Америка-Батыс Германия бірлескен танк жобасы (MBT 70)

American West German main battle tank

The MBT 70 (German: KPz 70 or KpfPz 70) was an American–West German joint project to develop a new main battle tank during the 1960s. The MBT 70 was developed by the United States and West Germany in the context of the Cold War, intended to counter the new generation of tanks developed by the Soviet Union for the Warsaw Pact. The new tank was to be equipped with a number of advanced features such as newly developed "kneeling" hydropneumatic suspension and housing the entire crew in the large turret, and was armed with a 152mm XM150 gun/launcher, which could use both conventional ammunition and the MGM 51 Shillelagh missile for long range combat. The program faced significant challenges from the start, including poor communication and coordination between the American and West German teams working on the project. The U. S. Army and the German Bundeswehr had different requirements which were not aligned and were not resolved before the project was too far advanced to be changed. By the late 1960s, the development of the MBT 70 was well over budget, leading West Germany to withdraw from the project in 1969. The United States continued development of the MBT 70 (spun off as the XM803) until 1971 when the program was finally cancelled, with funds and technology from the MBT 70 project redirected to the development of the M1 Abrams. West Germany independently developed the Leopard 2 as its new main battle tank.

The progenitor of the joint German–US main battle tank program was US Secretary of Defense Robert McNamara. After serving in the US Army Air Forces during World War II, McNamara became a "Whiz Kid" at Ford Motor Company, where he later rose to become president. McNamara's interest in German engineering had been shown during his tenure as head of Ford. He had shepherded development of the abortive Ford Cardinal – a cancelled project involving the redevelopment for US and other international markets of a compact family car designed by engineers in both the US and Germany. This, it was hoped, would result in a new, competitive product for international markets, with reduced development costs. Many Americans both inside and outside the project, including General Creighton Abrams, hoped for an amicable end to German involvement in the program. Burba was succeeded by Brigadier General Bernard R. Luczak in mid 1968. Luczak agreed that the German partnership was not working out. Luczak found support from Deputy Secretary David Packard, who brokered an agreement to end the tank partnership in January 1970. This gun/launcher could fire conventional 152 mm rounds like High Explosive, anti personnel, M409A1 High Explosive Anti Tank (HEAT) and the XM578E1 Armor Piercing Fin Stabilized Discarding Sabot (APFSDS) rounds, but also the MGM 51 Shillelagh missile, a 152 mm guided missile, which had a combat range of some Another new feature of the ammunition was that the tank rounds were "caseless"; i. e., they had combustible cases. The gun could be retracted into a container behind the driver's rotating cupola for protection as well as to reduce overall height, and was operated remotely by the commander. The US prototypes were fitted with the M73 machine gun, while the German version utilized the MG 3 machine gun. The ammunition load of the MBT 70 prototype seen in the Deutsches Panzermuseum consists of 42 tank rounds, 6 Shillelagh missiles, 660 20×139 mm cannon rounds and 2,700 7.62×51mm NATO machine gun rounds. The frontal arc of the MBT 70 was protected against 105 mm APDS ammunition fired from 800 m distance. The High Performance Armour contained 9% of nickel and 4% of cobalt and was produced by vacuum arc remelting. It was heat treated to 500 BHN, like the other types of high hardness armor, but it was produced from the start in the form of plates 40 mm thick. Two watertight armored transverse bulkheads separated the crew in the center from the multi ply rubber fuel tank in the front compartment and the engine compartment in the rear. To save weight, aluminum was used for the engine compartment floor and for access doors on the engine deck. The MBT 70 was protected against electromagnetic pulses and nuclear, biological and chemical weapons as well. The tank's low silhouette, which could be lowered from to only , was also a large advantage. Compared to the M60 tank, the MBT 70 had a lower profile. With the hydropneumatic suspension lowered it was also smaller than the Leopard 1, which gave the MBT 70 a better hull down position. The MBT 70 was equipped with eight XM176 smoke grenade dischargers, each discharger barrel contained two smoke grenades; one AN M8 HC and one M34 WP. Actuated from the commander's station, these launchers provided close in protection and concealment for the vehicle. The KPz 70 was equipped with 16 in four rows of 4.

