The Armstrong Siddeley Jaguar is an

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbin ...

developed by

Armstrong Siddeley Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury vehicles and aircraft engines. The company was created following t ...

. The Jaguar was a

petrol Gasoline (North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When formul ...

-fuelled air-cooled 14-cylinder two-row

radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...

design. The Jaguar III was first used in 1923, followed in 1925 by the Jaguar IV and in 1927 by the Jaguar VI. In 1925 the Jaguar became the first production aero engine incorporating a geared

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...

."World Encyclopedia of Aero Engines – 5th edition" by

Bill Gunston Bill Gunston (1 March 1927 – 1 June 2013) was a British aviation and military author. He flew with Britain's Royal Air Force from 1945 to 1948, and after pilot training became a flying instructor. He spent most of his adult life doing researc ...

, Sutton Publishing, 2006. p.13

Design and development

The Jaguar was developed from the

Royal Aircraft Factory Royal may refer to: People * Royal (name), a list of people with either the surname or given name * A member of a royal family or royalty Places United States * Royal, Arkansas, an unincorporated community * Royal, Illinois, a village * Royal, ...

RAF.8 design proposal of 1916. The RAF.8 was the work of a design team led by F.M. Green, and incorporated the findings of research into aluminium air-cooled cylinders by Samuel D. Heron and Professor A. H. Gibson. Disillusioned by political and press criticism of the Royal Air Factory, Green and his design team, including Heron, left the Factory in January 1917 and took up positions with the

Siddeley-Deasy The Siddeley-Deasy Motor Car Company Limited was a British automobile, aero engine and aircraft company based in Coventry in the early 20th century. It was central to the formation, by merger and buy-out, of the later Armstrong Siddeley Motor ...

company. There they were required by official policy to suspend work on the RAF.8 and focus efforts to get the unreliable

Siddeley Puma The Siddeley Puma is a British aero engine developed towards the end of World War I and produced by Siddeley-Deasy. The first Puma engines left the production lines of Siddeley-Deasy in Coventry in August 1917, production continued until Decem ...

into effective service, an engine that had been ordered in large numbers despite a lack of testing. As a result, the RAF.8 design, then known as the Jaguar, was not run until 21 June 1922. Initial performance was not as expected; as a result the stroke was increased to 5.5 in (139.7 mm) on all variants after the Jaguar I. By that time, the engine had been fitted with a gear-driven

. Throughout its career the Jaguar suffered from vibration due to the lack of a

crankshaft A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...

centre bearing. The most powerful version of the engine, the Jaguar VIC, produced a maximum of 490 hp (365 kW) on

takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a tr ...

at 1,950

rpm Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...

and weighed 910 lb (413 kg). The later

Lynx A lynx ( ; : lynx or lynxes) is any of the four wikt:extant, extant species (the Canada lynx, Iberian lynx, Eurasian lynx and the bobcat) within the medium-sized wild Felidae, cat genus ''Lynx''. The name originated in Middle Engl ...

was designed using one row of Jaguar cylinders.

Variants

;Jaguar I :1922, 300 hp. ;Jaguar II :1923, 385 hp, increased stroke,

capacity Capacity or capacities may refer to: Mathematics, science, and engineering * Capacity of a container, closely related to the volume of the container * Capacity of a set, in Euclidean space, the total charge a set can hold while maintaining a giv ...

1,512 cu in (24.8 L). ;Jaguar III :1923, 385 hp. ;Jaguar IIIA :1923, 380 hp. ;Jaguar IV :1925, 385 hp, twin carburettors ;Jaguar IVA :420 hp, Geared propeller drive. ;Jaguar IVC :1928, 400 hp, revised

connecting rod A connecting rod, also called a 'con rod', is the part of a reciprocating engine, piston engine which connects the piston to the crankshaft. Together with the crank (mechanism), crank, the connecting rod converts the reciprocating motion of the p ...

design, enclosed valve gear. ;Jaguar IV(S) :1925, 365 hp, fully supercharged. ;Jaguar V :1928. ;Jaguar VI :1927. ;Jaguar VI(S) :1928, supercharged version of Jaguar VI. ;Jaguar VIC :1927, 470 hp, geared propeller drive version of Jaguar VI. ;Jaguar VID :1928. ;Jaguar VIIA :1929, 400 hp, fully supercharged. ;Jaguar VIII :1928, 405 hp, fully supercharged, geared propeller drive

Applications

Airco DH.4 The Airco DH.4 is a British two-seat biplane day bomber of the First World War. It was designed by Geoffrey de Havilland (hence "DH") for Airco, and was the first British two-seat light day-bomber capable of defending itself. It was desig ...

