The Bristol Jupiter is a British nine-cylinder single-row piston

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. ...

that was built by the

Bristol Aeroplane 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 ...

. Originally designed late in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turned it into one of the finest engines of its era. The Jupiter was widely used on many aircraft designs during the 1920s and 1930s. Thousands of Jupiters of all versions were produced, both by Bristol and abroad under licence. A turbo-supercharged version of the Jupiter known as the Orion suffered development problems and only a small number were produced. The "Orion" name was later re-used by Bristol for an unrelated

turboprop A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, compressor, combustor, turbine, and a propellin ...

engine. The Bristol Jupiter was licensed by the Soviet Union as the Shvetsov M-22.

Design and development

The Jupiter was designed during

Roy Fedden Sir Alfred Hubert Roy Fedden MBE, FRAeS (6 June 1885 – 21 November 1973) was an engineer who designed most of Bristol Engine Company's successful piston aircraft engine designs. Early life Fedden was born in the Bristol area to fairly weal ...

of Brazil Straker and later Cosmos Engineering. The first Jupiter was completed by Brazil Straker in 1918 and featured three carburettors, each one feeding three of the engine's nine cylinders via a spiral deflector housed inside the induction chamber. During the rapid downscaling of military spending after the war, Cosmos Engineering became

bankrupt Bankruptcy is a legal process through which people or other entities who cannot repay debts to creditors may seek relief from some or all of their debts. In most jurisdictions, bankruptcy is imposed by a court order, often initiated by the de ...

in 1920, and was eventually purchased by the

on the strengths of the Jupiter design and the encouragement of the

Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force and civil aviation that existed from 1918 to 1964. It was under the political authority of the ...

. The engine matured into one of the most reliable on the market. It was the first air-cooled engine to pass the Air Ministry full-throttle test, the first to be equipped with automatic boost control, and the first to be fitted to airliners. The Jupiter was fairly standard in design, but featured four valves per cylinder, which was uncommon at the time. The

cylinders A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...

were machined from steel forgings, and the cast

cylinder head In a piston engine, the cylinder head sits above the cylinders, forming the roof of the combustion chamber. In sidevalve engines the head is a simple plate of metal containing the spark plugs and possibly heat dissipation fins. In more modern ...

s were later replaced with aluminium alloy following studies by the

Royal Aircraft Establishment The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...

. In 1927, a change was made to move to a forged head design due to the rejection rate of the castings. The Jupiter VII introduced a mechanically-driven supercharger to the design, and the Jupiter VIII was the first to be fitted with reduction gears. In 1925, Fedden started designing a replacement for the Jupiter. Using a shorter stroke to increase the

revolutions per minute 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 de ...

(rpm), and including a

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 ...

for added power, resulted in the

Bristol Mercury The Bristol Mercury is a British nine-cylinder, air-cooled, single-row, piston radial engine. Designed by Roy Fedden of the Bristol Aeroplane Company it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from ...

of 1927. Applying the same techniques to the original Jupiter-sized engine in 1927 resulted in the

Bristol Pegasus The Bristol Pegasus is a British nine-cylinder, single-row, air-cooled radial engine, radial aircraft engine, aero engine. Designed by Roy Fedden of the Bristol Aeroplane Company, it was used to power both civil and military aircraft of the 1 ...

. Neither engine would fully replace the Jupiter for a few years. In 1926 a Jupiter-engined Bristol Bloodhound with the registration G-EBGG completed an endurance flight of , during which the Jupiter ran for a total of 225 hours and 54 minutes without part failure or replacement.

Licensed production

The Jupiter saw widespread use in licensed versions, with fourteen countries eventually producing the engine. In France, Gnome-Rhone produced a version known as the Gnome-Rhône 9 Jupiter that was used in several local civilian designs, as well as achieving some export success. Siemens-Halske took out a licence in Germany and produced several versions of increasing power, eventually resulting in the Bramo 323 Fafnir, which saw use in German wartime aircraft. In Japan, the Jupiter was licence-built from 1924 by Nakajima, forming the basis of its own subsequent radial aero-engine design, the Nakajima Ha-1 Kotobuki. It was produced in Poland as the PZL Bristol Jupiter, in Italy as the Alfa Romeo 126-RC35, and in

Czechoslovakia Czechoslovakia ( ; Czech language, Czech and , ''Česko-Slovensko'') was a landlocked country in Central Europe, created in 1918, when it declared its independence from Austria-Hungary. In 1938, after the Munich Agreement, the Sudetenland beca ...

Walter Engines Walter Aircraft Engines is an aircraft engine manufacturer and former automotive manufacturer. Its notable products include the Walter M601, M601 turboprop. The company is based in Prague, Czech Republic. It has been a subsidiary of GE Aerospac ...

