In the memoirs and technical literature dedicated to the Great Patriotic War, high marks are often given to the anti-tank capabilities of the Soviet self-propelled artillery installations SU-152 and ISU-152. At the same time, the authors who extol the high damaging effect of a 152-mm projectile when it is exposed to enemy armored vehicles completely forget about other characteristics of a large-caliber gun, as well as about what heavy self-propelled guns were primarily intended for.
After the failure with the KV-2 heavy assault tank, which was actually a self-propelled gun with a 152-mm howitzer installed in a rotating turret, in conditions when our troops were engaged in heavy defensive battles, there was no particular need for a heavy self-propelled gun. In connection with the seizure of the strategic initiative, in the conditions of offensive combat operations, the armored units of the Red Army needed qualitatively new models of equipment. Taking into account the existing operating experience of the SU-76M and SU-122, the question arose about the creation of self-propelled assault gun mounts armed with large-caliber guns. Such self-propelled guns were primarily intended for the destruction of capital fortifications when breaking through a well-prepared enemy defense. During the planning of offensive operations in 1943, it was expected that Soviet troops would have to break into long-term defense in depth with concrete pillboxes. Under these conditions, the need arose for a heavy self-propelled gun with weapons similar to the KV-2. However, by that time, the production of 152 mm M-10 howitzers had been discontinued, and the KV-2s themselves, which had not proved themselves too well, were almost all lost in the battles. After comprehending the experience of operating self-propelled gun mounts, the designers came to the understanding that from the point of view of obtaining optimal weight and size characteristics, placing a large-caliber gun in an armored wheelhouse on a combat vehicle is more optimal than in a rotating turret. The abandonment of the tower made it possible to increase the volume of the fighting compartment, reduce the weight and reduce the cost of the car.
Heavy self-propelled artillery unit SU-152
At the end of January 1943, at the Chelyabinsk Kirov Plant (ChKZ), the construction of the first prototype of the SU-152 heavy self-propelled gun was completed, armed with a 152-mm ML-20S gun - a tank modification of a very successful 152-mm howitzer-gun mod. 1937 (ML-20). The gun had a horizontal firing sector of 12 ° and elevation angles from -5 to + 18 °. The ammunition consisted of 20 rounds of separate-case loading. In the course of tests for the rate of fire when using the first-stage stacks, it was possible to achieve the result of 2, 8 rds / min. But the real combat rate of fire did not exceed 1-1, 5 rds / min. The firing range using the ST-10 telescopic sight against visually observed targets reached 3, 8 km. The vehicles of the first batch used the T-9 (TOD-9) sight, originally developed for the KV-2 heavy tank. For shooting from closed positions, there was a panoramic sight PG-1 with a panoramic view of Hertz. The maximum firing range is 6, 2 km. Theoretically, it was possible to fire at a long range, but shooting from closed positions for a number of reasons, which will be discussed below, was rarely practiced by self-propelled guns.
The base for the new self-propelled gun was the KV-1s tank. The SPG layout was the same as that of most Soviet SPGs of that time. The fully armored hull was split in two. The crew, gun and ammunition were located in front in the armored wheelhouse, which combined the fighting compartment and the control compartment. The engine and transmission were housed in the rear of the vehicle. Three crew members were to the left of the gun: in front of the driver, then the gunner and loader behind, and the other two, the vehicle commander and the castle commander, on the right. One fuel tank was located in the engine compartment, and the other two were located in the combat, that is, in the habitable space of the vehicle.
The level of security of the SU-152 was practically the same as the KV-1S tank. The thickness of the frontal armor of the wheelhouse was 75 mm, the thickness of the hull forehead - 60 mm, and the sides of the hull and wheelhouse - 60 mm. Combat weight - 45, 5 tons. Diesel engine V-2K with an operating power of 500 hp. accelerated the self-propelled gun on the highway to 43 km / h, the speed on the march on a dirt road did not exceed 25 km / h. In store down the highway - up to 330 km.
In February 1943, military representatives accepted the first batch of 15 vehicles. On February 14, 1943, simultaneously with the adoption of the SU-152, GKO decree # 2889 "On the formation of heavy self-propelled artillery regiments of the RGK" was issued. The document provided for the formation of 16 heavy self-propelled artillery regiments (TSAP). Initially, the TSAP had 6 batteries with two units each. Subsequently, based on the experience of hostilities, the organizational and staff structure of the TSAP was revised towards unification with the staff of the regiments armed with SU-76M and SU-85. According to the new staffing table, the TSAP had 4 batteries of three self-propelled guns in each, the number of regiment personnel was reduced from 310 to 234 people, and the command platoon KV-1s and the BA-64 armored car were added to the command platoon.
