In the 1930s Bristol developed a new line of radials based on the sleeve valve principle, which would develop into some of the most powerful piston engines in the world, and could continue to be sold into the 1950s. In 1956 the division was renamed Bristol Aero Engines, and then merged with Armstrong Siddeley in 1958 to form Bristol Siddeley as a part of the airframe mergers that formed BAC. In 1966 Bristol Siddeley merged with Rolls-Royce, leaving only one major aero-engine company in England, Rolls-Royce.

The Bristol Centaurus has 18 cylinders in two rows, and is a sleeve-valved radial air-cooled engine. The first version produced 2,000 bhp, and the most powerful variant produced 3,200 bhp. It was the ultimate radial engine, and was developed primarily for heavy bomber and transport aircraft. Over 8,000 were produced. The Centaurus radial engine made the Sea Fury one of the fastest piston-engine aircraft ever built

The Centaurus powered the Hawker Tempest, Hawker Fury and Sea Fury, Airspeed Ambassador, Blackburn Beverley, Bristol Brigand and Vickers Warwick. The Centaurus was also used on the Bristol Brabazon prototype, which had four pairs of 2,500 bhp Centaurus engines, each pair driving a set of contra-rotating propellers. The Bristol Centaurus is still used today to power many of the Furys that take part in 'Plylon-Racing' at Reno. The inset shows a Bristol Centaurus cylinder and its sleeve. Note the intake and exhaust ports in the sleeve. These ports were the secret to the sleeve valve’s extremely good volumetric efficiency.

Scaling up smaller designs to the high-point of engine performance is not an easy task. While Bristol maintained the engine dates to 1938, production couldn't start until 1942 (nor was there a need for it). In fact the engine didn't see any use until near the end of the war, first appearing on an upscale version of the Vickers Wellington, the Warwick. Other wartime, or just-post-wartime, uses include the Bristol Brigand (and Buckmaster), Hawker Tempest and  Fury/Sea-Fury, and the Blackburn Firebrand. The engine also saw post-war use in civilian airliners.

Other piston engines of this size were developed by both Pratt and Whitney and Wright, but neither could be considered as successful during the war. The Wright was famous for bursting into flame on takeoff, and both designs required considerable development periods before becoming reliable enough for civilian use. The Centaurus, on the other hand, was considered to be very reliable right from 1942.