Editing Bristol Taurus

{{short description|1930s British piston aircraft engine}}
{{Use dmy dates|date=December 2016}}
{{Use British English|date=December 2016}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{|{{Infobox aircraft begin
 |name=Taurus
 |image=bristol.taurus.arp.750pix.jpg
 |caption=Preserved Bristol Taurus
}}{{Infobox aircraft engine
 |type=[[Piston]] [[aircraft engine]]
 |manufacturer=[[Bristol Aeroplane Company]]
 |first run=November 1936
 |major applications=[[Fairey Albacore]]<br />[[Bristol Beaufort]]
 |number built = 
 |program cost = 
 |unit cost = 
 |developed from =[[Bristol Aquila]]
 |developed into = 
 |variants with their own articles =
}}
|}

The '''Taurus''' is a British 14-cylinder two-row [[radial engine|radial]] [[aircraft engine]], produced by the [[Bristol Engine Company]] starting in 1936. The Taurus was developed by adding cylinders to the existing single-row [[Bristol Aquila|Aquila]] design and transforming it into a twin-row radial engine, creating a powerplant that produced just over {{convert|1,000|hp|kW|abbr=off}} with very low weight.

==Design and development==
Bristol had originally intended to use the Aquila and [[Bristol Perseus|Perseus]] 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. 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 [[Bristol Hercules|Hercules]].

The Taurus used [[sleeve valve]]s, resulting in an uncluttered exterior and little mechanical noise. It offered high power with a relatively low weight, starting from {{cvt|1015|hp}} in the earliest versions. It was also compact, with a diameter of {{cvt|46|in|mm}}  which made it attractive for fighters. Unfortunately, the engine was also described as "notoriously troublesome", with protracted development and a slow growth in rated power. After several years of development, power had only increased from {{cvt|1015|hp}} to {{cvt|1130|hp}}. As the most important applications of this engine was in aircraft that flew at low altitude, development efforts focused on low-altitude performance.

The first Taurus engines were delivered just before [[World War II]], and was used primarily in the [[Fairey Albacore]] and Bristol's [[Bristol Beaufort|Beaufort]]. In April 1940, a suggestion was made to replace the Taurus engines of the latter with the [[Pratt & Whitney R-1830]] ''Twin Wasp'', which had a slightly larger {{cvt|48|in}} diameter, but this change was postponed to the autumn of 1941 while attempts were made to cure the Taurus's reliability problems, and later had to be temporarily reversed because of shortages of Twin Wasps. The Twin Wasp was, however, strongly preferred, especially for overseas postings, because of its better reliability. The reliability problems were mostly cured in later models of the Taurus engine by a change in the cylinder manufacturing process, although the engine reputation never recovered, and in the Albacore the Taurus engine was used until the end of that aircraft's production in 1943.<ref>Lumsden 2003, p.115.</ref>

There were no other operational applications of the Taurus engine, because its initial reliability problems discouraged development of Taurus-powered aircraft, and because later-war combat aircraft demanded more powerful engines. Production ended in favour of the Hercules engine.

==Variants==
* '''Taurus II''' (1940) – {{cvt|1140|bhp|kW}} maximum power with {{cvt|4.25|psi|kPa}} boost at 3,225 rpm for take off or one minute using 87 octane fuel. Medium supercharged.{{sfnp|Lumsden|1994|p=118}}
* '''Taurus III''' – {{cvt|935| hp|kW}} maximum continuous power, medium supercharged, compression ratio 7.2:1.{{sfnp|Lumsden|1994|p=119}}
* '''Taurus VI''' – {{cvt|985|hp|kW}} maximum continuous power, medium supercharged, compression ratio 7.2:1.{{sfnp|Lumsden|1994|p=119}}
* '''Taurus XII''' (1940) – {{cvt|985|hp|kW}} maximum continuous power, medium supercharged, compression ratio 7.2:1.{{sfnp|Lumsden|1994|p=119}}
* '''Taurus XVI''' (1940) – {{cvt|985|hp|kW}} maximum continuous power, medium supercharged, compression ratio 7.2:1.{{sfnp|Lumsden|1994|p=119}}
* '''Taurus XX''' – trials engine only, one built.{{sfnp|Lumsden|1994|p=119}}

