The Taurus is a British 14-cylinder two-row

radial Radial is a geometric term of location which may refer to: Mathematics and Direction * Vector (geometric), a line * Radius, adjective form of * Radial distance, a directional coordinate in a polar coordinate system * Radial set * A bearing f ...

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years ma ...

, produced by the

Bristol Engine Company The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aircraft engines. Notable a ...

starting in 1936. The Taurus was developed by adding cylinders to the existing single-row Aquila design and transforming it into a twin-row radial engine, creating a powerplant that produced just over 1,000

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are t ...

(750 kW) with very low weight.

Design and development

Bristol had originally intended to use the Aquila and

Perseus In Greek mythology, Perseus ( /ˈpɜːrsiəs, -sjuːs/; Greek: Περσεύς, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer ...

as two of its major product lines in the 1930s, but the rapid increase in size and speed of aircraft in the 1930s demanded much larger engines than either of these. The mechanicals from both of these designs were then put into two-row configurations to develop much larger engines, the Aquila becoming the Taurus, and the Perseus becoming the

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the ...

. The Taurus was a

sleeve valve The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve. Sleeve valve engines saw use in a number of pre-World War II luxury cars and in the United States in the Willys-Knight car and light truc ...

design, resulting in an extraordinarily uncluttered exterior and very low mechanical noise. It offered high power with a relatively low weight, starting from 1,015 hp (760 kW) in the earliest versions. It was also compact, with a diameter of 46 inches (1170 mm) which made it attractive to fighter designers. Unfortunately, the engine has also been described as "notoriously troublesome", with protracted development and a slow growth in rated power. After several years of development, power had been increased from 1,015 hp (760 kW) to only 1,130 hp (840 kW). As the most important applications of this engine were in aircraft that flew at low altitude, engine development efforts focussed on low-altitude performance. The first Taurus engines were delivered just before

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

began and found some use primarily in the

Fairey Albacore The Fairey Albacore is a single-engine biplane torpedo bomber designed and produced by the British aircraft manufacturer Fairey Aviation. It was primarily operated by the Royal Navy Fleet Air Arm (FAA) and was heavily used during the Second ...

and Bristol's own

Beaufort Beaufort may refer to: People and titles * Beaufort (surname) * House of Beaufort, English nobility * Duke of Beaufort (England), a title in the peerage of England * Duke of Beaufort (France), a title in the French nobility Places Polar regions * ...

torpedo bomber A torpedo bomber is a military aircraft designed primarily to attack ships with aerial torpedoes. Torpedo bombers came into existence just before the First World War almost as soon as aircraft were built that were capable of carrying the weight ...

. Starting from April 1940, it was suggested to replace the Taurus engines of the latter by the famous

Pratt & Whitney R-1830 The Pratt & Whitney R-1830 Twin Wasp is an American air-cooled radial aircraft engine. It displaces and its bore and stroke are both . The design traces its history to 1929 experiments at Pratt & Whitney on twin-row designs. Production be ...

''Twin Wasp'', itself possessing a slightly larger 48 inch (1.22 meter) diameter, but this change was postponed to the autumn of 1941 while attempts were made to cure the reliability problems of the Taurus, and later had to be temporarily reversed because of shortages of Twin Wasp engines. The Twin Wasp was, however, strongly preferred, especially for overseas postings, because of its much greater reliability. In later models of the Taurus engine the reliability problems were mostly cured by a change in the cylinder manufacturing process, although the engine kept a poor reputation, and in the Albacore the Taurus engine was retained until the end of that aircraft's production in 1943. There were no other operational applications of the Taurus engine, because its initial reliability problems discouraged the development of Taurus-powered aircraft, and because later-war combat aircraft demanded more powerful engines. Its production lines were closed down in favour of the Hercules engine.

Variants

;Taurus II :1940 1110 hp at 3100 rpm with 4.25 lb boost @ 4000 ft. ;Taurus III :1060 hp. ;Taurus VI :1130 hp. ;Taurus XII :1940 1130 hp at 3100 rpm with 4.75 lb boost @ 3500 ft. Supercharger ratio decreased, impeller diameter increased. ;Taurus XVI :1940 1130 hp. ;Taurus XX :Trials engine only, one built.

Applications

''Note:''List from Lumsden, the Taurus may not be the main powerplant for these aircraft types Gloster f9 37

Bristol Type 148 The Bristol Type 148 was a two-seat, single-engine low-wing monoplane built in 1937 to an Air Ministry specification for an army cooperation aircraft. It lost in the competition to the Westland Lysander and did not progress past the two prototy ...

Bristol Beaufort The Bristol Beaufort (manufacturer designation Type 152) is a British twin-engined torpedo bomber designed by the Bristol Aeroplane Company, and developed from experience gained designing and building the earlier Blenheim light bomber. At le ...

Fairey Battle The Fairey Battle is a British single-engine light bomber that was designed and manufactured by the Fairey Aviation Company. It was developed during the mid-1930s for the Royal Air Force (RAF) as a monoplane successor to the Hawker Hart and ...

testbed only * Gloster F.9/37

Specifications (Taurus II)

References

Notes

Bibliography

*Gunston, Bill. ''World Encyclopedia of Aero Engines: From the Pioneers to the Present Day''. 5th edition, Stroud, UK: Sutton, 2006. *Lumsden, Alec. ''British Piston Engines and Their Aircraft''. Marlborough, UK: Airlife Publishing, 2003. . *White, Graham. ''Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II''. Warrendale, Pennsylvania: SAE International, 1995. {{Bristol aeroengines Aircraft air-cooled radial piston engines Taurus Sleeve valve engines 1930s aircraft piston engines