Armstrong Siddeley Mamba

Design and development

The Mamba was a compact engine 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 ASMa (Armstrong Siddeley Mamba). The ASMa.3 gave 1,475 ehp and the ASMa.6 was rated at 1,770 ehp. A 500-hour test was undertaken in 1948 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.

Variants and applications

;ASMa.3 Mamba: :Armstrong Whitworth Apollo :Avro Athena :Boulton Paul Balliol :Breguet Vultur :Miles M.69 Marathon II :Douglas C-47 Dakota :Short SB.3 ;ASMa.5 Mamba:Development engine for Armstrong Siddeley ASMD.3 Double Mamba ;ASMa.6 Mamba: :Short Seamew ;ASMa.7 Mamba:A version for civil applications ;Swiss-Mamba SM-1 (aft turbofan variant) :EFW N-20 ;Mamba 112: (ASMa.6)

Engines on display

Surviving Mambas are on display in the UK at the Midland Air Museum, Coventry Airport, Warwickshire and the East Midlands Aeropark. Another example is to be found at the Hertha Ayrton STEM Centre at Sheffield Hallam University, UK and a Mamba Mk 110 (serial number 654606 - ZP3043, believed originally flown in a Short Seamew) is on loan from the Rolls-Royce Heritage Trust to BAE Systems at Farnborough Airport, Hampshire.

Overseas, a Swiss-Mamba SM-1 is displayed at the Flieger-Flab-Museum Dübendorf in Switzerland and another Mamba can be seen at the Aviation Heritage Museum (Western Australia).

Specifications (ASMa.6)

• Frontal area: 5.9 sqft |power/weight=2.08 hp/lb (equivalent shaft horsepower) |thrust/weight=

References

Bibliography

References

1. "Aero Engine Information". RAF Museum.
2. Gunston 1989, p.20.
3. Taylor, John W.R. FRHistS. ARAeS. (1955). "Jane's All the World's Aircraft 1955-56". Sampson, Low, Marston & Co Ltd.
4. "Armstrong Siddeley Mamba".
5. Wilkinson, Paul H.. (1957). "Aircraft engines of the World 1957". Sir Isaac Pitman & Sons Ltd..