The Oldest IS

It often so happens that a truly unique tank stands in shadow, unknown to those around it. There are many examples. For instance, the T-34 tank "Kantemirovets" on display at the Road of Life exhibit is no simple tank. It turns out that this is the only "general's" T-34 that used to carry an RSB-F radio. Now it needs to be reunited with its former components, but that's a whole separate affair. Secret past lives of tanks that appear to be well known are discovered every so often.

How the hero of this article looks today.

The Kirov Factory in St Petersburg has an IS-2 installed as a monument on its grounds. It was installed here in 1947. This tank is fairly well known. It is often referred to as an IS-2 from the first production batches. However, this tank is even more interesting than this. It is actually one of the progenitors of the whole IS tank series with a very complicated fate.

Heavy Without Alternatives

One can often encounter brainstorms about how individual vehicles or even entire tank building schools ought to have evolved. Most of these brainstorms are done by people that are far removed from the field of history, but sometimes even notorious historians take part in this exercise. Among Soviet tanks, the T-28 is a popular character in alternative history. Modern improvements to this tank know no bounds, but the fact that the T-28 was replaced by the KV-1 and not the T-34 is often ignored, as is the fact that a replacement for the T-28 by the name of T-29 already existed. 

Object 237 accepted into service with the Red Army as the IS-85 (IS-1).

The IS-85 heavy tank was accepted into service with the Red Army on September 4th, 1943. This was the finale of the program aimed at developing a successor to the KV. One can often hear claims that if the KV remained in production and was modernized then it could be made into a heavy tank that was no worse than the IS-85. You may laugh, but these claims were not just made by alternative historians. Attempts to preserve the KV-85 were made at the highest levels, even in 1944. Nevertheless, the KV had to make room on the assembly line for its successor. Read on to find out why this happened and why there was no alternative to the IS tank.

German Tank Intel 1944

 "Top Secret

Inspector General of the Tank Forces
#046/44 Top Secret

June 26th, 1944

Copy 1 out of 5

Notes on the report to the Fuhrer

[...]

Based on information received at 2:00 on June 25th from Tank Group West and Colonel Emichen, the following picture is formed on English and American tanks:

1. The new Cromwell tank is armed with one 75 mm L/34 gun. The American Sherman tank used to be armed with a 75 mm L/40 gun and now has a longer 76.2 mm L/52.8 tank gun (previously used on the M10 SPG).

85 mm for Dummies

 "To Commanders of Army Artillery and Commanders of Tank Armies

USSR NKO

Main Artillery Directorate of the Red Army

Artillery Committee

December 25th, 1943

#800868

Moscow

The Main Artillery Directorate of the Red Army learned that troops do not always correctly use ammunition for 85 mm tank and SPG guns. I ask you to explain the following to the troops:

85 mm tank and SPG guns are equipped with ammunition from the 85 mm AA gun:

1. BR-365 armour piercing-tracer rounds
2. O-365K steel cased HE rounds with KTM-1 fuses.

IS-1 Variants

Development of 85 mm tank guns in the USSR began on May 5th, 1943. Multiple competing variants were developed. A new tank was being designed in parallel, and when it was finished there were two 85 mm guns available for it: the S-31 and D-5.

An IS in the Hand

An experimental prototype of the IS-1 tank, formerly called KV-13, was sent to factory trials on March 9th, 1943. This was a fully fledged heavy tank, a little lighter than the KV-1S, but much more mobile and protected. However, during the government trials in the spring of 1943, it became clear that it needs a number of improvements, some of them quite serious. The German Tiger tank was the last nail in the coffin of the IS-1. It turned out that an 85 mm gun was necessary to combat this tank, which would not fit into the turret of the experimental Soviet vehicle. This was the start of the story of the Object 237, the last step towards the creation of the heavy IS tank.

High Caliber Convertibles

History often repeats itself. This well known fact is often confirmed in tank building. For instance, Soviet SPGs, especially heavy ones like the SU-14, were created in order to mechanize artillery. The requirements changed during the process of their creation. The Red Army was in need of an assault gun that was capable of direct fire and had shell-proof armour. The 212 SPG and subsequent vehicles were designed according to this concept. Work resulted in the creation of the SU-152. However, one day the Red Army once more found itself in need of a self propelled gun with an open fighting compartment equipped with a 203 mm B-4 gun.

IS #1 and #2

"To the People's Commissar of Tank Production, comrade I.M. Zaltsmann

In accordance with the GOKO decree and your orders, the Kirov factory and factory #100 jointly produced two IS tanks, one with a 76 mm gun (IS-1) and one with a 122 mm gun (IS-2).

Both tanks were built in accordance with the tactical-technical characteristics outlined in the GOKO decree:

	IS-1	IS-2
Mass	Up to 38.5 tons (37,160)	Up to 39.5 tons (37,900)
Top speed	55 kph	55 kph
Transmission	8-speed gearbox, planetary turning mechanism, planetary final drives	Same
Armour	120 mm cast front 100 mm cast turret platform, turret 90 mm rolled sides	Same
Engine	V-2K 600 hp with electro-inertial starter	V-2K 600 hp with electro-inertial starter
Armament	76 mm F-34 gun 3 DT machine guns (coax, rear in turret, hull)	122 mm gun 2 DT machine guns (coax and hull)
Ammunition	80-85 76 mm rounds 32 machine gun magazines	30-35 122 mm rounds 32 machine gun magazines
Crew	4	5

IS Debut

"Military Council of Armoured and Mechanized Forces of the Red Army

April 1st, 1944

#481904ss

To commander of the 2nd Ukrainian Front, Marshal of the Soviet Union, comrade Konev

The regiments of heavy IS tanks and ISU-152 SPGs consist of the first tanks and SPGs of this type. As tanks and SPGs of the first production batch, they have a number of minor technical drawbacks, as there is not yet sufficient experience in their use. I ask you to take measures and offer assistance in the matters of studying these vehicles in battle, discovery of their usage and technical drawbacks, and study of the best way to use them in battle.

