Chieftain Tank Development

Abraham Gubler

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Here are a few pictures of the British Army development of the Chieftan tank. The first was the original concept for the Leyland FV4201 medium tank to replace the Centurion when Conqueror production was due to end in 1957. Then there is the '40 ton Centurion' FV4202 to prove the reclined driver's position and also with a turret sans mantlet. Then of course the first Chieftan mockups which looked quite nice without all the boxes that covered it in production.
 

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JFC Fuller

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Does anybody have any information / details about the L11A4 105mm that was developed for the Chieftain??? Apparently it had an autoloader in an effort to reduce crew size and speed up engagement time but, perhaps inevitably, never worked.

As a side note, an external gun was considered in the early design stages for the Chieftain but never got off paper.
 

red admiral

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sealordlawrence said:
Does anybody have any information / details about the L11A4 105mm that was developed for the Chieftain???
"Cheiftain" by Rob Griffin has quite a lot of information in it, but little mention of an automatic 105mm gun. First mention is of initial design work being carried out around the US 105mm gun in the early 1950s. By the mid 1950s there was a 105mm gun with a bagged charge à la 120mm L11. Some comments that the 120mm L11 would have been interchangeable with the US 90mm smoothbore on the T95.

There's also a section on AFVs in "Cold War, Hot Science" by Richard Ogorkiewicz which is very detailed, but no mention of a 105mm L11A4. There is mention of the 110mm EXP-7 which had brass cartridges and was interchangeable with the 105mm L7. Then there was a 110mm EXP-14 with semicombustible cartridges. Things moved on to the 120mm M7, then redesigned into the 120mm M13A with one piece cartridges that came a close second to the Rheinmetall 120mm L/44 in competition for arming the M-1.

External gun doesn't seem to have been for Cheiftain, but was from around the same time period for a much smaller and lighter tank - even some one-man tank designs with 2x120mm recoilless guns.
 

JFC Fuller

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Red Admiral,

Thank you for the reply, having double checked my notes I realise that the L11A4 was actually a 120mm (not one of my finer moments! :-[). I have a copy of Cold War Hot Science and I must say that it is an outstanding publication. Does Rob Griffin's book discuss the autoloader for the L11A4?

Thanks again.
 

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It would appear that the tank they used to trial the autoloader made it back into service: http://www.arrse.co.uk/rac/138682-so-ive-got-tank-l11a4-marked-gun-breech.html
 

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To clarify the information in "Cold War, Hot science" book.

The correct designation for UK experimental ordnance took the form EXP##-M#x. The 120mm ordnance's referred to should actually be 120mm EXP19-M7 and EXP19-M13A. The latter was the UK proposal for the US XM1 MBT up against the US improved 105mm M68 and the then new GE 120mm SB.

Re: L11A4. This was a variant of the L11 breech which incorporated a different breech mechanism for the interlocks to the steel obturator seal. This was superseded by revisions to the existing design which were adopted and produced as the L11A5.

Re: Autoloaders. There was one worked on/built in the ROF in (I believe the 1960's) but this was for a 105mm L7 as it used full length cased ammunition.
 

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Abraham Gubler said:
. Then there is the '40 ton Centurion' FV4202 to prove the reclined driver's position and also with a turret sans mantlet. T
Does anyone know if these features were possible in earlier smaller tanks?
 

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Does anyone no any drawings for the FV4202 40ton centurion and where to get them?
 

PMN1

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Does anyone know what the specs for the A45 Universal tank were to be?
 

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The A45 was intended to share a number of components (i,e turret tracks etc) with the A41 but with thicker armour. it was finally chosen as the basis for FV201 which turned into conqueror. There is on picture in Modern Combat Vehicles :2 by Simon Dunstan and published by Ian Allan. Good luck getting an inexpensive copy of the book as they don`t come cheap. The same picture (there may be som elsewhere) is also available in the Squadron Signal book Centurion in action.
There may well be a more comprehensive description in the Conqueror book published by Crowwood which is fairly easy too come by.
Sorry , not much but I hope it helps.
 

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I'm reading the New Vanguard book on the Centurion and its says that fundamental to the Universal Tank design, was the ability to adapt it to specialised roles and it was thought the Centurion could not be adapted to do so.

What was it about the Centurion that made the General Staffs think this and what was it about the Universal Tank design FV200 series that would have made it adaptable?
 

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Found this photo on flickr by emdjt42

"This is the prototype Chieftain with a 1000hp engine, whose development was not carried forward, and was donated to the Yorkshire Air Museum by Vickers Defence Industries, and is seen there on October 5th 2008."
 

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Blurb on the 1,000hp Chieftain: http://www.yorkshireairmuseum.org/exhibits/historic-military-vehicles/vickers-chieftain-battle-tank
 

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Why develop a 1,000hp Chieftain when you already have a 1,200hp engine in the Shir 1 (Khalid)?
 

Sea Skimmer

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Low cost, these would be the third rate last ditch reserve tanks, plus standardization with certain foreign units. The 1000hp engine fitted was basically the same German engine being used for a German M48 upgraded program which was expected to spread to other NATO states. It was also used in several other European armored vehicles, I think Italy used it for tanks and SPHs. This however was all taking place around 1990 and you know what happened next. Not much needed to be developed, both engine and transmission existed and other then that all you need are different mounting bolts and a wiring harness.
 

