|Manufacturer:||Mitsubishi Heavy Industries|
|Product type:||Armoured Vehicles|
In 1969, the Technical Research and Development Headquarters of the Japanese Ground Self-Defence Force started design work on a new 155 mm self-propelled howitzer. Mitsubishi Heavy Industries built the hull while Nihon Seiko Jyo/Japan Steel Works built the 155 mm gun and turret. The two prototypes, completed in 1971-72, differed only in their ammunition loading systems. Trials with the two prototypes were undertaken between 1973 and 1974 and in October 1975 the vehicle was standardised as the Type 75 155 mm self-propelled howitzer.
By late 1978, the first 20 vehicles had been delivered to the Japanese Ground Self-Defence Force. By the end of 1988, 201 Type 75 self-propelled howitzers were in service with the Japanese Ground Self-Defence Force and production was complete. This system was never offered on the export market. There are no known plans for this system to be upgraded.
The 155 mm Type 75 serves alongside very small quantities of the locally built 105 mm Type 74 and larger numbers of locally manufactured US-designed 203 mm M110A2 systems. This has now started to be supplemented by the new 155 mm Type 99 full tracked self-propelled artillery system, details of which are given in a separate entry.
As the more recent 155 mm Type 99 self-propelled howitzer is being built in small numbers, typically six or seven per year, the older Type 75 is expected to remain in service for many years. When compared to the Type 75 155 mm SPH, the more recent Type 99 has improved mobility and firepower, but is also heavier.
The hull and turret of the Type 75 155 mm self-propelled howitzer are made of all-welded aluminium. This provides the crew with protection from small arms fire and shell splinters. The crew of six consists of the commander, layer, two ammunition loaders, radio operator and driver.
The hull is divided into three compartments: driver at the front on the right, power pack to his left and the turret at the rear. The driver has a single-piece hatch cover, which opens to the right, and in front of this are three day periscopes. The centre one can be replaced by a passive night vision device. The driver can also enter and leave his compartment via the turret.
The turret is fully enclosed, with the commander and gunner seated on the right and the ammunition loaders on the left. The commander has a single-piece hatch cover that opens to the rear and a single day periscope for forward observation. One of the two ammunition loaders is also provided with a single-piece hatch cover that opens to the rear, in front of which is a .50 (12.7 mm) M2 HB MG anti-aircraft machine gun with a small shield. On each side of the turret is a square hatch that opens to the rear.
At the rear of the hull are two doors that open either side of the vehicle. The torsion bar suspension either side consists of six dual rubber-tyred aluminium road wheels, with the drive sprocket at the front and the sixth road wheel acting as the idler. The first and fifth road wheel stations are provided with a hydraulic shock-absorber. There are no track-return rollers.
The Type 75 is provided with an NBC system, located in the left side of the fighting compartment, a fire extinguishing system, a heater, and night vision equipment.
Main armament consists of a 155 mm 30 calibre weapon with a double-baffle muzzle brake, a fume extractor and a stepped thread interrupted screw-type breech block which opens to the right. A gun travelling lock is fitted on the glacis plate.
The weapon fires a Japanese HE projectile (maximum charge 9) to a maximum range of 19,000 m or an American M107 HE projectile (maximum charge 7) to a maximum range of 15,000 m. A 155 mm Rocket-Assisted Projectile (RAP) has been developed with a range of around 24,000 m. Some sources have stated that the Type 75 has a maximum range of 19,000 m, firing a projectile of an undisclosed type.
The 155 mm/39 calibre gun has an elevation of +65°, a depression of -5° and the turret can be traversed through a full 360°. Gun elevation and turret traverse are hydraulic by means of a single lever. Movement in the horizontal plane controls the turret position in azimuth and movement in the vertical plane controls the gun in elevation. The traverse of the turret and the elevation of the gun are stopped whenever the layer halts the movement of the lever. Manual controls are provided for emergency use and the turret can also be traversed by the commander.
The gun has a variable recoil mechanism that consists of twin hydraulic cylinders, one on the left above the cradle and the other on the right side under the cradle. The variable recoil system is fitted to prevent the breech hitting the floor when the gun is being fired at a high angle. The recuperator is pneumatic and the recoil damper, which is on the centreline under the cradle, is hydraulic.
When the gun is fired, the 155 mm weapon automatically moves to an elevation of +6° for reloading and returns to its firing elevation once reloaded. Mounted in the rear part of the turret are two drum-type rotating magazines, an extensible loading tray and a hydraulic rammer. Each drum holds nine 155 mm projectiles, is rotated electrically or manually and can be reloaded from inside the vehicle or from outside via two small circular doors in the turret rear. The axis of the drums, two-stage extensible loading tray and the rammer are on the same axis as the gun when it is returned from its firing position for loading. Each of the two magazines holds nine 155 mm projectiles which, coupled with the use of the extensible loading tray and the hydraulic rammer, enable 18 rounds to be fired in 3 minutes, that is 6 rds/min. A further 10 projectiles are carried inside the gun compartment plus 56 fuzes and 28 bagged charges.
Fire-control equipment includes a J2 day panoramic sight, with a magnification of ×4 and a 10° field of view, a J3 day direct telescopic sight with a magnification of ×4 and a 10° field of view, an electric elevation sight which includes a cant angle sensor, an angle indicator and an inverter, and finally a collimator. All fire-control equipment is mountedin front of the commander's position and is operated by the layer.
A total of 20 of these were built for the Japanese Ground Self Defence Force with the first deliveries taking place in 1975. It is understood that these systems have now been phased out.
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