M8 Howitzer Motor Carriage
Aberdeen Tank Museum
The prototype model was produced by Cadillac Motor Car Division of General Motors Corp on a M5 light tank chassis.1,3 The T-47 was tested at Aberdeen in early 1942.1
Hull was completely welded except for some of the front, top, and rear, which can be removed for maintenance.
Equipped HQ companies of medium tank battalions.
First use was in Italy in late 1943.1 Used in France extensively, and supplied to the Free French.1 Also used in the Pacific.
The 75 mm gun fired a 18 lb HE shell at a muzzle velocity of 1,250'/sec.3 The .50 cal MG fired at 2,900'/sec.3
M8:
Based on M5 chassis. Fitted with trailer hook for an ammo trailer.
M8A1:
Used M5A1 chassis.
Rate of fire for howitzer was 25 rounds/minute. Muzzle velocity of 1,250 ft/sec, range 9,610 yards
| M8 Howitzer Motor Carriage | |
|---|---|
| Crew | Commander, gunner, driver, co-driver2 41,2,3 |
| Physical Characteristics | |
| Weight | 33,000 lb3, 36,000 lb 15.446 tons1, 16.4 tons2 15,695 kg1 |
| Length w/gun | 14' 3"1, 14' 6.75"3 4.34 m1,2 |
| Length w/o gun | |
| Height | 7' 6.5"3, 7' 7"1 2.29 m2, 2.31 m1 |
| Width | 7' 4.25"3, 7' 5"1 2.24 m2, 2.26 m1 |
| Width over tracks | |
| Ground clearance | 6.5"3, 16.5" |
| Ground contact length | 120"3, 10' 1" |
| Ground pressure | 11.6 psi, 11.83 psi3 |
| Turret ring diameter | 54.5" |
| Armament | |
| Main | 75 mm M21 75 mm M2 or M3 howitzer2 M1A1 75 mm M2 or M3 75 mm Howitzer M33 |
| Secondary | |
| MG | 12.7 mm (.50 cal) MG1 .50 cal MG, AA2 M2 .50 cal AA .50 cal HBM2 MG, AA3 |
| Side arms | .45 cal submachine gun M1 .30 Carbines Grenades |
| Quantity | |
| Main | 461,2,3 |
| Secondary | |
| MG | 4003 |
| Side arms | 600 735 8 |
| Armor Thickness (mm) | (Actual thickness at horizontal) Front: 302 Side: 252 |
| Hull Front, Upper | 1.5"@0°3, 1 1/8" (2.5") |
| Hull Front, Lower | 1.75" (2.5") |
| Hull Sides, Upper | 1.125"@0°3, 1" (1 1/8") |
| Hull Sides, Lower | |
| Hull Rear | 1"@0°3 |
| Hull Top | 0.5" |
| Hull Bottom | 3/8-0.5" |
| Turret Front | 1.5"@0°3 |
| Turret Sides | 1"@0°3 |
| Turret Rear | 1" |
| Turret Top | 3/8" |
| Engine (Make / Model) | 2: Cadillac Series 421,3 |
| Bore / stroke | |
| Cooling | Water3 |
| Cylinders | 2 x V-83 |
| Capacity | |
| Net HP | 2202,3 |
| Power to weight ratio | |
| Compression ratio | |
| Transmission (Type) | Hydromatic3 6 forward, 1 reverse3 |
| Steering | Controlled differential3 |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Gasoline3 |
| Octane | |
| Quantity | 89 gallons3 |
| Road consumption | 2 mpg3 |
| Cross country consumption | |
| Performance | |
| Traverse | 360°3 Manual3 |
| Max speed | 36 mph1, 45 mph3 58 kph1, 60 kph2 |
| Cross country speed | 24 mph |
| Road radius | 100 miles1, 180 miles3 161 km1 |
| Cross country radius | |
| Turning radius | |
| Elevation limits | +40° to -20°2,3 |
| Fording depth | 2' 6"3, 3' |
| Trench crossing | 5' 4", 5' 5"3 |
| Vertical obstacle | 1' 6", 2'3 |
| Climbing ability | 30° slope3 |
| Suspension (Type) | Vertical volute Vertical volute springing3 |
| Wheels each side | 4 2 double wheel bogies3 |
| Return rollers each side | 23 |
| Tracks (Type) | Steel or rubber with rubber bushed track pins3 |
| Length | |
| Width | 11 5/8"3 |
| Diameter | |
| Number of links | 673 |
| Pitch | 5.5"3 |
| Tire tread | Rubber3 |
| Track centers/tread | 6' 1.5", 73"3 |
| Production | Cadillac Motor Car Division, GMC 9/1942-1/1944: 1,7781 1942: Cadillac Motor Car Co.3 |
Sources:
- 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
- Jane's World War II Tanks and Fighting Vehicles The Complete Guide, Leland Ness, 2002
- Tank Data 2, Aberdeen Proving Grounds Series, E. J. Hoffschmidt and W. H. Tantum IV, 1969
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