Tonights instalment of Ed Francis’s British Cold War tank development is the MBT-80 project.
In Ed’s words, “Much has been written about MBT-80 on the internet over the last few years, most of it wrong.” So let’s set the record straight.

The first references to what might evolve into MBT-80 goes all the way back to the first years of the 1970’s. One of the earliest reports written up by a member of the Fighting Vehicle Research and Development Establishment (F.V.R.D.E) covers the subject of what will be required to replace Chieftain in the 1980’s and beyond. The writer, Mr T.C. Leggett of the Project Coordination Branch (tracked) highlighted some of the issues and suggestions in a non-formal memo on the matter.
His first point was that any government specification would ultimately require the weight expectation for any future Main Battle Tank to be at least 45 tons and that previous suggestions of 30 tons were entirely un-feasible given the growing trend in tank development.
The memo suggested that an extensive study be carried out to determine the improvements that could be achieved by using Chieftain long term development items along with the latest technical developments to produce a tank that he rather optimistically suggests could be ready for service by 1973. It should be noted that at this period the FMBT-70 program between the UK and West Germany was in place and were it not for the allocated Fighting Vehicle (FV) numbers one could be forgiven for assuming that it was this project that he was referring to.

MBT-80 was given the designation FV4601 it never received an official personalised name and so became only ever commonly known as MBT-80. It was to have a crew of 4, a fully rotating turret and mount a new, improved British 120mm rifled gun. It was to have a predicted power to weight ratio of 25bhp/tonne and incorporate heavy layers of the new Chobham armour over the entire front, including the lower nose and unlike many other MBT’s was to be protected down the sides with heavy Chobham as well. A new advanced fire control system (FCS) was to be fitted as standard capable of 100% chance of a first round hit even when on the move. The engine chosen was the Rolls Royce CV12 (1500) Condor (although the XM1’s gas turbine was a close second choice) and the power was to be delivered through the David Brown TN28 transmission.

The new British 120mm rifled gun, the XL28 was to fire two part ammunition with a Depleted Uranium (DU) Kinetic Energy (KE) round able to defeat any Soviet tank of the time at ranges out to 3.5km. Secondary rounds would have been HESH and Smoke. Originally is was hoped for 50 rounds of ammunition to be stowed but later this was dropped to 45. Ammunition was to be kept below the turret ring for increased survivability. A 7.62mm Hughes chain gun and commanders machine gun were to be fitted for close protection. The gunner and commander had a full electronic optics system, day/night sights, laser range finder, a metrological sensor system (MET system) and a Thermal Imaging (TI) suite. The laser range finder and TI suite were combined in a new and revolutionary Panoramic, Thermal Imager, Laser Integrated Sight (PANTIL) system.

In line with the British practice of the period the crew were still given the best possible chance for survival. To this end the Chobham armour packages were to be thick enough to withstand the whole spectrum of attacks the Soviets may have been able to field against it. This included being immune to Soviet 125mm KE and CE rounds at point blank ranges. The sides, top and rear were to be immune to 14.5mm AP rounds and 152mm HE shells at 10 meters. In order to ease logistics and maintenance in peacetime it was expected that several parts of the Chobham armour could be removed for everyday use.
The basic hull armour was pound for pound superior than all other MBT’s of its period due to the composite frame made from steel and aluminium plates welded via transition joints using Explosive welding, (a welding process that uses precision explosions to bond two dissimilar metals while retaining the mechanical, electrical and corrosion properties of both) to form the strongest bond possible. All aspects of the frame likely to face incoming hits were to be steel whereas areas less likely to be hit or where armour weight would make negligible difference such as the rear are constructed of a light aluminium alloy.

For improved cross country performance Hydrogas suspension was chosen with 7 pairs of rubber rimmed road wheels. The tracks were to be of the the same type used on the XM1.

The image we have is of the scale model of MBT-80 held in the archives at Bovington and has not been published before. You can see that although there are some obvious similarities to the ATR vehicles that were part of the development process of MBT-80 the final design was different to both ATR’s.

While this is far from the full story of MBT-80 is does begin to shine a light on one of the most speculated upon of British tank designs. The eventual choice of FV4030 Challenger over MBT-80 is not only a contentious one but also long winded. In truth it’s likely that British Army (and the British tank industry) lost an excellent opportunity. MBT-80 on paper was a far superior design with enough design and upgrade life to have made Challenger 2 unnecessary. As for potential export, who knows but it’s just possible it could have been a winning design.

To expand on some elements of the story. The transition jointed hull test rig, ATR2, was a nightmare to manufacture while maintaining the necessary low weld inter-pass temperatures. To mass produce it would have been expensive and complicated. The aim of if was armour optimisation to try and save weight. The steel backed Chobham was more weight efficient than aluminium against the frontal threat while aluminium was more weight efficient against the side and rear threats (14.5 Ap) the result of all this complexity saved, I recall, about a tonne on a vehicle whose weight (heading for 60 tonnes plus) complexity and cost and development timescale were all getting out of control. It is a fatal mistake made by many to put a date in a project title. While some turret castings were made for ballistic testing. MBT80 did not reach prototype stage. The test rigs were not MBT80 designs. ATR1 was chieftain FV4211 Based and ATR2 was based on FV4030 design and components. I was part of this as a young engineer. If my memory is wrong I am sure others can correct me.