The Armstrong Siddeley Viper is a British turbojet engine developed and produced by Armstrong Siddeley and then by its successor companies Bristol Siddeley and Rolls-Royce Limited. It entered service in 1953 and remained in use with the Royal Air Force, 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 engine — the Viper is in effect a large-scale Adder. Like the similar J85 built in United States, the Viper was originally developed as an expendable engine for production versions of the Jindivik 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 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 and Orao Sarajevo acquired the license for the Viper engine, which propelled various Romanian and Yugoslav built aircraft.

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

Applications

• Aermacchi MB-339 • Aermacchi MB-326 • Aero L-29 Delfin (prototype only) • Atlas Aircraft Impala • Avro Shackleton • BAC Jet Provost • BAC Strikemaster • Bell X-14 • Blue Origin Charon • Dassault M.D.550 Mystere-Delta • Embraer AT-26 Xavante • Folland Midge • GAF Jindivik • Hawker Siddeley Dominie • Handley Page HP.115 • IAR 99 • Piaggio PD.808 • Saunders-Roe SR.53 • Soko J-22 Orao/IAR-93 Vultur • Soko G-2 Galeb • Soko G-4 Super Galeb

Specifications (Viper ASV.12)