Main Menu

Armstrong Siddeley Mongoose


The Armstrong Siddeley Mongoose is a British five-cylinder, single-row, air-cooled radial aero engine produced by Armstrong Siddeley.

First run in 1926, it was used in the Hawker Tomtit trainer and Parnall Peto seaplane amongst others.

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).

With a displacement of 540 cubic inches (9 litres) the Mongoose had a maximum power output of 155 horsepower (115 kilowatts).

The Mongoose was later developed into the Serval.


Mongoose I
1926, 135 hp.

Mongoose II
1930, 155 hp.

Mongoose III

Mongoose IIIA
1929, civil use.

Mongoose IIIC
1929, Military use based on IIIA.


Avro 504N
Avro 504R
Avro Tutor
Avro Type 621 Trainer
Handley Page Hamlet
Handley Page Gugnunc
Hawker Tomtit
Parnall Peto


Mongoose I
Type: 5-cylinder single-row radial
Bore: 5 in (127 mm)
Stroke: 5.5 in (139.7 mm)
Displacement: 540 cu in (8.9 L)
Length: 36.6 in (93 cm)
Diameter: 45.6 in (116 cm)
Dry weight: 340 lb (154 kg)
Valvetrain: Overhead poppet valves
Fuel type: 77 Octane petrol
Cooling system: Air-cooled
Reduction gear: Direct drive, left-hand tractor
Power output: 138 hp (103 kW) at 1,750 rpm at sea level
Compression ratio: 5:1
Power-to-weight ratio: 0.4 hp/lb (0.67 kW/kg)


Copyright © 2023 all-aero. All Rights Reserved.
Joomla! is Free Software released under the GNU General Public License.
slot gacor
rtp slot