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 (9 litres) the Mongoose had a maximum power output of 155 horsepower (115 kilowatts).

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 (100-115 kW).

Variants

 * Mongoose I
 * 1926, 135 hp.


 * Mongoose II
 * 1930, 155 hp.


 * Mongoose III
 * 1929.


 * Mongoose IIIA
 * 1929, civil use.


 * Mongoose IIIC
 * 1929, Military use based on IIIA.

Applications
Note:
 * ANBO III (Second batch, 1931)
 * Avro 504N
 * Avro 504R
 * Avro Tutor
 * Avro Type 621 Trainer
 * Handley Page Hamlet
 * Handley Page Gugnunc
 * Hawker Tomtit
 * Parnall Peto
 * Fokker S.IV

Survivors
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.