Armstrong Siddeley Mongoose

The Armstrong Siddeley Mongoose is a British five-cylinder radial aero engine produced by Armstrong Siddeley. Developed in the mid-1920s it was used in the Hawker Tomtit trainer and Parnall Peto seaplane amongst others. With a displacement of 540 cubic inches the Mongoose had a maximum power output of 155 horsepower.
A Mongoose engine powers the sole remaining airworthy Hawker Tomtit, based at Old Warden.

Design and development

The Mongoose is a five-cylinder, single-row, air-cooled radial piston engine. The engine features twin forward-mounted ignition magnetos and enclosed valve rockers, the cylinders being the same as those used for the earlier Jaguar engine. An unusual feature of the Mongoose is the vertical position of the lower cylinder, a design thought likely to promote oil fouling of the spark plugs.
Built in several variants, power output ranged between 135 and 155 hp.

;Mongoose I
;Mongoose II
;Mongoose III
;Mongoose IIIA
;Mongoose IIIC

Note:

An Armstrong Siddeley Mongoose IIIC powers the sole remaining airworthy Hawker Tomtit, K1786/G-AFTA, owned and operated by the Shuttleworth Collection this aircraft flies regularly throughout the summer months.