Kotin's Bobtail

In early 1943 the Red Army Main Armoured Vehicle Directorate (GBTU) and People's Commissariat of Tank Production (NKTP) agreed that the age of the KV-1S is coming to an end. Instead, the IS-1 (233), a further development of the KV-13, was to be produced in Chelyabinsk. This tank had the same firepower, but was more mobile and better protected. However, the experimental IS-1 was too unrefined and suffered from assembly issues. In addition, trials of the German Tiger tank showed that the Red Army was in need of a tank with an 85 mm gun. This was how the KV-85 was created, the last mass produced tank in the KV family.

Intermediate IS

Joseph Stalin signed GKO decree #4043 "On the production of IS tanks" on September 4th, 1943. This was the end to a long process of the creation of a new Soviet heavy tank that could replace the KV-1 in production. While it was being developed, Chelyabinsk had time to master both the KV-1S and KV-85. However, such a long journey was not for nothing: the Red Army received a completely new tank, the combined characteristics of which put it among the best heavy tanks in the world at the time. The age of the IS-1 (IS-85) was not long. Very shortly it gave up its first place to its descendant, the IS-2, which became the best Soviet heavy tank of the Great Patriotic War.

The First Coming of the IS-2

The 122 mm U-11 gun designed in the fall-winter of 1941 was rather controversial. Its designers succeeded in their task of installing a gun with the ballistics of the M-30 in a minimally altered KV-1 turret. However, the howitzer had a low rate of fire, and its penetration characteristics were poor. As a result, the planed KV-9 batch remained on paper. Nevertheless, the GABTU did not give up on the idea of a howitzer tank. Despite opposition from the GAU, work on howitzer tanks continued in 1943.

IS-3, Take One

"Report on experimental work at factory #100 for the first 10 days of June, 1943

Most effort at the factory was directed towards production and assembly of IS-3 components according to altered blueprints and continuation of factory trials of IS-1 and IS-2 tanks, bringing the total distance travelled to 2000 km.

IS-1 (Object 237) Characteristics

"Tactical-technical characteristics of the IS tank

1. Full combat weight: 43-44 tons
2. Crew: 5
3. Armour
1. Front: at least 120 mm thick, cast
2. Side: at least 90 mm thick, rolled
3. Floor and roof: at least 20 mm thick, rolled
4. Rear: at least 60 mm (at an angle of 45 degrees), rolled
5. Turret: at least 100 mm, cast

Second to Last Step

The first prototype of the KV-13 heavy tank entered trials on September 26th, 1942. The vehicle was quite unusual. With the protection of a heavy tank, it had both the size and weight of a medium. This later caused many hypotheses about a "medium tank with heavy armour". In reality, the KV-13 was never a medium. It was developed as a heavy tank from the very beginning, and the small size and mass were a direct consequence of the requirements issued by the GABTU. For a number of reasons, work on the KV-13, which also earned the name IS-1 during its design, did not continue past a second prototype. However, it was an important milestone towards the creation of a next generation Soviet heavy tank.

IS Bug Report

"To the Deputy Chair of the Committee of Defense, comrade Molotov

I report that, in accordance with GOKO decree #2943ss, issued on February 24th, 1943, Kirov factory and factory #100 produced two experimental prototypes of IS tanks:

1. IS-1 tank with a 76 mm gun (F-34)
2. IS-2 tank with a 122 mm gun (U-11)

New Heavy Tanks, 1943

"To the Chief of the GBTU TU 6th Department, Regional Engineer at the Kirov Factory

July 5th, 1943

I report on the experimental work performed at factory #100 during June of 1943.

The most attention was paid to Objects 237 (experimental IS tank) and 239 (KV-1S tank with an IS tank turret and 85 mm gun).

Imagination Versus Hitler

As practice shows, the temptation to make up your own tank is great. Sadly (or thankfully), few people are destined to become tank designers. Here is where limitless human imagination steps in to create more "improved" or completely fictional projects than there were real tanks made.

Most of these made up tanks and SPGs belong to Germany. This is not surprising, since German dreams of Wunderwaffen firmly lodged themselves in people's heads. However, a lot of made up tanks were "invented" for Germany's enemies. There are a few of these vehicles in World of Tanks, but this article is not only dedicated to them. There were plenty of authors around the world, including during the war. Of course, some of these tanks were only partially fictional.

IS-9

CIA-RDP82-00046R000500390005-9

Cheating at Statistics 19: Time Travelling Tigers

One of the first uses of the IS-85 tank was in the Korsun Pocket. The 13th Guards Heavy Tank Regiment, equipped with brand new IS-85s, was sent to block Kampfgruppe Bake (an unusual formation equipped with both Tiger and Panther tanks) from breaking through to the pocket. Forczyk describes this engagement as not particularly favourable to the IS tanks.

"These heavy tanks were committed into action on 15 February and unwisely attacked Kampfgruppe Bake instead of sitting on the defense; the Panthers and Tigers knocked virtually all of them out. Following this incident, the GABTU resolved to upgrade the new IS-series heavy tanks to the 122 mm gun."

Oof, that's quite a mistake for a book published in 2015. The decree titled "On IS tanks" authorized the production of an IS tank armed with a 122 mm gun in September of 1943. By February 15th, these tanks were not only in production, but had already reached the front lines.

However, there's something else fishy in play here. This unit that was destroyed by Tigers and Panthers mysteriously pops up on the very next page to wreak havoc on Kampfgruppe Bake and Frank's attempts to break through to the encircled men. Let's take a look at what actually happened.