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SSPH 1 Primus (Singapore Self-Propelled Howitzer 1)

Self-Propelled Gun

The SSPH Pegasus self-propelled gun platform entered service with the Singapore Armed Forces in 2004.
Authored By: Staff Writer | Edited: 6/14/2017
National Flag Graphic


Year: 2004
Manufacturer(s): Singapore Technologies Kinetics (ST Kinetics) - Singapore
Production: 60
Capabilities: Fire Support/Assault/Breaching;
Crew: 4
Length: 33.50 ft (10.21 m)
Width: 9.84 ft (3 m)
Height: 10.76 ft (3.28 m)
Weight: 34 tons (31,200 kg); 68,784 lb
Power: 1 x Detroit Diesel Corporation 6V 92TA diesel engine delivering 550 horsepower.
Speed: 31 mph (50 kph)
Range: 217 miles (350 km)
Operators: Singapore
Singapore Technologies Kinetics (ST Kinetics) has designed the SSPH 1 "Primus" (Singapore Self-Propelled Howitzer 1) to fulfill a Singapore Army requirement. Design work began in 1996 and also involved the Defence Science and Technology Agency (DSTA) as well as input from the Singapore Armed Forces (SAF) itself with adoption of the vehicle announced in 2002 and formal introduction coming in 2004. The SSPH 1 was developed after a defense review of existing foreign systems then available - all of the frontrunners being capable in their own right but lacking certain qualities required by the Singapore Army. As a result an indigenous approach was taken.

By all accounts, the SSPH 1 is a largely conventional Self-Propelled Howitzer (SPH). It features a multi-wheeled track-over-wheel arrangement seeing seven double-tired road wheels to a hull side with the drive sprocket at front and track idler at rear. The hull contains the engine at front-right with the driver at front-left. Additional crew - the commander, gunner, and loader - are seated in the boxy turret structure mounting the 155mm NATO-compatible main gun (with double-baffled muzzle brake). The gun is supported through an automatic interrupted screw design with an electronic rammer in play. This provides for a semi-automatic loading action which helps to reduce crew fatigue in action and maintain a reasonable rate-of-fire. An all-modern ballistics computer is also featured. A 7.62mm General Purpose Machine Gun (GPMG) is carried on the turret roof for local defense as are smoke grenade dischargers.

The mounting hardware for the main gun allows for an elevation span of -5 to +75 degrees with full 360-degree traversal. Rate-of-fire is approximately six rounds maximum with sustained fire in the 2 rpm range and burst fire (over a 20 second span) in the 3 rpm range. Projectiles can reach out to 19 miles with rocket-assist.

The finalized hull structure features armor protection up to 25mm thick and a well-sloped glacis plate. Dimensions include a length of 33 feet (with gun forwards), a width of 9 feet, 10 inches, and a height to turret top of 10 feet, 9 inches. Combat weight is listed at 31 tons (short). The SSPH 1 chassis is believed to be based on that of the American M109 "Paladin" SPH.

Power to the vehicle is through a Detroit Diesel 6V 92TA series diesel-fueled engine developing 550 horsepower. This supplies the SSPH 1 with a maximum road speed of 31 miles per hour with a 220 mile road range. The powerpack is said to be similar to one already in use by the ST Kinetics Bionix Infantry Fighting Vehicle (IFV) detailed elsewhere on this site.

Since inception, the SSPH 1 has stocked the inventory of the Singapore Army through the 21st Battalion Singapore Artillery.


1 x 155mm main gun
1 x 7.62mm roof-mounted machine gun
6 x Smok Grenade Dischargers

26 x 155mm projectiles
2,500 x 7.62mm ammunition
6 x Smoke Grenades

Variants / Models

• SSPH 1 "Primus" ("Singapore Self-Propelled Howitzer 1") - Base Production Series Designation.
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