SSPH Primus Design
The chassis is based on the proven United Defense M109 155 mm self propelled howitzer. This has been upgraded in a number of key areas and has a new power pack similar to that fitted to ST Kinetics Bionix infantry fighting vehicle (IFV), which is already in SAF service. The use of common subsystems for the Primus and Bionix IFV offers several advantages, including easier training and reduced logistics.
The Primus power pack consists of a Detroit Diesel Corporation 6V 92TIA diesel engine developing 550 hp coupled to a General Dynamics Land Systems HMPT-500-3EC fully automatic transmission.
The maximum road speed of the Primus is 50 km/h, with an operating range of 350 km, its combat weight is of 28.3 tons allows it to use the SAF 's current military bridging systems. The Primus could be deployed by the future Airbus A400M Transport aircraft.
The turret is fitted with a locally developed 155 mm/39-cal barrel with a muzzle brake and fume extractor. This meets the NATO Joint Ballistics Memorandum of Understanding. The range of the Primus' gun would depend on the type of projectile and charge combination used, but is probably about 19 km with the old M107 high explosive (HE) projectile and 30 km (19 mi) with an extended range full bore base bleed projectile. In addition to smoke, HE and illumination projectiles, the locally developed 155 mm cargo round can also be fired.
A semi-automatic loading system is provided to increase the rate of fire and reduce crew fatigue. The fused projectiles are loaded and rammed automatically; the modular charges are loaded manually. The Primus has a burst rate of fire of three rounds in 20 seconds and a maximum rate of fire of 6 rounds per min. The bustle mounted magazine holds up to 22 rounds of 155 mm projectile.
The digital fire control system automates the complete projectile loading process and gun laying operation. An ammunition inventory management system keeps track of all on board ammunition as well as ammunition expenditure during firing. The weapon is laid to the target using an automatic fire control system, which includes an on board positioning and navigation system. This can receive target information from the battery or regimental command post. It takes less than 60 seconds to come into action and open fire and 40 seconds to re-deploy.
SSPH Primus Specifications
| SSPH Primus | |
|---|---|
| Type | Self-propelled artillery |
| Place of origin |  Singapore |
| Service history | |
| In service | 2002 - Present |
| Used by | Singapore Armed Forces |
| Production history | |
| Designer | ST Kinetics |
| Designed | 1996 |
| Manufacturer | ST Kinetics |
| Produced | 2000 |
| Specifications | |
| Weight | Combat weight: 28.3 tonnes (31.2 short tons; 27.9 long tons) |
| Length | Chassis: 6.6 metres (21 ft 8 in) Overall: 10.21 m (33 ft 6 in) |
| Width | Chassis: 2.8 m (9 ft 2 in) Overall: 3.0 m (9 ft 10 in) |
| Height | 3.28 m (10 ft 9 in) |
| Crew | 4 (Commander, Driver, Ammo Loader, Charge Loader) |
| | |
| Shell | 155 mm NATO |
| Caliber | 155 mm 39 calibre |
| Breech | Full automatic Interrupted screw with electronic rammer and semi-auto loader |
| Elevation | -5°/+75° |
| Traverse | 360° |
| Rate of fire | Burst: 3 rounds/20 sec Maximum: 6 rpm Sustained: 2 rpm |
| Maximum range | 30 km (19 mi) with ER projectile |
| | |
| Armor | 25 mm Aluminium |
| Main armament | 155 mm Howitzer gun |
| Secondary armament | 1× 7.62 mm GPMG |
| Engine | Detroit Diesel Corporation (DDC) 6V 92TA 550 horsepower (410 kW) |
| Power/weight | 19.43 hp/tonne |
| Suspension | Torsion bar suspension |
| Operational range | 350 km (220 mi) |
| Speed | 50 km/h (31 mph) |
Special Features
- Automatic loading system, enables operation with 4 men crew
- Automated targeting based on GPS and Datalink
- Datalink system for shared targeting within battalion and information feeding from forward observers.
Mobility
- Number of road wheel: 7 per side
- Climbing side slope : 31°
