Leonardo da Vinci sketched an aerial screw, a spiral-shaped flying device often described as an early helicopter concept.
Leonardo drew the aerial screw around 1489 in his notebooks. The design shows a large helical surface wrapped around a central mast, supported by a framework. Leonardo proposed that turning the structure could make the helical surface “screw” upward through the air, an idea analogous to how a screw moves through a solid material.
The aerial screw was a conceptual design rather than a working aircraft. Its proposed materials and human power source could not produce enough thrust, and it lacked the aerodynamic understanding and engine technology needed for controlled flight. Modern helicopters use powered rotors, not a single large linen-covered spiral. The aerial screw is therefore best understood as a striking historical precursor to vertical-flight thinking, not as a functioning helicopter built by Leonardo.