A rotor
that turned on its own

In January 1923, at Getafe, the autogiro of Juan de la Cierva took to the air. A twenty-seven-year-old engineer, he had set out to build a machine that could fly slowly without falling from the sky. He succeeded with a rotor that turned on its own, driven by the air, while a conventional propeller drew the machine forward. The first models overturned on take-off; the answer lay in articulated blades that rose and fell as they turned, a solution later inherited by the helicopter