Main Menu
Soviet Union's IS-851, IS-11, JS-17 heavy tank
| IS-1 heavy tank with 85 mm: |
IS-1 heavy tank: |
Design
IS stood for Iosef Vissarionovich Stalin.2
The need to increase the firepower of the KV series was seen by the end of 1942 with the Germans introducing Tiger tanks a new tank was needed to combat it.2 The IS-85 was intended to be a 4-man tank, with an 85 mm gun, not weigh more than a KV-1, and that had thick enough armor to defeat the German 50 mm anti-tank gun.7
The IS-85 was designed by a design bureau led by Lieutenant-Colonel Kotin.1 He split the bureau into two and each team had different specifications to design for.1 One of the teams was told to improve the KV series as a stopgap for a new heavy tank.1 This design was to become the KV-85.1 The other team was to design the new heavy tank, the IS-85.1 The team was headed by, released from a labor camp, N. V. Tseits.1 The design was initially called the KV-13 and had a redesigned hull and chassis from the KV series.1
Based on the KV series it had a new hull, improvements in the suspension, transmission, and power train.1 The turret was cast and the hull had cast and rolled parts welded together.1,2
Main Armament
The IS-85's design first started out with same 85 mm gun as the T-34/85 and a few were produced in late 1943. The cast turret (which was used in the KV-85) was designed by General A. A. Petrov.2 A heavier gun was needed as the T-34/85 was being produced and having a heavy tank with the same armament as a medium was thought to be inefficient. The 100 mm designed by V. Grabin was tried with great success and known as the IS-100.2 The 122 mm was tried but it was only a little more effective, however the 100 mm was in short supply. The superstructure extended out over the tracks and this allowed for a bigger turret.5
There was no MG in the hull which allowed for a better ballistic shape.5
Prototype
A design bureau was headed by N. F. Shashmurin at Tankograd in the Urals that developed the IS series.2 By the end of 1943 prototypes were available.2
Only a short test was done and the State Defense Committee approved the tanks for use in the Red Army in October 1943.2
The KV-13 prototype was tested at Chelyabinsk's Experimental Test Factory in May 1942.1 It was found to have problems with the transmission and would often throw a track.1
Production
After a few models were produced, production was switched to the IS-2. The models that were left were converted to IS-2 standards.
In 1943 the IS-85 was redesignated the IS-1.1
- IS-1:
- 1943: 100, 676
- 1944: 406
Variants
- KV-92: Prototype.2 122 mm howitzer.2
- KV-131,2: Prototype.1,2
- IS-1 (85)8, IS-1:
- IS-1 (122)8, IS-1B:
Usage
Some saw action in the Ukraine in early 1944.
| IS-1, IS-1 (85)8 | IS-1 19432, IS-1A5 | IS-1B5, IS-1 (122)8 | |
|---|---|---|---|
| Crew | 43,4,5,6,7,8 | 42,5 | 45,8 |
| Physical Characteristics | |||
| Weight | 97,000 lb, 44 tons4,6,8, 45.3 tons3,7 46,000 kg3,7 |
44 tons2 | 44.5 tons8 |
| Length w/gun | 27.3'4,8, 27' 3"3,7, 29' 4" |
8.56 m2 | 31' 6"8 |
| Length w/o gun | 6.77 m2 | ||
| Height | 8.9'4,8, 9' 6"3,7 2.735 m6, 2.9 m3,7 |
2.73 m2 | 8.9'8 |
| Width | 10' 3"4,8, 10' 8"3,7, 11' 3.07 m6, 3.25 m3,7 |
3.07 m2 | 10' 3"8 |
| Width over tracks | |||
