The Nemesis – A British MBT Concept from the 1970s
The Nemesis is a main battle tank concept drawn up in the 1970s, and is an interesting little footnote from British tank design. Unlike the major main battle tanks we are used to today, like the Chieftain, Leopard 2 and Challenger 2, the Nemesis was not designed to fight the latest Soviet armor.
Instead, it was tailor made to suit nations with smaller militaries, who wanted a capable tank but not one that had to face mass tank attacks on Europe’s Eastern flank.
The tank was created in 1974 at the 24th long armor infantry course at the Royal Armor Corps Center in Bovington, a follow-on from the School of Tank Technology courses.
As it was a conceptual study, the tank would not be built. But today, the scale model from the project still exists.
The Nemesis, named after the Greek goddess of divine retribution, was a 59 week long project carried out primarily by British officers from the Royal Armoured Corps (RAC) as well as infantry officers and some US and Commonwealth soldiers.
On this course, these servicemembers with varying areas of knowledge and expertise came together to design a vehicle. At the end, a decision would be made on whether it was worthy or not.
The task given; develop a non-European main battle tank. At the time, many of the newest tanks were designed for the European market, built to face off against superior numbers of Soviet tanks. As a result, they were often heavier, more complex, and more costly than was required elsewhere.
There was therefore a large number of non-European countries that wanted high-quality tanks, but did not need them to meet the specialized conditions of the European theater. Any tank designed would thus need to have a wide appeal so that a large volume of sales would allow its production at a reasonable price.
9 officers were chosen to design the tank using the knowledge gained over the previous year as well as support from a wide variety of industrial leads such as Vickers, Rolls Royce and MVEE along with serving armor specialists from the UK, Germany, and others.
The first step undertaken was an assessment of the current nations who might be interested in a tank; what threats they faced, terrain types, political ramifications of arming that nation and how their neighbors would react. The nations’ previous relationships and their financial stability to place large orders were also taken into consideration.
This was set into 3 priority groups. Those with close ties with Russia or China were put to the bottom as were nations likely to use the tanks in actions against their own people.
The next step was to see what each nation wanted, and assign a scale of importance averaged over each nation. The top requirements were for a low-cost tank, able to defeat both Soviet but also American vehicles. The need for night fighting equipment was high, while medium armor was more desirable than heavy armor.
For medium importance, the engine requirements were mixed but the ability to eliminate insurgents or light anti-tank teams was present. At the low end was NBC equipment and a snorkel system. Over 60 nations were assessed and the requirements on average were calculated.
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The team also had to evaluate the type of war the nations would likely use the tank in. The most desired traits were for a mobile, offensive role in a conventional war, close fire support abilities for infantry and anti-armor defense against a superior force. Any vehicle needed to be effective out to 2,000 meters, and do so after a long-distance march in difficult environments.
The team also worked out the cost of what people were willing to pay. They excluded soviet and Chinese vehicles for this, as one was never going to produce a better vehicle than the T-55 at a lower cost. The vehicles therefore chosen for comparison were the AMX-30 at £225,000, the S-tank at £217,000, the Chieftain at £200,000, the Vickers Medium at £103,000, and finally the M60, which was the cheapest at just £72,000.
They also looked at current British vehicles that could be converted over to a new role. The trusty old centurion was chosen first but was not deemed suitable as it only had an estimated service life of 10 years left – even with a Vickers overhaul.
The weight of 50 tons at the time could not be reduced without sacrificing too much, and the power to weight ratio of 13:1 was not desirable. To bring the Centurion up to scratch would effectively make it unsuitable in several areas essential to the majority of customers.
On the other hand, the Chieftain at 200k was deemed too expensive, losing about 60% of the nations that would want to buy a tank. Its weight alone lost a further 30% of possible customers, while its low power-to-weight ratio further hindered it. The idea of giving it a new engine would require a complete rework of the transmission, adding costs, and by simply using budget components would have wasted under-armor volume.
The Vickers medium tank, or Mk 1, had the most desirable basic traits, with medium armor, good power-to-weight ratio, an affordable price, and proven ability to work in hot and humid climates. Its downside was its mediocre mobility.
With that said and done the team then listed what the customers wanted overall which would be used to design their new tank.
It required a very high degree of reliability, with easy replacement of parts and minimal crew servicing, a gun able to defeat the T-62 out to 1,500 to 2,000 meters, HE and canister capability, as well as the highest possible accuracy.
Protection of the Nemesis was to be enough to stop the T-62 at 1,500m, sides to stop heavy MG and light handheld weapons and the roof resistant to HE bursts. Also, the vehicle must ideally be below 40 tons, 35 if possible, and have a power-to-weight ratio of 25:1 and a road speed of 65kph.
