IS-1 Heavy Tank,
JS-1 Heavy Tank7:
IS-1 with 85 mm
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.
It 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
A design bureau was headed by N. F. Shashmurin at Takograd in the Urals. By the end of 1943 prototypes were available. Based on the KV series it had a new hull, improvements in the suspension, transmission, and power train. The turret was cast and the hull had cast and rolled parts welded together.
Only a short test was done and the State Defense Committee approved the tanks for use in the Red Army in October 1943.
IS stood for Iosef Stalin.
Design first started out with same 85 mm gun as the T-34/85 which was known as the IS-85 and a few were produced in late 1943. The cast turret (which was used in the KV-85) was designed by General F. Petrov. 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 ineffecient. The 100 mm designed by V. Grabin was tried with great success and known as the IS-100. 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
After a few models were produced, production was switched to the IS-2. Some saw action in the Ukraine in early 1944. The models that were left were converted to IS-2 standards.
| IS-1 | IS-1 1943, IS-1A5 | IS-1B5 | |
|---|---|---|---|
| Crew | 43,4,5,6,7 | 42,5 | 45 |
| Physical Characteristics | |||
| Weight | 97,000 lb, 44 tons4,6, 45.3 tons3,7 46,000 kg3,7 |
44 tons2 | |
| Length w/gun | 27.3'4, 27' 3"3,7, 29' 4" |
8.56 m2 | |
| Length w/o gun | 6.77 m2 | ||
| Height | 8.9'4, 9' 6"3,7 2.735 m6, 2.9 m3,7 |
2.73 m2 | |
| Width | 10.25'4, 10' 8"3,7, 11' 3.07 m6, 3.25 m3,7 |
3.07 m2 | |
| Width over tracks | |||
| Ground clearance | 0.47 m6 | 0.46 m2 | |
| Ground contact length | 4.3 m6 | ||
| Ground pressure | 0.78 kp/(cm2)6 | 0.78 kp/(cm2)2 | |
| Turret ring diameter | |||
| Armament | |||
| Main | 85 mm3,4 100 mm7 |
85 mm M1943 D-5 T2 85 mm or 100 mm5 |
122 mm5 |
| Secondary | |||
| MG | 2: 7.62 mm DT MG3 4: MG4 2: 7.62 mm MG7 |
3: 7.62 DT MG mm, coaxial, hull, rear2 | |
| Side arms | |||
| Quantity | |||
| Main | 71 |
592 | |
| Secondary | |||
| MG | 1,330 |
2,5202 | |
| Side arms | |||
| Armor Thickness (mm) | 1327 30 - 1323, 19 - 1204 |
||
| Hull Front, Upper | 120 - 606 | 120-1602 | |
| Hull Front, Lower | |||
| Hull Sides, Upper | 906 | 902 | |
| Hull Sides, Lower | |||
| Hull Rear | 606 | 602 | |
| Hull Top | 306 | 20-302 | |
| Hull Bottom | 20-302 | ||
| Turret Front | 1002 | ||
| Turret Sides | 902 | ||
| Turret Rear | 60-902 | ||
| Turret Top | 302 | ||
| Engine (Make / Model) | V-2-IS3,7 |
V-2-IS2 ( V-2K) |
|
| Bore / stroke | |||
| Cooling | |||
| Cylinders | 127 | ||
| Capacity | |||
| Net HP | 5107, 5134 | ||
| Power to weight ratio | 11.8 hp/ton6 | ||
| Compression ratio | |||
| Transmission (Type) | |||
| Steering | |||
| Steering ratio | |||
| Starter | |||
| Electrical system | |||
| Ignition | |||
| Fuel (Type) | Diesel4,7 | ||
| Octane | |||
| Quantity | 800 liters2 | ||
| Road consumption | |||
| Cross country consumption | |||
| Performance | |||
| Traverse | 360° | ||
| Max speed | 23 mph4, 24.8 mph3, 24.9 mph7 37 kph6, 40 kph3,7 |
37 kph2 | |
| Cross country speed | 15 mph | ||
| Road radius | 149 miles, 155 miles3,7 250 km3,7 130 - 240 km6 |
150 km2 | |
| Cross country radius | 110 - 125 km6 | ||
| 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 | |||
| Suspension (Type) | |||
| Wheels each side | |||
| Return rollers each side | |||
| Tracks (Type) | |||
| Length | |||
| Width | |||
| Diameter | |||
| Number of links | |||
| Pitch | |||
| Tire tread | |||
| Track centers/tread | |||
| Production | 1943: 100, 676 1944: 406 |
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
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