and was never successfully flown.
A modern helicopter uses powered rotor blades that generate lift through carefully shaped airfoils. Leonardo’s aerial screw relied on a much broader spiral surface and lacked an engine capable of supplying the necessary power.
The idea is sometimes called a “helicopter” in popular summaries, but “aerial screw” is the more specific historical name for Leonardo’s drawing. It is distinct from his flapping-wing ornithopter.