The Chieftain Mk 13 Main Battle Tank

Started by Pellson, March 30, 2021, 07:57:12 AM

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Chieftain Mk 13

Replacing the venerable Centurion tank, in 1967, the Chieftain Main Battle Tank came into service with the Royal Armoured Corps. While experiencing initial teething troubles, as time went by and the regiments worked themselves into the new tank, most issues were solved. However, one big issue remained – the drivetrain. The problem was mainly focused at the multifuel Leyland L60 engine which neither delivered the promised power nor reliability – by far. The original L60 in the Chieftain mk 1 only gave about 450 hp on the sprocket, rendering the tank perilously slow also on the road. Also, problems with linings caused annoying coolant leaks causing massive clouds of white smoke to emerge, not ideal when you're trying to stay concealed, and also not very good if you want to have a cool engine as you easily ran out of coolant. During the seventies, various engine upgrades gave increased power and, to an extent, better reliability, but most of these improvements were soon overtaken by weight creep, caused by improvements in armour and other systems. Late in the decade, the Belzona upgrade finally gave a reasonable power rise, giving 850 hp on the sprocket and also curing the worst lining issues. In parallel, other system upgrades in communication as well as targeting kept the Chieftain on par with its competition. In particular, the Thermal Observation and Gunnery System (TOGS) gave the crew the ability to shoot at very very long distances indeed with extremely good accuracy.

While not by far the export success the Centurion had been, the Chieftain sold well in the Middle East, and in particular the Iranian army bought and operated over 700 Chieftains, liking them enough to order an improved version, the Shir 1, in the mid-seventies.
However, the Royal Army was not sitting on its hands, rather looking for an entirely new tank than up-armouring the Chieftain. At first, collaboration was sought with both the USA and Germany, but as many times before, difficulties in coming together on one common specification as well as overruns in cost and time meant that the UK decided to go on its own with the MBT80 project. This tank was to be delivered in the mid- to late eighties and was an entirely new design, featuring a hydropneumatic suspension, vastly improving comfort and cross-country performance compared to the Horstmann design in the Chieftains, as well as a completely new drivetrain focused around a turbocharged Rolls-Royce V12 diesel engine.
When the Shah of Iran fell in February 1979, all work on the Iranian follow-on order of an improved Shir 1, called Shir 2, were immediately cancelled, leaving Royal Ordnance Factory in Leeds entirely without work to sustain its personnel.  With at least five years to production of the new MBT80 tank, the situation was acute as the flight of skilled workforce and thereby loss of competence was seen as a strategic issue. Hence, a quicker solution was sought and eventually the Shir 2 became the base for the new Project MBT85, soon to be renamed Challenger. In 1980 the Iran-Iraq war began, and when Iranian Chieftains fought Iraqi T-62s, it was found that APFSDS and HEAT rounds from the T-62s 115 mm gun more often than not penetrated the front hull and turret of the Chieftain, forcing improvements in protection. The solution would eventually become an add-on armour package known as the Stillbrew armour, so named after its inventors, the MVEE colonel Still and his engineer colleague, John Brewer. It consisted of steel and rubber shaped in blocks and installed on the turret and around the drives hatch. When installed, the tank was deemed sufficiently protected to be able to take on the T-62 regardless of ammunition as well as the hollow and shaped charges of the RPG-7 and Sagger antitank missile.

While the Chieftain now looked good enough to cope for the time being, and the forthcoming Challenger project moving on well, some problems, mainly in relation to the new suspension on the Challenger remained to sort out and as the cold war was rapidly deteriorating with the Iranian revolution, the Soviet invasion of Afghanistan and the Iran – Iraq war, tanks that were up to date were needed faster than the Challenger could be produced. Accordingly, the Chieftains were put up for upgrade, the first Stillbrew Chieftains being delivered in 1984. Originally, this was seen as a stopgap measure only, but as the tension increased in Europe as hardliner Yuri Andropov became general secretary of the Soviet Union in 1984, it was realised that still larger number of tanks would be needed sooner than the Challenger production could be increased. Accordingly, the Chieftains would have to stay on.

During the early eighties, it was found that while improving the Chieftain armour significantly, the Stillbrew package didn't provide full immunity against the new Russian 125 mm depleted uranium projectiles. To defeat this threat, a further 30% increased armour efficacy would be needed. Again put to the test, the MVEE armour team managed to design a second Stillbrew type package in record time, using Chobham technology. The new armour pack was, like its predecessor, an add-on system, but more modular and differing in profile. Another important difference was that now, it didn't only protect the turret, but also added units to the entire front of the glacis as well as properly armoured skirts along most of the sides of the tank. The new armour pack became known as Chopsticks, derived from the name of the Chobham material and the many pieces in which it came when being delivered for installation. Also included in the update, and to cope with the increased weight, the suspension was somewhat redesigned and reinforced, giving not only the desired weight carrying capacity but also some improvements in ride, albeit not on par with the hydropneumatic suspension in the Challenger.

