After seeing that tanks with riveted construction were vulnerable it was decided to produce a welded tank.1
In September 1936, during maneuvers in Byelorussia, British General Wavell and Colonel Martel saw the tank.7 Martel wrote: "The design of the fighting body is not very good but the performance of the machine is at least twice as good as the A9."7 He further suggested that the British War Office purchase one.7
Had new Saslavsky brakes, new main clutch, new turret1, thicker armor1, and all welded1,10.2
The main gun was the 45 mm model 1934 / 45 mm Model 351 tank gun.2
In 1938 an improved gun sighting system, called TOS, was installed.2,6 This was developed by V. A. Pavlov and A. Z. Tumanov.6 The main armament could now better fire on the move.6
The engine was a copy of a German BMW aircraft engine.1
New engine with an improved gearbox with 3 forward gears.2,10 Used a control stick for steering.2
The first turrets for the BT-7 were the same cylindrical turret that was used on the BT-5.2 A conical turret was then used with MG in rear.1,2,10 It had round hatches on top which led to the nickname "Mickey Mouse" from German troops.2
Used by the 2nd Mechanized Brigade at Lake Hasan against the Japanese in 1938.9 The 6th and 11th Tank Brigades had 400 BT-7s and BT-5s, and fought against the Japanese at the Khalkin Gol River from May to August 1939.2,9
Used during the invasion of Poland in 1939 and in Finland in 1939-1940.1,2,7
The BT-7s broke down from the lack of maintenance, were lightly armored, and as a result would destroyed in large quantities by the Germans.5
| BT-7 (1936 model) | |
|---|---|
| Crew | 31,2,3,4,5,10 |
| Physical Characteristics | |
| Weight | 30,450 lb 13.68 tons1, 13.7 tons10, 13.8 tons2,4, 14 tons5 13,900 kg1,10 |
| Length w/gun | 18', 18' 7"1,10, 18' 8"3,7, 18.65'4, 20' 0.5" 5.68 m3, 5.66 m1,2,5,10, 6.8 m5 |
| Length w/o gun | |
| Height | 7' 6"3,7, 7.5'4, 7' 11"1,10, 7' 11.3"5, 8' 7" 2.28 m3, 2.41 m10, 2.42 m1,2,5 |
| Width | 7'3, , 7' 6"1,5, 7' 11.5"10, 7.98'4, 8'7, 8' 7" 2.29 m1,2,5, 2.43 m3,10 |
| Width over tracks | |
| Ground clearance | 1' 2", 4-4.2 m2 |
| Ground contact length | |
| Ground pressure | 11.24 psi, 0.75 kp/cm2 2 |
| Turret ring diameter | |
| Armament | |
| Main | 45 mm4,5,10 45 mm M-323 45 mm 19342 45 mm 1934 L/46, 45 mm1 45 mm Model 351 |
| OR | |
| Secondary | |
| MG | 2: MG4 2: 7.62 mm DT MG3,10 2: 7.62 mm MG1,5 |
| MG - coaxial | 7.62 mm MG2 |
| MG - rear turret | |
| MG - hull | 7.62 mm MG2 |
| Side arms | |
| Quantity | |
| Main | 132 - 1882, 1461 |
| Secondary | |
| MG | 2,3942 |
| Side arms | |
| Armor Thickness (mm) | 10 - 225, 6 - 223,4, 227,10 Turret: 157 |
| Hull Front, Upper | 13- 22, 222 |
| Hull Front, Lower | 13, 222 |
| Hull Sides, Upper | 132 |
| Hull Sides, Lower | 132 |
| Hull Rear | 132 |
| Hull Top | 102 |
| Hull Bottom | 12, 6-102 |
| Turret Front | 152 |
| Turret Sides | 152 |
