Post by son-of-tiny on Feb 22, 2007 22:55:22 GMT
Mark IV
An up-armoured version of the Mark I with all fuel stored in a single external tank (located between the rear track horns) in an attempt to improve crew safety. The sponsons could be pushed in to reduce the width of the tank for rail transportation. Rails on the roof carried an unditching beam. 1220 were built: 420 Males, 595 Females and 205 Tank Tenders which were supply tanks.
The director of the Tank Supply Department, Albert Gerald Stern, first intended to fit the Mark IV with a new engine and transmission. Production of battle tanks was halted until the new design was ready, necessitating the Mark II and III as interim training tanks. He failed however to complete development soon enough to start production in time to have 200 tanks ready for the promised date of 1 April 1917. He was ultimately forced to take a Mark IV in production in May 1917 that was only slightly different from the Mark I.
The Mark IV Male carried 4 Lewis machine guns as well as the two sponson guns (now with shorter barrels). The Female had six machine guns. Two of the machine guns were operated by the gun loaders.
Specs
Crew: 8
Combat Weight
Male: 28 tons (28.4 tonnes), Female: 27 tons (27.4 tonnes)
Armour: .25-.47 in (6.1 - 12 mm)
Armament
Two 6-pounders & Four .303 Lewis MG (Male), Six .303 Lewis MG (Female)
Ammo storage
6 pounder: 180 HE rounds and remainder Case
Mark V
The Mark V was first to be a completely new design. When however in December 1917 the desired new engine and transmission became available, this design was abandoned and the designation switched to an improved version of the Mark IV, in fact a Mark IV as it was originally intended: more power (150 bhp) with a new Ricardo engine, improved steering mechanism and epicyclical transmission, only one driver was needed. Cabin for machine-gunner on the roof. 400 were built, 200 each of Males and Females. Several were converted to Hermaphrodites by swapping sponsons to give a single 6 pounder gun for each.
Mark V*
Sir William Tritton in 1917 developed the Tadpole Tail: an extension of the tracks to be fitted to the back of a tank to improve trench crossing abilities. This was necessary because the Hindenburg Line had 3.5 metre wide trenches to stop the British tanks. When Major Philip Johnson of Central Tank Corps Workshops heard of this project, he immediately understood that the weight of the heavy girders strengthening the attachment might be put to a better use by creating a larger tank. He cut a Mark IV in half and stretched the hull, lengthening it by six feet. When details had been forgotten it has for a long time been assumed that most Mark V* had been field conversions made by Johnson. We now know that they were all factory-built. It had a larger 'turret' on the roof and doors in the side of the hull. The weight was 33 tons. 645 were built out of an order for 500 Males and 200 Females.
The extra section was also designed to house a squad of infantry. This was the first ever purpose designed tracked armoured personnel carrier (APC), it was also the first APC to be significantly armed, as some earlier conversions of tanks into supply carriers lacked any armament. It could operate as a tank as well as carrying troops, and it was not until the post WWII era Merkava that a tank that could also carry troops under protection was produced.
Mark V**
Because the Mark V* had been lengthened, its original length-width ratio had been spoiled. Lateral forces in a turn now became unacceptably high causing thrown tracks and an enormous turn circle. Therefore Major Wilson redesigned the track in May 1918, with a stronger curve reducing ground contact (but increasing ground pressure as a trade-off). An uprated 225 hp Ricardo engine was fitted. The cabin for the driver was combined with the roof cabin; there now was a separate machine gun position in the back. 197 were built out of an order for 750 Males and 150 Female
Mark V***
See: Mark X.
[ Mark VI
Main article: Mark VI (tank)
The Mark VI was a project with a gun in the front of a completely redesigned hull without sponsons. It did not progress past the stage of a wooden mock-up.
Mark VII
One of the Mark IIs used as test vehicles had had a hydraulic transmission. In October 1917 Brown Brothers in Edinburgh were granted a contract to develop this line of research further. In July 1918 the prototype was ready. Its drive system was very complex. The Ricardo engine drove into Variable Speed Gear pumps that in turn powered two (Williams-Janney)hydraulic motors, moving one track each by means of several chains. To ward off the obvious danger of overheating there were many fans, louvres and radiators. Steering was easy and gradual however and the version was taken into production to equip one tank battalion. Three were built out of an order for 74 when war ended. The hull was slightly lengthened in comparison with the Mark V. No Mark VIIs survive.
