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Great Britain's Light Tank Mark VII, A17, Purdah, PR, Tetrarch

Photos

Light Tank Mk VII, Tetrarch:
Great Britain's Light Tank Mk VII, Tetrarch
Light Tank Mk VII, Tetrarch:
Great Britain's Light Tank Mk VII, Tetrarch
Light Tank Mk VII, Tetrarch coming out of a Hamilcar glider:
Great Britain's Light Tank Mk VII, Tetrarch coming out of a Hamilcar glider
Light Tank Mk VII, Tetrarch coming out of a Hamilcar glider:
Great Britain's Light Tank Mk VII, Tetrarch coming out of a Hamilcar glider
Light Tank Mk VII, Tetrarch, with duplex drive:
Great Britain's Light Tank Mk VII, Tetrarch, with duplex drive

Design

Vickers created the Light Tank Mk VII as a private venture in 1937.5 The Light Tank Mk VII was adopted by the British Army in 1938.1,8 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.1,8

Originally called the Purdah or PR tank it was renamed Tetrarch in 1943.1,3,6,8,9

The hull did not extend over the tracks. Smoke discharges on each side of the turret. Some vehicles had a spare gas tank on top of the rear deck.

Crew

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.

The turret was in the center and could hold the commander and the loader.5

Suspension

The tracks were meant to be removed so that the tank could travel faster on roads. It used skid steering (developed by Leslie Little) which involved pivoting the wheels to make the tracks flex.1,3,6,9 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

Armament

The coaxial MG was fitted to the same mounting as the main armament and rotated and elevated with it.

Some vehicles were fitted with the Littlejohn adaptor to increase the muzzle velocity of the 2 pdr.1

Prototype

The Tetrarch's first prototype started trials in 19373,5 / 1938 and was produced by Vickers Armstrongs.1

Production

  • Tetrarch Mk I: 1771,3 , ~1809
    • Production: 1940 - 19491

Variants

  • Tetrarch Mk I:
  • Tetrarch Mk I CS: Had a 76.2 mm (3") howitzer installed for close support.5,9
  • 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
  • Light Tanks Mk VIII Harry Hopkins: The Harry Hopkins used the Tetrarch's design.5

Usage

In 1943 they were adopted for airborne use.6,9 The Hamilcar glider was designed for the Tetrarch.5,6,9

Some were sent to Russia through Lend-Lease.1,3,5,6,7,8,9

Africa

Used by 8th Army in Africa. They were found to overheat in the desert conditions.9

Used in the invasion of Madagascar in May 1942.3,5,6,7,9

Flown into Normandy

One squadron of the Airborne 6th Armored Reconnaissance Regiment was sent in by Hamilcar glider on June 6, 1944 with 6th Airborne Division at the River Orne.1,5,7

Over the Rhine

Used during Rhine crossing on Mar. 24, 1945.5,6,9

Specifications

  Mark VII Tetrarch
Crew Commander, gunner, driver.2
31,2,3,4,5,6,8,9
Physical Characteristics  
Weight 16,764 lb8, 16,800 lb2,5
7.5 tons1,3,4,6,9
7,620 kg1,5,6,8,9
Length w/gun 13' 6"1,2,3,4,6,9, 14' 1.5"5,8
4.11 m1,6,9, 4.305 m5,8
Length w/o gun 13' 6"5,8
4.115 m5,8
Height 6' 11"1,2,3,4, 6' 11.5" 5,6,8,9
2.1 m1, 2.12 m6,9, 2.121 m5,8
Width 7' 7"1,2,3,4,5,6,8,9
2.31 m1,5,6,8,9
Width over tracks  
Ground clearance  
Ground contact length  
Ground pressure  
Turret ring diameter  
Armament  
Main 1: 2 pdr QFSA2,6,9
1: 2 pdr1,3,4,5,8
Secondary  
MG 1: 7.92 mm Besa MG2
1: Besa MG4
MG - coaxial 1: 7.92 mm MG5
1: 7.92 mm Besa MG1,3,6,8
1: 7.92 mm / 0.312" Besa MG9
Side arms  
Quantity  
Main 502
Secondary  
MG 2,0252
Side arms  
Armor Thickness (mm) 42, 142,6,9, 163, 4 - 141, 4 - 164,8
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 MAT1,6,9, Meadows2,5,8
Bore / stroke  
Cooling  
Cylinders 122,5,6,8,9
Net HP 1652,5,6,8,9
Power to weight ratio  
Compression ratio  
Transmission (Type) 5 forward.
Steering Skid steering6
Steering ratio  
Starter  
Electrical system  
Ignition  
Fuel (Type) Gasoline6,8
Octane  
Capacity  
Road consumption  
Cross country consumption  
Performance  
Traverse 360°2
Speed - Road 37 mph3, 39.74 mph1, 40 mph2,5,6,8,9
64 kph1,5,6,8,9
Speed - Cross Country 28 mph2,5,8
45 kph5,8
Range - Road 139.73 miles1, 140 miles2,6,8,9
224 km8, 225 km1,6,9
Range - Cross Country  
Turning radius  
Elevation limits  
Fording depth 0.914 m5,8
3'2,5,8
Trench crossing 1.524 m5,8
5'2,5,8
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
  Mark VII Tetrarch CS
Crew  
Physical Characteristics  
Weight  
Length w/gun  
Length w/o gun  
Height  
Width  
Width over tracks  
Ground clearance  
Ground contact length  
Ground pressure  
Turret ring diameter  
Armament  
Main 1: 3" howitzer2,3,4,6
1: 76.2 mm5,6
Secondary  
MG  
Side arms  
Quantity  
Main  
Secondary  
MG  
Side arms  
Armor Thickness (mm)  
Hull Front, Upper  
Hull Front, Lower  
Hull Sides, Upper  
Hull Sides, Lower  
Hull Rear  
Hull Top  
Hull Bottom  
Turret Front  
Turret Sides  
Turret Rear  
Turret Top  
Engine (Make / Model)  
Bore / stroke  
Cooling  
Cylinders  
Net HP  
Power to weight ratio  
Compression ratio  
Transmission (Type)  
Steering  
Steering ratio  
Starter  
Electrical system  
Ignition  
Fuel (Type)  
Octane  
Capacity  
Road consumption  
Cross country consumption  
Performance  
Traverse  
Speed - Road  
Speed - Cross Country  
Range - Road  
Range - Cross Country  
Turning radius  
Elevation limits  
Fording depth  
Trench crossing  
Vertical obstacle  
Climbing ability  
Suspension (Type)  
Wheels each side  
Return rollers each side  
Tracks (Type)  
Length  
Width  
Diameter  
Number of links  
Pitch  
Tire tread  
Track centers/tread  

Sources:

  1. 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
  2. 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
  3. World War Two Tanks, George Forty, 1995
  4. Tanks of the World, 1915-1945, Peter Chamberlain, Chris Ellis, 1972
  5. The Encyclopedia of Weapons of World War II, Chris Bishop, 1998
  6. The Illustrated Guide to Tanks of the World, George Forty, 2006
  7. Tanks of World War II, Duncan Crow, 1979
  8. Armored Fighting Vehicles, 300 of the World's Greatest Military Vehicles, Philip Trewhitt, 1999
  9. World War I and II Tanks, George Forty, 2012
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