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The Rolls-Royce Spey (company designations RB.163 and RB.168 and RB.183) is a low-bypass turbofan engine originally designed and manufactured by Rolls-Royce that has been in widespread service for over 40 years. A co-development version of the Spey between Rolls-Royce and Allison in the 1960s is the Allison TF41.

An RB.168 Mk 202 Spey as fitted to the F-4K Phantom
Type Turbofan
Manufacturer Rolls-Royce Limited
Turbomecanica Bucharest
First run 1964
Major applications BAC One-Eleven/Rombac One-Eleven
F-4K Phantom
Blackburn Buccaneer
JH-7 Flying Leopard
AMX International AMX
Number built 2,768
Variants Allison TF41
Developed into Rolls-Royce Marine Spey

Intended for the civilian jet airliner market when it was being designed in the late 1950s, the Spey concept was also used in various military engines, and later as a turboshaft engine for ships known as the Marine Spey, and even as the basis for a new civilian line, the Rolls-Royce Tay.

Aviation versions of the "base model" Spey have accumulated over 50 million hours of flight time. In keeping with Rolls-Royce naming practices, the engine is named after the River Spey.

Design and developmentEdit

In 1954 Rolls-Royce introduced the first commercial bypass engine, the Rolls-Royce Conway, with a 21,000 lbf (94 kN) thrust aimed at what was then the "large end" of the market. This was far too large for smaller aircraft such as the Sud Caravelle, BAC One-Eleven or Hawker Siddeley Trident which were then under design. Rolls then started work on a smaller engine otherwise identical in design derived from the larger RB.140/141 Medway - which itself had been cancelled after British European Airways (BEA) had demanded the downsizing of the Trident,[1] the RB.163, using the same two-spool turbine system and a fairly small fan delivering bypass ratios of about 0.64:1. Designed by a team under Frederick Morley,[1] the first versions of what had become the 'Spey' entered service in 1964, powering both the 1-11 and Trident. Several versions with higher power ratings were delivered through the 1960s, but development was ended nearing the 1970s due to the introduction of engines with much higher bypass ratios, and thus better fuel economy.

In 1980, Turbomecanica Bucharest acquired the license for the Spey 512-14 DW version, which propelled the Romanian built BAC One-Eleven aircraft (Rombac One-Eleven).[2]

Spey-powered airliners continued in widespread service until the 1980s, when noise limitations in European airports forced them from service.

Tailored for the BuccaneerEdit

In the late 1950s the Soviet Union started the development of the Sverdlov-class cruisers that would put the Royal Navy at serious risk. After studying the problem, the RN decided to respond in a non-linear fashion, and instead of producing a series of new cruisers themselves, they would introduce a new strike aircraft with the performance needed to guarantee successful attacks on the Soviet fleet. The winning design was the Blackburn Buccaneer, which had an emphasis on low altitude performance (to evade enemy radar) as opposed to outright speed.

Afterburner section of an RB.168

Flying at low altitude, in denser air, requires much more fuel; the air-fuel mixture in a jet engine needs to be kept very close to a constant value to burn properly, and more air requires proportionally more fuel. This presented a serious problem for aircraft such as the Buccaneer, which would have had very short range unless the engines were optimised for low-level flight. The early pre-production versions, powered by the de Havilland Gyron Junior, also proved to be dangerously underpowered.

Rolls-Royce addressed this problem by offering a militarized version of the Spey, which emerged as the RB.168. The resulting Spey-powered Buccaneer S.2 served into the 1990s. The Spey proved so successful in this role that it was produced under licence in the United States as the TF41 and F113, and was used in a number of British and US designs.

