The IS I - 85, it was based on the IS chassis and was in use from 1944. General Details (Heavy Tank) Specifications Operational Date(s) 1944 Ordnance classification Quantity Produced 0 Weight unknown Crew 4 M.G's small 4 M.G's large(>10mm) n/a Length 8.40 mtr Width 3.15 mtr Height 2.74 mtr Engine Details/Performance Max Road Speed 23 mph Max Cross Country Speed 12 mph Range Road 150 miles Range Cross Country 130 miles Fuel Type Unknown Fuel Capacity 115 gal Horse Power 513 hp Power/Weight unknown General Information The IS I - 85, it was based on the IS chassis and was in use from 1944. It was armed with 4 light machine guns. Its main armament consisted of a 85 mm ZiS-S-53 M1939 L/55 weighing 9.540 kg. Armour Details Turret Front 100mm @ 10° (102mm) Side 75mm @ 10° (76mm) Rear 50mm @ 10° (51mm) Top 35mm @ 90° (35mm) Superstructure Front 120mm @ 45° (170mm) Side 90mm @ 30° (104mm) Rear 64mm @ 20° (68mm) Top 25mm @ 90° (25mm) Hull Front 120mm @ 45° (170mm) Side 90mm @ 0° (90mm) Rear 64mm @ 0° (64mm) Top 25mm @ 90° (25mm) Armour (x)mm @ (y)° (Effective mm @ 0°) Effective Armour - Maximum 170 mm - Minimum 25 mm Weapon Details 85 mm ZiS-S-53 M1939 L/55 (Tank Gun) History Developed from the 85 mm air defense gun M1939 (52-K) this was the heavier tank gun used in vehicles such as the T34/85 Manufactured 1939 - 1945 Calibre 85mm Length L/55 Rate of Fire 10 rpm Ammunition Details Name/Id Calibre Weight MVelocity Explosive Content 85mm/L52 (D-5T) (AP Armor Piercing) 85mm 9.2Kg 792M/Sec Quoted Penetration 125mm @ 500mtr/30° ( ? 144mm/0?) Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.26 0.52 1.08 1.68 2.31 2.97 3.67 Penetration(mm@30°) 114 111 106 96 86 78 70 63 Penetration(mm@0°) 133 129 123 111 100 91 82 74 Hit Probability(%) 98 98 95 88 68 55 37 15 85mm/L52 (D-5T) (APCR Armor Piercing Composite Rigid) 85mm 5.3Kg 1050M/Sec Quoted Penetration 136mm @ 500mtr/30° ( ? 157mm/0?) Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.1 0.19 0.39 0.8 1.23 1.69 2.16 2.65 Penetration(mm@30°) 144 141 136 126 117 108 100 92 Penetration(mm@0°) 167 164 158 146 135 125 116 107 Hit Probability(%) 98 98 98 95 88 68 55 37 85mm/L52 (D-5T) HE (HE High Explosive) 85mm 9.54Kg 793M/Sec 0.741Kg explosive Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.26 0.52 1.08 1.67 2.3 2.96 3.66 lateral dispersion means the side to side variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 80% of shells land within +/- (mtr) 95% of shells land within +/- (mtr) range dispersion means the back to front variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 80% of shells land within +/- (mtr) 95% of shells land within +/- (mtr) Direct Fire Range(Mtr) 100 200 400 800 Flight Time(Secs) 0.13 0.26 0.53 1.1 Hit Probability(%) 98 98 95 88 Blast/Fragmentation Effects Burst radius Infantry in open 99% kill 2 mtr Burst radius Infantry in open 66% kill 5 mtr Burst radius Infantry in open 33% kill 14 mtr  Armour Penetration inc roof at 1 mtr 2 mm An explosion within 2 mtr of infantry in the open will cause 99% casualties - lethal. An explosion within 5 mtr of infantry in the open will cause > 66% casualties and could damage some AFV's. An explosion within 14 mtr of infantry in the open will cause 33% casualties. The blast effect of this shell exploding within 1 mtr of an armoured vehicle will penetrate 2 mm of the tank armour including the roof. About Penetration Figures All penetration figures in this database are calculated to a common standard based on German WWII testing criteria (complete penetration with functioning fuze). This allows direct comparison between all nations' guns. Original national test figures would be higher for some nations due to different criteria: German: 1.00? (baseline - strictest) British: 1.02? (slightly looser) American: 1.05? (50% mass through plate) Soviet: 1.10? (75% mass through plate) For example, a Soviet gun showing 159mm here would be published as ~175mm in Soviet documents, and a German gun showing 120mm would be published as 120mm in German documents. The 159mm figure is directly comparable to the German 120mm - the Soviet gun really was more powerful. National Testing Standards German: 1.00? - Complete penetration, fuze functions (strictest) British: 1.02? - Complete penetration American: 1.05? - 50% of shell mass through plate Soviet: 1.10? - 75% of shell mass through plate All database figures are normalized to German standard for direct comparison. Multiply by the factor above to see original national test figures.

Hit probability is based on a static 2 x 2.4 metre panel at 0 degrees(vertical) at the range specified.

The data that has been used to create these records has come from Wikipedia, The Lone Sentry, The Bundes Archive and numerous books and websites that have provided the detailed information that has not been available anywhere else. The information we use to calculate the penetration tables, flight times and the hit probability comes from the Gun Calibre, the Shell Mass(Kg) and the muzzle velocity, plus range reductions to allow for gravity and wind resistance. This calculation originally came from a pre-war Krupp calculation which has been modified, and seems to fit the actual test results.

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