Leonardo da Vinci’s vertical-lift flying-machine design was called the aerial screw.
Leonardo drew the aerial screw around 1489, describing a linen-covered helical surface that would screw upward through the air if rotated rapidly. The design is often compared with a modern helicopter rotor, although it could not have flown as drawn because its materials and human power source were inadequate.
The aerial screw was not a powered aircraft that Leonardo built. It was a theoretical machine in his notebooks, part of his broader study of birds, air resistance, and mechanical motion. Leonardo believed that a rotating screw could compress or push air downward and thereby raise a craft.
It is sometimes incorrectly called the first helicopter. A helicopter uses powered rotor blades, while Leonardo’s design used a continuous spiral surface. The concept is historically important because it shows Leonardo reasoning about vertical flight centuries before practical helicopters appeared.