Armstrong Siddeley Mamba

ASM.3 engine at the Armstrong and Aircraft Museum at Bamburgh Castle.
Type Turboprop
National origin United Kingdom
Manufacturer Armstrong Siddeley
First run April 1946
Major applications Boulton Paul Balliol
A.W. Apollo
Short Seamew
Developed into Armstrong Siddeley Double Mamba
Armstrong Siddeley Adder

The Armstrong Siddeley Mamba was a British turboprop engine produced by Armstrong Siddeley in the late 1940s and 1950s, producing around 1,500 effective horsepower (1,100 kW).

Armstrong Siddeley gas turbine engines were named after snakes.

Design and development

The Mamba was a compact engine [1] with a 10-stage axial compressor, six combustion chambers and a two-stage power turbine. The epicyclic reduction gearbox was incorporated in the propeller spinner. Engine starting was by cartridge. The Ministry of Supply designation was ASM (Armstrong Siddeley Mamba). The ASM.3 gave 1,475 ehp and the ASM.6 was rated at 1,770 ehp. A 500-hour test was undertaken in 1948[1] and the Mamba was the first turboprop engine to power the Douglas DC-3, when in 1949, a Dakota testbed was converted to take two Mambas.

The Mamba was also developed into the form of the Double Mamba, which was used to power the Fairey Gannet anti-submarine aircraft for the Royal Navy. This was essentially two Mambas lying side-by-side and driving contra-rotating propellers separately through a common gearbox.

A turbojet version of the Mamba was developed as the Armstrong Siddeley Adder, by removing the reduction gearbox.[2]

Variants and applications

The Armstrong Siddeley Mamba-powered Douglas C-47B Dakota testbed in 1954 showing the slim outline of the Mambas
ASM.3 Mamba[3]
Armstrong Whitworth Apollo
Avro Athena
Boulton Paul Balliol
Breguet Vultur
Miles M.69 Marathon II
Douglas C-47 Dakota
ASM.6 Mamba[3]
Short Seamew
A version for civil applications[3]
Swiss-Mamba SM-1 (aft turbofan variant)
EFW N-20

Engines on display

An Armstrong Siddeley Mamba is on static display at the Midland Air Museum, Coventry Airport, Warwickshire and at the Royal Air Force Museum Cosford.

A Mamba is also on display at the Aviation Heritage Museum (Western Australia).[4]

Specifications (ASM.3)

Mamba and propeller from the Apollo airliner

Data from Flight[5]

General characteristics



See also

Related development

Related lists



  1. 1 2 "Aero Engine Information". RAF Museum. Retrieved 2008-06-06.
  2. Gunston 1989, p.20.
  3. 1 2 3 4 Taylor, John W.R. FRHistS. ARAeS (1955). Jane's All the World's Aircraft 1955-56. London: Sampson, Low, Marston & Co Ltd.
  5. "Aero Engines 1954", Flight,, p. 446, 9 April 1954, retrieved 4 November 2008


  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

External links

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