A 17 Light Tank Mark VII, Tetrarch
Tetrarch Duplex Drive
First prototype started trials in 1938 and was produced by Vickers Armstrongs.1 Was adopted by the British Army in 1938.1 Production started in 1940, but was halted due to the vulnerabilities of light tanks on the battle fields of Europe.1 Production started back up in 1941 when it was decided the vehicle could be used by the airborne forces.1
Originally called the Purdah8 or PR tank it was renamed Tetrarch in 1943.1
The tracks were meant to be removed so that the tank could travel faster on roads. It was supposed to be a fast reconnaissance tank. The coaxial MG was fitted to the same mounting as the main armament and rotated and elevated with it.
The hull did not extend over the tracks. There was a square box that covered the driver's head and shoulders. This could be swung open to allow the driver better visibility. No cupola for the commander and he also was the loader for the main gun. Smoke discharges on each side of the turret. Some vehicles had a spare gas tank on top of the rear deck.
It used skid steering8 (developed by Leslie Little) which involved pivoting the wheels to make the tracks flex.1,3 The center wheels would move in or out to bow the track. It was controlled by the steering wheel. However, if the driver needed a very sharp turn then he needed to also use 2 levers and apply the brakes.1
Some vehicles were fitted with the Littlejohn adaptor to increase the muzzle velocity of the 2 pdr.1
Some were sent to Russia.1,3,7,8
Used by 8th Army in Africa. Used in the invasion of Madagascar (May 1942).3,7,8
In 1943 they were adopted for airborne use.8 The Hamilcar glider was designed for the Tetrarch.8
One squadron of the Airborne 6th7 Armored Reconnaissance Regiment was sent in by Hamilcar glider on June 6, 1944 with 6th Airborne Division at the River Orne.1
Used during Rhine crossing8 on Mar. 24, 1945.
Tetrarch Mk I CS:
Had a 76.2 mm (3") howitzer installed for close support.
Tetrarch Mk I DD:
First to have the Duplex Drive system installed.7 Had the Straussler Duplex Drive fitted, and was tested at Brent Reservoir in June 1941.1 This lead to the fitting of the Sherman with Duplex Drive.1
| Mark VII Tetrarch | Mark VII Tetrarch CS | |
|---|---|---|
| Crew | Commander, gunner, driver.2 31,2,3,4,5,8 |
|
| Physical Characteristics | ||
| Weight | 16,800 lb2,5 6.8 tons6, 7.5 tons1,3,4,8 7,620 kg1,5,8 |
|
| Length w/gun | 13' 3", 13' 6"1,2,3,4,8, 14' 1.5"5 4.05 m6, 4.11 m1,8, 4.305 m5 |
|
| Length w/o gun | 13' 6"5 4.115 m5 |
|
| Height | 6' 11"1,2,3,4, 6' 11.5" 5,8 2.1 m1, 2.11 m6, 2.12 m8, 2.121 m5 |
|
| Width | 7' 7"1,2,3,4,5,8 2.31 m1,5,6,8 |
|
| Width over tracks | ||
| Ground clearance | ||
| Ground contact length | ||
| Ground pressure | ||
| Turret ring diameter | ||
| Armament | ||
| Main | 2 pdr QFSA2,8 2 pdr (40 mm)1,3,5 2 pdr4,6 |
3" howitzer2,3,4,8 76.2 mm5,8 |
| Secondary | ||
| MG | 7.92 mm Besa MG2,6, coaxial.1,3,8 Besa MG4 7.92 mm MG, coaxial.5 |
|
| Side arms | ||
| Quantity | ||
| Main | 502,6 |
|
| Secondary | ||
| MG | 2,0252 | |
| Side arms | ||
| Armor Thickness (mm) | 42, 142,8, 163,6 4 - 141 4 - 164 |
|
| Hull Front, Upper | 14 | |
| Hull Front, Lower | ||
| Hull Sides, Upper | ||
| Hull Sides, Lower | ||
| Hull Rear | ||
| Hull Top | ||
| Hull Bottom | 4 | |
| Turret Front | ||
| Turret Sides | ||
| Turret Rear | ||
| Turret Top | ||
| Engine (Make / Model) | Meadows MAT1,8
Meadows2,5 |
|
| Bore / stroke | ||
| Cooling | ||
| Cylinders | 122,5,8 | |
| Net HP | 1652,5,8 | |
| Power to weight ratio | ||
| Compression ratio | ||
| Transmission (Type) | 5 forward. | |
| Steering | Skid steering8 | |
| Steering ratio | ||
| Starter | ||
| Electrical system | ||
| Ignition | ||
| Fuel (Type) | Gasoline8 | |
| Octane | ||
| Capacity | ||
| Road consumption | ||
| Cross country consumption | ||
| Performance | ||
| Traverse | 360°2 | |
| Max speed | 37 mph3, 40 mph2,5,8, 39.74 mph1 25 kph6, 64 kph1,5,8 |
|
| Cross country speed | 28 mph2,5 45 kph5 |
|
| Road radius | 140 miles2,8, 139.73 miles1 225 km1,8 |
|
| Cross country radius | ||
| Turning radius | ||
| Elevation limits | ||
| Fording depth | 0.914 m5 3'2,5 |
|
| Trench crossing | 1.524 m5 5'2,5 |
|
| Vertical obstacle | 1' 8" | |
| Climbing ability | ||
| Suspension (Type) | Steerable steel road wheels independently sprung.2 | |
| Wheels each side | 4 | |
| Return rollers each side | ||
| Tracks (Type) | ||
| Length | ||
| Width | 9.5"2 | |
| Diameter | ||
| Number of links | ||
| Pitch | ||
| Tire tread | ||
| Track centers/tread | 6' 6"2 | |
| Production | 1773 1940-1949: 1771 |
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
- British and American Tanks of World War Two, The Complete Illustrated History of British, American, and Commonwealth Tanks 1933-1945, Peter Chamberlain and Chris Ellis, 1969
- World War Two Tanks, George Forty, 1995
- Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
- The Encyclopedia of Weapons of World War II, Chris Bishop, 1998
- Jane's World War II Tanks and Fighting Vehicles The Complete Guide, Leland Ness, 2002
- Tanks of World War II, Duncan Crow, 1979
- The Illustrated Guide to Tanks of the World, George Forty, 2006
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