| Ground clearance | 0.47 m6 | 0.46 m2 | |
| Ground contact length | 14.3'8 4.3 m6 |
14.3'8 | |
| Ground pressure | 0.78 kp/cm2 6 | 0.78 kp/cm2 2 | |
| Turret ring diameter | |||
| Armament | |||
| Main | 85 mm3,4 85 mm M19438 100 mm7 |
85 mm M1943 D-5 T2 85 mm or 100 mm5 |
122 mm5 122 mm M19438 |
| Secondary | |||
| MG | 2: 7.62 mm DT MG3 4: MG4 2: 7.62 mm MG7 3: 7.62 mm MG8 |
3: 7.62 mm MG8 | |
| MG - coaxial | 1: 7.62 DT MG mm2 | ||
| MG - rear | 1: 7.62 DT MG mm2 | ||
| MG - hull | 1: 7.62 DT MG mm2 | ||
| MG - antiaircraft | 1: 12.7 mm DShK8 | 1: 12.7 mm DShK8 | |
| Side arms | |||
| Quantity | |||
| Main | 718 | 592 | 288 |
| Secondary | |||
| MG | 1,3308 | 2,5202 | 2,3308 |
| Side arms | |||
| Armor Thickness (mm) | 1327, 30 - 1323, 19 - 1204 | ||
| Hull Front, Upper | 120 - 1606, 1208 | 120 - 1602 | 1208 |
| Hull Front, Lower | |||
| Hull Sides, Upper | 89 - 908, 906 | 902 | 89 - 908 |
| Hull Sides, Lower | |||
| Hull Rear | 606 | 602 | |
| Hull Top | 258, 306 | 20-302 | 258 |
| Hull Bottom | 258 | 20-302 | 258 |
| Turret Front | 30 - 1008 | 1002 | 30 - 1028 |
| Turret Sides | 902 | ||
| Turret Rear | 60-902 | ||
| Turret Top | 302 | ||
| Engine (Make / Model) | V-2-IS3,7, V-2-IS (V2K)8 | W-2-IS2 (V-2K) |
V-2-IS (V2K)8 |
| Bore / stroke | 4 stroke2 | ||
| Cooling | |||
| Cylinders | 127,8 | V-122 | 128 |
| Capacity | |||
| Net HP | 5107, 5134,8 | 600@2,000 rpm2 | 5138 |
| Power to weight ratio | 11.8 hp/ton6 | 14.1 hp/ton2 | |
| Compression ratio | |||
| Transmission (Type) | |||
| Steering | |||
| Steering ratio | |||
| Starter | |||
| Electrical system | |||
| Ignition | |||
| Fuel (Type) | Diesel4,7,8 | Diesel8 | |
| Octane | |||
| Quantity | 800 liters2 | ||
| Road consumption | |||
| Cross country consumption | |||
| Performance | |||
| Traverse | 360° | ||
| Max speed | 23 mph4,8, 24.8 mph3, 24.9 mph7 37 kph6, 40 kph3,7 |
37 kph2 | 23 mph8 |
| Cross country speed | 15 mph | ||
| Road radius | 149 miles, 150 miles8, 155 miles3,7 250 km3,7, 130 - 240 km6 |
150 km2 | 150 miles8 |
| Cross country radius | 130 miles8 110 - 125 km6 |
130 miles8 | |
| Turning radius | |||
| Elevation limits | |||
| Fording depth | 1.3 m6 | 1.3 m2 | |
| Trench crossing | 2.5 m6 | 2.5 m2 | |
| Vertical obstacle | 1 m6 | 1 m2 | |
| Climbing ability | 30 - 36°2 | ||
| Suspension (Type) | |||
| Wheels each side | |||
| Return rollers each side | |||
| Tracks (Type) | |||
| Length | |||
| Width | 2' 1.63"8 | 2' 1.63"8 | |
| Diameter | |||
| Number of links | |||
| Pitch | |||
| Tire tread | |||
| Track centers/tread |
Sources:
- Russian Tanks of World War II Stalin's Armored Might, by Tim Bean & Will Fowler, 2002
- Russian Tanks and Armored Vehicles 1917-1945, by Wolfgang Fleischer, 1999
- The Encyclopedia of Tanks and Armored Fighting Vehicles - The Comprehensive Guide to Over 900 Armored Fighting Vehicles From 1915 to the Present Day, General Editor: Christopher F. Foss, 2002
- Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
- Tanks of World War II, Duncan Crow, 1979
- Russian Armour Volume 1: The IS Tanks IS-1, IS-2, IS-3, Mikhail Baryatinskiy, 2006
- The Illustrated Guide to Tanks of the World, George Forty, 2006
- Airfix Magazine Guide 22 Russian Tanks of World War 2, John Milsom and Steve Zaloga, 1977
