Leonardo da Vinci sketched an aerial screw as a flying device with a large rotating screw above its frame.
Leonardo drew the design around 1489 in his notebooks. It has a helical surface made from linen stretched over a reed or cane framework. His idea was that rotating the screw would push against the air and lift the machine, using a principle that resembles the action of a modern helicopter rotor.
The aerial screw was not a working helicopter. Leonardo did not build a full-scale powered version, and the materials and human power available in the Renaissance could not supply enough lift. It is also often called a “helicopter” in popular accounts, but that modern term describes a later aircraft category. The drawing is important because it shows Leonardo reasoning about vertical flight centuries before powered helicopters became practical.