The combat activity of the TSAP was originally planned by analogy with artillery regiments armed with 152-mm howitzers-cannons ML-20. However, in practice, the SU-152 gunners most often fired at visually observed targets, in this case the advanced artillery observers and reconnaissance spotters in the TSAP were in little demand. Self-propelled guns usually supported attacking tanks with fire, moving behind them at a distance of 600-800 m, firing direct fire at enemy fortifications, destroying defense nodes, or acting as an anti-tank reserve. Thus, the tactics of the TSAP actions differed little from the tactics of tank subunits and SAPs with the SU-76M and SU-85.
Some TSAPs on the SU-152 retained the old state, while others were transferred to a new one, remaining with the same material part. Due to the shortage of the SU-152, there were cases when the TSAP were equipped with other vehicles, for example, the restored KV-1s or the new KV-85s. And vice versa, when heavy tank regiments received SU-152s instead of tanks lost in battles or departed for repairs. So in the Red Army, separate heavy self-propelled tank regiments appeared, and subsequently this practice took place until the end of the war. At the final stage of the war, the ISU-122 and ISU-152 could be operated in the TSAP, formed in 1943-1944, in parallel with the SU-152.
Despite the fact that the first 152-mm installations were delivered back in February 1943, they began to enter the troops only in April. It took a lot of time to eliminate manufacturing defects and "childhood sores". In addition, according to the results of the first combat use of the SU-152 at the front, it turned out that when firing inside the fighting compartment, a large amount of powder gases accumulated, which led to a loss of crew performance. This became known not only at the GABTU, but also at the highest level. The question of solving this problem on September 8, 1943, during the demonstration in the Kremlin of new samples of armored vehicles, was raised by Stalin personally. In accordance with his order, two fans were installed on the roof of the fighting compartment of the SU-152.
From the army, there were complaints about visibility from the fighting compartment. Periscopic instruments had large areas of unseen space, which often became the reason for the loss of machines. There were many complaints about the relatively small amount of ammunition. The units practiced increasing the ammunition load to 25 shots by placing an additional 5 shots under the gun. These shells and charges lay on the floor, secured with homemade wooden blocks. Loading the new ammunition was a time consuming and physically demanding operation that took more than 30 minutes. The presence of a fuel tank inside the fighting compartment in the event of penetration of the armor by an enemy projectile often became the cause of the death of the entire crew.
Nevertheless, of the first three Soviet assault SPGs put into mass production after the outbreak of the war, this vehicle turned out to be the most successful. The SU-152, unlike the SU-76, had no obvious defects associated with the general design of the engine-transmission group. In addition, the fighting compartment of the self-propelled gun, built on the chassis of the KV-1S heavy tank, was more spacious than on the SU-122. By itself, the design of the combat vehicle, equipped with a very powerful 152 mm gun, turned out to be quite successful.
As far as we know, the combat debut of the SU-152 took place at the Kursk Bulge, where there were two TSAPs. During the period from 8 to 18 July, the 1541st TSAP reported on 7 destroyed "Tigers", 39 medium tanks and 11 self-propelled guns of the enemy. In turn, the 1529th TSAP on July 8 destroyed and knocked out 4 tanks (2 of them "Tigers"), as well as 7 self-propelled guns. During the battle on the Kursk Bulge, self-propelled guns, moving behind the tanks, provided them with fire support and fired from closed firing positions. For firing at the enemy, only high-explosive fragmentation shells were used, there was no armor-piercing 152-mm shells in the ammunition load at that moment. Due to the fact that there were few direct clashes with German tanks, the losses of self-propelled guns were relatively small. However, it should be understood that the frontal armor of the SU-152 by the middle of 1943 no longer provided adequate protection and could be penetrated by the long-barreled gun of the modernized "four" from 1000 m. A number of sources say that the Germans were able to study in sufficient detail the damaged SU-152 in the summer of 1943. …
In reports on the results of hostilities among the armored vehicles destroyed by the crews of the SU-152, heavy tanks "Tiger" and PT ACS "Ferdinand" repeatedly appear. Among our soldiers, self-propelled guns SU-152 have earned the proud name "St. John's Wort". Due to the fact that only 24 heavy SPGs occasionally participated in the battle, they did not have much influence on the course of hostilities. But at the same time, it should be recognized that the SU-152 in the summer of 1943 was the only Soviet self-propelled gun capable of confidently hitting heavy German tanks and self-propelled guns at all combat distances. At the same time, one must understand that the enemy's losses in reports on combat activities were often greatly overestimated. If you believe all the reports received from the army, our tankmen and artillerymen destroyed several times more "Tigers" and "Ferdinands" than they were built. In most cases, this was not because someone wanted to ascribe to themselves non-existent merits, but because of the difficulty of identifying enemy armored vehicles on the battlefield.