Still, however, the Chieftain drivetrain problem remained. A quick but thorough study revealed that it would be possible to install the new and much better RR CV12 engine from the Challenger by completely redesigning the packing of the unit, including mating it to an entirely new and very compact semiautomatic transmission. The only exterior giveaway would be a raised engine deck and while this CV12 version due to the cramped installation and rerouted inlet and exhaust channels wasn't quite as powerful as in the Challenger, it still delivered just short of 1100 hp, immediately making the Chieftain a much more agile vehicle indeed. Finally, the opportunity was taken to improve and increase some auxiliary systems, such as communications and climatic systems, resulting in a rather bigger box at the rear end of the turret, and to match that, bigger stowage bins were put next to it. Despite the changes, a fully armoured, armed and fuelled Chieftain now weighed just short of 65 tons, more than five tons less than a battle ready Challenger.
Entering service in 1986, the now thoroughly updated Chieftain Mk 13 was rapidly fielded across the armoured regiments not slated for immediate Challenger delivery. As the conversion was simple enough to be done in field workshops, the tanks to be converted wasn't shipped to any factory but rather small teams of specialists travelled with the first kits to be delivered to each regiment, assisting and training the resident REME teams in doing the upgrade themselves. Due to this, the entire Chieftain fleet to be reconstructed, well over 500 tanks all in all, was completed in less than a year and a half, with many obviously stored as attrition replacements.

In service, the Mk 13 was seen as just about as good as the Challenger. It was somewhat faster on the road but slower in terrain due to its inferior suspension. The armament and sight was equal but the armour slightly less efficient, in particular as the Challenger soon gained add-on armour itself. 

When Iraq invaded Kuwait on the night to the 2nd of August 1990, B Company, 1st Battalion 1RTR was on exchange in Kuwait with six Mk 13s. When their hosts in the 7th Battalion, 35th Armoured Brigade, also equipped with Chieftains but not similarly upgraded, were put on alert late in the evening of the 1st, the British tankers found that all communications with home was down and they were left on their own. Realising that they either would have to leave their equipment behind or fight their way out, they quickly elected to fight alongside their hosts, but as a precaution, under the Kuwaiti flag.
During the morning on the 2nd, they participated in the Battle of the Bridges where two of their number were hit, however left virtually intact and operational. Later in the day, the combined Anglo-Kuwaiti force managed to sneak out of a threatening encirclement and B Company reached the Saudi border together with their local comrades at 16:30 in the afternoon, spending the night on alert on Kuwaiti soil and then crossing over into Saudi Arabia in the morning. Whether the Brits inflicted any damage to the opposing Iraqi invaders has been kept a very tight secret, but it is known that the Iraqi 17th Brigade took heavy losses during this day.

The Mk 13 remained in service until 2002 when the last tank was given a formal honourable discharge by its unit, 1RTR, a good fit being the only British regiment having taken the Chieftain to battle. At that time, the Challenger 2 had been introduced to many armoured regiments, effectively replacing all the Chieftains as well as some early Challengers while others were upgraded to replace the reserve Chieftains.

The kit is the venerable Airfix Chieftain in 1/76, which, by the way, is close enough to Gods Own Scale to pass if you aren't looking too closely.

I built it originally many moons ago, long before webshops etc, so the local market for armoured vehicles in these small scales were rather limited. However, as I later came across Matchbox Challenger 1, the Chieftain looked quite dated and I for a while considered rebuilding it to a SPH but eventually decided against and put it to one side for quite a few years. Much later I found a resin conversion for the Mk 11 Stillbrew, but that was in my view both excruciatingly expensive and somewhat cumbersome, so I stalled on the conversion again. A few years ago, though, when having found whiffing more fun than just copying reality, I just got to it and built this extended add-on armour set from plasticard. While good good fun in itself, I have to admit that the best part was to design and build the storage bins on the turret and the TOGS box. Together, they really give the turret and the entire tank this big, flat appearance we have come to connect with modern AFVs.

Now back to the varnishes..

Praise the Lord and pass the ammunition!

Steel Penguin

the things you learn, give your mind the wings to fly, and the chains to hold yourself steady
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Finally got time to add the pics.  Sorry for delay.
Praise the Lord and pass the ammunition!



The dogs philosophy on life.
If you cant eat it hump it or fight it,
Pee on it and walk away!!

Old Wombat

Has a life outside of What-If & wishes it would stop interfering!

"The purpose of all War is Peace" - St. Augustine

veritas ad mortus veritas est


Quote from: Old Wombat on March 31, 2021, 05:18:11 AM
Damned good for mini scale! :thumbsup:

My thoughts exactly  :bow: I was staggered when I read that final bit about it being 1/76
Do not condemn the judgement of another because it differs from your own. You may both be wrong.