Finally, it had to come in under £150,000, including spares for 5 years.
With the requirements laid out, the team then began to work on the Nemesis.
They looked at the main weapon and debated over a gun or anti-tank guided missiles (ATGM), which were popular at the time, but as the vehicle had to engage both tanks and light armor and infantry, a guided weapon system wasn’t an option.
The gun/missile hybrid system such as that used on the M551 Sheridan was considered but quickly dropped; not only would it take up more volume with less ammunition but it added a layer of complexity and cost that was not needed. Thus a conventional high-velocity gun was required.
They also debated whether the vehicle should be turreted or not. A turretless tank had a few advantages in weight and as a tank destroyer in open countryside, but it is completely unsuitable for the potential close-range fighting and jungle conditions that customers might need it for.
Next was whether it should have a pod-style gun, which was a somewhat fashionable concept in this period, or a conventional turret.
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The pod gun idea has the advantage of a reduced silhouette and a lighter build as well as better crew protection but suffered from poor all-round vision and vulnerable ammunition.
Oscillating turrets were also looked at. These were constructed from two independent halves, had a smaller turret ring diameter and were better suited for an autoloader. This meant that they had a lower silhouette while hull-down, but they were difficult to seal for NBC systems and required more power for stabilisation.
The last of the odd turrets looked at was the cleft turret. These are quite interesting, with the turret split in half by the gun. This offers a low silhouette in hull-down positions and low weight but creates vision and loading issues.
Ultimately the deciding factor for many of these was also that the vehicle may be built as bridge layer or AVRE variants. This made the more interesting turret layouts more or less redundant.
A list of potential guns was drawn up. These were the 76 mm ARMD L5A1, the 105 mm L7A1, the 110 mm short gun, and the 120 mm L11A3.
The gun chosen was the 110 mm, as it had better performance than the L7, while not being overkill like the 120 mm. This would be fitted with a basic hydropneumatic recoil system, and have 10 degrees of gun depression and 20 degrees of elevation. Ammunition capacity was to be 28 rounds of armor-piercing discarding sabot (APDS), 12 rounds of high-explosive anti-tank (HEAT), and 2 rounds of smoke.
The gun was to be fully stabilized for accurate firing on the move however rangefinding was an issue. The team agreed that a .50 caliber ranging machine gun should be used, as this was the cheapest option.
However, some customers might want a laser rangefinder, so provisions to fit and mount one would come as standard. The team later dropped the .50 caliber when they fitted an autocannon coaxial to the main gun for anti-personnel and light anti-armor work.
This coaxial was the 25 mm TRW-6425 cannon, then under consideration for the bushmaster program. This would have 64 rounds of HE and 64 rounds of AP fed into it, with a total of 428 rounds available in the tank.
With this, Nemesis could engage light armor, infantry, and ranging options all with one gun.
The next step was the protection layout. Various ideas were floated, from ceramic, dual hardness, and liquid armor, however, all were either expensive, prohibited, or too complex for many customers. In the end, they chose to go with a dual steel and aluminum concept, with the front being steel and the rear being aluminum. The two ends were explosively welded together, much as had been proposed for MBT-80.
The glacis plate was 94 mm thick but angled back at 70 degrees for an effective thickness of 274 mm of steel. The lower nose was 177 mm at 45 degrees for 250 mm of effective thickness, while the sides of the upper hull were 100mm thick, tapering down to 40 mm on the lower sides. The rear was 89 mm thick aluminum.
The turret front was well protected, with the armor ranging from 79mm to 339mm at the thickest, and 89mm on the sides and the rear.
Finally, we have the mobility
The Nemesis was required to have a road speed of no less than 40 mph (65 kph), with fast acceleration, good cross-country performance, and reliability.
The idea of a conventional petrol engine was quickly dropped, leaving diesel and gas turbines open for discussion. Diesel engines from MTU, Rolls-Royce, and Caterpillar were suggested and the Lycoming 1500 and Rolls-Royce twin turbines as the other options.
The gas turbine was dropped due to the high fuel requirements, which is all fine and dandy if you are a large American formation, but less desirable for smaller nations with limited logistics.
In the end, the German 8 cylinder MTU 870 multi-fuel engine was chosen, thanks to high power density, build quality and ease of removal and installation. This would be coupled with an epicyclic gearbox and torque converter.
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The nemesis was never built, remaining a study concept, and the papers were downgraded from secret to confidential in 1984. Today, both the workbook and the scale concept model survive at The Tank Museum, Bovington in the UK.