. The most produced version was in the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

, where its Shvetsov M-22 version powered the initial Type 4 version of the Polikarpov I-16 (55 units produced). Type 4 Polikarpovs can be identified by their lack of exhaust stubs, rounded NACA cowling and lack of cowling shutters, features which were introduced on the

Shvetsov M-25 The Shvetsov M-25 was an aircraft radial engine produced in the Soviet Union (USSR) in the 1930s and 1940s, a licensed production variant of the Wright R-1820-F3. Design and development The first M-25s were produced from kits imported from the ...

powered Type 5 and later variants (total production 4,500+ units). Production started in 1918 and ceased in 1930.

Variants

The Jupiter was produced in many variants, one of which was the Bristol Orion of 1926.

Metallurgy Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the ...

problems with this turbo-supercharged engine caused the project to be abandoned after only nine engines had been built. ;Brazil Straker (Cosmos) Jupiter I :(1918) ; only two engines assembled. ;Cosmos Jupiter II :(1918) ; a single engine assembled. ;Bristol Jupiter II :(1923) . ;Bristol Jupiter III :(1923) . BristolJupiter

;Bristol Jupiter IV :(1926) ; fitted with variable valve timing and a Bristol Triplex carburettor. ;Bristol Jupiter V :(1925) . ;Bristol Jupiter VI :(1927) ; produced in both high- (6.3:1) and low- (5.3:1)

compression ratio The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine. A fundamental specification for such engines, it can be measured in two different ways. Th ...

versions. ;Bristol Jupiter VIA :(1927) ; civil version of Jupiter VI. ;Bristol Jupiter VIFH :(1932) ; version of Jupiter VI equipped with gas starter motor. ;Bristol Jupiter VIFL :(1932) ; version of Jupiter VI with compression ratio of 5.15:1. ;Bristol Jupiter VIFM :(1932) ; version of Jupiter VI with compression ratio of 5.3:1. ;Bristol Jupiter VIFS :(1932) ; version of Jupiter VI with compression ratio of 6.3:1. ;Bristol Jupiter VII :(1928) ; fitted with supercharger, with compression ratio of 5.3:1; also manufactured by Gnome-Rhone as the 9ASB. ;Bristol Jupiter VIIF :(1929) ; version of Jupiter VII with forged cylinder heads. Bristol Jupiter VIIIF 2

;Bristol Jupiter VIIFP :(1930) ; version of Jupiter VII with pressure feed lubrication to wrist-pins. ;Bristol Jupiter VIII :(1929) ; first version with propeller reduction gearing; compression ratio 6.3:1. ;Bristol Jupiter VIIIF :(1929) ; version of Jupiter VIII with forged cylinder heads and lowered compression ratio (5.8:1). ;Bristol Jupiter VIIIFP :(1929) ; version of Jupiter VIII with pressure feed lubrication ( time between overhauls at this stage in development was only 150 hours due to multiple failures). ;Bristol Jupiter IX : ; compression ratio 5.3:1. ;Bristol Jupiter IXF : ; version of Jupiter IX with forged cylinder heads ;Bristol Jupiter X : ; compression ratio 5.3:1. ;Bristol Jupiter XF : ; version of Jupiter X with forged cylinder heads ;Bristol Jupiter XFA : ;Bristol Jupiter XFAM : ;Bristol Jupiter XFBM : ;Bristol Jupiter XFS :Fully supercharged. ;Bristol Jupiter XI :Compression ratio 5.15:1. ;Bristol Jupiter XIF : ; compression ratio 5.15:1. ;Bristol Jupiter XIFA : ; version of Jupiter XIF with 0.656:1 propeller gear reduction ratio ;Bristol Jupiter XIFP : ; version of Jupiter XIF with pressure feed lubrication. ;Bristol Orion I :(1926) Jupiter III, turbo-supercharged, abandoned programme. ;Gnome-Rhône 9A Jupiter:French licence production primarily of 9A, 9Aa, 9Ab, 9Ac, 9Akx and 9Ad variants. ;Siemens-Halske Sh20, Sh21 and Sh22 :Siemens-Halske took out a licence in Germany and produced several versions of increasing power, eventually resulting in the Bramo 323 Fafnir, which saw use in wartime models. ;Nakajima Kotobuki :In Japan, the Jupiter was licence-built from 1924 by Nakajima. ;PZL Bristol Jupiter: Polish production. ;Alfa Romeo Jupiter :Italian licence production, . ;Alfa 126 R.C.35 :Alfa Romeo developed variant ;Walter Jupiter: Licence production in Czechoslovakia by Walter Engines ;Shvetsov M-22: The most produced version; manufactured in the

. ;IAM 9AD Jupiter: Licence production of the Gnome-Rhône 9A in

Yugoslavia , common_name = Yugoslavia , life_span = 1918–19921941–1945: World War II in Yugoslavia#Axis invasion and dismemberment of Yugoslavia, Axis occupation , p1 = Kingdom of SerbiaSerbia , flag_p ...

