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The ISU-152 was a Soviet self-propelled gun used during World War II.
Contents |
History
The ISU-152 (in Russian ИСУ-152) used the same concept as the earlier SU-152: a large gun-howitzer mounted in the hull of a heavy tank. The ISU-152 was armed with the same gun as the SU-152, but on the hull of an IS-2 tank instead of the KV-1.
Development began in June 1943 in the Design Bureau of Experimental Factory No. 100 in Chelyabinsk. At that time it had become clear that the KV-1S heavy tank would be replaced by a new heavy tank design, the Iosef Stalin (IS). The combat performance of the SU-152 self-propelled gun, based on the KV-1S, prompted Soviet engineers to investigate the production of a mobile gun using the new tank as a base.
The design work was conducted under the supervision of Joseph Yakovlevich Kotin, the chief designer of Soviet heavy tanks. The main designer for the ISU-152 was G.N. Moskvin. During early design work, the project was designated IS-152. In October 1943 the first prototype, "Object 241", was built. It successfully passed plant and state testing. The vehicle, now named ISU-152, started mass production at the Chelyabinsk Kirov Factory (Chelyabinskiy Kirovskiy Zavod, ChKZ) in November 1943. In the following month the ISU-152 completely replaced its predecessor the SU-152 on ChKZ production lines.
The ISU-152 was developed further during 1944. A new hull front was added and the gun shielding was increased from 60 mm to 100 mm. Several essential minor improvements were also made at this time: internal and external fuel capacity were increased, a 12.7-mm anti-aircraft DShK machine gun was installed by the right forward hatch, and the 10R radio set was upgraded to a 10RK.
Between November 1943 and May 1945, 1,885 ISU-152s were built. Mass production ceased in 1947, with 3,242 vehicles produced in total.
Post-war ISU-152 modernisation included installation of night vision apparatus, replacing of the engine (V-2-IS was changed to V-54), and increasing the main ammunition stowage to thirty rounds.
Construction and design
The ISU-152 followed the same design as other Soviet self-propelled guns (except the SU-76). The fully armoured hull was divided into two compartments: fighting compartment for the crew, gun, and ammunition in the front of the hull, engine and transmission separate in the rear. The gun was mounted slightly to the right of centre with a limited traverse of 12 degrees left and right. Three of the crew were to the left of the gun: driver to the front, then gunner and last the loader. The vehicle commander and lockman were to the right.
The suspension consisted of twelve torsion bars for the six road wheels on either side. The drive sprockets were at the back, and the front idlers were identical to the road wheels. Each track was made up of 90 links. There were three internal fuel tanks, two in the crew area and one in the engine compartment. These were usually supplemented with four unconnected external fuel tanks. Twelve and 24-volt electrical power supplies came from a 1 kW generator feeding four accumulator batteries.
For observation from the interior, all roof hatches had periscopes and there were two gun sights: telescopic ST-10 (СТ-10) and panoramic. For crew communication a TPU-4-BisF intercom was fitted, and for inter-vehicle communication there was a single 10R or 10RK radio. These were better than Soviet equipment at the start of the war but still inferior to German equipment.
The crew were given two PPSh or PPS submachine guns and twenty F-1 grenades for short-range self-defence.
Variants
- ISU-152 based on the IS-2 model 1943 chassis with single piece cast glacis;
- ISU-152 based on the IS-2 model 1944 chassis with glacis constructed of two welded flat plates. These vehicles also had a thicker gun shield and fuel tankage with increased volume.
- ISU-152 fitted with a 12.7 mm DShK anti-aircraft machine gun. These were installed directly by the ChKZ factory from the end of 1944, but also on some earlier production vehicles after repairs.
Combat history
The ISU-152 combined three main battle roles: heavy assault gun and ersatz heavy tank destroyer in the direct fire role, and self-propelled howitzer in the indrect fire support role. The main usage was as an infantry and tank support vehicle. The 152.4-mm (6 inch) ML-20S gun-howitzer used a powerful OF-540 high-explosive shell, with an overall weight of 43.56 kg and containing nearly 6 kg of TNT. These projectiles were effective against both unprotected infantry (with detonator set on fragmentary action) and fortifications such as pillboxes and trenches (with high explosive detonator setting). A single 95-lb projectile impacting an un-fortified medium-sized city house was usually sufficient to demolish most of the building and kill anyone inside.