| Turret Rear | 152 |
| Turret Top | 10, 152 |
| Engine (Make / Model) | M-15 T2,3,10 M-17T2,5,7 |
| Bore / stroke | 4 stroke2 |
| Cooling | |
| Cylinders | 122, V-125,10 |
| Capacity | |
| Net HP | 4504,7,10, 405@1,750 rpm2, 5005 |
| Power to weight ratio | 32.6 hp/ton2 |
| Compression ratio | |
| Transmission (Type) | 3 forward, 1 reverse2 |
| Steering | |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Gasoline4,5,10 |
| Octane | |
| Quantity | 167 gallons, 790 liters2 |
| Road consumption | |
| Cross country consumption | |
| Performance | |
| Traverse | 360° |
| Max speed | 53.4 mph3,5, 46 mph, 45 mph1,4 72 kph1, 86 kph3,5 |
| Max speed - tracks | 33 mph7, 45 mph10 53 kph2, 72 kph10 |
| Max speed - wheels | 45 mph7, 70 mph10, 73 kph2, 112 kph10 |
| Speed - Cross Country | 31 mph |
| Cross country speed - tracks | |
| Range - Road | 155 miles3,5, 311 miles, 265 miles1 250 km3,5, 430 km1 |
| Road radius - tracks | 249 miles10, 375 km2, 400 km10 |
| Road radius - wheels | 311 miles10, 500 km2,10 |
| Range - Cross Country | |
| Cross country radius - tracks | |
| Turning radius | 20' 6" |
| Elevation limits | |
| Fording depth | 4'5 1.2 m2, 1.22 m5 |
| Trench crossing | 6'5, 6' 7", 1.83 m5, 2 m2 |
| Vertical obstacle | 1' 10", 2' 6"5, 0.55 m2, 0.76 m5 |
| Climbing ability | 32°2 |
| Suspension (Type) | Christie |
| Wheels each side | 4 |
| Return rollers each side | |
| Tracks (Type) | |
| Length | |
| Width | 10" |
| Width - tire | |
| Width - track | |
| Diameter | |
| Number of links | |
| Pitch | |
| Tire tread | |
| Track centers/tread |
| BT-7-1 | BT-7-1V | |
|---|---|---|
| Crew | 36,8 | 38 |
| Physical Characteristics | ||
| Weight | 13.8 tons6,8 | 13.6 tons8 |
| Length w/gun | 18.656,8 | 18.658 |
| Length w/o gun | ||
| Height | 7.5'6,8 | 7.5'8 |
| Width | 7.986,8 | 7.988 |
| Width over tracks | ||
| Ground clearance | Wheels: 10.5"8 Tracks: 12"8 |
Wheels: 10.5"8 Tracks: 12"8 |
| Ground contact length | 12'6,8 | 12'8 |
| Ground pressure | 10.2 psi8 | 10.2 psi8 |
| Turret ring diameter | ||
| Armament | ||
| Main | 45 mm L/468 45 mm L/46 A/TK6 |
45 mm L/468 |
| OR | ||
| Secondary | ||
| MG | 2: 7.62 mm MG6 2: 7.62 mm DTMG8 |
2: 7.62 mm DTMG8 |
| MG - coaxial | ||
| MG - rear turret | ||
| MG - hull | ||
| Side arms | ||
| Quantity | ||
| Main | 1728, 172 - 1886 | 1888 |
| Secondary | ||
| MG | 2,3946,8 | 2,3948 |
| Side arms | ||
| Armor Thickness (mm) | 15 - 206 | |
| Hull Front, Upper | 226,8 | 228 |
| Hull Front, Lower | ||
| Hull Sides, Upper | 136,8 | 138 |
| Hull Sides, Lower | ||
| Hull Rear | 138 | 138 |
| Hull Top | 6 - 106,8 | 6 - 108 |
| Hull Bottom | 6 - 106,8 | 6 - 108 |
| Turret Front | 10 - 136, 138 | 138 |
| Turret Sides | 138 | 138 |
| Turret Rear | 138 | 138 |
| Turret Top | 108 | 108 |
| Engine (Make / Model) | M-17T Liberty6 MT-17T Liberty modified Aero8 |
MT-17T Liberty modified Aero8 |
| Bore / stroke | 120 mm8 / 146 mm8 | 120 mm8 / 146 mm8 |