;SABCA Jupiter: licensed production in

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

SABCA SABCA () is a Belgian aerospace company. Its main sectors of activity are civil aviation, space and defence. SABCA was established during 1920. Presently, it is owned by the Belgian group Orizio, itself owned by the Société Fédérale de Par ...

(''Société Anonyme Belge de Constructions Aéronautiques'') ;Piaggio-Jupiter: Licensed production by Piaggio

Applications

The Jupiter is probably best known for powering the Handley Page H.P.42 airliners, which flew the London-Paris route in the 1930s. Other civilian uses included the

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. ...

and de Havilland Hercules, the

Junkers G 31 The Junkers G 31 was an advanced tri-motor airliner designed and produced by the German aircraft manufacturer Junkers. It would be the first airliner operated by Deutsche Luft Hansa to feature a flight attendant. Development of the G 31 took pl ...

and the huge Dornier Do X flying boat, which used no less than twelve engines. Military uses were less common, but included the parent company's

Bristol Bulldog The Bristol Bulldog is a British Royal Air Force single-seat biplane Fighter aircraft, fighter designed during the 1920s by the Bristol Aeroplane Company. More than 400 Bulldogs were produced for the RAF and overseas customers, and it was one ...

, as well as the Gloster Gamecock and

Boulton Paul Sidestrand The Boulton Paul P.29 Sidestrand was a twin-engine biplane medium bomber of the Royal Air Force. Designed for daylight operations, it was manoeuvrable and provided with three defensive gun positions. Named after Sidestrand, a village on the Norf ...

. It was also found in prototypes around the world, from Japan to Sweden. By 1929 the Bristol Jupiter had flown in 262 different aircraft types, ''Note:''

Cosmos Jupiter

* Bristol Badger * Bristol Bullet * Sopwith Schneider * Westland Limousine

Bristol Jupiter

* Aero A.32 * Airco DH.9 * Arado Ar 64 * Avia BH-25 * Avia BH-33E * Bernard 190 * Blériot-SPAD 51 * Blériot-SPAD S.56 * Boulton & Paul Bugle * Boulton Paul P.32 * Boulton Paul Partridge *

* Blackburn Beagle * Blackburn Nile *

Blackburn Ripon The Blackburn T.5 Ripon was a carrier-based torpedo bomber and reconnaissance biplane designed and produced by the British aircraft manufacturer Blackburn Aircraft. It was the basis for both the license-produced Mitsubishi B2M and the improv ...

* Bristol Badger * Bristol Badminton * Bristol Bagshot * Bristol Beaver * Bristol Bloodhound * Bristol Boarhound * Bristol Brandon *

* Bristol Bullfinch * Bristol Jupiter Fighter * Bristol Seely * Bristol Type 72 * Bristol Type 75 * Bristol Type 76 * Bristol Type 89 * Bristol Type 92 * Bristol Type 101 * Bristol Type 118 * de Havilland Dingo * de Havilland DH.72 * de Havilland DH.50 * de Havilland Dormouse * de Havilland Hercules * de Havilland Hound *

* de Havilland Survey * Dornier Do 11 *

Dornier Do J The Dornier Do J ''Wal'' ("whale") is a twin-engine German flying boat of the 1920s designed by ''Dornier Flugzeugwerke''. The Do J was designated the Do 16 by the Reich Air Ministry (''RLM'') under its RLM aircraft designation system, aircraft ...

* Dornier Do X * Fairey IIIF * Fairey Ferret * Fairey Flycatcher * Fairey Hendon * Fokker C.V * Fokker F.VIIA * Fokker F.VIII * Fokker F.IX * Gloster Gambet * Gloster Gamecock * Gloster Gnatsnapper * Gloster Goldfinch * Gloster Goral * Gloster Goring *

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 ...

* Gloster Mars * Gloster Survey * Gourdou-Leseurre LGL.32 * Handley Page Clive * Handley Page Hampstead * Handley Page Hare * Handley Page Hinaidi * Handley Page HP.12 * Handley Page H.P.42 * Hawker Duiker * Hawker Harrier *

Hawker Hart The Hawker Hart is a British two-seater biplane light bomber aircraft that saw service with the Royal Air Force (RAF). It was designed during the 1920s by Sydney Camm and manufactured by Hawker Aircraft. The Hart was a prominent British aircraf ...

