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MBT 70: The Battle Tank Ahead of its Time

Written by Matthew Copes

Between the late ‘50s and mid-’70s the Soviet Union produced approximately 90,000 T-54/55 and T-62 main battle tanks for domestic use.

A right side view of a Soviet T-55A main battle tank with a laser rangefinder fitted over the 100 mm main gun. https://picryl.com/media/a-right-side-view-of-a-soviet-t-55a-main-battle-tank-with-a-laser-rangefinder-c229f3

By comparison, between 1960 and 1983 Chrysler produced just 15,000 M60 tanks at the Detroit Arsenal Tank Plant. 

Featuring lower profiles, simple designs and lethal high-velocity guns, the Soviet machines were generally less expensive and easier to manufacture than their western counterparts.

Depending on variant and equipment, Soviet tanks typically cost less than 2 million USD in today’s money, while each M60 cost nearly twice as much. 

By the mid-’60s American M60s and German Leopard 1s made up the bulk of the armored force that would be expected to counter the Soviets if all hell broke loose. 

Armed with 105 mm rifled cannons derived from the Royal Ordnance L7, both had fared with Israeli forces in the Middle East, but the next generation of Soviet tanks had thicker armor and new 115 mm smoothbore cannons with longer ranges and better penetrating power. 

It was commonly assumed that western tanks were technologically superior and that this alone would negate Soviet numerical superiority, but this may have been wishful thinking on the part of NATO countries.  

In the event of war involving huge formations of main battle tanks thundering toward one another across the plains of Western Europe, many Soviet armored vehicles would have been just as capable as their rivals, and in some respects superior.  

Not surprisingly, developing a new main battle tank was a priority in the west, but rather than going it alone the United States and West Germany teamed up to develop a game-changing “super tank” – the MBT-70. 

https://commons.wikimedia.org/wiki/File:MBT-70.Aberdeen.0007s3qe.jpg

Tipping the scales at about 54 tons (49,000 kg), featuring a revolutionary pneumatic suspension system and a whopping 152 mm dual purpose cannon/missile launcher, the MBT-70 was a huge divergence from tank design of the day. 

In addition to having the lowest silhouette of any contemporary tank, the entire 3-man crew resided inside the large, flat turret to improve efficiency and survivability. 

During the early going the MBT-70 looked like a world-beater, and it might have swayed the outcome of any battle it had gone into. 

Except that it never went into battle, nor was any production unit ever manufactured, largely because America and Germany couldn’t agree on guns, engines, tracks, suspensions, armor or fire control systems, let alone whether the tanks’ thousands of nuts, bolts and screws nuts, would be imperial or metric. 

Enter Robert McNamara. 

Background

Shortly after the Second World War, Ford Motor Company president Henry Ford II hired McNamara and a small cadre of Army Air Forces veterans to transform the company his grandfather founded into a leaner, more efficient and more profitable enterprise. 

The group largely succeeded by implementing a number of new, controversial and largely unpopular systems and programs, and as a result McNamara himself later became the company’s president. 

However he wasn’t particularly well liked by rank-and-file employees, particularly engineers. 

They, and pretty much everybody else saw him as an insufferable micromanager and shameless penny pincher whose main objectives were reducing costs and speeding development times, often at the expense of sound engineering principles and good old-fashioned common sense. 

Later as US Secretary of Defense in the ‘60s, McNamara applied these same methods to the development and procurement of military equipment in America, often with less than favorable results, as was the case with the McDonnell-Douglas F-111.  

https://commons.wikimedia.org/wiki/File:Robert_McNamara_official_portrait.jpg#/media/File:Robert_McNamara_official_portrait.jpg

According to McNamara, another glaring problem in dire need of a solution was that various NATO nations fielded hundreds of different weapons systems, nearly all of which lacked common designs, parts and ammunition. 

This meant that huge amounts of time and money were being wasted developing similar systems that would be used by allies for nearly identical purposes, all of which added up to gobs of waste, inefficiency and redundancy – three things that drove the ex-auto executive nuts. 