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Interesting side note at the other end of the Chieftains history regarding its engine, it was originally planned to fit the type with a V8 engine that was intended to be produced by Rolls Royce (but was seemingly being developed by FVRDE) but was abandoned following the decision to go multi-fuel which in turn lead to the decision to pursue the opposed piston Leyland L60. Apparently an auxiliary engine would have been mounted in the Vee (between the cylinder banks).
 

Abraham Gubler

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One of the concepts explored for the tank that became the Chieftan was an external gun mounted in a cleft turret. The crew roles and positions in the turret were conventional but the gun was mounted outside the turret. The loader placed rounds into a tray which was then automatically moved outside the turret, aligned and rammed into the breech.

The reason for the cleft turret was that with the gun removed from the turret the later could be much smaller for the size of the gun. I.e. tank guns would no longer be limited by the size of the turret ring as had bedevilled British tank development in WWII. Also the gun could be mounted further to the rear of the tank reducing barrel overhang and improving centre of gravity balance. Also with the gun mounted outside the turret the crew were no longer confronted by noise, smoke and spent brass cases after firing.

However despite these advantages the external gun made the turret higher to enable breech clearance when elevated (conversely made depression much easier). Also the complex turret shape made for a much heavier turret. Since the objective of the design efforts leading up to Chieftan were to find weight savings the concept was abandoned.
 

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Herman

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Reply to post # 15
Interesting side note at the other end of the Chieftains history regarding its engine, it was originally planned to fit the type with a V8 engine that was intended to be produced by Rolls Royce (but was seemingly being developed by FVRDE) but was abandoned following the decision to go multi-fuel which in turn lead to the decision to pursue the opposed piston Leyland L60. Apparently an auxiliary engine would have been mounted in the Vee (between the cylinder banks).

This decision turned out to be a disaster. The L60 was a dismal engine and haunted the Chieftain to the end of its days. With a good, simple diesel such as the US AVDS 1790 or presumably the planned RR V-8 unit, it would have been a much better vehicle although the fire-control systems were also not great and the seperate-loading ammunition remained controversial.
 

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Abraham Gubler said:
However despite these advantages the external gun made the turret higher to enable breech clearance when elevated (conversely made depression much easier). Also the complex turret shape made for a much heavier turret. Since the objective of the design efforts leading up to Chieftan were to find weight savings the concept was abandoned.

intresting, what is this picture from?
 

Abraham Gubler

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Andrei_bt said:
intresting, what is this picture from?
A book about the history of UK tank development. The name escapes me at the moment and I'm away from my 'files' but from memory it was 'The Quest for the Universal Tank' or something like that, though that could be a chapter name.

The picture is from the book "Chieftan" by George Forty as part of its eight page introduction to UK tank concept thinking between Centurion and Chieftan.
 

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With regards as to the 'Chieftain 1000', also known as the MTU Chieftain:
robunos said:
Herman said:
Reply to post # 14.
Robin, this is a really, really interesting piece of information. It would be very interesting to know when this prototype was built and by whom. It would also be interesting to know which MTU engine is fitted in the vehicle. The Leopard I, which corresponded with the Chieftain chronologically, was fitted with a 10 cylinder, 830hp unit but it used a ZF gearbox. The Leopard 2 had a V12, 1500hp MTU engine and that was indeed coupled to a Renk gearbox. The Leopard 2 is however a later tank than the Chieftain, corresponding more to the Challenger. Why would anybody stick a Leopard 2 powerpack into a Chieftain? It will also not be simple, technically; the Leopard powerpack is considerably larger than that of the Chieftain.
Here we go...

"The development of the Chieftain with a 1000hp engine and enhanced transmission was a project by Vickers Defence Industries, in partnership with the German companies RENK, MTU and Krupp-MAK, to offer a significant performance and reliability upgrade for existing Chieftain tanks. The first customer was to be Kuwait immediately before the first Gulf War. The MoD expressed an interest in upgrading their engineer vehicles and the BARV (Beach Armoured Recovery Vehicle) of the Royal Marines. Subsequently most of Kuwait’s Chieftain fleet was scrapped. The improved design was not developed further, however, leaving this unique prototype as the most powerful Chieftain Tank ever built.

The prototype was donated by Vickers Defence Industries to the Museum and delivered on 15th January 2002. The German engine and transmissions include features which are still regarded as industrial secrets and there are strict conditions relating to access attached to the donation. The tank, which still functions, has been partially restored with support from RENK, Vickers and 150 Regiment, Royal Logistics Corp."

Source :-

http://yorkshireairmuseum.org/exhibits/historic-military-vehicles/vickers-chieftain-battle-tank/

Also, another image from the magazine article quoted in post #14; caption reads

"The strange contraption on the pack (sic) of the MTU Chieftain is actually a lifting frame to help lift one piece engine deck which is not on a torsion bar unlike a similar system in Challenger. The frame is stowed when not in use so as not to hinder traverse."


cheers,
Robin.


As already mentioned by Sea Skimmer earlier in the thread, it was also intended as a low cost way to boost British tank numbers in general.
 

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At the end of the day, Chieftain was a deeply flawed tool, the engine by no means as bad as its reputation suggests was a backward step compared with the Meteor in the Conqueror. The gun and systems for gun laying were comparable for the time and the match for the opposition for quiet some time after introduction. Frontal armour was good, for the time but side armour less than a late model Panther medium tank. Disorganisation and terribly flawed so called fixes did nothing to improve it so the later suggestions of our adopting a better engine/transmission were too little too late. A pity that the current so called fixes for Challenger 2 are equally short of those needed.
 
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