==Applications==
''Note:''<ref>List from Lumsden, the Taurus may not be the main powerplant for these aircraft types</ref>
[[File:Gloster f9 37.jpg|thumb|right|Bristol Taurus powered Gloster F.9/37]]
*[[Bristol Type 148]]
*[[Bristol Beaufort]]
*[[Fairey Albacore]]
*[[Fairey Battle]] testbed only
*[[Gloster F.9/37]]

==Specifications (Taurus II)==
{{pistonspecs
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|ref=''Lumsden.''<ref>Lumsden 2003, p.118.</ref>
|type=14-cylinder, two-row, supercharged, air-cooled [[radial engine]] with dual ignition
|bore={{convert|5|in|mm|0|abbr=on}}
|stroke={{convert|5.625|in|mm|0|abbr=on}}
|displacement={{convert|1,550|cuin|L|abbr=on}}
|length={{convert|49.2|in|mm|abbr=on}}
|diameter={{convert|46.25|in|mm|abbr=on}}
|width=
|height=
|weight={{convert|1,301|lb|kg}}
|valvetrain=[[Sleeve valve]]
|supercharger=Single-speed [[centrifugal type supercharger]]
|turbocharger=
|fuelsystem=[[Claudel-Hobson]] [[carburetor|carburettor]]
|fueltype=87 [[octane rating|Octane]] [[gasoline|petrol]]
|oilsystem=
|coolingsystem=Air-cooled
|power=<br>
*{{convert|1,140|hp|kW|abbr=on}} at 3,225 rpm for takeoff
*{{convert|1,050|hp|kW|abbr=on}} at 3,225 rpm at {{convert|5,000|ft|m|abbr=on}}
|specpower=0.68 hp/in<sup>3</sup> (30.83 kW/L)
|compression=7.2:1
|fuelcon=
|specfuelcon=0.43 lb/(hp·h) (261 g/(kW·h))
|oilcon=
|power/weight=0.81 hp/lb (1.33 kW/kg)
|reduction_gear=[[Farman Aviation Works|Farman]] [[epicyclic gearing]], 0.444:1
}}

==See also==
{{aircontent
<!-- other related articles that have not already linked: -->
|see also=

<!-- designs which were developed into or from this aircraft: -->
|related=
*[[Bristol Aquila]]
<!-- aircraft that are of similar role, era, and capability this design: -->
|similar aircraft=

<!-- relevant lists that this aircraft appears in: -->
|lists=
*[[List of aircraft engines]]

<!-- For aircraft engine articles. Engines that are of similar to this design: -->
|similar engines=
*[[Fiat A.74]]
*[[Gnome-Rhône 14N]]
*[[Mitsubishi Kinsei]]
*[[Nakajima Sakae]]
*[[Piaggio P.XIX]]
*[[Pratt & Whitney R-1830 Twin Wasp]]
*[[Shvetsov ASh-82]]
*[[Tumansky M-88]]

<!-- See [[WP:Air/PC]] for more explanation of these fields. -->
}}

==References==
{{Commons category|Bristol Taurus}}

===Notes===
{{reflist}}

===Bibliography===
*Gunston, Bill (2006). ''World Encyclopedia of Aero Engines: From the Pioneers to the Present Day''. 5th edition, Stroud, UK: Sutton.{{ISBN|0-7509-4479-X}}
* {{cite book |last=Lumsden |first=Alec |date=1994 |title=British Piston Engines and Their Aircraft |location=Shrewsbury |publisher=Airlife Publishing Ltd |isbn=1-85310-294-6}}.
*White, Graham (1995). ''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. {{ISBN|1-56091-655-9}}

<!--==External links== -->
{{Bristol aeroengines}}

[[Category:Aircraft air-cooled radial piston engines]]
[[Category:Bristol aircraft engines|Taurus]]
[[Category:Sleeve valve engines]]
[[Category:1930s aircraft piston engines]]