For much of the ‘50s West Germany had grudgingly used American M48 Pattons, but the country’s military was intent on building its own indigenous main battle tanks. 

McNamara considered Germany a key NATO ally as well as an engineering powerhouse, and he theorized that joint development on such an important project would reduce cost, decrease development time and produce a better vehicle than each country would be capable of developing on its own. 

Though they’d been in service for less than a decade, the Army was already itching to replace its M60s, so the timing couldn’t have been better.  

Detractors claimed that after the Second World War German engineering had failed to keep pace with developments in Britain and America, and that the program would result in a huge one-way transfer of technology out of the United States. 

Hence, if a MBT was to be co-developed, England would be a far more suitable partner. 

McNamara countered that Germany was in a better financial position to take on the project, and that geographically speaking the country was literally on the front line of the Cold War, whereas Britain was an island nation buffeted by Western European countries and the English Channel. 

As a result, it made sense that Germany had more incentive to develop the new MBT, since its very survival might some day depend on it. 

In August of 1963, the United States and Germany signed a memorandum of understanding to develop the new tank.

Former tank commander General Welborn G. Dolvin was tasked with leading a team of engineers from US automakers Chrysler, GM and Ford, while in Germany a semi-private development corporation was formed to oversee the project.

To ensure that each team had adequate input, it was decided that the first phase of development would take place in Germany, after which everyone would pack up and move to the United States. 

Ironically, when in Germany the Americans would manage the project, and the roles would be reversed when the Germans were in America. 

As they say – what could possibly go wrong? 

Design

From the outset the MBT-70 was designed to incorporate the best mix of firepower, mobility and protection. 

American versions were originally to be powered by gas-turbines similar to the ones now used in Abrams tanks, but in addition to having alarmingly high fuel consumption, engineers found it nearly impossible to filter the air adequately before it was sucked into the engine. 

As a result, it was decided that diesels were more suitable, despite their increased size and weight.  

Apogee Arts

Germany’s tanks would use 1,500-horsepower Daimler-Benz and later MTU turbo-diesel engines, while the Americans would opt for a Continental V-12 producing about 1,470 horsepower. 

Power was sent through a Renk 8-speed transmission, and with an internal fuel volume of about 345 US gallons (1,300 liters), operational range was approximately 400 miles (645 km).

On both German and American tanks, drivetrains could be replaced in less than an hour, largely because engines and transmissions were housed in compartmentalized “power packs” located at the rear of the hull behind the turret. 

But perhaps the most notable feature was the tank’s hydropneumatic suspension system, which  together with an exceptionally high power-to-weight ratio gave the 50+ ton machines unparalleled cross-country mobility. 

This complex suspension also gave MBT-70s “hull-down” capabilities that allowed them a much wider range of fire on the vertical plane. 

On an incline when the back of the tank was sitting lower than the front, the rear suspension could be raised to allow the gun to depress farther to fire at targets below it. 

This design feature allowed MBT-70s to fire from behind hilltops, ridges and manmade defensive positions without exposing most of the tank.

Regardless of terrain or firing position, the suspension could be raised or lowered by the driver. 

During cross-country maneuvers tanks could be raised more than 2 feet (61 cm) to improve ground clearance, and in stationary firing positions they could be lowered until the bottoms of the hulls were just 4 inches (10 cm) off the ground. 

Had they not had such revolutionary suspensions, MBT-70s would still have been among the lowest turreted tanks ever built, especially in comparison to the M60, which was one of the tallest. 

With their suspensions in the lowest possible position, MBT-70s were just over 6 feet (1.8 m) tall. 

To put this into perspective, Germany’s turretless Hetzer tank destroyers of WWII were slightly more than 7 feet tall, and M60s were nearly 11 feet tall (3.3 m). 

Though this made MBT 70s difficult targets, it left no room for drivers in the hull. 

Instead, drivers sat in cupolas in the turret that always faced forward regardless of the position of the turret itself, which at least in theory this was meant to keep them from getting disoriented. 