Mark VIII
Main article: Mark VIII (tank)
American involvement in the development of the tank design led to the Mark VIII, also known as 'Liberty' or Anglo-American tank (though initially the French were partially involved).
The engine was compartmentalised from the crew, and the turret structure included forward and rear firing machine guns. Of a planned (shared production) 1500 each, 24 were built by the British before they pulled out of the project and 100 completed by the Americans. The 100 were produced between September 1918 - 1920, at the Rock Island Arsenal, at a cost of $35,000 apiece ($430,000 in 2006).
They were used and upgraded up until the 1930s when given to Canada for training (as opposed to the M1917's which were sold at scrap value). The tank itself was over 34 feet long, and there had been an even longer 44 foot version planned but never made (the Mark VIII*). The tank was outdated by the 1930s due to its speed (under 6 mph) and armour (16 - 6 mm) but it did have one of the longest independent trench crossing capabilities of any AFV ever made. Modern MBT's and AFV's rely on bridge laying tanks for crossing large deep trenches.
Crew: 12 (later 10)
Weight 37 tons to 40 tons
Length/Height/Width : 34.16'/10.25'/12.33' (Mark VIII* length 44')
Engine: Ricardo 300 hp gasoline (UK), Liberty V12 340 hp (US)
Mark IX
Main article: Mark IX tank
The Mark IX was a troop carrier or infantry supply vehicle - among the first tracked Armoured personnel carrier not counting experiments with the lengthened Mk V's. 34 were built out of an order for 200.
Mark X
Paper only project to improve the Mark V, originally known as Mark V***. This was basically a contingency plan in case the Mark VIII project would fail (if so a production of 2000 was foreseen for 1919), trying to produce a tank with as many parts of the Mark V as possible but with improved manoeuvrability and crew comfort.
An up-armoured version of the Mark I with all fuel stored in a single external tank (located between the rear track horns) in an attempt to improve crew safety. The sponsons could be pushed in to reduce the width of the tank for rail transportation. Rails on the roof carried an unditching beam. 1220 were built: 420 Males, 595 Females and 205 Tank Tenders which were supply tanks.
The director of the Tank Supply Department, Albert Gerald Stern, first intended to fit the Mark IV with a new engine and transmission. Production of battle tanks was halted until the new design was ready, necessitating the Mark II and III as interim training tanks. He failed however to complete development soon enough to start production in time to have 200 tanks ready for the promised date of 1 April 1917. He was ultimately forced to take a Mark IV in production in May 1917 that was only slightly different from the Mark I.
The Mark IV Male carried 4 Lewis machine guns as well as the two sponson guns (now with shorter barrels). The Female had six machine guns. Two of the machine guns were operated by the gun loaders.
Specs
Crew: 8
Combat Weight
Male: 28 tons (28.4 tonnes), Female: 27 tons (27.4 tonnes)
Armour: .25-.47 in (6.1 - 12 mm)
Armament
Two 6-pounders & Four .303 Lewis MG (Male), Six .303 Lewis MG (Female)
Ammo storage
6 pounder: 180 HE rounds and remainder Case
Mark V
The Mark V was first to be a completely new design. When however in December 1917 the desired new engine and transmission became available, this design was abandoned and the designation switched to an improved version of the Mark IV, in fact a Mark IV as it was originally intended: more power (150 bhp) with a new Ricardo engine, improved steering mechanism and epicyclical transmission, only one driver was needed. Cabin for machine-gunner on the roof. 400 were built, 200 each of Males and Females. Several were converted to Hermaphrodites by swapping sponsons to give a single 6 pounder gun for each.
