Sakhalia NetHistory of the RailwaySahara TerritoryBaykal.esAcceptance of cookiesAcceptance of cookies

You are logged off and have no access to the contents of this section!

Please log in or register. Or you may alternatively visit the articles list to search for more content.

DISCLAIMER: This website discourages its users from submitting duplicated content. If this article contains such and you, the visitor, are the creator of the original content, please report it to the administrator of this website instead of reporting the website itself. You can send a report if you are a registered user or alternatively use the e-mail address provided at the bottom of the Privacy Policy.

IS tanks


By Sakhal

When in August 1968 the Soviet tanks marched by the roads of Prague and not exactly like in a parade, the military observers noticed that those were the same vehicles that had marched through Berlin in 1953 and through Budapest in 1956. They belonged to the long family of the "Stalin tanks" and they were the most prestigious ones built by the Soviet Union in the 1940s. These tanks originated from the powerful KV tanks which, after having demonstrated their strenght in the first years of the Second World War, were passed to a second line when the Germans discovered their defects.

In August 1942 the Soviet High Staff was well informed about the new heavy tanks that Germany was developing, fitted with more powerful armament and thicker armor. Hence, the works for building a new heavy tank were rapidly started. To the same team responsible of the project of the heavy tanks of the series KV, led by General Kotin, was entrusted, in the beginning of 1943, the task of projecting the successor tank. The wheel arrangement of the new tank was of the same type of the one developed for the T-100 and the SMK. In each side there were six small road wheels, on six axes suspended from torsion bars, with three return rollers. Three prototypes were prepared to be tested in the autumn; at first glance it was noticeable that the new vehicle had the structure of a very superior tank. Its hull, totally welded, had an armor with a maximum thickness of 120 millimeters, while the turret was a cast piece in the same fashion than the one installed in the KV-85 and the T-34/85. This first tank was denominated IS-85. The acronym was after Iosif Stalin and, following the western transcription, it was often spelled as JS. The main difference between the series KV and IS was that the latter one had a lower wheel arrangement, which meant a reduction in the height of the tracks and hence a decrease in the capability of surmounting obstacles. But at the same time the superstructure emerged above the tracks, achieving so a lower tank, which allowed to mount a larger turret ring. The IS-85 in order of battle weighed 2 tonnes less than the KV-85, thanks to its careful design and in spite of being its armor 50 millimeters thicker in the most vulnerable areas.

The IS-85 entered a limited production in October 1943; since the 85-millimeter cannon was already specified for medium tanks, it was deemed as inadequate to arm a heavy tank with the same weapon. Also, the apparition of the German Pak 43 88-millimeter anti-tank cannon increased as well the necessity of more powerful cannons. Hence it was ordered to the projects team the creation of a version that were able to mount a 100-millimeter cannon. A few prototypes were made armed with the 100-millimeter cannon (IS-100) but they were not accepted for production. Thus, another team, led by General F. Petrov, had to conceive in two weeks a turret capable of housing the D-25 122-millimeter cannon. This one fired piercing projectiles weighing 25 kilograms with a muzzle speed of 780 meters/second, which allowed to perforate 160 millimeters of homogeneous armor at a distance of 1000 meters. The tank, armed with the D-25 cannon, was developed with the denomination IS-122; it ended its trials in the late October and the day 31 it was accepted for production with the final denomination IS-2. At the end of the year about 100 exemplars had been delivered and in the end of 1944 more than 2200 had been built. This tank was used for the first time in February 1944 in Korsun Shevkenskovski; in this battle General Kotin personally observed the prestations of the new tank, obtaining vital information about its difficulties as well. It was clear that the IS-2 was a formidable tank, but its development would not end there.

After producing some experimental vehicles of the same type the works for a more advanced disposition of the armor would lead to the new IS-3 in the late 1944. The project of this tank, realized by a team directed by N. Dukhov, was conceived around the phylosophy of the armor of the T-34. The hull of the IS-2 was totally remodeled; the armor plates, thicker and of better ballistic shape, were strongly sloped to grant the maximum protection. A distinctive trait was the inclined front plate in the shape of inverted V. Petrov, who had projected the original model of cast turret capable of mounting a 85-millimeter cannon and improved it for the IS-2, conceived a new turret with an even better profile. This inverted bowl, with variations in the thickness of the armor between 25 and 230 millimeters, could still be seen in tanks so modern as the T-80 - which was produced until the late 1980s - and it was copied as well by the People's Republic of China for their light and heavy tanks. Still, the weight was kept under 46 tonnes: about 10 tonnes less than the Tiger I and up to 23 tonnes less than the Tiger II. The IS-3, as it was called the improved model, posed a pression on the ground similarly as the T-34/76A, which was an important factor considering that it had to operate in the extensive and humid rural areas of the Soviet Union. The IS-3 surpassed without doubt any of its German rivals, both in firepower - albeit having lesser fire of rate - and protection. If the IS-3 had some defects, these were a very narrow interior for the crew and a reduced ammunition supply of only 28 projectiles.

Both the IS-2 and the IS-3 served in first line during long time, with the Soviet Union and their satellite countries, until well into the 1970s. Syria still operated some of them during the Yom Kippur War in 1973 and the Israeli admitted how hard was to put them out of action, even in such advanced date. Many variants were made, including self-propelled cannons and mortars of even 420 millimeters, apart from versions for launching tactical and intercontinental missiles. The last version of this notable tank would enter service in the Red Army in 1957, with the denomination T-10.

IS tanks

IS-2 (upper picture) and IS-3 (lower picture). The heavy tanks of the IS (Iosif Stalin) series appeared between 1943 and 1945. The IS-3 came too late to intervene in actions in the Second World War, but it had a significative influence in the postwar projects.

The T-10

After the Second World War it was continued the production of the IS series, making small improvements to their armament, protection and engine. A reduced number of IS-4 entered service in 1946-47 and from this version derived the IS-5, IS-6, IS-7, IS-8, IS-9 and IS-10. After the death of Stalin in 1953, the Soviet authorities no longer saw a reason to continue giving his name to a tank; the new version that left the assembly lines in Kharkov was called T-10. It still was a similar tank to the IS-3, but its hull had been elongated, mounting a seventh road wheel. It was also somewhat heavier than the IS-3, with a weight of about 50 tonnes. The T-10 was seen in public for the first time in the parade at Moscow the 7th November 1957, in the 40th anniversary of the revolution. As well as the American M103 was created to give fire support to the M48 and the British Conqueror to make the same with the Centurion, the T-10 was intended to support the T-54/55.

The modified D-74 122-millimeter cannon fired a piercing projectile weighing 25 kilograms with a muzzle speed of 885 meters/second, being able to perforate 185 millimeters of vertical armor at a distance of 1000 meters. The other type of projectile available was a high-explosive breaker one weighing 27.3 kilograms. The cannon had a maximum range of 16600 meters at full elevation angle - which was 17 degrees in the T-10 - and an effective range in anti-tank role from 1200 to 2000 meters. Like all the cannons whose projectiles and propulsion charges are separated, the D-74 was slow to reload and its rate of fire was practically two or three shots per minute. Same than in the T-54/55, the small depression angle in the cannon - of only 3 degrees in the T-10 - posed a problem for firing from emplacements with the hull raised. The angle of depression was limited by the low profile of the turret: simply there was no space to elevate more the mechanisms of the cannon. However, in the case of this tank, the danger was minimized by the very sloped frontal armor with a thickness of 122 millimeters and by the excellent overall ballistic shape in the hull and the turret. And, despite of its 50 tonnes, its Diesel engine V-2-IS with 12 cylinders in V and 700 horsepower - which was a development of the one built for the tank A-20 circa 1935 - achieved a maximum speed of 42 kilometers/hour. The tracks were 71 centimeters in width, keeping ground pressure under reasonable limits. Its 900 liters of fuel gave an operational range of about 250 kilometers; it was not much for Soviet standards, but perfectly adequate for a support tank.

The T-10 was updated in the mid 1960s and this improved variant was called T-10M. The armor was increased and a two-axis stabilizator was added to the cannon, apart from a new shaped-charge fin-stabilized projectile with a muzzle speed of 900 meters/second whose 14-kilogram warhead could perforate almost 500 millimeters of armor within its efective range; this is, it could pierce everything in its way. The two DshK 12.7-millimeter machine guns - one co-axial and the other in the commander's cupola - were replaced by the KPV 14.5-millimeter machine guns. The twin muzzle brake of the cannon was replaced by a multiple one but it was preserved the fume extractor. The T-10 was already provided with infrared driving lights, but the T-10M, like the last T-54 tanks, was fitted as well with an orientable infrared searchlight on the commander's cupola for exploration and another projector to the right of the cannon, with which it was co-axial, thus moving with it in elevation. The T-10 could ford up to 1.2 meters without preparation; the T-10M could use a snorkel for deep fording. It was provided as well the installation of a system for NBQ (Nuclear-Bacteriological-Chemical) protection. Most of the T-10M had a large box in the rear of the turret to store spare parts, while in the rear of the hull it could be adapted up to four supplementary fuel tanks.

Albeit the T-10 was retired from first line service in the late 1970s, being kept in reserve many of them, they still were seen during another decade more in the armies of the Soviet clients, among them Syria. The T-10 was used by Egypt and Syria during the war with Israel in 1973; these admitted that they were very hard to defeat but in the Soviet Union it was seen that the days of the heavy tanks were gone in their doctrine. This tank was intended for long-range anti-tank missions in support of the main battle tanks T-55 and T-62; it could be used as well as spearhead in a breakthrough action in a vital sector, where its firepower and armor would prove useful. The T-10 was the most resistent Soviet tank of its time. But there were a number of inconvenients. First, it was slower than the T-55 and the T-62 so in the advance these would be forced to decrease their speed to not leave it behind. Second, as it was mentioned, the small depression angle difficulted firing from negative slopes. And third, also mentioned, the slow rate of fire - three or four shots per minute - imposed by the ammunition with separate charges.

IS tanks

T-10M, improved version of the T-10. The T-10 was an improvement of the successive versions of the IS-3 and it entered service with the Red Army in 1957. The T-10M was armed with a 122-millimeter cannon, a co-axial KPVT machine gun and an anti-aircraft KPV machine gun in the top of the turret; it was provided with a long-range nocturnal illumination equipment, including driving lights and two infrared projectors.

Specifications for IS-2

Crew: 4

Armament: One D-25 M 1943 L/43 122-millimeter cannon; one DT or DTM 7.62 millimeters co-axial machine gun; one DT or DTM 7.62-millimeter machine gun in the rear of the turret; one DShK M 1938 12.7-millimeter machine gun in the commander's cupola

Ammunitions: 28 for 122-millimeter cannon; 2520 for 7.62-millimeter machine guns; 945 for 12.7-millimeter machine gun

Armor: Up to 120 millimeters

Length (total): 9.83 meters

Width: 3.07 meters

Height: 2.73 meters

Weight: 46 tonnes

Ground clearance: 37 centimeters

Engine: V-2-IS (V2K) Diesel with 12 cylinders, water-cooled, developing 520 horsepower at 2000 revolutions per minute

Power/weight ratio: 11.3 horsepower/tonne

Maximum speed (in road): 37 kilometers/hour

Maximum speed (in cross-country): 19 kilometers/hour

Maximum operational range (in road): 240 kilometers

Maximum operational range (in cross-country): 210 kilometers

Maximum surmountable trench: 2.48 meters

Maximum surmountable step: 1 meter

Maximum surmountable slope: 36 degrees

Maximum fording: 1.3 meters



Specifications for IS-3

Crew: 4

Armament: One D-25 M 1943 L/43 122-millimeter cannon; one DT or DTM 7.62 millimeters co-axial machine gun; one DShK M 1938 12.7-millimeter machine gun in the commander's cupola

Armor: 19-132 millimeters in the hull; up to 250 millimeters in the turret

Length (total): 10.74 meters

Width: 3.44 meters

Height: 2.93 meters

Weight: 46.25 tonnes

Ground pressure: 0.79 kilograms/square centimeter

Engine: V-2-IS (V2K) Diesel with 12 cylinders, water-cooled, developing 520 horsepower at 2000 revolutions per minute

Power/weight ratio: 11.2 horsepower/tonne

Maximum speed: 37 kilometers/hour

Maximum operational range: 150 kilometers

Maximum surmountable trench: 2.86 meters

Maximum surmountable step: 1 meter

Maximum surmountable slope: 36 degrees



Specifications for T-10

Crew: 4

Armament: One D-74 122-millimeter cannon; one DShK 12.7 millimeters co-axial machine gun; one DShK 12.7-millimeter machine gun in the commander's cupola

Ammunitions: 30 for 122-millimeter cannon; 1000 for 12.7-millimeter machine guns

Armor: 20-250 millimeters

Length (total): 10.60 meters

Length (hull): 7.04 meters

Width: 3.57 meters

Height: 2.43 meters (not including the machine gun)

Weight: 50 tonnes

Ground pressure: 0.75 kilograms/square centimeter

Engine: V-2-IS (V2K) Diesel with 12 cylinders, water-cooled, developing 700 horsepower at 2000 revolutions per minute

Maximum speed: 42 kilometers/hour

Maximum operational range: 250 kilometers

Maximum surmountable trench: 3 meters

Maximum surmountable step: 0.90 meters

Maximum surmountable slope: 60 percent

Maximum fording: 1.2 meters



Specifications for T-10M

Crew: 4

Armament: One D-74 122-millimeter cannon; one KPVT 14.5 millimeters co-axial machine gun; one KPV 14.5-millimeter machine gun in the commander's cupola

Armor: 20-250 millimeters

Length (total): 10.60 meters

Length (hull): 7.04 meters

Width: 3.57 meters

Height: 2.43 meters (not including the machine gun)

Weight: 52 tonnes

Ground pressure: 0.78 kilograms/square centimeter

Engine: V-2-IS (V2K) Diesel with 12 cylinders, water-cooled, developing 700 horsepower at 2000 revolutions per minute

Maximum speed: 42 kilometers/hour

Maximum operational range: 250 kilometers

Maximum surmountable trench: 3 meters

Maximum surmountable step: 0.90 meters

Maximum surmountable slope: 60 percent

Maximum fording: 1.2 meters



Categories: Tanks - World War Two - Cold War - 20th Century - [General]

E-mail:

Website: Military History

Article submitted: 2014-12-27


This article has been seen/reloaded times since 2017-03-05 (or since publishing date).

This article has been voted 0 times.

You are logged off and have no access to the contents of this section!