Don Juan de la Cierva was greatest pioneer of autogyro (his registered name: Autogiro). Convinced rotary wings could give safe non-stallable lift, he fitted contrarotating superimposed rotors to Deperdussin to produce C.I at Madrid 1920. Trial/error with C.I, C.II (2) and C.3 led to C.4 with rotor with 4 articulated blades; after changes made first successful flight at Getafe 9 January 1923. After similar C.5 Cierva received Spanish government assistance, but in 1925 he brought C.6, based on Avro 504, to England, and Air Ministry ordered 2 from A.V. Roe, Hamble. Cierva Autogiro Co. formed 24 March 1926 to hold patents and grant constructional licences. Latter went to A.V. Roe and to Parnall, Weymann-Le Père, Pitcairn, de Havilland, Westland, Comper, Focke-Wulf, Airwork, SNCASE, LeO and British Aircraft. Pitcairn perfected clutch for pre-spinning rotor by engine in 1932, and in same year Cierva company moved to Hanworth, while A.V. Roe moved to Manchester, Hamble becoming AST (Air Service Training) which handled Cierva training and modification, though main Cierva school established at Hanworth. Principal production version was C.30 (1933), 66 by Avro and others by other licensees. Cierva ironically killed in DC-2 1936. Final model C.40 (Avro Rota) could perform direct jump take-off. From outset Cierva chairman had been Air Cdre J.G. Weir, who provided considerable financial backing. He had his own company G. & J. Weir at Glasgow, concentrating on helicopters. Companies merged 1943, and after war helicopters replaced autogyros: W.9 with tail rotor replaced by reaction exhaust jet; W.11 Air Horse, giant machine with 3 rotors driven by RR Merlin; and W.14 Skeeter 2-seater. W.9 unsuccessful, W.11 crashed, but W.14 developed via Saro Skeeter into production Westland Skeeter.

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