MBT-70 - WikiHQ

The MBT-70 (German: or ) was an American–West German cancelled 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.

History

Background

The joint German–US main battle tank program was the brainchild of 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, Beehive anti-personnel 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 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.

The frontal arc of the MBT-70 was protected against 105 mm APDS ammunition fired from 800 m distance.

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.

thumb|350px|Sketch showing spaced frontal armor, low profile and seating arrangement of crew

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.

Mobility

;American variant

The American variant was powered by a Continental Motors AVCR-1100 diesel engine, . This was paired to a German Renk electro-hydraulic transmission.

Testing

thumb|Pilot #2 at Aberdeen Proving Ground undergoing trials

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.

Problems

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 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. 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.

The U.S. spent $305.4 million on the MBT-70 and XM803 programs, while Germany spent $100 million.

Germany subsequently started the development of the "Keiler" tank on its own. Later this program would lead to the Leopard 2.

XM803

thumb|XM803 at the [[U.S. Army Armor & Cavalry Collection. Note the two return rollers, versus three on the MBT-70.]]

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-unit 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. Systems were simplified or eliminated altogether to save costs. The XM150E5 gun-launcher was replaced with an XM150E6, which included a closed breech scavenging system. A 24-round General Motors autoloader was installed. Ammunition capacity was increased to 50 rounds. The commander's 20 mm cannon was replaced by a .50 caliber M85 machine gun. The driver's escape hatch was deleted and his television, as well as those of all the other crew, were eliminated. The Continental AVCR-1100-3B engine was derated to at 2600 rpm and paired to a General

Motors XHM-1500-2B transmission. A simplified National Water Lift hydropneumatic suspension was installed. Side skirts were installed, which allowed some armor to be removed from the hull. Meanwhile, the U.S. Army studied installing a gas-turbine AGT-1500 generating (this was the engine that would come to power the M1 Abrams).

Only one of the two pilot vehicles authorized for construction was completed. In addition, a surrogate vehicle based on the components of MBT-70 the M60 and the M88 armored recovery vehicle, was constructed.

These changes were ultimately insufficient to allay concerns about the tank's cost. In September 1971, an amendment by Senator Thomas Eagleton was defeated that would cut $35.3 million in funding for XM803 prototype production. but 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.

Comparative table

{| class="wikitable" style="text-align:center;"

! style="width:18em;" | MBT-70

! style="width:18em;" | Kpz-70

! style="width:18em;" | XM803

! Country

| United States

| West Germany

| United States

! Number of prototypes

| 14

| 7

| 1

! Weight, combat loaded

! Engine

| Continental AVCR-1100-3A

| Daimler-Benz/MTU MB-873 Ka-500

| Continental AVCR-1100-3B

! Displacement

| 22.2 L

| 39.8 L

| 22.2 L

! Net horsepower

| at 2800 rpm

| at 2600 rpm

! Net torque

| at 2200 rpm

| at 1950 rpm

| unknown

! Transmission

| colspan="2"| Renk HSWL 354/2

| General Motors XHM-1500-2B

! Top speed

! Range

! Suspension

| National Water Lift Model 812

(twin cylinder)

| Frieseke & Höpfner Hydrop-Feder

| National Water Lift

(single cylinder)

! Tracks

|colspan="2"|Diehl 170 double pin tracks

| unknown

! Tracks width

|colspan="2"|

! Main armament

|colspan="2"|XM150E5 152 mm gun/launcher

| XM150E6 152 mm gun/launcher

! Autoloader

| Rh or GM

| Rheinmetall (24 rounds)

| General Motors (26 rounds)

! Rate of fire

| 6 rounds/min (on the move, shells and missiles)

| 10 rounds/min (stopped, shells only)

| 8 rounds/min, (shells only)

! 152 mm ammunition carried

| 48

| 46

| 50

! Secondary weapon

|colspan="2"|Rh-202 autocannon retractable into a capsule

| M85 heavy machine gun mounted on top of the commander's stabilized day/night

! Coaxial machine gun

| General Electric M73

| Rheinmetall MG3A1

| General Electric M73

Legacy

thumb|right|MBT-70 with suspension lowered at the [[U.S. Army Armor & Cavalry Collection]]

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."

Surviving vehicles

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.

American prototypes

One prototype is located at Fort Lee (military base) in Prince George County, Virginia. It was formerly at Aberdeen Proving Ground.
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 Benning, 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.

German prototypes

One prototype is located in the Deutsches Panzermuseum Munster
Another is located in the Wehrtechnische Studiensammlung Koblenz

File:Aberdeen proving grounds 037.JPG|MBT-70 at Aberdeen Proving Ground

File:MBT70Koblenz.JPG|Kampfpanzer 70 at Koblenz

File:MBT-70 Danbury, CT.jpg|MBT-70 pilot #2 at Danbury, Connecticut

File:XM803 surrogate at the Armor and Cavalry Collection.jpg|XM803 surrogate at the Armor and Cavalry Collection, Fort Benning, Georgia, made from the MBT-70 and M60 parts.

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References

;Notes

;Bibliography

External links

Department of Defense Appropriations for 1972: Hearings Before the Subcommittee