Both the German and American version of the tank could reach approximately 45 miles per hour (70 km/h) compared to just 30 miles per hour (48 km/h) for most other western tanks like M60s and Leopard 1s, and newer Soviet T-62s. 

However for the 3-man crew crammed inside the claustrophobic fighting compartment the ride was exceptionally smooth, and the tanks’ mobility and agility went a long way toward reducing the amount of time they’d be subject to fire. 

https://flic.kr/p/cr8neJ

Armament

For main armament, MBT-70s featured stabilized,152 mm XM150 guns capable of firing standard cannon rounds and Shillelagh guided missiles. 

XM150s were improved long-barrel variants of XM-81s used on M551 Sheridan light tanks, and this ability to fire multiple munition types would have given MBTs a huge advantage over the Soviet tanks they’d likely face in combat.  

During the ‘60s the maximum effective ranges of most 100, 105 and 115 mm tank guns was between 2,000 and 2,500 yards. 

XM150 cannons had slightly longer ranges than their predecessors and could fire various ammunition types including high-explosive, anti-personnel and discarding sabot armor piercing rounds, the latter of which used a new and far denser tungsten alloy that allowed projectiles to penetrate thicker armor at long ranges. 

Another new feature that turned out to be an Achilles heel was the caseless cannon ammunition. 

In other words, there was no metal case behind the projectile containing the propellant. 

Instead, the case itself was formed with hardened propellant that ignited when the round was fired. 

However these rounds were vulnerable to moisture and prone to damage due to mishandling.

Worse yet, uncombusted portions of the case left in the breach after firing could ignite the next round prematurely, causing a potentially catastrophic phenomena known as “cooking off.”

The complex auto-loader was capable of handling both cannon rounds and Shillelagh missiles, 

both of which were stored in vertically rotating magazines. 

But though the mechanism saved weight and eliminated the need for a dedicated loader, it was never deemed to be as reliable as an actual human being ramming rounds into the breach. 

Under optimal conditions rate of fire was about 12 rounds per minute, and in the event of autoloader malfunction the crew could manually load the gun, though rate of fire would drop to about two rounds per minute. 

The gun itself did have its drawbacks, but it was considered likely that on modern battlefields armored engagements would take place at much longer ranges than the cannons were capable of firing. 

With their guided missile capability, MBT-70s could have destroyed enemy vehicles from as far away as 10,000 feet (3,050 m).

The secondary armament consisted of a remote-controlled 20 mm autocannon for use against aircraft, troops, structures and lightly armored vehicles.

However, the cannons proved to be so tedious that they were largely disregarded by crews.

MBT-70s also had .30 caliber (7.62 mm) machine guns mounted coaxially alongside the main gun for close-in defense.

All told, each vehicle would have carried approximately 42 cannon rounds, 6 Shillelagh missiles, and more than 3,000 rounds for the autocannon and machine gun combined.  

MBT-70s were also equipped with eight smoke grenade launchers, each of which contained two grenades that would have provided valuable concealment when the tanks were in particularly open, vulnerable areas.  

Protection

The frontal portion of the MBT-70’s hull and turret were protected by spaced armor consisting of multiple plates between 20 and 40 mm thick, the outermost of which was High Performance Armor (HPA) developed in the United States in the mid-’60s. 

Though its composition was a highly-guarded secret at the time, it’s now known that in addition to steel, HPA contained 9% nickel and 4% cobalt, all of which were forged into a relatively light and tough alloy through a process known as vacuum arc remelting. 

The armor in the downward sloped portion of the upper hull was capable of shrugging off Soviet armor-piercing discarding sabot rounds fired from as close as 800 yards.  

Inside, crews were separated from ammunition, the engine compartment in the rear and the large multi-layer rubber fuel tank in the front by a series of armored bulkheads in both the hull and turret. 

However as aluminum was used for the engine compartment floor to save weight, MBT-70s would have been particularly vulnerable to mines, though they were equipped with polyethylene radiation shielding to protect crews against electromagnetic pulses and chemical, biological and nuclear agents in the atmosphere. 

