Leonardo da Vinci’s proposed flying machine with a large rotating spiral was called the aerial screw.
Leonardo drew the design around 1489. It consisted of a helical sail, or screw, wrapped around a central mast. He suggested that people could turn the structure so its spiral surface would push against the air and lift the machine, an idea that resembles the principle of a helicopter rotor.
The aerial screw was a concept rather than a working aircraft. Its proposed materials and human-powered mechanism could not provide enough lift with Renaissance technology. It is often called a helicopter precursor, but it was not a helicopter in the modern engineering sense: it lacked powered rotors, a practical control system, and a tested airframe.