German medium tanks Pz. KpfW. IV of late modifications, equipped with long-barreled guns and anti-cumulative screens mounted on the side of the hull and turret, changed their shape beyond recognition and looked like a heavy "Tiger". Since the summer of 1943, the Red Army called all German self-propelled guns with a rear-mounted fighting compartment "Ferdinands". It should also be taken into account that the enemy had a very well-organized service for evacuating damaged tanks from the battlefield. Quite often, "Tigers", "destroyed" in Soviet reports, were successfully restored in field tank repair shops and went into battle again.
Serial production of the SU-152 continued until January 1944. A total of 670 self-propelled guns of this type were delivered. The SU-152s were most actively used at the front from the fall of 1943 to the summer of 1944.
Compared to tanks, the SU-152 self-propelled guns suffered less losses from anti-tank artillery fire and enemy tanks. It may seem strange, but a noticeable number of heavy SPGs were decommissioned due to the full depletion of the resource. Apparently, tank repair enterprises in the conditions of saturation of troops with self-propelled guns based on the IS tank did not want to engage in labor-intensive restoration of vehicles built on the basis of the discontinued KV-1S. But part of the SU-152, which underwent refurbishment, took part in the hostilities until the surrender of Germany.
Heavy self-propelled artillery unit ISU-152
In November 1943, the ISU-152 heavy self-propelled artillery unit was put into service. However, due to the overload of ChKZ's production facilities, at first the new ACS was produced in very small volumes and the SU-152 and ISU-152 were assembled in parallel.
When designing the ACS ISU-152, created on the basis of the heavy tank IS-85, the experience of operating the SU-152 was taken into account, and the developers tried to get rid of a number of design flaws that emerged during combat use. Taking into account the increase in the firepower of the German anti-tank artillery, the protection of the ISU-152 has increased significantly. The thickness of the frontal armor of the hull and the casemate was 90 mm. The thickness of the upper side of the hull and deckhouse is 75 mm, the lower part of the hull is 90 mm. The gun mask is 100 mm. In the second half of 1944, the production of vehicles with a welded front part of the hull made of rolled armor plates instead of one solid part was started, the thickness of the gun's armored mask was increased to 120 mm.
The security of the ISU-152 was generally good. The frontal armor withstood the hits of armor-piercing shells fired from the Pak 40 75-mm anti-tank gun and the Kw. K.40 L / 48 tank gun at distances over 800 m. The self-propelled gun was fairly easy to repair. The vehicles damaged by the enemy in most cases quickly recovered in the field.
The designers paid a lot of attention to improving the reliability of the engine-transmission part of the IS-85 tank and the vehicles produced on its basis. The ISU-152 ACS was equipped with a V-2-IS diesel engine with a maximum power of 520 hp. A vehicle with a combat weight of 46 tons could move along the highway at a speed of 30 km / h. The speed of movement on a dirt road usually did not exceed 20 km / h. In store down the highway - up to 250 km.
The main armament, sighting devices and the composition of the crew remained the same as on the SU-152. But compared to the previous model, the working conditions of self-propelled guns and the view from the machine have been improved. The gun had vertical guidance angles from −3 ° to + 20 °, the horizontal guidance sector was 10 °. Ammunition - 21 rounds.
At the end of 1944, the 12.7 mm DShK anti-aircraft machine gun began to be installed on the ACS. At the final stage of the war, a large-caliber anti-aircraft machine-gun mount was rarely used against enemy aircraft, but it turned out to be very useful during street battles.
During the production process, changes were made to the design of the ISU-152 aimed at improving the combat and operational qualities and reducing the cost of the ACS. After elimination of "children's sores" ISU-152 has established itself as a very reliable and unpretentious machine. Due to the saturation of the Red Army with anti-tank artillery and the mass production of the SU-85, the anti-tank role of the ISU-152 in comparison with the SU-152 has decreased. In the second half of 1944, when the ISU-152 self-propelled guns appeared at the front in noticeable numbers, enemy tanks began to appear on the battlefield less often, and heavy self-propelled guns were mainly used for their intended purpose - to destroy long-term firing points, make passes in obstacles, fire support for advancing tanks and infantry.