F-4K and M PhantomEdit

The British versions of the McDonnell Douglas F-4 Phantom II (designated Phantom FG.Mk.1 and FGR.Mk.2) replaced the 16,000 lb wet thrust J79 turbojets with a pair of 20,515 lb wet thrust Spey 201 turbofans. These provided extra thrust for operation from smaller British aircraft carriers, and provided additional bleed air for the boundary layer control system for slower landing speeds. The air intake area was increased by twenty per cent, while the aft fuselage under the engines had to be redesigned. Compared to the original turbojets, the afterburning turbofans produced a ten and fifteen per cent improvement in combat radius and ferry range, respectively, and improved take-off, initial climb, and acceleration, but at the cost of a reduction in top speed because compressor outlet temperatures would be exceeded in an essentially subsonic civil design.[3][4]


During its lifetime the Spey has garnered an impressive safety record. Its relatively low maintenance costs provide one of the major reasons it continued in service even when newer designs were available. With the need for a 10,000 to 15,000 lbf (44 to 67 kN) thrust class engine starting up again with the removal of the Spey from service, Rolls-Royce then used the Spey turbomachinery with a much larger fan to produce the Rolls-Royce Tay, a more modern design whose ancestors can be traced to the 1950s.

AMX developmentEdit

A fully updated version of the military RB.168 was also built to power the AMX International AMX attack aircraft.


Rolls-Royce Spey RB.163 Mk.505-5 for the Trident in RAF Museum Cosford
Rolls-Royce Spey Mk 202 at the RAF Museum in London
RB.163 Mk.505-5
RB.163 Mk.505-14
RB.163 Mk.506-5
RB.163 Mk.506-14
RB.163 Mk.511-8
Gulfstream II and Gulfstream III (USAF designation F113-RR-100 for the Gulfstream C-20)
RB.163 Mk.512-14DW
BAC One-Eleven/Rombac One-Eleven
AR 963
(RB.163) Boeing 727 (proposed); it was to have been built under licence by Allison[5][6]
US military designation for the Mk.511-8 engines fitted to the Gulfstream C-20.
RB.168 Mk.101
(Military Spey) Blackburn Buccaneer S2
RB.168 Mk.202
(Military Spey) McDonnell Douglas F-4 Phantom II modified F-4J for British service ("Phantom FG1"). (Surplus engines were purchased and used by Richard Noble for the Thrust SSC land speed record car of 1997.)
RB.168 Mk.250
(Military Spey) Hawker Siddeley Nimrod MR1/MR2
RB.168 Mk.251
(Military Spey) Hawker Siddeley Nimrod R1 and AEW
RB.168 Mk.807
AMX International AMX, built under licence by FiatAvio
AR 168R
Joint development with Allison Engine Company for the TFX competition (won by the Pratt & Whitney TF30[7]
RB.183 Mk 555-15 Spey Junior
Fokker F28
WS-9 Qinling
Chinese license-produced copy of the RB.168 Mk.202 manufactured by the Xi'an Aero-Engine Corporation. It was used to power the Xian JH-7 and JH-7A.[8] An improved WS-9A developing 97 kilonewtons (22,000 lbf) of thrust is reportedly in development.[8]

Marinised versionsEdit

Marinised Spey delivering 18,770 shp
Marinised Spey delivering 26,150 shp


Engines on displayEdit

Specifications (Spey Mk 202)Edit

Data from[citation needed]

General characteristics

  • Type: Low bypass turbofan
  • Length: 204.9 in (5204.4 mm)
  • Diameter: 43.0 in (1092.2 mm)
  • Dry weight: 4,093 lb (1856 kg)


  • Compressor: axial flow, 5-stage LP, 12-stage HP
  • Combustors: 10 can-annular combustion chambers
  • Turbine: 2-stage LP, 2-stage HP


See alsoEdit


  1. ^ a b "World Encyclopedia of Aero Engines - 5th edition" by Bill Gunston, Sutton Publishing, 2006, p.197
  2. ^ About Turbomecanica
  3. ^ "Spey Powered Phantoms". Flying Review International. Volume 22 No 1: 8, 10. September 1966.
  4. ^ McDonnell F-4K Phantom FG.Mk.1
  5. ^ "Boeing 727" ANALYSING THE 727
  6. ^ Boeing's Trimotor: BACKGROUND TO THE DEVELOPMENT OF THE 727
  7. ^ "Aeroengines 1962", Flight International: 1019, 28 June 1962
  8. ^ a b Fisher, Richard (27 May 2015). "ANALYSIS: Can China break the military aircraft engine bottleneck?". Flightglobal. Retrieved 28 May 2015.
  • Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X.

External linksEdit