Heavy assault gun
As a heavy assault gun, the ISU-152s were an extremely valuable weapon in urban combat operations such as the assaults on Berlin, Budapest and Königsberg. The vehicle's excellent armour protection finally provided the 152mm platform with good protection from most German AT guns, allowing it to advance into the face of direct AT fire, while the huge low-velocity HE rounds were excellent at blasting open even the most heavily fortified and reinforced enemy strongpoints. Such actions would be much more dangerous and much less effective for a conventional towed artillery piece (with their high crew exposure and low mobility) or even a tank (with their smaller main guns).
To minimize the risks of being knocked out by Panzerfaust-equipped units during urban operations, the ISU-152 usually acted in one or two vehicle detachments alongside infantry squads for protection. The infantry squad would include a specialist sniper (or at least a sharpshooter), some submachine gunners and sometimes a flamethrower. The ISU-152's heavy calibre DShK machinegun was also useful for targeting Panzerfaust gunners hiding on upper floors of city buildings or behind protective cover, barricades, etc. Effective teamwork between the ISU-152 crew and supporting infantry allowed them to achieve their goals with minimal losses, but if such tactics were not adhered to, the attacking vehicles were easily attacked and destroyed, usually through the weaker armor on the roof or rear compartment.
Heavy tank destroyer
The ISU-152 could also operate as an effective ersatz heavy tank destroyer. Though it was not designed for the role, the vehicle inherited the nickname Zveroboy ("animal killer") from its predecessor the SU-152 for its rare ability to reliably kill the heaviest German armored vehicles, the Tiger, Panther, and Elefant. The weight of the 152mm shells made for an extremely low fire rate, only one or two shots per minute, and they were not as accurate at long range as high-velocity antitank guns, but the massive 98 lb HE charge was capable of blowing the turret completely off a Tiger from sheer blast force alone. No tank crew could expect to survive a direct impact from a 152mm round, though the chassis itself was sometimes salvageable. For anti-tank operations following the Battle of Kursk, the even-larger 102 lb. BR-540 solid-core armour-piercing round and charge was developed, with an eye towards giving the howitzer a more traditional AT capability. However, these rounds were expensive, in short supply, and only moderately more effective than the standard non-penetrating HE round, since (as a howitzer) the ML-20S exchanged velocity and battlefield-level accuracy for throw weight and distance, and was not intended to compete with true AT guns. A primitive shaped charge shell was also developed, which proved to be a similarly minimal improvement over the HE round in the AT role and suffered from poor accuracy and reliability.
The ISU-152's 90mm of sloped frontal armor, in contrast to the SU-152's 65mm, provided excellent frontal protection from the 75mm KwK 40 gun of the ubiquitous Panzer IV and StuG family at all but the closest ranges, while also forcing the Tiger (with its vaunted 88mm KwK 36 gun) to close to medium ranges in order to successfully penetrate the vehicle, negating its traditional long-range superiority and exposing more of its vulnerable flanks to the 85mm ZiS-S gun of the Russian T-34/85.
It should be noted that the ISU-152 was not a true purpose-built tank destroyer; it had a very low rate of fire compared with specialised tank destroyers such as the German Jagdpanther or the Soviet SU-100, which could manage a brief burst of 5-8 shots per minute. However, prior to the introduction of the SU-100 it was the only Soviet armored vehicle capable of tackling the German heavy tanks with any kind of reliability, and its ability to satisfy multiple roles meant it was produced in far greater numbers than the SU-100. Attention to camouflage, quick relocation between firing positions, and massed ambushes of 4-5 vehicles firing in salvo at a single target's flanks reduced the disadvantage of the low rate of fire. Using these tactics, the ISU-152 became greatly feared by German heavy tank commanders, robbing them of their prior sense of invulnerability to Russian guns and forcing them to commit their forces more cautiously and sparingly.
Self-propelled howitzer
The ISU-152 was also sometimes used as a self-propelled howitzer for indirect fire. The Red Army had not developed specialized vehicles for this purpose such as the German Hummel, US Howitzer Motor Carriage M7 or the Canadian Sexton self-propelled howitzers. The tank and mechanized units of the Red Army were well equipped with towed artillery, but towed guns were very vulnerable while moving and they could not support tanks and motorized infantry during rapid advances into enemy positions.
ISU-152s were often used for preparatory bombardments. The gun's maximum range was nearly thirteen kilometres, although its elevation was limited to a maximum of +20 degrees. Its indirect fire capability was further limited by the slow speed of reloading.
