Armstrong Siddeley Double Mamba

The Armstrong Siddeley Double Mamba is a turboprop engine design developed in the late 1940s of around. It was used mostly on the Fairey Gannet anti-submarine aircraft developed for the Fleet Air Arm of the Royal Navy.

Design and development

The Double Mamba was a development of the Armstrong Siddeley Mamba with two Mambas driving contra-rotating propellers through a combining gearbox.
Engine starting was by cartridge; forced air restart was possible in flight. One engine could be shut down in flight to conserve fuel. Shutting down one engine also stopped one of the propellers.

Variants

;ASMD.1: used on Fairey Gannet A.S. Mk.1 and Blackburn B-88
;ASMD.3: used on Fairey Gannet A.S. Mk.4
;ASMD.4: used on Fairey Gannet AEW Mk.3
;ASMD.8: used on Fairey Gannet AEW Mk.3

Applications

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 engines.

Engines on display

Preserved Double Mamba engines are on public display at the: