The IS-4, also known as the Object 701, was a

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

heavy tank Heavy tank is a term used to define a class of tanks produced from World War I through the end of the Cold War. These tanks generally sacrificed mobility and maneuverability for better armour protection and equal or greater firepower than tanks ...

that started development in 1943 and began production in 1946. Derived from the

IS-2 The IS-2 (russian: ИС-2, sometimes romanized as JS-2The series name is an abbreviation of the name Joseph Stalin (russian: Иосиф Сталин); IS-2 is a direct transliteration of the Russian abbreviation, while JS-2 is an abbreviation of ...

and part of the

IS tank family The IS tanks (russian: ИС) were a series of heavy tanks developed as a successor to the KV-series by the Soviet Union during World War II. The IS acronym is the anglicized initialism of Joseph Stalin (, '). The heavy tanks were designed as a r ...

, the IS-4 featured a longer hull and increased armor. With the

IS-3 The IS-3 (also known as Object 703) is a Soviet heavy tank developed in late 1944. Its semi-hemispherical cast turret (resembling that of an upturned soup bowl), became the hallmark of post-war Soviet tanks. Its pike nose design would also be ...

already in production, as well as the decreased need for tanks (particularly heavy tanks) and sluggish mobility, many were sent to the

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admini ...

with some eventually becoming pillboxes along the

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...

border in the 1960s. Less than 250 were produced.

Design and production

Development of the IS-4 started in November 1943 with the purpose of improving upon the IS-2 and incorporating captured enemy technology. This created a blend of IS-2 features and unique features not found in other Soviet tanks. The IS-2's stepped front plate was judged to be a weak point and made into a single glacis with additional armor for the driver. This was in order to accomplish the IS-4's design parameters which included the ability to defeat the German

8.8 cm Pak 43 The Pak 43 (''Panzerabwehrkanone 43'' and ''Panzerjägerkanone 43'') was a German 88 mm anti-tank gun developed by Krupp in competition with the Rheinmetall 8.8 cm Flak 41 anti-aircraft gun and used during World War II. The Pak 43 was the ...

anti-tank gun. The side hull of the IS-4 is a simple angular step instead of angling out like the IS-3. The right side of the tank was fitted with clamp rings to carry an unditching log. The driver's position was described as cramped, though the writer of the review was taller than what was typical for tankers of the time. The IS-4 track system is based on the IS-2 with an additional set of cast road wheels bringing the total to 7 pairs on a torsion bar suspension system. The IS-4 has bump stops similar to other torsion bar systems but notably does not have shock absorbers to stop rocking, relying instead on mass. The track is similar to others in the IS series, except it has a center guide on every track link instead of alternating ones. Each track is held in place by a single pin with a clip and washers. In the rear, each fender was able to hold two external 90-liter fuel tanks side by side. The rear also could hold an "MDH" ("Small Naval Generator") smoke generator which was equipped with a quick detach under the control of the driver who could activate it from inside the tank. The IS-4 had a rear transmission system and a rear gun travel lock. The engine was a V12 which was an improvement over the V2 and fitted with a newly designed transmission and steering system capable of neutral steering. The IS-4 has two circular radiator fans externally identical to German World War II tanks, though internally different. It had two internal fuel tanks; the left 295 liters and the right 115 liters. The turret resembles that of the IS-2 but also features components from the IS-3, a large access port to remove the cannon and a similar hatch layout. The commander was originally intended to have a rotating cupola similar to a late model

M4 Sherman } The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the Military history of the United States during World War II, United States and Allies of World War II, Western Allies in World War II. The M4 Sherman prove ...

but this seems to have not been implemented. Unlike the IS-3, the IS-4 featured a dedicated bustle rack for ammunition in the rear of the turret. The IS-4 turret, with powered traverse, was noted by Nicholas Moran to be larger and roomier than the IS-3 turret, allowing for more ammunition for the

coaxial machine gun A weapon mount is an assembly or mechanism used to hold a weapon (typically a gun) onto a platform in order for it to function at maximum capacity. Weapon mounts can be broken down into two categories: static mounts and non-static mounts. Static ...

. The IS-4 may have had an intercom system on the back of the turret to allow mounted infantry to talk with the tank crew. Production started in 1946, too late for

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. It was found to be overweight, and its original purpose (to fight against the Germans) was not needed anymore. Furthermore, the IS-3 was already in production, and for these reasons less than 250 were built. Most of them were transferred to the Russian Far East. Later in the 1950s, a side skirt was added. In the early 1960s they were retired from service, with some serving on the

border as pillboxes.

Operators

; *

Soviet Army uk, Радянська армія , image = File:Communist star with golden border and red rims.svg , alt = , caption = Emblem of the Soviet Army , start_date ...

: Accepted into service on 29 April 1946

Surviving vehicles

Kubinka Tank Museum The Kubinka Tank Museum (Центральный музей бронетанкового вооружения и техники - Tsentral'nyy Muzey Bronetankovogo Vooruzheniya I Tekhniki -Central Museum of Armored Arms and Technology) is a larg ...

, Russia.

References

{{reflist

Design and production

Operators

Surviving vehicles

References

See also

Tanks of comparable role