SU-152G

The SU-152G uses an open turret mounted on the hull. The hull was welded from rolled homogeneous armor (RHA) and is divided into 3 compartments: the power compartment which houses the transmissions and the engine, the driving compartment, and the combat compartment. The engine and the transmissions were housed in the front right part of the vehicle. To its left were the driving mechanisms with chassis controls. In the middle of the vehicle was the combat compartment, which was equipped with armored shielding. The ammo rack is located to the rear, analogous to that of the SU-100P. The gun was located on the turret above the hull. The turret had a traverse range of 71.5 degrees to either the left or the right, and the maximum elevation range was from -5 to +40 degrees. The entire vehicle needed a crew of 5 to operate. The armor was made to withstand gunfire and shrapnel damage. The armor for the hull was 25 mm thick (0.98 in), while the turret had 15 mm-thick (0.59 in) armor.

Main 152.4-mm shells used by the SU-152G. Note how the letter Г is incorrectly shown as r. 1. OF-530 High Explosive Fragmentation shell 2. O-530A Fragmentation shell 3. G-530 High Explosive Anti-Concrete shell

The main armament of the SU-152G was the D-50/D-1 152-mm howitzer. It had identical ballistic characteristics, internal mechanisms and uses the same ammunition with the D-1 152 mm towed howitzer. The barrel was connected to the breech, and a muzzle brake was fitted to the barrel. A vertical, wedged gate was installed in the breech, along with a semi-automatic, free-floating ejector. To ease the loading process, a mechanical loader was placed as well. The gunner's seat has a ZIS-3 panoramic sight for high-elevation indirect firing, and an OP1-7 direct-firing sight for observation of shell impact. The ammo rack of the SU-152G holds 42 shells.

The main shell employed by the D-50/D-1 was the 53-OF-530 High Explosive Fragmentation shell fitted with an RGM, RGM-2 or a D-1 fuse. When fired with full propellant charge, the shells had a muzzle velocity of 508 meters per second with a maximum range of 12.39 km. The 53-OF-530 has a steel casing and 5.83 kg of TNT as payload. When equipped with a contact fuse, it was capable of a 2100-square-meter area denial against enemy infantry in a standing profile, and was able to create a crater up to 1.2 m deep and up to 3.5 m in diameter. For greater effect against infantry the 53-O-530A fragmentation round was used with an RGM-2 or D-1-U fuse, or the 53-OF-530R High Explosive Fragmentation shell and the 3OF9, armed with AR-26 and AR-30 radio-fuzes for air-bursting capabilities, respectively.

For anti-tank fire the SU-152G was capable of using 53-BP-540 HEAT shells, with a penetration capability of up to 250 mm of Rolled Homogeneous Armor at a range of up to 3 km. Naval High-Explosive, Semi-Armor-Piercing A3-PB-35 shells were also available, with the capability of penetrating 68 mm of RHA at a range of 2 km. The range of choice also included special-purpose shells, which include illumination rounds, smoke shells, concrete-piercing shells and chemical shells. 4Zh5 and 54-Zh-536M propellant charges were used to fire HEAT and naval shells. The 54-Zh-536 propellant charge was used for the rest, intended for D-1 and M-10 howitzers, the 54-Zh-534 propellant, on the other hand, was dedicated to firing from 152 mm howitzer model M1909/30s, and their use was recommended to be avoided since their use could lead to chamber expansion and consequentially, difficult shell exits.

The SU-152G was equipped with a 10-RT radio station for communications, while internal communications between the crew was accomplished by the TPU-47-3 intercom.[12][13]

A V-105 (V-54-105) V12 4-piston engine was mounted on the SU-152G, capable of outputs of up to 400 horsepower. It is modified from a V-54 engine while making the following adjustments:

• The spring corrector of the NK-10 pump was removed;
• The outlet nozzles, intake manifold, fan drive and the water pump cover was modified;
• The "Kimaf-STZ" oil filter was installed on a separate bracket;
• A G-74 3 kW generator was installed;
• The motor resource was increased;
• The radiator grille was changed for better cooling efficiency.[14][15]

The SU-152G utilizes planetary transmission, with six shifts for going forward and two for reversing. The maximum speed at shift 6 was found to be at 63 km/h.[13]

