The Armstrong Siddeley Viper is a British turbojet engine developed and produced 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 ...

and then by its successor companies

Bristol Siddeley Bristol Siddeley Engines Ltd (BSEL) was a British aero engine manufacturer. The company was formed in 1959 by a merger of Bristol Aero-Engines Limited and Armstrong Siddeley Motors Limited. In 1961 the company was expanded by the purchase of t ...

and

Rolls-Royce Limited Rolls-Royce Limited was a British luxury car and later an aero-engine manufacturing business established in 1904 in Manchester by the partnership of Charles Rolls and Henry Royce. Building on Royce's good reputation established with his Crane ( ...

. It entered service in 1953 and remained in use with the

Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...

, powering its Dominie T1 navigation training aircraft until January 2011.

Design and development

The design originally featured a seven-stage compressor based on their

Adder ''Vipera berus'', also known as the common European adder Mallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. . and the common European viper, ...

engine — the Viper is in effect a large-scale Adder. Like the similar

J85 J85 may refer to: *General Electric J85, a small single-shaft turbojet engine *HMS Seagull (J85), a Halcyon class minesweeper of Royal Navy *J85, the Johnson solid notation for a snub square antiprism In geometry, the snub square antiprism is t ...

built in United States, the Viper was originally developed as an expendable engine for production versions of the

Jindivik The GAF Jindivik is a radio-controlled target drone produced by the Australian Government Aircraft Factories (GAF). The name is from an Aboriginal Australian word meaning "the hunted one". Two manually-controlled prototypes, were built as the G ...

target drone. Like the J85, the limited-life components and total-loss oil systems were replaced with standard systems for use in crewed aircraft. Because it was initially developed as an expendable engine, the Viper was subject to many recurring maintenance issues. This led to the development of the first

Power by the Hour Aircraft maintenance is the performance of tasks required to ensure the continuing airworthiness of an aircraft or aircraft part, including overhaul, inspection, replacement, defect rectification, and the embodiment of modifications, compliance ...

program in which operators would pay a fixed hourly rate to Bristol Siddeley for the continual maintenance of the engines. In the 1970s, Turbomecanica

Bucharest Bucharest ( , ; ) is the capital and largest city of Romania. The metropolis stands on the River Dâmbovița (river), Dâmbovița in south-eastern Romania. Its population is officially estimated at 1.76 million residents within a greater Buc ...

and Orao

Sarajevo Sarajevo ( ), ; ''see Names of European cities in different languages (Q–T)#S, names in other languages'' is the Capital city, capital and List of cities in Bosnia and Herzegovina, largest city of Bosnia and Herzegovina, with a population of 2 ...

acquired the license for the Viper engine, which propelled various Romanian and Yugoslav built aircraft.INCAS - IAR 93 and SOKO /VTJ - J - ORAO Specifications
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Variants

''Data from:''Jane's All the World's Aircraft 1955-56, Jane's all the World's Aircraft 1959-60, Jane's All the World's Aircraft 1962-63 ;ASV.1:Short life design study; . ;ASV.2:Developed short life version, first run in April 1951; . ;ASV.3: (Mk.100) Short life for missile/target applications, flight-tested in the tail of an

Avro Lancaster The Avro Lancaster, commonly known as the Lancaster Bomber, is a British World War II, Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to ...

November 1952; . ;ASV.4:Short life for missile/target applications first run in 1952, . ;ASV.5:(Mk. 101) Extended life version for crewed aircraft. ;ASV.6:Short life for missile/target applications; . ;ASV.7: ;ASV.7/R: ASV.7 with re-heat; . ;ASV.8: (became Viper 8 and Mk.102); Long-life version rated at for Jet Provost T Mk.3. ;ASV.9: (became Viper 9 and Mk.103) Similar to ASV.8 with improved turbine materials; . ;ASV.10:Long-life version with re-designed Sapphire-style compressor first run in January 1956; . ;ASV.11: (became Viper 11 and Mk.200) ASV.10 with increased mass-flow; . ;ASV.12: (became Viper 12) up-rated ASV.11 with higher JPT and rated at ;Viper 8: (Mk.102 / Mk.104): Engines for the Hunting-Percival Jet Provost TMk.3 (Mk.102) and GAF Jindivik Mk.102B target drone (Mk.104). ;Viper 9: (Mk.103): Powered the

