Vickers Jockey
The Vickers Type 151 Jockey was an experimental low-wing monoplane interceptor fighter powered by a radial engine. It was later modified into the Type 171 Jockey II, which had a more powerful engine and detail improvements. Only one was built; it was lost before its development was complete, but the knowledge gained enabled Vickers to produce the more refined Venom. Development. In the late 1920s the idea of the interceptor fighter was forming. To deal with the faster and higher flying bombers, fighters had both to be fast at height and quick to get there. The Air  Ministry was keen to determine the best aircraft configuration and sought, under Air Ministry specification F.20/27, manufacturers to build biplanes and both low- and high-wing monoplanes. Vickers were asked for a prototype low-wing fighter and this became (somewhat unofficially) called the "Jockey", or sometimes the Jockey I. The name covered Vickers Types 151 and 171; the Jockey II was an early name for the later Vickers Venom. The Type 151 Jockey was a compact and rather angular, low cantilever wing monoplane, built using the Wibault-Vickers corrugated skinned all-metal method as used on the Vireo. The unstressed  skin was riveted onto a largely duralumin structure, a few steel tubes forming highly stressed members. The parallel chord, square-tipped wing used the thick, high-lift RAF 34 cross-section that Vickers had employed on the Viastra. The tailplane was equally rectangular and the fin clipped. All control surfaces apart from the rudder were unbalanced. The pilot's open cockpit was at the highest part of the fuselage at mid-chord. The Bristol Mercury IIA nine-cylinder radial engine was initially mounted without a cowling. A single-axle undercarriage had legs attached to front and rear wing spars. The  Jockey was taken to RAF Martlesham Heath for its first flight in April 1930 and subsequent testing. A rear fuselage vibration was at first thought to be aerodynamic but proved to be structural; it was cured after Barnes Wallis redesigned the internal bracing. The rudder was modified, its balance removed and a trim tab installed. Spats were added to the undercarriage and a Townend ring enclosed the engine. The same aircraft was renamed the Type 171 Jockey when the Mercury was replaced by a supercharged Bristol Jupiter VIIF. The intention to power the Jockey with a supercharged Mercury IVS2 was  never realised, after the sole Jockey was lost in a flat spin on 5 July 1932, crashing at Woodbridge, Suffolk, the pilot bailing out at . The results of the tests had been sufficiently good to encourage Vickers to refine its design into the Vickers Venom.