Engines of the Red Army in WW2

JS-1 Heavy Tank

The "White 6-26", 3rd Belorussian Front, Baltic, Summer 1944

JS-1 Heavy Tank

With the arrival of the first Tiger tanks on Russian battlefields in late 1942, it became obvious that a new heavy was needed to counter the threat. So the SKB 2 heavy tank design bureau in Chelyabinsk started the KV-13 program to build a heavy tank with both sufficient mobility and heavier armour. The so-called IS-85 was intended to be a 4-man tank, with an 85 mm gun, no more weight than a KV-1, and with thicker armor to withstnd the improved German 75mm and 88mm guns.

Based on the KV series the new tank had a new hull, improvements in the suspension, transmission, and power train. There was no machine gun in the hull which allowed for a better ballistic shape.

The superstructure extended out over the tracks and allowed for a bigger cast turret. The design team chose the 85mm D-5T tank as armament, the same gun used in the early T-34/85 and SU-85 SPG.

As a stopgap until the final production, the new turret was installed to the KV-1s chassis thus creating the KV-85.

The first IS-85 heavy tanks were delivered by the Chelyabinsk Kirov Plant in October 1943.

These were issued to the 1^st, 8^th, and 13^th Guards Heavy Tank Regiments fighting in the Ukraine.
These units were heavily engaged in early 1944 at Starokonstantinov, Korsun-Shevshenkovskiy and Fastov Station west of Kiev.
Later on, most IS-1s were found engaged in Slovakia and some were later given to Slovakian free units during the uprising.
However, production ceased after 200 samples raising the curtain for the ultimate new heavy tank, the IS-2.

ZiS-5-BZ »Benzinozisterna« refuelling a JS-1

With the 13^th Guards Heavy Breakthrough Tank Regiment in the Southern Ukraine, Winter 1943/44

The 13^th Guards Heavy Tank Regiment was formed on 28 October 1942 in the Moscow Military District from the 34^th Tank Brigade with KV-1 tanks.
It first saw combat with the 3^rd Shock Army on the Northwestern Front in January 1943.
In early 1944 it was assigned to the 2^nd Tank Army after being re-equipped with new IS-85 heavy tanks.
By February 15, 1944, the regiment arrived in the region of Fastov - Belaya Tzerkov with 21 JS-1 tanks.
It was ordered to support the 109^th Tank Brigade in an assault on Lisyanka village (Ukraine).

This fighting took place during the Korsun-Shevcheskovsk Operation.
The 109^th Tank Brigade was an element of 16^th Tank Corps which was attached to the 2^nd Tank Army.
This Army fought against the German 3^rd Panzer Corps.
A commander of the 13^th Regiment detached one company of 5 JS-1's and sent them into action.
At that moment all the tanks of 109^th Brigade were knocked out by German Panthers and assault guns camouflaged somewhere in the village.
Soviet tanks approached within 600-700 metres, when the Germans opened fire.
All the Soviet tanks were knocked-out; two of them were burned out. Each of the JS's received up to 7 hits.

The next day Lisyanka was encircled and liberated.
The Russians captured 16 abandoned Panthers, 2 Pz-IV and 2 StuG-40. They were abandoned after running out of fuel.
On March 15, 1944, fifteen JS-1's from the 13^th Guards Heavy Breakthrough Tank Regiment were supporting an attack of 50^th Tank Brigade near the Uman.
During that battle, five JS-1 were destroyed by German 88 mm Flak guns.
Three tanks failed due to technical breakdowns, and one tank fell into a river (near Polkovnichie).
During that battle a rare incident occurred: the lower frontal armor of an JS-1 was penetrated by a German Pz.B-41 anti-tank rifle.

Source: Russian Battlefield, Flames ofWar