IS-2 Heavy Tank
Although the KV tanks had proven useful early in the war, it was appreciated that a more powerful tank was needed to deal with the latest generation of German armor. The resulting vehicle, based partly on the KV chassis with an improved suspension and transmission, debuted as the IS (Iosef Stalin) in late 1943 with an 85mm gun. Further improvements lead to the more powerful IS-2.
The IS-2 first saw action in early 1944. It had thick armor, with reasonably good sloping on the front of the hull and turret. The 122mm D-25T gun was formidable, although the large bore size severely restricted internal ammo capacity and the gun was slower to load than the German 88mm tank guns. Some 2,350 IS-2’s were built.
The IS-2M has a crew of four. The commander sits in the turret and mans the A/A HMG adjacent to his cupola. Also in the turret is the gunner (who fires the cannon and coaxial LMG) and the loader/radio operator (who also fires the LMG in the rear turret). The driver/mechanic sits in the body and fires the fixed hull LMG. The gunner and loader manually traverse the turret at 1 degree per second. The IS-2 uses 17.3 gallons per hour at routine usage.
IS-2M
Subassemblies: Very Large Tank chassis +4 with medium
slope, full rotation Small TD turret with mild slope [Body:T] +2, tracks
+4.
Powertrain: 383-kW diesel engine w/ 383-kW tracked drive
train and 137 gallons in standard fuel tank [body]; 16,000-kWs batteries.
Occupancy: 2 CS Body, 1 CS Turret, 2 CS Both Cargo:
2 Body.
| Armor | F | RL | B | T | U |
| Body | 5/700 | 4/350 | 5/350 | 4/100 | 4/75 |
| Tracks | 4/50 | 4/50 | 4/50 | 4/50 | 4/50 |
| Turret | 5/580 | 4/350 | 4/350 | 4/115 | 0/0 |
Weaponry
122mm Medium TG/D-25T [Tur:F] (28).
Ground LMG/7.62mm DT [Tur:F] (*).
Ground LMG/7.62mm DT [Tur:R] (*).
Ground LMG/7.62mm DT [Body:F] (*).
Very Long Ground HMG/12.7mm DShK [OM:F] (945).
* 2,330 rounds for all LMGs
Statistics
| Size: 32’¥10’¥9’ | Payload: 2.9 tons | Lwt: 48.9 tons |
| Volume: 187 | Maint.: 24 hours | Price: $63,300 |
HT: 9
HP: 2300 [Body], 285 [Turret], 800 [Each Track]
| gSpeed: 28 | gAccel: 2 | gDecel: 20 | gMR: 0.25 | gSR: 6 | GP: High (1/2) |
Design Notes
The design purchased 138 gallons of fuel tanks and 2,500 rounds of
LMG ammo. The historical values have been used instead. The design weight
was reduced 20% to match historical weight. Historically, the turret side
armor was slightly sloped and the rear turret armor mildly sloped. As the
tank is badly overweight, a larger turret (to allow more sloping) was not
bought, nor was turret DR increased. Given that the sloping was well under
the 30 degrees of mild sloping on the sides, this probably does not distort
reality too much. Turret armor is Expensive.
Some sources do not list a hull LMG. Those that do list it note that it was fixed and fired remotely (probably by the driver). It is possible that they were removed in the field.
External fuel tanks were frequently carried. Each carried 23.8 gallons of fuel, were DR 2 and weighed 350 lbs full. The IS-1 carried up to four and the IS-2 up to three.
Variants
The IS-1 (1943) was similar, but mounted the 85mm D-5T85 (85mm Medium
Tank Gun) initially, which also gave it the name IS-85. At the end of 1943,
a 100mm gun was developed and installed in new IS-1’s as well as being
refitted to old ones (these were also known as IS-100’s). The 100mm actually
had slightly better penetration than the 122mm, but the latter had a significantly
better HE effect. Only about 100 total IS-1’s were built and it is possible
that none entered combat with the 85mm gun.
The IS-2 (1944) lacked the AA machinegun, but was otherwise the same.
The IS-3 (1945) may or may not have seen action in WWII. Only 350 are believed to have been built before VJ-Day. The armor was better shaped and the turret was larger, with DR 925 armor on the front and sides.
Several assault guns were built based on the IS chassis. There were two ISU-122 vehicles, one mounting the 122mm D-25S (ISU-122S) and the other the older 122mm A-19S gun (ISU-122). Other than the A-19S having half the rate of fire of the D-25S, there was no significant difference between the two; both carried 20-30 rounds of cannon ammo. Hull armor was increased to DR 760 on the front and the superstructure was DR 350 frontally. The ISU-152 mounted a 152mm ML-20S gun (150mm Short Howitzer) with 20 rounds. All mounted a 12.7mm DShK for anti-aircraft use, with 500-1000 rounds of ammo. Some 2,000 ISU-152 and 4,000 ISU-122 were built. In general, the ISU-152 was used as a direct-fire artillery piece while the ISU-122 was used as a tank destroyer, although both vehicles could perform both roles.
122mm Medium Tank Gun: This represents the Russian D-25T
and D-25S.
Stats: Dam 7dx13 (2) + 7dx8 [10d] APEX, SS 30, Acc 15,
1/2 Dam 1,900, Max 7,100, RoF 1/20, Loaders 1, Cost $ 14,000, Wt 5,400
lbs, VSP 21.6, WPS 120, CPS $60, 2 VSP for 2 shells