SU-122-54 Self-propelled artillery - Design
From the very beginning, in the project “Object 600” it was proposed to use the layout, developed during the creation of the previous SAU with similar weapons. The crew and weapons should be placed in a single wheelhouse front location. At the same time, it was possible to preserve the aft engine compartment, greatly simplifying the design and mass production. This layout had some flaws, but in the new project they decided to come to terms with them.
In terms of its layout, the self-propelled gun was still different from the base tank, which led to the need for a noticeable redesign of the hull structure. In front of the vehicle, a large wheelhouse appeared, made of several armor plates of various shapes and sizes. Frontal projection of the body was covered with a large top sheet 100 mm thick, located at an angle of 51° to the vertical. Below it was a narrow bottom sheet 80 mm thick with a tilt angle of 55°. On the sides of the upper frontal sheet there were two trapezoidal "cheeks" ["zygomatic"], placed at angles to the horizontal and vertical. The back of them connected to the 80-mm sides. From above the cabin was covered with a roof 20 mm thick. The on-board part of the wheelhouse formed developed flank niches.
The lower and aft parts of the hull were borrowed from the T-54 tank, but underwent some changes. In particular, for reasons of strength, the thickness of some parts was changed, and also some attachments of the undercarriage units were moved. The rest of the bottom and hull feed were similar to the units of the serial medium tank of the latest modifications at that time.
Self-propelled gun retained the powerplant of the base tank. In the aft compartment of the hull fit a diesel engine V-54 of 520 hp. With the help of a mechanical transmission, the engine was connected to the drive wheels of the aft layout. As part of the “Object 600” project, it was decided to dispense with major changes in the power plant, ensuring maximum unification with existing equipment.
The suspension of the SAU was based on the units of the T-54, but had some differences. On each side of the hull it was planned to install five large-diameter road wheels with an individual torsion bar suspension. In front of the hull mounted guide wheels in the stern - leading. Due to the large diameter of the rollers, the chassis did not receive support rollers. A characteristic feature of the chassis of the T-54 was an increased gap between the two front pairs of track rollers, due to the peculiarities of the weight distribution of the structure. "Object 600" differed by the location of the other rinks. Due to the large and heavy logging in the front of the hull, there were minimal gaps between the second and third, as well as the fourth and fifth pairs of rollers. The first and third intervals were longer.
In the front of the hull there was a large embrasure for mounting the main gun. It was proposed to mount a cannon and a twin machine gun on common mounts with the possibility of aiming in horizontal and vertical planes. The weapon opening was covered with a large mask of a complex shape allowing it to move. In its place, the mask on the outside was fixed with an appropriately shaped plate fixed to the bolts. The mask had three through holes of different sizes: for a cannon, a coaxial machine gun and a sight.
In accordance with the original terms of reference, the self-propelled gun of the new type was supposed to carry a 122-mm tank gun D-25. This gun had a semi-automatic wedge bolt, used separate-sleeve loading and was equipped with a muzzle brake of a two-chamber design. The nomenclature of used D-25 cannon ammunition included shots of several types for various purposes, suitable for combating manpower, fortifications and enemy equipment.
A serious disadvantage of the self-propelled guns of the previous models was the entry of powder gases into the habitable compartment. Because of this, “Object 600” was supposed to have a desing to avoid this problem. In the first versions of the project, it was proposed to use a barrel purge after a shot using compressed air pumped by a separate compressor. The first prototype self-propelled guns received just such a means of reducing gas pollution. However, after testing it was decided to use other systems. As a result, the equipment was equipped with a gun with a gas ejector that showed great efficiency went into the series production.
Especially for the updated version of the SAU "Object 600" an improved version of the D-25 gun with an ejector and a number of other design changes was created. This product has received the designation D-49. It is noteworthy that the D-49 was the first domestic tank gun of 122mm caliber, equipped with built-in means for the removal of powder gases. Subsequently, such ejectors were widely used in the field of tank guns.
The D-49 gun was equipped with a 48.7 caliber rifled barrel with a dual-chamber muzzle brake. According to the main characteristics of the fire, it was not inferior to the existing D-25. Means of installation of the gun allowed to perform horizontal guidance within the sector width of 16°. Vertical guidance varied from -4° to + 16°. Ammunition of the gun consisted of 35 separate loading shells placed on several racks of the fighting compartment. To facilitate the work of the loaders there was an electromechanical rammer.
Two KPV machine guns of 14.5mm caliber were used as additional weapons. One of them was mounted on a common installation with a cannon, the second was placed on the loader's hatch and served as an anti-aircraft gun. Ammunition of the machine guns amounted to 600 rounds.
To manage the new SAU was a crew of five people: the driver, the commander, gunner and two loaders. In front of the habitable compartment, to the right of the gun installation, was the workplace of the driver. The driver had his own hatch in the roof, equipped with periscope viewing devices. Unlike some previous Soviet self-propelled guns, the driver's seat did not have viewing devices in the front. To the left of the gun was the gunner, at whose disposal there was a second hatch in the roof. At the starboard side there was a commander's hatch, equipped with a TKD-09 optical rangefinder. At the left side, closer to the stern, was the loader with the turret for the machine gun.
In the course of combat work, the commander had to search for targets, assign target designation to the gunner, as well as determine the distance to the detected object. An optical rangefinder with a 900 mm base was used to determine the distances. Depending on the situation, the gunner could use a telescopic or panoramic sight. All crew hatches were equipped with viewing devices to improve overall visibility. In addition, several periscopes were fixed in the corresponding holes of the roof.
The “Object 600” self-propelled artillery installation had a 6 m long hull, and the machine with a cannon reached a length of 9.97 meters. The width was 3.27 m, the height of the roof of the cabin was 2.07 meters. The weight could exceed 14.5 tons. Due to these indicators, the maximum speed reached 45-48 km / h with a range of up to 400 km.
|
NEWSLETTER
|
| Join the GlobalSecurity.org mailing list |
|
|
|