Testing & Evaluation

Of the fourteen hulls manufactured between 1965 and 1966, most wouldn’t be completed and ready for testing and evaluation until mid-1968, and by then the tank’s future was far from certain. 

In fact, the program was nearly a year behind schedule and additional delays were imminent by the time the Americans unveiled their new tank at the Association of the United States Army headquarters in Washington, D.C the following year.

The Germans demonstrated their MBT-70 in Augsburg in front of journalists, politicians, military brass and the general public, but during the event the vehicle became inoperable after a hydraulic system malfunction sent thick plumes of white smoke billowing from hatches in the hull and turret. 

Nonetheless, after the event German officials claimed that by 1972 MBT-70s would replace all M48 Pattons then in service. 

However, over the next few years the program ran into a number of difficulties, many of which stemmed from competing interests and requirements from both the German and American sides. 

Drivers increasingly complained about becoming severely disoriented when the turret was rotated, and more importantly, the gun/missile system was turning out to be far more expensive and troublesome than expected.

Eventually Germany decided to scrap the XM150 altogether and replace it with a 120 mm smoothbore Rheinmetall 120 mm cannon, much like the one used on both Abrams and Leopard tanks today.  

In addition, as is often the case when developing tanks and armored vehicles, the MBT-70 was becoming heavier than initially anticipated. 

The increase from 50 to 54 tons meant that expensive and time-consuming redesigns were needed, but in the end this was just one symptom of the real problems – that the project was too ambitious, relied too heavily on international cooperation, and incorporated too much untested technology. 

And then there was the cost…

By 1970 the per-unit cost estimates had increased fivefold.

In addition, overall development costs were initially projected to be around 80 million USD, but just a few years in the project had already cost 303 million USD, or about 2.4 billion USD today. 

West Germany alone ended up paying more than the whole project was supposed to cost in the first place. 

In America, the House Armed Services requested that funding for the project be suspended until comprehensive reviews from the Department of Defense and Government Accounting Office could be conducted. 

After each published its findings, it was determined that the program could continue, but on a much smaller scale. 

Government officials were ultimately persuaded by Army leaders that the program had merit, but by then it was clear that both America and Germany would be better going their own separate ways.  

Shortly after termination Germany began developing the Keiler tank, which would later become the Leopard 2. 

https://commons.wikimedia.org/wiki/File:Minenr%C3%A4umpanzer_Keiler.jpg

Originally designated XM803, in the United States work began on converting the existing MBT-70s into low-cost alternatives that utilized only American-made components.

Congress hoped to drive the per-tank cost down significantly by switching to less expensive steel armor, using a conventional cannon, and simplifying or altogether eliminating the effective but unreliable suspension. 

General Motors received a 16.5 million USD (130 million USD today) contract to develop the tank in the summer of 1971, but despite these compromises, shortly into development the XM803 design began to match the MBT-70 in complexity, delays and cost overruns. 

In December of the same year, Congress officially canceled the program, appropriating 20 million USD (165 million USD today) for cancelation costs, and another 20 million for – you guessed it – yet another new tank program. 

Thankfully, this last program would eventually lead to the development of M1 Abrams main battle tanks, various variants of which have been in continuous service since 1980. 

According to many who worked on and oversaw the MBT-70 program both at home and abroad, its cancellation was cause for celebration. 

Another often cited reason for the program’s demise was that American auto manufacturers charged an exorbitant amount for their services, perhaps because during peacetime defense-related work was such a small part of their overall business. 

In addition, the Americans claimed that the Germans were reluctant to share their technology, and insisted on using domestically manufactured components even when they were “obviously” inferior to the ones made in America. 

For their part, the Germans said the same of the Americans, and in the end, they were probably both right.   

Now the Germans and Americans have their own main battle tanks – the Leopard and M1 respectively. 

https://commons.wikimedia.org/wiki/File:Leopard_2_A5_AGDUS_KADAG_equipped.jpg

Since each was developed independently, if they don’t fare well against adversaries in battle, the countries have no one to blame but themselves, and perhaps that’s the way it should be. 

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