What spiral-powered flying machine did Leonardo da Vinci design around 1489?

Leonardo da Vinci designed an aerial screw around 1489, a spiral-powered flying machine often described as an early helicopter concept.

His drawing shows a large helical structure made from reeds, cloth, and wire. Leonardo reasoned that if the screw rotated rapidly enough, its spiral surface might push against the air and lift the machine. The design was probably inspired partly by the Chinese flying top, or bamboo-copter, whose rotating blades can rise briefly when spun.

The aerial screw was never demonstrated as a practical aircraft. It lacked an adequate lightweight engine and a reliable way to generate the necessary rotation. Modern helicopters use powered rotors that create lift through carefully shaped blades, a principle related to Leonardo’s rotary-flight idea but not identical to his cloth-covered helix.

The machine is commonly called a helicopter in popular writing, but “aerial screw” is the more precise historical name. It is best understood as a conceptual study of vertical flight, not a working helicopter built in the Renaissance.