Mark V*
Sir William Tritton in 1917 developed the Tadpole Tail: an extension of the tracks to be fitted to the back of a tank to improve trench crossing abilities. This was necessary because the Hindenburg Line had 3.5 metre wide trenches to stop the British tanks. When Major Philip Johnson of Central Tank Corps Workshops heard of this project, he immediately understood that the weight of the heavy girders strengthening the attachment might be put to a better use by creating a larger tank. He cut a Mark IV in half and stretched the hull, lengthening it by six feet. When details had been forgotten it has for a long time been assumed that most Mark V* had been field conversions made by Johnson. We now know that they were all factory-built. It had a larger 'turret' on the roof and doors in the side of the hull. The weight was 33 tons. 645 were built out of an order for 500 Males and 200 Females.
The extra section was also designed to house a squad of infantry. This was the first ever purpose designed tracked armoured personnel carrier (APC), it was also the first APC to be significantly armed, as some earlier conversions of tanks into supply carriers lacked any armament. It could operate as a tank as well as carrying troops, and it was not until the post WWII era Merkava that a tank that could also carry troops under protection was produced.
Mark V**
Because the Mark V* had been lengthened, its original length-width ratio had been spoiled. Lateral forces in a turn now became unacceptably high causing thrown tracks and an enormous turn circle. Therefore Major Wilson redesigned the track in May 1918, with a stronger curve reducing ground contact (but increasing ground pressure as a trade-off). An uprated 225 hp Ricardo engine was fitted. The cabin for the driver was combined with the roof cabin; there now was a separate machine gun position in the back. 197 were built out of an order for 750 Males and 150 Female
Mark V***
See: Mark X.
[ Mark VI
Main article: Mark VI (tank)
The Mark VI was a project with a gun in the front of a completely redesigned hull without sponsons. It did not progress past the stage of a wooden mock-up.
Mark VII
One of the Mark IIs used as test vehicles had had a hydraulic transmission. In October 1917 Brown Brothers in Edinburgh were granted a contract to develop this line of research further. In July 1918 the prototype was ready. Its drive system was very complex. The Ricardo engine drove into Variable Speed Gear pumps that in turn powered two (Williams-Janney)hydraulic motors, moving one track each by means of several chains. To ward off the obvious danger of overheating there were many fans, louvres and radiators. Steering was easy and gradual however and the version was taken into production to equip one tank battalion. Three were built out of an order for 74 when war ended. The hull was slightly lengthened in comparison with the Mark V. No Mark VIIs survive.
Mark VIII
Main article: Mark VIII (tank)
American involvement in the development of the tank design led to the Mark VIII, also known as 'Liberty' or Anglo-American tank (though initially the French were partially involved).
The engine was compartmentalised from the crew, and the turret structure included forward and rear firing machine guns. Of a planned (shared production) 1500 each, 24 were built by the British before they pulled out of the project and 100 completed by the Americans. The 100 were produced between September 1918 - 1920, at the Rock Island Arsenal, at a cost of $35,000 apiece ($430,000 in 2006).
They were used and upgraded up until the 1930s when given to Canada for training (as opposed to the M1917's which were sold at scrap value). The tank itself was over 34 feet long, and there had been an even longer 44 foot version planned but never made (the Mark VIII*). The tank was outdated by the 1930s due to its speed (under 6 mph) and armour (16 - 6 mm) but it did have one of the longest independent trench crossing capabilities of any AFV ever made. Modern MBT's and AFV's rely on bridge laying tanks for crossing large deep trenches.
Crew: 12 (later 10)
Weight 37 tons to 40 tons
Length/Height/Width : 34.16'/10.25'/12.33' (Mark VIII* length 44')
Engine: Ricardo 300 hp gasoline (UK), Liberty V12 340 hp (US)
Mark IX
Main article: Mark IX tank
The Mark IX was a troop carrier or infantry supply vehicle - among the first tracked Armoured personnel carrier not counting experiments with the lengthened Mk V's. 34 were built out of an order for 200.
Mark X
Paper only project to improve the Mark V, originally known as Mark V***. This was basically a contingency plan in case the Mark VIII project would fail (if so a production of 2000 was foreseen for 1919), trying to produce a tank with as many parts of the Mark V as possible but with improved manoeuvrability and crew comfort.