(first run in 1949)

The Armstrong Siddeley Double Mamba was created by combining two small Armstrong Siddeley Mamba turboprop engines.  This arrangement drove separate propellers rotating in opposite directions from the same gearbox.  This engine was used mainly on the Fairey Gannett naval anti-submarine aircraft.

The Armstrong Siddeley Mamba was a small axial flow turboprop engine first run in 1946.  It had a maximum power of 1,230kW (1,650 shp) and was used on several early but unsuccessful aircraft.

The Double Mamba had a maximum power 2,207kW (2,960shp) so it could be used on larger aircraft than the single Mamba engine.  One of the engines could be shut down when the aircraft was cruising to save fuel and be restarted again when more power was needed.

There were several attempts to make more engines like the Double Mamba with two linked turboprop engines.  However this was the only successful engine that went into series production.

This engine powered the Fairey Gannett anti-submarine aircraft which first flew in 1949.  The Royal Australian Navy took delivery of 36 Gannets which it flew successfully from HMAS Melbourne between 1956 and 1967.