Building Leonardo da Vinci's Aerial Screw — The Ancestor of the Helicopter

Around 1489 Leonardo da Vinci sketched a machine to rise straight up into the air: a huge screw of starched linen that, spun fast enough, would 'make its spiral in the air and rise'. It is the earliest known design for vertical flight — the direct ancestor of the helicopter rotor. This blueprint reconstructs Leonardo's aerial screw from a cane-and-linen helix on a spun axle, and is honest about the outcome: at human power it could never lift its own weight, yet its principle — a turning helical wing driving air downward — is exactly how every helicopter flies today, 450 years later.