The armour of the ISU-152 was adequate for the latter stages of World War II. The 90-mm front armour plate, sloped at 30 degrees from the vertical, was sufficient protection from German PaK 40 75mm anti-tank guns at distances over 800 metres. By comparison, the T-34 tank was vulnerable under the same conditions. The ISU-152 was easy to repair. Often a knocked-out ISU could be repaired and returned to service after only a couple of days' repair in the field. After eliminating the problems of early-production vehicles the ISU-152 proved technically very reliable, and it was easy to train novice crews in its use.
Despite the ISU-152's good features it suffered in some other areas. The greatest disadvantage was that internal stowage was limited to only twenty rounds of ammunition. Replenishing the vehicle's ammunition supply took over forty minutes and required a very strong loader, due to the large size and weight of the shells. The ST-10 telescopic sight used for direct fire was graduated up to 900 metres. A second, panoramic, sight was used for direct fire up to 3,500 m range. However, it was problematic for the gunner to switch between the two visors. To compensate it was simpler to concentrate the fire of several vehicles onto the target—sacrificing accuracy for sheer volume of firepower. The high-explosive shells were large enough to take out even a heavily armoured vehicle. The usual complement of shells was 13 shells HE and 7 armour-piercing or concrete-piercing.
The compact layout of equipment within the hull kept the overall vehicle size down. However the fuel tanks were inside the crew's fighting compartment, presenting a greater risk of the crew being burned if the tanks were punctured, although this was mitigated by the use of less-flammable diesel fuel.
The ISU-152 was liked by Soviet soldiers, as it provided an effective countermeasure to the German Tiger and Panther tanks. They described it as "Nekrasivo, no spasibo!" ("Not pretty, but thanks!"). Russian soldiers called the tank Glorious Beast or Big Hunter.
Organisation
The ISU-152, like the earlier SU-152 and contemporary ISU-122, was employed by Independent Heavy Self-propelled Artillery Regiments (Otdel'niy Tyazheliy Samokhodno-Artilleriyskiy Polk, OTSAP). Between May 1943 and 1945 fifty-three OTSAPs were formed. Many of these were re-formed tank regiments, and employed similar direct-fire tactics as used by tanks when supporting infantry.
Each OTSAP had twenty-one guns, divided into four batteries of five vehicles and the commander's vehicle. The Soviets built no specialised command vehicle variants of their guns, unlike other combatant nations. The unit commander was usually a colonel or lieutenant-colonel and the battery commanders would be captains or senior lieutenants. Gun commanders were commissioned lieutenants. Usually the mechanic-driver and the gunner were regular sergeants, while the other two were privates. For support the OTSAP had some supplementary unarmoured vehicles such as trucks, jeeps, or motorcycles.
Starting in December 1944, Guards Heavy Self-propelled Artillery Brigades were formed, to provide heavy fire support to tank armies. They were organized along the model of tank brigades, each with sixty-five ISU-152 or ISU-122 guns.
For bravery and valour during the liberation of Belarusian cities, eight OTSAPs were named after cities in honour of these battles and three OTSAPs were awarded the Order of the Red Banner.
Surviving examples
Most of the ISU-152s produced survived the Second World War and examples can be seen. Many ISU-152s were installed as monuments in and around Russia and Belarus in honour of their crews and creators. Preserved ISU 152s can be seen in the museums of the Russia Central Artillery and Engineer Troops in St Petersburg, the Kubinka Tank Museum, the Central Museum of the Russian Army, the Museum of the Great Patriotic War, Kiev, the Museum of Heroic Defense and Liberation of Sevastopol on Sapun Mountain in Sevastopol (Sevastopol ISU-152 was manufactured in 1943-1950[1]) and other tank museums in Finland, Poland and Israel.
References
- ^ (Russian) Sapun Mountain. Guide. Museum of Heroic Defense and Liberation of Sevastopol. Simferopol: PoliPRESS Publisher, 2006.
See also
- List of Soviet tanks - covers all periods
External links
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Wikimedia Commons has media related to: ISU-152 |
- JSU-122 and the JSU-152 assault guns battlefield.ru
- A. Solyankin et al. Self Propelled Gun ISU-152 on Vasiliy Chobitok's ArmorSite (Russian)
- A. Sorokin. Self Propelled Gun ISU-152 on Vasiliy Chobitok's ArmorSite (Russian)
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| List of armoured fighting vehicles of World War II · Soviet armored fighting vehicle production during World War II |
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