Bristol Aeroplane Company - Bristol Engine Company

The Bristol Engine Company was originally a separate entity, Cosmos Engineering, formed from the pre-First World War automobile company Brazil-Straker. In 1917 Cosmos was asked to investigate air-cooled radial engines, and under Roy Fedden produced what became the Cosmos Mercury, a 14-cylinder two-row (helical) radial, which they launched in 1918. This engine saw little use, but the simpler nine-cylinder version known as the Bristol Jupiter was clearly a winning design.

With the post-war rapid contraction of military orders Cosmos Engineering went bankrupt, and the Air Ministry let it be known that it would be a good idea if the Bristol Aeroplane Company purchased it. The Jupiter competed with the Armstrong Siddeley Jaguar through the 1920s, but Bristol put more effort into their design and by 1929 the Jupiter was clearly superior. In the 1930s, and led by Roy Fedden, the company developed the new Bristol Perseus line of radials based on the sleeve valve principle, which developed into some of the most powerful piston engines in the world, and continued to be sold into the 1960s.

In 1956 the division was renamed Bristol Aero Engines, and then merged with Armstrong Siddeley in 1958 to form Bristol Siddeley as a counterpart of the airframe-producing company mergers that formed BAC. In 1966 Bristol Siddeley was purchased by Rolls-Royce, leaving the latter as the only major aero-engine company in Britain. Rolls-Royce continues to produce aircraft engines as Rolls-Royce plc. A number of Bristol Siddeley engines of Bristol heritage continued to be developed by Rolls-Royce, notably the Olympus turbojet and the Pegasus. The classical names favoured by Bristol indicated their heritage in a Rolls-Royce lineup named after British rivers.