The chassis of the SU-152G was based on that of the SU-100P self-propelled anti-tank gun, and consisted of 6 pairs of rubberized support and three pairs of supporting rollers. On the rear part of the vehicle the guide wheels were installed, while the driving sprockets were mounted on the front. The tracks consisted of small links with rubber-metal forged hinges. Each track measured 412 by 133 millimeters. The SU-152G used individual torsion for suspension. Hydraulic shock absorbers were installed on the first and the sixth pair of rollers.[16]

The main differences between the SU-152G and the ISU-152 as well as its variants, and that between it and 2S3 made it what appeared to be a middle ground between these two self-propelled guns. The ISU-152 was intended to be a heavy assault gun from the beginning, which required capability of direct firing, and a weak transition towards firing from closed positions began. In addition, the crew of the vehicles were often poisoned by the exhaust gases after firing in closed combat compartments. Despite the overt advantage of the SU-152G over the ISU-152 in terms of firing from closed positions, serial production of the SU-152G was never put in effect. All the work on Soviet self-propelled guns were put into a halt in the 1960s and only resumed when the First secretary of the TsK KPSS was removed from position. As a result, the 2S3 "Acacia" was made, favorably different from its predecessor with further increased vertical traverse angles, a closed combat compartment, CBRN protection, a turret capable of circular fire and an increased angle.[20]

	Soviet Union—SU-152G	France--F3[21]	US--M44[22]	UK--FV 3805[23][24]
Designed	1946—1955	Early 1950s	1946—1951	1950s
Combat weight, t	23.8	17.4	25.3	50
Crew, # people	5	10	5	5
Gun caliber, mm	152.4	155	155	139.7
Gun length, calibers	23	33	23.2	30
Vertical traverse range, degree	−5...+40	0...+67	−5...+65	−5...+45
Horizontal traverse range, degree	143	46—50	60
Ammunition, rounds	42	25	24
Maximum range of HEF shells, km	12.39	14.7	15	14,63[note 6]/16,46[note 7]
HEF shell weight, kg	40.00	43.75	43.88	45.34/36.28
Maximum speed on-road, km/h	65	60	56.3	34
Unit power, hp/t		15.6	14	10.73
Unit pressure, kg/cm2		0.71	0.84
Range on-road, km	290	300	120	120

The US had developed a new 155-mm self-propelled howitzer on the basis of the T41 light tank from 1946 to 1947, receiving the designation of T99. The T99 was a 155-mm T97 howitzer mounted in a closed armored compartment, which in turn is mounted on a chasses. To fire the howitzer a separated loading procedure is mandatory. It also came with an automated fire control. However, the results of the Korean War had forced the US military to accelerate the process of designing a new self-propelled howitzer. The resulting T99E1 had a capped loading procedure. The gun control system was also simplified and differed from that used on SPGs of the Second World War. During the course of further development of the T99E1, the T194 was created, featuring an open combat compartment with a reduced ammunition load from 30 to 24 rounds. The T194 was subsequently adopted into use as the M44[25]

On the basis of the Centurion Mk.7 the 139.7 mm self-propelled howitzer, designated FV3805, was created. The main armament of this self-propelled gun was the 5.5-inch cannon-howitzer. The maximum range achievable with a 45.35 kg shell was 14.8 km, however, a lighter 36.28 kg shell also used for the cannon had a better range of 16.46 km. The body of the SPG provides armored protection for the crew at the base of the vehicle. To increase stability of the automatic control system during firing, a folding opener was located in the rear of the hull.[26][27] An easier option with an open installation of the gun was available as well, but it did not go further than a prototype obtained by combining the Crusader tank with some parts of the FV300 series.[28]

France in the beginning of the 1950s developed a 155 mm SPG, designated the F3, on the basis of the AMX-13 light tank. The maximum range was 14.7 km with M107 shells. An advantage over the SU-152G, the F3 had a lighter combat weight (17.4 t against 23.8 t), however, it could only carry a total of 25 rounds. Additionally, it required 10 people to operate, two would station in the vehicle while it was mobile, an additional 4 would be transported when it was preparing for firing missions, while the rest would be transported in a special truck that would accompany the SPG.[29]

Local conflicts during the post-war period had proved the necessity of this class of self propelled guns. A series of SPGs were created by the USSR in an attempt to design new self-propelled howitzers, which included the SU-152G. However, most of the work ceased when Nikita Khrushchev issued an order in 1955. The result of this decision was a backstep in the following decades for the USSR, compared to NATO countries, which could only be liquidated by the early 1970s.[30] [31]