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Cierva's C.4 Autogiro Takes Off:
The Autogiro was pioneered in Spain by Juan de la Cierva, who flew the first successful rotary-wing aircraft, his C.4 Autogiro, in 1923. The Autogiro served as a laboratory to refine many components necessary for the practical helicopter, including effective rotor blades and their essential flapping and lead-lag hinges. It was also one of the safest aircraft types of its time.
Airmail by Autogiro:
John Miller takes off in a Kellett KD-1B from the Philadelphia Post Office roof during an experimental Eastern Airlines airmail service, which operated in 1939-40. In the mid-1930s, Autogiro designers introduced "direct control," exchanging airplane-style wings and control surfaces with tilting rotorheads for safer low-speed handling. |