The Bristol Hercules was a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the first of their single sleeve valve (Burt-McCollum, or Argyll, type) designs to see widespread use, powering many aircraft in the mid- World War II time frame. The Bristol Jupiter was a British nine-cylinder single-row piston radial engine built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turned it into one of the finest engines of its era. The Jupiter was widely used on many aircraft designs during the 1920s and 30s. Thousands of Jupiters of all versions were produced, both by Bristol and abroad under license. A turbo-supercharged version of the Jupiter known as the Orion suffered development problems and only a small number were produced.