| Cooling | Water8 | Water8 |
| Cylinders | 126, V-128 | V-128 |
| Capacity | ||
| Net HP | 4506, 450@1,750 rpm8 | 450@1,750 rpm8 |
| Power to weight ratio | 32.6 hp/ton8 | 32.6 hp/ton8 |
| Compression ratio | ||
| Transmission (Type) | Wheels: Chain drive8 Tracks: Sliding gear8 |
Wheels: Chain drive8 Tracks: Sliding gear8 |
| Steering | ||
| Steering ratio | ||
| Starter | ||
| Electrical system | ||
| Ignition | ||
| Fuel (Type) | Gasoline6,8 | Gasoline8 |
| Octane | ||
| Quantity | 174 gallons8 | 174 gallons8 |
| Road consumption | ||
| Cross country consumption | ||
| Performance | ||
| Traverse | 360°8 | 360°8 |
| Max speed | 46 mph6 | |
| Max speed - tracks | ||
| Max speed - wheels | 45.6 mph8 | 45.6 mph8 |
| Speed - Cross Country | ||
| Cross country speed - tracks | 33 mph8 | 33 mph8 |
| Range - Road | 310 miles6 | |
| Road radius - tracks | ||
| Road radius - wheels | 310 miles8 | 310 miles8 |
| Range - Cross Country | 220 miles6 | |
| Cross country radius - tracks | 220 miles8 | 220 miles8 |
| Turning radius | 40'8 | 40'8 |
| Elevation limits | -4° to +40°8 | -4° to +40°8 |
| Fording depth | 3.98'8 | 3.98'8 |
| Trench crossing | 6'8 | 6'8 |
| Vertical obstacle | Wheels: 8"8 Tracks: 30"8 |
Wheels: 8"8 Tracks: 30"8 |
| Climbing ability | ||
| Suspension (Type) | Christie Independent type8 | Christie Independent type8 |
| Wheels each side | 48 | 48 |
| Return rollers each side | ||
| Tracks (Type) | ||
| Length | ||
| Width | ||
| Width - tire | 2 x 3.95"8 | 2 x 3.95"8 |
| Width - track | 10.25"6,8 | 10.25"8 |
| Diameter | 32.5"8 | 32.5"8 |
| Number of links | ||
| Pitch | ||
| Tire tread | ||
| Track centers/tread | 6.33'8 | 6.33'8 |
| BT-7-2 | |
|---|---|
| Crew | 36,8 |
| Physical Characteristics | |
| Weight | 13.68 tons1, 13.8 tons6,8 13,900 kg1 |
| Length w/gun | 18.65'6,8, 18' 7"1 5.66 m1 |
| Length w/o gun | |
| Height | 7.5'6,8, 7' 11"1 2.42 m1 |
| Width | 7' 6"1, 7.98'6,8 2.29 m1 |
| Width over tracks | |
| Ground clearance | Wheels: 10.5"8 Tracks: 12"8 |
| Ground contact length | 12'6,8 |
| Ground pressure | 10.2 psi8 |
| Turret ring diameter | |
| Armament | |
| Main | 45 mm L/468 45 mm L/46 A/TK6 |
| OR | |
| Secondary | |
| MG | 2: 7.62 mm MG6 2: 7.62 mm DTMG8 |
| MG - coaxial | |
| MG - rear turret | |
| MG - hull | |
| Side arms | |
| Quantity | |
| Main | 132 - 1466 With radio: 1468 Without radio: 1888 |
| Secondary | |
| MG | 2,3946,8 |
| Side arms | |
| Armor Thickness (mm) | 6 - 221 |
| Hull Front, Upper | 226,8 |
| Hull Front, Lower | |
| Hull Sides, Upper | 136,8 |
| Hull Sides, Lower | |
| Hull Rear | 138 |
| Hull Top | 6 - 106,8 |
| Hull Bottom | 6 - 106,8 |
| Turret Front | 10 - 136, 158 |
| Turret Sides | 158 |
| Turret Rear | 158 |
| Turret Top | 108 |
| Engine (Make / Model) | M-17T Liberty6 MT-17T Liberty modified Aero8 M17-TV-121 |
| Bore / stroke | 120 mm8 / 146 mm8 |
| Cooling | Water8 |