A prototype series started in 1965, with two mild steel hull and six "complete" hulls of both the US and German versions, for a total of 14 hulls. The lower hull and drivetrain were tested in 1966, and full trials began in 1968. The tank proved to have better mobility than the M60: it was considerably faster, both in all out speed and, more importantly, with about three times the acceleration. All of this led to a reduction in the time the tank was exposed to fire, in testing it was 1/3 less likely to be seen while maneuvering than the M60, and it could run a obstacle course in 30% less time. A year behind schedule, the U. S. and Germany debuted their MBT 70s publicly in October 1967. An American prototype was displayed outside the Association of the United States Army in Washington. The German demonstration in Augsburg ended prematurely: smoke poured out of the tank after the turret's hydraulics malfunctioned. Observers were nonetheless impressed and German officials said the tank was on track to replace all M48 Pattons of the Bundeswehr by 1972.

An unanticipated problem was that the drivers complained of disorientation when the turret was rotated, contrary to the predictions of the designers who felt the location of the cupola near the center of rotation would eliminate this effect. The German 120mm gun proved excellent, although only firing APFSDS and HEAT, but the XM150 gun/launcher had serious problems. The similar but smaller XM81 gun/launcher mounted on the M551 Sheridan proved to be just as troublesome. There were also several problems with the ammunition. The caseless design made conventional tank rounds too vulnerable to water. Wet rounds expanded so they would not fit into the barrel anymore or left hard residues after being fired. However, turbine engines need very clean air, and the quantities of dust churned up by tank operations proved problematic. After initial efforts to solve the problem using air filters, the turbine engine was replaced with conventional piston engines. Commentators on the MBT 70 typically assert that though it was innovative in many respects, the project was ruined by the use of too many untried and unproven technologies. Senator James W. Fulbright commented that to drive an MBT 70, a master's degree from a technical institute would be required. In August 1969, Senator Thomas Eagleton was granted a request that the Government Accounting Office undertake an audit of the program. The GAO recommended the tank development program proceed on an austere basis. Acting on this recommendation, Deputy Secretary of Defense David Packard agreed to withhold $25 million earmarked for the production of six prototypes while the DoD completed a review of the project. Packard was ultimately persuaded by Army leaders that the American MBT 70 project was technically sound. The Army agreed that development would be better off without German cooperation. In January 1970, the Department of Defense ended its tank partnership with Germany and committed to forging ahead with its own design. Germany started the development of the "Keiler" on its own. Later this program would lead to the Leopard 2.

Work began on converting the existing MBT 70 design into a low cost "austere" alternative that would use only American made components, resulting in the visually similar XM803 prototype. Congress hoped to drive down the per tank cost to $500,000–$600,000, saving $200,000 per tank versus the MBT 70. General Motors received a $16.5 million contract to develop the tank in July 1971. Despite these compromises, the XM803 design began to match the MBT 70 in complexity as development progressed. In September 1971, Congress defeated an amendment by Senator Thomas Eagleton that would cut $35.3 million in funding for six XM803 prototypes. In December 1971, Congress canceled the tank in the defense appropriation bill. The bill appropriated $20 million for cancelation costs and $20 million for the development of a new tank program. This became the XM1 design project, which led to the production model M1 Abrams tank.

In a post mortem report of his four years on the project, American program manager Brig. Gen. Bernard Luczak attributed the high cost of the tank to the difficulties of managing a joint program. Luczak claimed General Motors charged a premium for its defense contract work, which it considered insignificant compared to its burgeoning automotive business. In the 1989 book King of the Killing Zone author Orr Kelly called the end of the MBT 70 program, "one of the most fortunate occurrences to befall the U. S. Army."

Altogether 14 prototypes and test beds were built, two made of mild steel. Some of them have survived in museums and can still be visited today.

One prototype is located in the Anniston Army Depot in Anniston, Alabama. Another prototype, as well as a prototype of the XM803, is located in the Armor Museum Restoration Yard at Fort Moore, Georgia. A mild steel prototype in bad condition could be seen in the Military Museum of Southern New England in Danbury, Connecticut until October 2019. Following the closure of the museum, it was sold for scrap metal. Only the turret remains.