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Inf Tank Mk IV (Churchill 7 - VIII)
Ordnance classification - A22

Tweet The Inf Tank Mk IV was designed in 1943, manufactured by Vauxhall Motors based on the existing fully tracked Churchill and was in use from 1944 to 1945. General Details Specifications Operational Date(s) 1944 - 1945 Ordnance classification A22 Quantity Produced 1600 Weight 40 tonne Crew 5 M.G's small 2 M.G's large(>10mm) n/a Length 7.51 mtr Width 3.28 mtr Height 2.49 mtr Engine Details/Performance Max Road Speed 16 mph Max Cross Country Speed 8 mph Range Road 90 miles Range Cross Country 36 miles Fuel Type Petrol Fuel Capacity 190 gal Horse Power 350 hp Power/Weight 8 hp/tonne General Information The Inf Tank Mk IV was designed in 1943, manufactured by Vauxhall Motors based on the existing fully tracked Churchill and was in use from 1944 to 1945. The vehicle was powered by Bedford '350HP' petrol powerplant producing 350 HP which could drive the vehicle on roads at up to 16 mph with a range of about 90 miles before refuelling. Its cross country performance was adequate providing a max speed of about 8 mph and a range of about 36 miles. It was armed with 2 light machine guns. Its main armament consisted of an Ordnance Q.F. 75mm which could penetrate 114 mm of flat plate at 100 metres The Churchill Infantry tank was designed as a tank that could cope with movement through heavily shelled areas, and provide adequate protection for the crew. The vehicle was layed out in a similar way to the tanks from the First World War with the rear Bedford 350hp engine driving the tracks, to the front via small idlers to the fron main idler, then via 11small sprung road wheels. The first vehicles had many mechanical faults and hence many subsequent modifications. The MkVII this was a major redesign with a new turret firing the 75mm and redesigned hull and massively thicker armour than the MkVI. Armour Details Turret Front 88mm @ 0° (88mm) Side 76mm @ 0° (76mm) Rear 89mm @ 0° (89mm) Top 16mm @ 90° (16mm) Superstructure Front 88mm @ 20° (94mm) Side 76mm @ 0° (76mm) Rear 64mm @ 0° (64mm) Top 16mm @ 90° (16mm) Hull Front 38mm @ 70° (111mm) Side 76mm @ 0° (76mm) Rear 64mm @ 0° (64mm) Top 16mm @ 90° (16mm) Armour (x)mm @ (y)° (Effective mm @ 0°) Effective Armour - Maximum 111 mm - Minimum 16 mm Weapon Details Ordnance Q.F. 75mm (Tank Gun) History This was a temporary fix to the problem of 6pdr guns not having a powerful enough HE shell. It was created by boring out the British 57mm 6pdr to take the American 75mm AP/HE shells, which reduced the Anti Tank performance but provided HE support. Manufactured 1943 - 1945 Calibre 75mm Length L/32   Ammunition Details Name/Id Calibre Weight MVelocity Explosive Content AP M72 U.S. (AP Armor Piercing) 75mm 6.58Kg 618M/Sec Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.16 0.33 0.68 1.45 2.31 3.29 4.41 5.71 Penetration(mm@30°) 98 91 83 73 64 55 46 38 Penetration(mm@0°) 114 106 96 85 74 64 54 45 Hit Probability(%) 98 98 98 88 54 25 15 3 HE M48 (HE High Explosive) 75mm 6.76Kg 625M/Sec 0.680Kg explosive Maximum Range not shown as gun elevation is limited Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.16 0.33 0.68 1.43 2.29 3.25 4.36 5.65 Direct Fire Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.16 0.33 0.68 1.43 2.29 3.25 4.36 5.65 Hit Probability(%) 98 98 98 88 57 25 15 3 Blast/Fragmentation Effects Burst radius Infantry in open 99% kill 3 mtr Burst radius Infantry in open 66% kill 6 mtr Burst radius Infantry in open 33% kill 16 mtr  Armour Penetration inc roof at 1 mtr 2 mm An explosion within 3 mtr of infantry in the open will cause 99% casualties - lethal. An explosion within 6 mtr of infantry in the open will cause > 66% casualties and could damage some AFV's. An explosion within 16 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.

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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