| Cylinders | 126, V-128 |
| Capacity | |
| Net HP | 4506, 450@1,750 rpm8, 500@1,760 rpm1 |
| Power to weight ratio | 32.6 hp/ton8 |
| Compression ratio | |
| Transmission (Type) | Wheels: Chain drive8 Tracks: Sliding gear8 |
| Steering | |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Gasoline6,8 |
| Octane | |
| Quantity | 174 gallons8 |
| Road consumption | |
| Cross country consumption | |
| Performance | |
| Traverse | 360°8 |
| Max speed | 45 mph1, 46 mph6 72 kph1 |
| Max speed - tracks | |
| Max speed - wheels | 45.6 mph8 |
| Speed - Cross Country | 31 mph1 50 kph1 |
| Cross country speed - tracks | 33 mph8 |
| Range - Road | 265 miles1, 310 miles6 430 km1 |
| Road radius - tracks | |
| Road radius - wheels | 310 miles8 |
| Range - Cross Country | 220 miles6 |
| Cross country radius - tracks | 220 miles8 |
| Turning radius | 40'8 |
| Elevation limits | -4° to +40°8 |
| Fording depth | 3.98'8 |
| Trench crossing | 6'8 |
| Vertical obstacle | Wheels: 8"8 Tracks: 30"8 |
| Climbing ability | |
| Suspension (Type) | Christie Independent type8 |
| Wheels each side | 48 |
| Return rollers each side | |
| Tracks (Type) | |
| Length | |
| Width | |
| Width - tire | 2 x 3.95"8 |
| Width - track | 10.25"6,8 |
| Diameter | 32.5"8 |
| Number of links | |
| Pitch | |
| Tire tread | |
| Track centers/tread | 6.33'8 |
| BT-7A | |
|---|---|
| Crew | 36,8 |
| Physical Characteristics | |
| Weight | 13.8 tons6,8 |
| Length w/gun | 18'6, 18.658 |
| Length w/o gun | |
| Height | 7.5'6,8 |
| Width | 7.986,8 |
| Width over tracks | |
| Ground clearance | 12"8 |
| Ground contact length | 12'8, 12' 6"6 |
| Ground pressure | 10.2 psi8 |
| Turret ring diameter | |
| Armament | |
| Main | 76.2 mm L/16.56,8 76.2 mm1 |
| OR | |
| Secondary | |
| MG | 2: 7.62 mm MG6 7.62 mm DTMG8 |
| MG - coaxial | |
| MG - rear turret | |
| MG - hull | |
| Side arms | |
| Quantity | |
| Main | 501, 1328, 172 - 1886 |
| Secondary | |
| MG | 2,3946,8 |
| Side arms | |
| Armor Thickness (mm) | |
| Hull Front, Upper | 226,8 |
| Hull Front, Lower | |
| Hull Sides, Upper | 136,8 |
| Hull Sides, Lower | |
| Hull Rear | 138 |
| Hull Top | 6 - 106,8 |
| Hull Bottom | 6 - 106,8 |
| Turret Front | 10 - 136, 158 |
| Turret Sides | 158 |
| Turret Rear | 158 |
| Turret Top | 108 |
| Engine (Make / Model) | M-17T Liberty6, MT-17T Liberty modified Aero8 |
| Bore / stroke | 120 mm8 / 146 mm8 |
| Cooling | Water8 |
| Cylinders | 126, V-128 |
| Capacity | |
| Net HP | 4506, 450@1,750 rpm8 |
| Power to weight ratio | 32.6 hp/ton8 |
| Compression ratio | |
| Transmission (Type) | Wheels: Chain drive8 Tracks: Sliding gear8 |
| Steering | |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Gasoline6,8 |
| Octane | |
| Quantity | 174 gallons8 |
| Road consumption | |
| Cross country consumption | |
| Performance | |
| Traverse | 360°8 |
| Max speed | 40 mph8, 46 mph6 |
| Max speed - tracks | |
| Max speed - wheels | |