* Hawker Hawfinch * Hawker Hedgehog * Hawker Heron * Hawker Woodcock * Junkers F.13 *

* Junkers W 34 * Parnall Plover * PZL P.7 *

Saunders Medina The Saunders A.4 Medina was a British flying boat built by S.E. Saunders at East Cowes, Isle of Wight. Development The Medina was built for the Air Council between 1925 and 1926 and was a plywood-covered wooden flying boat powered by two 450 ...

* Saunders Severn *

Short Calcutta The Short Calcutta or S.8 was a civilian biplane airliner An airliner is a type of airplane for transporting passengers and air cargo. Such aircraft are most often operated by airlines. The modern and most common variant of the airliner ...

* Short Chamois * Short Gurnard * Short Kent * Short Rangoon * Short Scylla * Short Springbok * Short S.6 Sturgeon * Short Valetta * Supermarine Seagull * Supermarine Solent *

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 *

Tupolev I-4 The Tupolev I-4 was a Soviet sesquiplane single-seat fighter. It was conceived in 1927 by Pavel Sukhoi as his first aircraft design for the Tupolev design bureau, and was the first Soviet all-metal fighter. Design and development After the fi ...

* Vickers F.21/26 * Vickers F.29/27 * Vickers Jockey * Vickers Type 143 * Vickers Type 150 *

Vickers Valiant The Vickers Valiant was a British high-altitude jet bomber designed to carry nuclear weapons, and in the 1950s and 1960s was part of the Royal Air Force's " V bomber" strategic deterrent force. It was developed by Vickers-Armstrongs in respon ...

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 Vellox * Vickers Vespa * Vickers Viastra * Vickers Victoria * Vickers Vildebeest *

Vickers Vimy The Vickers Vimy was a British heavy bomber aircraft developed and manufactured by Vickers Limited. Developed during the latter stages of the First World War to equip the Royal Flying Corps (RFC), the Vimy was designed by Rex Pierson, Vickers ...

* Vickers Vimy Trainer * Vickers Wibault Scout * Villiers 26 * Westland Interceptor *

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 Westbury * Westland Witch * Westland-Houston PV.3

Gnome-Rhône Jupiter

* Bernard SIMB AB 12 * Blanchard BB-1 * Breguet 19 * Fizir F1M-Jupiter * Latécoère 6 * Lioré et Olivier LeO H-15 * Potez 29/4 * Wibault Wib.220 * Denhaut Hy.479

Shvetsov M-22

* Kalinin K-5 * Kalinin K-12 * Polikarpov I-5 *

Polikarpov I-15 The Polikarpov I-15 () was a Soviet biplane fighter aircraft of the 1930s. Nicknamed ''Chaika'' (', "gull") because of its gulled upper wings,Gunston 1995, p. 299.Green and Swanborough 1979, p. 10. it was operated in large numbers by the Soviet ...

* Polikarpov I-16 *

* Yakovlev AIR-7

Engines on display

* A Bristol Jupiter VI is on static display at Aerospace Bristol in the former Bristol Aeroplane Company factory complex in Filton, a suburb of Bristol, United Kingdom. * A Bristol Jupiter VIIF is on static display at the Shuttleworth Collection in Old Warden, United Kingdom. * A Bristol Jupiter VIIIF is on static display at the Steven F. Udvar-Hazy Center of the

National Air and Space Museum The National Air and Space Museum (NASM) of the Smithsonian Institution is a museum in Washington, D.C., in the United States, dedicated to history of aviation, human flight and space exploration. Established in 1946 as the National Air Museum, ...

at Washington Dulles International Airport in Fairfax County, Virginia, United States. * A

complete with a Jupiter VIIFP engine is on static display at the

Royal Air Force Museum London The Royal Air Force Museum London (also commonly known as the RAF Museum) is located on the former Hendon Aerodrome, in North London's Borough of Barnet. It includes five buildings and hangars showing the history of aviation and the Royal Air ...

in Hendon, United Kingdom.

Specifications (Jupiter XFA)

References

Bibliography

* Bridgman, L. (ed.) ''Jane's Fighting Aircraft of World War II''. New York: Crescent Books, 1998. * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. . * Gunston, Bill. ''Development of Piston Aero Engines''. Cambridge, England. Patrick Stephens Limited, 2006. * Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. *

External links

* Contemporary article on Cosmos Engineering's air-cooled radial engines. Photos of the Cosmos Jupiter are o
page 870
and a short technical description is o

{{Walter aeroengines Aircraft air-cooled radial piston engines

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

1910s aircraft piston engines