Bell X-14 The Bell X-14 (Bell Type 68) is an experimental VTOL aircraft flown in the United States in the 1950s. The main objective of the project was to demonstrate vectored thrust horizontal and vertical takeoff, hover, transition to forward flight, ...

and

Handley Page HP 115 The Handley Page HP.115 was an experimental delta wing aircraft designed and produced by the British aircraft manufacturer Handley Page. It was built to test the low-speed handling characteristics to be expected from the slender delta configur ...

among others. ;Viper 11: (Mk.200): Powered the Hunting-Percival Jet Provost TMk.4(Mk202) and GAF Jindivik Mk.3 among others. ;Viper 12: see ASV.12 above ;Viper 20: (Mk.500 series): Powered the Hawker Siddeley HS.125 and Piaggio-Douglas PD.808 among others. ;Viper 22: Built under licence by

Piaggio Piaggio Group () is an Italian motor vehicle manufacturer, which produces a range of two-wheeled motor vehicles and compact commercial vehicles under five brands: Piaggio, Vespa, Aprilia, Moto Guzzi and Derbi. Its corporate headquarters are ...

for the Aermacchi MB.326 ;Mk.100: see ASV.3 above ;Mk.101: see ASV.5 above ;Mk.102: see ASV.8 above ;Mk.103: see ASV.9 and Viper 9 above ;Mk.104: see ASV.12 above ;Mk.200: see Viper 11 above ;Mk.201: ;Mk.202: see Viper 11 above ;Mk.204: ;Mk.301: ;Mk.521: ;Mk.522: ;Mk.525: ;Mk.601: ;Mk.632: Built under licence by Turbomecanica and Orao, as the non-afterburning engine for the

IAR-93 Vultur The Avioane Craiova IAR-93 Vultur (vulture/eagle) is a twinjet, subsonic, close support, ground attack and tactical reconnaissance aircraft with secondary capability as low level interceptor. Built as single-seat main attack version or combat ca ...

A/MB versions,

Soko J-22 Orao The Soko J-22 Orao ( sr-cyr, text=Oрао, translation=eagle) is a Yugoslavian/ Serbian twin-engined, subsonic ground-attack and aerial reconnaissance aircraft. It was developed and built in collaboration by SOKO in Yugoslavia and by Avioa ...

1 version,

IAR-99 The IAR 99 Șoim (''Hawk'') is an advanced trainer and light attack aircraft capable of performing close air support and reconnaissance missions. The IAR 99 replaced the Aero L-29 Delfin and Aero L-39 Albatros as the jet trainer of the Romania ...

Standard/Șoim versions, and

Soko G-4 Super Galeb The Soko G-4 Super Galeb (from ), also referred to as N-62, is a Yugoslav single-engine, advanced jet trainer and light ground-attack aircraft designed by the Aeronautical Technical Institute at Žarkovo and manufactured by the SOKO aircraft f ...

. ;Mk.633: Built under licence by Turbomecanica and Orao, as the afterburning engine for the

B version, and

2 version. ;M.D.30 Viper:Engines licence-built and developed by

Dassault Aviation Dassault Aviation SA () is a French Aerospace manufacturer, manufacturer of military aircraft and business jets. It was founded in 1929 by Marcel Dassault, Marcel Bloch as Société des Avions Marcel Bloch (Marcel Bloch Aircraft Company). After ...

;M.D.30R Viper: with afterburner.

Applications

Specifications (Viper ASV.12)

References

Notes

Bibliography

* * Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. * Smith, Tom. "Expendable to Indispensable: The Story of a Classic Turbojet - The Viper". ''Air Enthusiast'', No. 55, Autumn 1994, pp. 37–55.

External links

Rolls-Royce - Viper
{{RR aeroengines

Viper Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long (relative to non-vipe ...

1950s turbojet engines