Tom McGhee reports: Saturday 15 September 2001 was the date Rolls-Royce chose to hold an Anniversary party at Coventry Airport to celebrate 50 years of the Viper jet engine. Fifty years is always a good anniversary to celebrate and signifies a pretty good innings, but for a jet aircraft engine still to be in service after all these years is quite remarkable. However, this engine is not just still in service, but it is still actually in production, over half a century on from first manufacture! To put this into some kind of perspective, the RAF's standard fighter of the time was the Gloster Meteor.
The original Viper engine was produced by Armstrong Siddeley (later Bristol Siddeley, and now Rolls-Royce) to a requirement for a 10-hour lifed small jet engine to be fitted to airborne target drones. The engineers built in some leeway to allow for ground tests etc and were anticipating 14 hours between overhauls, however the first tests in 1951 revealed a basic engine core which was so well designed that it would eventually be upgraded and improved beyond the wildest dreams of those pioneering engineers.
The first generation Viper 3 engines produced 1,640 lbs of thrust at sea level and were built in Coventry mainly for use in Australia and Sweden, though some were supplied to the USA for "Bullgoose" decoy missile trials, and its basic simplicity is well illustrated in the picture below.
However the aircraft with which the Viper will mainly be associated with (in the UK at least) is the Jet Provost and Strikemaster. As the Jet Provost improved from its initial T1 version with the "constant thrust, variable noise" Viper 5, through the T3 with the improved Viper 8 (pictured below), up to the T4, T5 and T5A with the Viper 11, the turbojet power plant also improved to match, eventually outputting 2,500 lbs of thrust for countless RAF trainee aircrews. The military version of the Jet Provost was the Strikemaster, and this type was exported to numerous nations as a light attack aircraft fitted with the Viper 20.
Civil aircraft also took advantage of the engine, most successfully of all being the HS125 which initially had the Viper 20 (pictured below) and has sold in its hundreds all over the world, becoming one of the most successful "bizjets" of its time. The RAF took delivery of a few of these as VIP transports, as well as the Viper 30 powered navigation trainer version which they christened Dominie, a type which is still in RAF service today. A similar type to the HS125 is Italys Piaggio PD808, and this too is still in service with the AMI in an ECM role fitted with a pair of Viper 20s.
Viper engines were also manufactured under licence in numerous overseas countries for fitting into a wide variety of aircraft. Sud Aviation in France fitted their Mach 2 SO.9000 Trident fighter with MD530 (Viper 5) engines on the wingtips to supplement the fuselage mounted rocket engine. Other overseas producers/overhaulers included India (for the Kiran), South Africa (for the Impala), Romania (for the Orao and IAR99), Yugoslavia (Orao, Galeb, Jastreb and Super Galeb), Brazil (for the MB326) and Italy (MB326, MB339 and PD808).
A few of the perhaps lesser known uses of the Viper engine include fitting into the Folland Midge, the diminutive predecessor to the Orpheus equipped Gnat, plus as an additional takeoff boost for Shackleton Mk.3 aircraft fitted into the outer Griffon nacelles. Also, the engines inherent simplicity and reliability make it an obvious choice for speed freaks whose idea of a nice afternoons drive entails making sure your drag chutes are well packed!
Back to the present day, and the Viper is still in use today in its originally envisaged role as a drone power plant. The Australian built Jindivik is the standard UK target towing drone and is regularly flown from QinetiQ at Llanbedr in Wales providing targeting facilities for RAF Air Defence types like Tornado F3 and will continue to do so when the "Mighty Fin" is replaced by Eurofighter, a long way from those Gloster Meteor days!
The latest development to the Viper is for Polands Irdya jet trainer, and whos to say if this is the last we will see in this marvellous lineage. Britain should be justifiably proud of this fantastic technological achievement, roll on the next 50 years!
Aircraft present at Coventry were:
Thanks must go to Helen Stacey and Gary Atkins for facilitating this article.