* Airco DH.9 * Armstrong Whitworth Ajax * Armstrong Whitworth Aries *

Armstrong Whitworth Argosy The Armstrong Whitworth Argosy was a three-engine biplane airliner designed and produced by the British aircraft manufacturer Armstrong Whitworth Aircraft. It was the company's first airliner. The Argosy was developed during the early-to-mid ...

Armstrong Whitworth Atlas The Armstrong Whitworth Atlas was a British single-engine biplane designed and built by Armstrong Whitworth Aircraft. It served as an army co-operation aircraft for the Royal Air Force (RAF) in the 1920s and 1930s. It was the first purpose-desi ...

Armstrong Whitworth Siskin The Armstrong Whitworth Siskin was a sesquiplane single-seat fighter aircraft developed and produced by the British aircraft manufacturer Armstrong Whitworth Aircraft. It was also the first all-metal fighter to be operated by the Royal Air Force ...

Armstrong Whitworth Starling The Armstrong Whitworth A.W.14 Starling was a prototype British single-seat biplane fighter developed for the Royal Air Force in the late 1920s which unsuccessfully competed against the Bristol Bulldog. Development The A.W.14 Starling was de ...

* Armstrong Whitworth Wolf * Avro 642 * Blackburn Airedale * Blackburn C.A.15C * Blackburn Turcock * Boulton Paul P.71 *

De Havilland Dormouse The de Havilland DH.42 Dormouse and its two variants the de Havilland DH.42A Dingo I and II were two-seat single-engined biplanes designed for fighter-reconnaissance and army cooperation roles. They did not achieve production. Development Apa ...

De Havilland DH.50 The de Havilland DH.50 was a 1920s British large single-engined biplane transport built by de Havilland at Stag Lane Aerodrome, Edgware, and licence-built in Australia, Belgium, and Czechoslovakia. History In the early 1920s, Geoffrey de Hav ...

De Havilland Giant Moth The de Havilland DH.61 Giant Moth was a 1920s United Kingdom, British large single-engined biplane transport built by de Havilland at Stag Lane Aerodrome, Edgware. Intended primarily for use in Australia, a number were also shipped to Canada. ...

De Havilland Hyena The de Havilland DH.56 Hyena was a prototype British army cooperation aircraft of the 1920s. A single-engined biplane, the Hyena was designed against an RAF requirement, but was unsuccessful with only two being built, the Armstrong Whitworth A ...

* Fairey Ferret *

Fairey Flycatcher The Fairey Flycatcher was a British single-seat biplane Aircraft carrier, carrier-borne fighter aircraft made by Fairey Aviation Company which served from 1923 to 1934. It was produced with a conventional undercarriage for Aircraft carrier, car ...

Fokker C.V The Fokker C.V was a Dutch light reconnaissance and bomber biplane aircraft manufactured by Fokker. It was designed by Anthony Fokker and the series manufacture began in 1924 at Fokker in Amsterdam. Development The C.V was constructed in the ear ...

Fokker D.XVI The Fokker D.XVI (sometimes written as Fokker D.16) was a sesquiplane fighter aircraft developed in the Netherlands in the late 1920s. Development The Fokker D.XVI was a conventional, single-bay sesquiplane with staggered wings braced with V-st ...

* Gloster Gnatsnapper *

Gloster Grebe The Gloster Grebe was developed by the Gloster Aircraft Company from the Gloster Grouse (an experimental aircraft later developed as a trainer), and was the Royal Air Force's first post-First World War fighter aircraft, entering service in 192 ...