The 152-mm high-explosive fragmentation shells proved to be very effective in street battles. A projectile hitting a two-story brick city house with a fuse installed on a high-explosive action usually led to the collapse of interfloor ceilings and interior walls. After the explosion of 43.56 kg of the 53-OF-540 projectile containing almost 6 kg of TNT, only half-destroyed outer walls were often left of the building. Thanks to the relatively short barrel of the 152-mm self-propelled gun, they maneuvered quite freely on the tight streets of European cities. In the same conditions, it was much more difficult for the crews of the ACS SU-85, SU-100 and ISU-122 to operate.
From the statistics of the combat use of the ISU-152, it follows that most often self-propelled guns fired at the fortifications and manpower of the enemy. Enemy armored vehicles, as soon as they appeared in the gunner's field of vision, instantly became a priority target.
As a self-propelled howitzer, the ISU-152 was rarely used during the war. This was due to the difficulty of controlling the fire of self-propelled guns, as well as the fact that when firing from closed positions, the self-propelled guns were inferior to the towed howitzer-gun ML-20 with a maximum vertical guidance angle of 65 °. At an elevation angle of 20 °, the 152-mm ML-20S gun could not fire along high-steep hinged trajectories. This significantly narrowed the field of application as a self-propelled howitzer. The supply of shells from the ground during firing was difficult, which negatively affected the practical rate of fire. The ISU-152 demonstrated the best efficiency in the role of an assault gun mount, firing at visually observed targets. In this case, the consumption of shells when performing the same task was many times less than when the self-propelled gun fired from a closed position.
As for the anti-tank capabilities of the domestic 152-mm self-propelled guns, they are greatly exaggerated. The Panzerwaffe did not have vehicles capable of withstanding the hit of an armor-piercing projectile 53-BR-540 weighing 48, 9 kg with an initial speed of 600 m / s. At the same time, taking into account the fact that the range of a direct shot at a target with a height of 3 m from the ML-20S gun was 800 m, and the combat rate of fire was no more than 1.5 rds / min, in practice the SU-85 SAU demonstrated much better efficiency … A much cheaper self-propelled gun, built on the T-34 chassis and armed with an 85 mm cannon, was capable of firing up to 6 rounds per minute. At a distance of 800 m, an 85-mm armor-piercing projectile was likely to penetrate the Tiger's frontal armor with a fairly high probability. At the same time, the silhouette of the SU-85 was lower, and the mobility was better. In a duel situation, the crew of the Tiger or Panther had a much better chance of winning than the Soviet 152-mm self-propelled gun.
Self-propelled guns with 152-mm guns could successfully act against medium and heavy tanks with long-barreled 75-88-mm guns only from an ambush. At the same time, there are many examples of successful firing at enemy tanks with high-explosive fragmentation shells at a distance of up to 3800 m. In this case, several SPGs, as a rule, fired at the enemy. With a direct hit of a shell on an enemy tank, even if there was no armor penetration, it probably received heavy damage. A close burst of a heavy projectile disabled the chassis, weapons and optics. Having come under fire from 152-mm high-explosive fragmentation shells, enemy tanks in most cases quickly retreated.
At the final stage of the war, the ISU-152 became one of the most effective means of breaking into the enemy's long-term defenses. Although self-propelled guns, with competent tactics of use, suffered less losses than tanks, in the offensive they sometimes encountered anti-tank artillery operating from ambushes, installed on the front edge of the defense with 88-105-mm anti-aircraft guns and German heavy tanks.
In 1943, ChKZ handed over 35 ISU-152s to the military, and in 1944 - 1340 self-propelled guns. ISU-152, together with SU-152 and ISU-122, went to form heavy self-propelled artillery regiments. From May 1943 to 1945, 53 TSAPs were formed. Each regiment had 4 batteries of 5 self-propelled guns. The control platoon also had an IS-2 tank or a self-propelled gun of the regiment commander. In December 1944, the formation of guards heavy self-propelled artillery brigades began to provide fire support for tank armies. Their organizational structure was borrowed from tank brigades, the number of vehicles in both cases was the same - 65 self-propelled guns or tanks, respectively. For the entire 1944 year, 369 vehicles were irretrievably lost at the front.
Taking into account the fact that not all self-propelled units built in 1944 reached the front, and some of the vehicles were in training units, it can be assumed that among the ISU-152s participating in the battles in 1944, losses were more than 25%.
From November 1943 to May 1945, 1,840 ISU-152 were built. The production of self-propelled guns ended in 1947. In total, the military received 2,825 vehicles. In the post-war period, the ISU-152 was repeatedly modernized. They served in the Soviet Army until the mid-1970s, after which they were put into storage. Some of the vehicles were converted into tractors and mobile launchers for tactical missiles. Many self-propelled guns ended up in the role of targets at ranges. It is reliably known that the ISU-152 ACS was used in the liquidation of the consequences of the Chernobyl accident in 1986.
The end follows …
