MBT-70 / Kampfpanzer 70
By the early 1960s, with the Cold War now well into its second decade, Western intelligence learned the Soviets were preparing a vastly improved version of their T-62 main battle tank with upgraded armor, three-man crew and an autoloading main gun. The American and West German armies faced exactly the same threat in exactly the same theater of operation. As a result, the American and West German armies both needed a heavy tank that could move fast, fire a very large round and withstand as much as it could dish out.
But at the time, the U.S. defense planners concluded what was needed was a tank so advanced that it would keep us ahead of the Russians for a full generation, not just a couple years. American Defense Secretary Robert McNamara decided to do something no one had ever tried before or since; he got the West Germans to agree to jointly develop this “super-tank” with the United States. The program was to be called the Main Battle Tank 70 or MBT-70.
Today, many weapon systems are developed as part of a cooperative effort by two or more allied countries. But for some reason, nobody ever tries to jointly develop tanks. Nobody really knows why, although the MBT-70 experience might provide a clue.
There was one very good reason to think that the MBT-70 project might work. Initially, both parties saw eye to eye on the new tank’s basic design parameters; a primary one being that it should have a much lower silhouette than the current M60, which was several feet higher than the tallest Russian tank. Instead of having the crew stations inside the hull, as was usually the case, they were being put inside the MBT-70’s oversized turret, which would be protected against nuclear, biological and chemical (NBC) threats. This also made it easier to work out the tank’s armor layout, which they agreed should consist of two spaced layers; an outer layer made of thick, hard, cold-rolled steel and an inner layer made of “soft’ steel that would also protect against “spalling,” or interior fragmentation of the armor.
They also agreed to employ an advanced and complex hydro-pneumatic suspension system enabling it to travel cross-country at high speeds, despite its projected fifty-ton weight. The suspension would also be capable of being raised or lowered by the driver so that the tank could “crouch down” to only four inches off the ground when stationary or be raised up to a full twenty-eight inches when running cross-country.
But after that, there were disagreements. They differed on major elements like the main gun and engine, and even whether the design should use metric or SAE measurements. On this latter issue, they ultimately agreed to use both, which did nothing to contain the rising costs of the tank.
Instead of settling on one gun, they decided to both go with what they wanted, again causing the costs to skyrocket. The Germans chose a relatively simple, auto-loading, 120 mm Rheinmetall gun, while the Americans insisted on using the much more complex XM150 auto-loading, stabilized, laser rangefinder-equipped 152mm gun/launcher system, which, besides using an extensive variety of conventional tank rounds, could also fire the Shillelagh anti-tank missile.
The problem was, the American gun/launcher system never really worked. Variants of the system equipped the M551 Sheridan light reconnaissance vehicle and M60A1E2 tanks, but there were problems with the caseless 152 mm gun rounds, the overly complex Shillelagh missile, and the fire control and stabilization system. The extent of the problems with the M60A1E2 was such that most of the turrets were scrapped and the hulls re-equipped with turrets mounting conventional 105 mm cannon.
When the prototypes were built and testing started in 1968, both German and American contingents were pleased with the tank’s mobility. The German 120 mm gun also proved excellent, but the American XM150 continued to be problematic. As testing continued, they realized they had another big problem. Because the driver would be located inside a turret that would be rotating in battle, the tank’s designers had come up with the solution of mounting the driver inside his own contra-rotating cupola within the turret. Regardless of the direction the turret was facing, the cupola would automatically face forward. The drivers, however, accustomed to being located in a stationary position at the front of a tank’s hull, were becoming disoriented and suffering from motion sickness.
In the end, that was just one problem of several. So many leading-edge technologies incorporated into the tank’s design, from the hydro-pneumatic suspension, laser rangefinder, ballistic computer and night vision system to the remotely-operated 20 mm anti-aircraft cannon and the 152 mm gun/launcher, meant there were problems making these new and complex systems work, and costs rose.
They rose to roughly a million dollars a tank, five times the original estimated cost. By 1969, the Germans had pulled out of the program in favor of developing their own Leopard 2. Congress was also fed up. The Army tried placating them with a lower-cost system based on the same design, the XM803, but what they ended up with was an expensive version of the original M60. Congress cancelled the program at the end of 1971, and the Army plunged the remaining funds into development of what became the M1 Abrams the very next month.
The MBT-70 project was a massive failure, but many of the technologies that emerged from it were later perfected and employed in the M1 Abrams and West Germany’s subsequent Leopard II tank. A variant of the Germans’ 120 mm main gun, for example, equips the M1A1 and M1A2 Abrams today.