The Humber Armoured Car Mk IV was an Armoured Car designed in 1938, manufactured by Rootes Motors, it was based on the 4 x 4 drive Humber Mk 1 chassis and was in use from 1939 to 1945. General Details (Armoured Car) Specifications Operational Date(s) 1939 - 1945 Quantity Produced 2000 Weight 5.2 tonne Crew 3 M.G's small 1 M.G's large(>10mm) 1 Length 4.15 mtr Width 2.08 mtr Height 2.31 mtr Engine Details/Performance Max Road Speed 40 mph Max Cross Country Speed 20 mph Range Road 220 miles Range Cross Country 99 miles Fuel Type Petrol Fuel Capacity unknown Horse Power 90 hp Power/Weight 17 hp/tonne General Information The Humber Armoured Car Mk IV was an Armoured Car designed in 1938, manufactured by Rootes Motors, it was based on the 4 x 4 drive Humber Mk 1 chassis and was in use from 1939 to 1945. The vehicle was powered by Rootes '6 cylinder' petrol powerplant producing 90 HP which could drive the vehicle on roads at up to 40 mph with a range of about 220 miles before refuelling. Its cross country performance was good providing a max speed of about 20 mph and a range of about 99 miles. It was armed with 1 light machine gun , a BESA Machine Gun 7.92mm. and 1 large machine gun. Its main armament consisted of a 37mm Antitank Gun M6 weighing 0.730 kg and with a maximum range of 3,000 metres. This was the standard Humber Armoured car but with the Besa 15mm machine gun replaced by the US M5 or M6 37 mm gun. Armour Details Turret Front 14mm @ 20° (15mm) Side 14mm @ 20° (15mm) Rear 14mm @ 0° (14mm) Top 10mm @ 90° (10mm) Superstructure Front 14mm @ 40° (18mm) Side 14mm @ 15° (14mm) Rear 14mm @ 60° (28mm) Top 10mm @ 90° (10mm) Hull Front 14mm @ 40° (18mm) Side 14mm @ 15° (14mm) Rear 14mm @ 30° (16mm) Top 10mm @ 90° (10mm) Armour (x)mm @ (y)° (Effective mm @ 0°) Effective Armour - Maximum 28 mm - Minimum 10 mm Weapon Details 37mm Antitank Gun M6 (Anti Tank Gun) History This was the Tank mounted version of the 37mm M3 Manufacturer Watervliet Arsenal Calibre 37mm Number of Rounds  40 Ammunition Details Name/Id Calibre Weight MVelocity Explosive Content AP M74 Shot (AP Armor Piercing) 37mm 0.86Kg 885M/Sec Quoted Penetration 36mm @ 500mtr/0° Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.12 0.23 0.49 1.04 1.65 2.32 3.05 3.83 Penetration(mm@30°) 60 57 51 42 34 27 22 18 Penetration(mm@0°) 70 67 60 49 39 32 26 21 Hit Probability(%) 79 79 79 71 55 44 20 12 HE M63 Shell (HE High Explosive) 37mm 0.73Kg 792M/Sec 0.039Kg explosive Maximum Range not shown as gun elevation is limited Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.26 0.55 1.17 1.88 2.65 3.5 4.4 lateral dispersion means the side to side variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 0.12 0.12 0.12 0.21 0.32 0.43 0.53 0.64 80% of shells land within +/- (mtr) 0.15 0.15 0.15 0.27 0.41 0.55 0.68 0.82 95% of shells land within +/- (mtr) 0.24 0.24 0.24 0.41 0.63 0.84 1.04 1.25 range dispersion means the back to front variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 0.15 0.15 0.15 0.27 0.40 0.53 0.67 0.80 80% of shells land within +/- (mtr) 0.19 0.19 0.19 0.35 0.51 0.68 0.86 1.02 95% of shells land within +/- (mtr) 0.29 0.29 0.29 0.53 0.78 1.04 1.31 1.57 Direct Fire Range(Mtr) 100 200 400 800 1200 1600 2000 Flight Time(Secs) 0.13 0.27 0.56 1.23 1.99 2.84 3.77 Hit Probability(%) 79 79 76 71 55 30 12 Blast/Fragmentation Effects Burst radius Infantry in open 99% kill 0 mtr Burst radius Infantry in open 66% kill 1 mtr Burst radius Infantry in open 33% kill 3 mtr  Armour Penetration inc roof at 1 mtr 0 mm An explosion within 1 mtr of infantry in the open will cause > 66% casualties and could damage some AFV's. An explosion within 3 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 not cause any significant armour damage. Weapon Details BESA Machine Gun 7.92mm (Machine Gun) History Developed by BSA from the Czechoslovak ZB vz.53 heavy machine gun which used the German 7.92×57mm Mauser ammunition. It was mostly used as the main armament of the Light Tank Mk VIC and Armoured cars such as the Humber Mk I to Mk III. This 7.92mm gun was used in the armoured divisions as their supply lines were separated from the infantry who used .303 bullets. Once the British started capturing German ammunition this could be immediately used in these tank machine guns. Manufactured 1939 - 1966 Calibre 7.92mm Length L/93 Rate of Fire 450 rpm Number of Rounds  2000 Ammunition Details Name/Id Calibre Weight MVelocity Explosive Content Cartridge SA, 7.92 (AP Standard Small Arms) 7.92mm 0.011Kg 785M/Sec Quoted Penetration 11mm @ 1000mtr/0° Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.25 0.51 Penetration(mm@30°) 6 5 4 Penetration(mm@0°) 8 7 5 Hit Probability(%) 74 74 72 Cartridge SA, 7.92 (BALL Standard Small Arms) 7.92mm 0.012Kg 785M/Sec Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 Penetration(mm@30°) 1 Penetration(mm@0°) 2 Hit Probability(%) 74 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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