Armstrong Siddeley Double Mamba

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Double Mamba
ASDoubleMamba.JPG
Preserved Double Mamba at the Imperial War Museum Duxford
Type Turboprop
Manufacturer Armstrong Siddeley
First run 29 September 1949 (First flight)
Major applications Fairey Gannet
Developed from Armstrong Siddeley Mamba

The Armstrong Siddeley Double Mamba was a turboprop engine design developed in the late 1940s of around 3,000–4,000 hp (2,500–3,000 kW). It was used mostly on the Fairey Gannet anti-submarine aircraft developed for the Fleet Air Arm of the Royal Navy.

Design and development[edit]

The Double Mamba (rarely known as the Twin Mamba) was a development of the Armstrong Siddeley Mamba with two Mambas driving contra-rotating propellers through a combining gearbox.[1]

Engine starting was by cartridge, however, forced air restart was achieved in flight. One engine could be shut down in flight to conserve fuel.

Variants and applications[edit]

Fairey Gannet flying with one half of its Double Mamba engine shut down

The Ministry of Supply designation system for these engines reflects the obvious linkage to their Mamba lineage:
AS = Armstrong Siddeley
M = Mamba
D = Double
num = model

Table 1. ASMD Models and Aircraft
Model Thrust (ehp) Component
engines
Aircraft fitted
ASMD.1 2,950 2 x ASM.3 Fairey Gannet A.S. Mk.1
Blackburn B88 (prototype)
ASMD.3 3,145 2 x ASM.5 Fairey Gannet A.S. Mk.4
ASMD.4 3,875 2 x ASM.6 Fairey Gannet AEW Mk.3

The Double Mamba engine was also proposed for the Westland Westminster, a 30-seat helicopter that was later built as a prototype powered by a pair of Napier Eland E220 turboshaft tengines.

Engines on display[edit]

Preserved Double Mamba engines are on public display at the:

Specifications (ASMD.3)[edit]

Cut away of a double mamba power unit at The Flambards Experience in Cornwall
Double Mamba in a non-display aircraft at the Fleet Air Arm Museum (Australia).
Double Mamba - side view in-situ.

Data from Flight[2]

General characteristics

  • Type: Turboprop engine
  • Length: 102.25 in (2,597 mm)
  • Diameter: 52.8 in (1,341 mm)
  • Dry weight: 2,170 lb (984 kg)

Components

  • Compressor: 10 stage axial (x2)
  • Combustors: Six combustion chambers (x2)

Performance

See also[edit]

Related development
Comparable engines
Related lists

References[edit]

Notes[edit]

  1. ^ Gunston 1989, p.20.
  2. ^ Flight Global Archive -1954 www.flightglobal.com. Retrieved: 4 November 2008

Bibliography[edit]

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

External links[edit]