| Speed - Cross Country | 33 mph8 |
| Cross country speed - tracks | |
| Range - Road | 280 miles8, 310 miles6 |
| Road radius - tracks | |
| Road radius - wheels | |
| Range - Cross Country | 220 miles6,8 |
| Cross country radius - tracks | |
| Turning radius | 40'8 |
| Elevation limits | -4° to +60°8 |
| Fording depth | 3.98'8 |
| Trench crossing | 6'8 |
| Vertical obstacle | 30"8 |
| Climbing ability | |
| Suspension (Type) | Christie Independent type8 |
| Wheels each side | 48 |
| Return rollers each side | |
| Tracks (Type) | |
| Length | |
| Width | |
| Width - tire | 2 x 3.95"8 |
| Width - track | 10.25"6,8 |
| Diameter | 32.5"8 |
| Number of links | |
| Pitch | |
| Tire tread | |
| Track centers/tread | 6.33'8 |
| BT-7M (1939 model), BT-8 | |
|---|---|
| Crew | 32,6,8 |
| Physical Characteristics | |
| Weight | 32,300 lb, 14.4 tons1, 14.4-14.5 tons2, 14.6 tons7, 14.65 tons2,6,8 14,650 kg1 |
| Length w/gun | 18.65'6,8, 20'1, 20' 0.5" 5.66 m2, 6.11 m1 |
| Length w/o gun | |
| Height | 7.5'6,8, 8'1, 8' 0.75", 2.42 m2, 2.46 m1 |
| Width | 7.98'6,8, 8' 7", 2.29 m2 |
| Width over tracks | |
| Ground clearance | 0.35 m2 Wheels: 10.5"8 Tracks: 12"8 |
| Ground contact length | 12'6,8 |
| Ground pressure | 10.4 psi8 0.78 kp/cm2 2 |
| Turret ring diameter | |
| Armament | |
| Main | 45 mm Model 381 76.2 mm5 76.2 mm2 76.2 mm L/266,8 |
| OR | 45 mm 19382 |
| Secondary | |
| MG | 2: 7.62 mm MG6 |
| MG - coaxial | 7.62 mm DT MG2 |
| MG - rear turret | 7.62 mm DT MG2 |
| MG - hull | 7.62 mm DT MG2 |
| Side arms | |
| Quantity | |
| Main | 406,8 |
| Secondary | |
| MG | 2,3942,6 |
| Side arms | |
| Armor Thickness (mm) | |
| Hull Front, Upper | 222,6,8, 30 |
| Hull Front, Lower | 222 |
| Hull Sides, Upper | 132,6,8 |
| Hull Sides, Lower | 132 |
| Hull Rear | 6 - 106, 132,8 |
| Hull Top | 6 - 106,8, 102 |
| Hull Bottom | 6-102,6,8 |
| Turret Front | 10 - 156, 152,8 |
| Turret Sides | 152,8 |
| Turret Rear | 152,8 |
| Turret Top | 108, 152 |
| Engine (Make / Model) | W-22 V-26,8 |
| Bore / stroke | 150 mm8 / 187.7 mm8 4 stroke2 |
| Cooling | Water1,8 |
| Cylinders | 126, V-121,2,8 |
| Capacity | |
| Net HP | 5002,6, 500@2,200 rpm8 |
| Power to weight ratio | 34.7 hp/ton2, 35 hp/ton8 |
| Compression ratio | |
| Transmission (Type) | Wheels: Chain drive8 Tracks: Sliding gear8 |
| Steering | |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Diesel1,6,8 |
| Octane | |
| Quantity | 174 gallons8 |
| Road consumption | |
| Cross country consumption | |
| Performance | |
| Traverse | 360° |
| Max speed | 40 mph, 53.4 mph1, 54 mph6 86 kph1 |
| Max speed - tracks | 62 kpm2 |
| Max speed - wheels | 54 mph8 86 kph2 |
| Speed - Cross Country | 31 mph1, 39 mph8 50 kph1 |
| Cross country speed - tracks | |
| Range - Road | 435 miles, 440 miles6 |
| Road radius - tracks | 600 km2 |
| Road radius - wheels | 440 miles8, 700 km2 |
| Range - Cross Country | 375 miles6 |
