Dream-Engine

Sketch (pen and ink) · Leonardo da Vinci

Leonardo's sketch of an aerial screw, made around 1483 in Milan, is the founding document of helicopter aerodynamics. It does not work. The torque required to spin the canopy at the speed needed for l

Drawing (pen, brown ink and wash, over metalpoint) · Leonardo da Vinci

Leonardo solved a problem that two generations of earlier Italian humanists had failed to solve. The Roman architect Marcus Vitruvius Pollio, writing in the first century BCE, had asserted that the pr