The Mamba was Armstrong Siddeley's gas turbine turboprop engine design of around 1,500 hp (1,100 kW). It was used for the Short Seamew among other aircraft.

The Mamba was developed into the form of the Armstrong Siddeley Double Mamba on the Fairey Gannet anti-submarine aircraft developed for the Royal Navy.

Engine starting was by cartridge.

The Mamba has the distinction of being the first turboprop engine to power the Douglas Dakota. In 1949, a Dakota testbed aircraft was converted by Armstrong Siddeley to take two Mambas. (This aircraft was later re-converted to take the original engines.)

The Mamba was produced in various series. The numbering followed the convention: AS = Armstrong Siddeley M = Mamba num = model

ASM.3 gave 1,475 ehp; the ASM.6 was rated at 1,770 ehp.

A pure-jet (turbojet) version of the Mamba was developed as the Armstrong Siddeley Adder