* Handley Page Hampstead * Hawker Danecock *

Hawker Hawfinch The Hawker Hawfinch was a British single-engined biplane fighter of the 1920s. It was unsuccessful, with the Bristol Bulldog being selected instead. Development The Hawker Hawfinch fighter aircraft was designed in 1925 as a replacement for both ...

Hawker Hoopoe The Hawker Hoopoe was a British prototype naval fighter aircraft designed and built in 1927 by Hawker Aircraft. Service trials found the aircraft to be unsatisfactory, and it was superseded by the same company's Nimrod design. Design and deve ...

Hawker Woodcock The Hawker Woodcock was a British single-seat fighter built by the Hawker Engineering Company as the first fighter to be produced by Hawker Engineering (the successor to Sopwith Aviation). It was used by the Royal Air Force (RAF) as a night f ...

* Larkin Lascowl * Martinsyde ADC 1 *

Nieuport Nighthawk The Nieuport Nighthawk was a British fighter aircraft developed by the Nieuport & General Aircraft company for the Royal Air Force towards the end of the First World War. Although ordered into production before the aircraft first flew, it did ...

Parnall Plover The Parnall Plover was a British single-seat naval fighter aircraft of the 1920s. Designed and built by George Parnall & Co. for use on Royal Navy aircraft carriers, it was ordered into small-scale production but after extensive evaluation, t ...

* RAAF Experimental Section Warrigal II *

Supermarine Air Yacht The Supermarine Air Yacht was a British luxury passenger-carrying flying boat. It was designed by Supermarine's chief designer R. J. Mitchell and built in Woolston, Southampton in 1929. It was commissioned by the brewing magnate Ernest Guin ...

* Supermarine Nanok *

Supermarine Southampton The Supermarine Southampton was a flying boat of the interwar period designed and produced by the British aircraft manufacturer Supermarine. It was one of the most successful flying boats of the era. The Southampton was derived from the expe ...

Svenska Aero Jaktfalken Svenska Aero Jaktfalken ("The Gyrfalcon") was a Swedish biplane fighter aircraft, constructed in the late 1920s. The aircraft was first manufactured by Svenska Aero from 1929 to 1932 and later by AB Svenska Järnvägsverkstädernas Aeroplanavdelni ...

(SA-11) *

Vickers Vellore The Vickers Vellore was a large biplane designed as a freight and mail carrier, in single-engined and twin-engined versions, which saw limited use as freighters and long-range experimental aircraft. A final variant with a broader fuselage, the ...

Vickers Vespa The Vickers Vespa was a British army cooperation biplane designed and built by Vickers Limited in the 1920s. While not adopted by Britain's Royal Air Force, small numbers were bought by the Irish Free State and Bolivia, the latter of which used ...

* Vickers Viastra * Vickers Vimy Trainer (Type 156) *

Westland Wapiti The Westland Wapiti was a British two-seat general-purpose military single-engined biplane of the 1920s. It was designed and built by Westland Aircraft Works to replace the Airco DH.9A in Royal Air Force service. First flying in 1927, the Wa ...

Westland Weasel The Westland Weasel was a prototype British two-seat fighter/reconnaissance aircraft of the First World War. Designed to replace the Bristol Fighter, the Weasel was a single engined tractor biplane. Four prototypes were built, but no productio ...

Engines on display

A preserved Armstrong Siddeley Jaguar is on public display at the

Science Museum (London) The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded ...

Specifications (Jaguar I)

References

Notes

Citations

Bibliography

* * * *

External links

Virtual aviation museum
- a 1926 ''

Flight Flight or flying is the motion (physics), motion of an Physical object, object through an atmosphere, or through the vacuum of Outer space, space, without contacting any planetary surface. This can be achieved by generating aerodynamic lift ass ...

'' article on the Jaguar's endurance during a London-Cape Town-London flight by

Alan Cobham Sir Alan John Cobham, KBE, AFC (6 May 1894 – 21 October 1973) was an English aviation pioneer. Early life As a child he attended Wilson's School, which was then in Camberwell, London. The school was relocated to the former site of ...

{{Royal Aircraft Factory aeroengines Aircraft air-cooled radial piston engines

Jaguar The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...

1920s aircraft piston engines