| Cross country radius - tracks | 375 miles8 |
| Turning radius | 40'8 |
| Elevation limits | -10° to +40°8 |
| Fording depth | 3.25'8 1.2 m2 |
| Trench crossing | 6.85'8 2 m2 |
| Vertical obstacle | 0.55 m2 Wheels: 8"8 Tracks: 308 |
| Climbing ability | 32°2 |
| Suspension (Type) | |
| Wheels each side | |
| Return rollers each side | |
| Tracks (Type) | |
| Length | |
| Width | |
| Width - tire | 2 x 3.95"8 |
| Width - track | 10.25"6,8 |
| Diameter | 32.5"8 |
| Number of links | |
| Pitch | |
| Tire tread | |
| Track centers/tread | 6.338 |
| BT-IS | |
|---|---|
| Crew | 31,8 |
| Physical Characteristics | |
| Weight | 15.35 tons1, 15.6 tons8 15,600 kg1 |
| Length w/gun | 18' 11"1, 18.98'8 5.76 m1 |
| Length w/o gun | |
| Height | 7' 6"1,8 2.28 m1 |
| Width | 7' 6"1,8 2.28 m1 |
| Width over tracks | |
| Ground clearance | Wheels: 10.5"8 Tracks: 12"8 |
| Ground contact length | 12'8 |
| Ground pressure | 11 psi8 |
| Turret ring diameter | |
| Armament | |
| Main | 45 mm1 45 mm L/468 |
| OR | |
| Secondary | |
| MG | 2: 7.62 mm DTMG8 |
| MG - coaxial | |
| MG - rear turret | |
| MG - hull | |
| Side arms | |
| Quantity | |
| Main | 1328 |
| Secondary | |
| MG | 2,3948 |
| Side arms | |
| Armor Thickness (mm) | 301 |
| Hull Front, Upper | 308 |
| Hull Front, Lower | |
| Hull Sides, Upper | 158 |
| Hull Sides, Lower | |
| Hull Rear | 138 |
| Hull Top | 6 - 108 |
| Hull Bottom | 6 - 108 |
| Turret Front | 308 |
| Turret Sides | 208 |
| Turret Rear | 158 |
| Turret Top | 108 |
| Engine (Make / Model) | M17-T-V-121 V-28 |
| Bore / stroke | 150 mm8 / 187.7 mm8 |
| Cooling | Water8 |
| Cylinders | V-128 |
| Capacity | |
| Net HP | 5001, 500@2,200 rpm8 |
| Power to weight ratio | 32 hp/ton8 |
| Compression ratio | |
| Transmission (Type) | Wheels: Chain drive8 Tracks: Sliding gear8 |
| Steering | |
| Steering ratio | |
| Starter | |
| Electrical system | |
| Ignition | |
| Fuel (Type) | Diesel8 |
| Octane | |
| Quantity | 174 gallons8 |
| Road consumption | |
| Cross country consumption | |
| Performance | |
| Traverse | 360°8 |
| Max speed | 40 mph1 65 kph1 |
| Max speed - tracks | |
| Max speed - wheels | 70 mph8 |
| Speed - Cross Country | |
| Cross country speed - tracks | 40 mph8 |
| Range - Road | 250 miles1 400 km1 |
| Road radius - tracks | |
| Road radius - wheels | 430 miles8 |
| Range - Cross Country | |
| Cross country radius - tracks | 370 miles8 |
| Turning radius | 40'8 |
| Elevation limits | -10° to +40°8 |
| Fording depth | 3.25'8 |
| Trench crossing | 6.85'8 |
| Vertical obstacle | Wheels: 8"8 Tracks: 30"8 |
| Climbing ability | |
| Suspension (Type) | Christie Independent type8 |
| Wheels each side | 48 |
| Return rollers each side | |
| Tracks (Type) | |
| Length | |
| Width | |
| Width - tire | 2 x 3.95"8 |
| Width - track | 10.25"8 |
| Diameter | 32.5"8 |
| Number of links | |
| Pitch | |
| Tire tread | |
| Track centers/tread | 6.33'8 |
Sources: