Editing MBT-70 (section)

==Design==
[[File:MBT-70 interior arrangement.jpg|thumb|left|upright=1.3|Interior arrangement. Gunner's station in right foreground, commander's station to his rear, driver's rotating capsule partially obscured in left side of turret]]

Many features of the MBT-70 were ahead of their time. The vehicle used an advanced [[hydropneumatic]] [[suspension (vehicle)|suspension]] system that allowed for fast cross-country speeds even though it was to weigh {{convert|45|t|ST}}. The suspension could be raised or lowered on command by the driver, down to put the bottom of the tank just over {{convert|4|in}} from the ground, or up to {{convert|28|in}} for cross-country running.<ref name=mbt70atfprado>{{cite web|url=http://www.fprado.com/armorsite/mbt_70.htm|title=MBT-70 at armorsite|access-date=24 October 2010|archive-url=https://web.archive.org/web/20100926144600/http://www.fprado.com/armorsite/mbt_70.htm|archive-date=26 September 2010|url-status=live|df=dmy-all}}</ref><ref name=MBT-70atglobalsecurity/>

The MBT-70 was designed with a low silhouette, unlike the M60, one of the tallest tanks ever built. The MBT-70 ended up very low, just over {{convert|6|ft}} from the floor to the turret-roof. This left no room in the hull for the driver, who had to be moved into the turret. He was located in a [[cupola]] which was geared to rotate so that he was always looking in the same direction even if the turret turned. He could also spin the cupola around, so the tank could be driven backwards at full speed.<ref name="DerSpiegel" />

The US version was to mount the newly developed Continental AVCR air-cooled V-12 diesel of {{convert|1470|hp}}. German versions originally used a similar [[Daimler-Benz]] model, but later moved to an [[MTU Friedrichshafen|MTU]] design of {{convert|1500|hp}}. The MTU unit could be easily swapped out of the tank, along with the drive train, in 15 minutes. Both versions could reach {{convert|43|mph}} on their engines, compared to {{convert|31.06|mph}} for the T-62.

===Armament===
[[Image:MBT-70 Shillelagh rocket firing.JPG|thumb|right|MBT-70 prototype test firing an MGM-51 missile]]

The MBT-70's main armament was a stabilized '''XM150''' 152&nbsp;mm gun/launcher, a longer-barreled and improved variant of the XM-81 gun/launcher used in the light [[M551 Sheridan]] and the [[M60 Patton#M60A2|M60A2 "Starship"]].<ref name=MBT-70atglobalsecurity>{{cite web|url=http://www.globalsecurity.org/military/systems/ground/mbt-70.htm|title=MBT-70 at globalsecurity.org|access-date=8 November 2010|archive-url=https://web.archive.org/web/20100823045247/http://www.globalsecurity.org/military/systems/ground/mbt-70.htm|archive-date=23 August 2010|url-status=live|df=dmy-all}}</ref> This gun/launcher could fire conventional 152&nbsp;mm rounds like [[Explosive material|High Explosive]], [[anti-personnel]], M409A1 [[High explosive anti-tank warhead|High Explosive Anti-Tank]] (HEAT) and the XM578E1 [[Armor-piercing fin-stabilized discarding sabot]] (APFSDS) rounds, [[Beehive anti-personnel round|Beehive anti-personnel]] rounds, but also the [[Shillelagh missile|MGM-51 Shillelagh missile]], a 152&nbsp;mm guided missile, which had a combat range of some {{convert|3000|m}}.<ref name="DerSpiegel" />{{sfn|Hunnicutt|1990|p=130}}

In the 1960s the effective combat range of the 105&nbsp;mm [[Royal Ordnance L7|L7 tank gun]] was considered to be about {{convert|1800|m}}. The XM578 APFSDS round was made of a newly developed tungsten alloy, which was 97.5 percent tungsten. This new alloy had a density of 18.5 g·cm³, which was a big improvement compared to the older [[tungsten-carbide]] APDS and APFSDS rounds.<ref>{{cite web |url=http://www.globalsecurity.org/military/systems/munitions/m578.htm |title=XM578 152mm, APFSDS |access-date=2010-11-11 |publisher=GlobalSecurity.org |archive-url=https://web.archive.org/web/20100326164634/http://www.globalsecurity.org/military/systems/munitions/m578.htm |archive-date=2010-03-26 |url-status=live}}</ref> Another new feature of the ammunition was that the tank rounds were "caseless"; i.e., they had combustible cases.<ref name="DerSpiegel" />

[[Image:MBT-70 turret.JPG|thumb|Turret weapon layout, autocannon in stowed position, barrel pointing backwards]]
[[Image:MBT-70 secondary cannon 1.JPG|thumb|upright|The 20&nbsp;mm autocannon deployed]]
The MBT-70 was equipped with a [[laser rangefinder]] and a 26-round [[auto-loader]] in the turret bustle.{{sfn|Hunnicutt|1990|p=130}} Although the auto-loader was supposed to be capable of loading both missiles and combustible-case tank rounds,{{sfn|Hunnicutt|1990|p=130}} the German [[Rheinmetall]] autoloader was prone to deforming the ammunition's fragile combustible cases.<ref name="500 Germany" /> The Americans substituted the German autoloader with a General Motors design,{{sfn|Hunnicutt|1990|p=130}} which increased the ammunition capacity to 48 rounds.{{sfn|Hunnicutt|1990|p=299}} Italy had also contributed to the XM-150 as the automatic loading system was built by [[OTO Melara]] (now [[Leonardo S.p.A.|Leonardo]]). The automatic loading system had a vertical rotating magazine equipped with 16 containers, for 5 types of ammunition, which allowed a firing speed of 12 rounds per minute.{{Citation needed|date=November 2023}} 

46 152&nbsp;mm rounds could be carried on the models with Rheinmetall autoloaders. The MBT-70 with the GM autoloader could carry 48 rounds,{{sfn|Hunnicutt|1990|p=299}} and the XM803 could carry 50 rounds.{{sfn|Hunnicutt|1990|p=300}} The MBT-70 with the Rheinmetall loader carried 26 rounds in the autoloader. Twenty more rounds were carried in two compartments including eight rounds stowed on the rear hull bulkhead and twelve behind the driver's capsule.{{sfn|Hunnicutt|1990|p=131}}

The Germans were planning to use the MBT-70 in combination with the ''Keiler'', a tank equipped with a [[Rheinmetall]] 120&nbsp;mm [[smoothbore]] gun.<ref name="DerSpiegel" /> Therefore, a suggestion was made to base a version of the Keiler on the MBT-70 chassis; this version was nicknamed ''Eber'', but only a wooden mock-up was made. According to the German plans, the MBT-70 would destroy enemies at long ranges, while the ''Keiler'' would have an effective combat range of up to {{convert|2000|m}}.<ref name="DerSpiegel" />

The secondary armament of the MBT-70 consisted of a remote-controlled 20&nbsp;mm [[Rheinmetall Mk 20 Rh-202|Rh 202]] [[autocannon]] (with storage for 750 or 660 rounds) for use against aircraft and light armored vehicles.{{sfn|Hunnicutt|1990|p=134, 299}}<ref name="PzMuseumMunster" /> 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.<ref name="PzMuseumMunster" /> Furthermore, a 7.62&nbsp;mm was mounted co-axially alongside the main gun for close defense. The US prototypes were fitted with the [[M73 machine gun]],{{sfn|Hunnicutt|1990|p=134}} while the German version utilized the [[MG 3 machine gun]].{{cn|date=June 2024}}

The ammunition load of the MBT-70 prototype seen in the [[German Tank Museum|''Deutsches Panzermuseum'']] consists of 42 tank rounds, 6 [[Shillelagh missile]]s, 660 [[20 mm caliber|20×139 mm]] cannon rounds and 2,700 [[7.62×51mm NATO]] machine gun rounds.<ref name="PzMuseumMunster" />

===Protection===
The frontal area of both the hull and turret was protected by spaced armor and provision was made for the installation of a [[polyethylene]] radiation shielding to achieve an attenuation ratio of 20:1 against [[neutron radiation]].

The outer layer was made of High Performance Armour developed in the United States and incorporated in the mid-1960s in the design of the MBT-70.<ref>{{Cite book|title=Technology of Tanks (Vols 1-2)|last=Ogorkiewicz|first=Richard M.|publisher=Janes Information Group|year=1991|isbn=978-0710605955|location=London|pages=361}}</ref> 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&nbsp;mm thick. The armor was well protected against gun fired HEAT munitions, but lacked protection against kinetic munitions. 

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 pulse]]s and [[NBC (weapon)|nuclear, biological and chemical weapons]] as well.

[[File:MBT-70 final sketch.JPG|thumb|350px|Sketch showing spaced frontal armor, low profile and seating arrangement of crew]]
The tank's low silhouette, which could be lowered from {{convert|2.59|m}} to only {{convert|1.99|m}}, 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.{{Citation needed|date=February 2013}}

The MBT-70 was equipped with eight XM176 [[smoke grenade|smoke]] [[grenade discharger]]s, each discharger barrel contained two smoke grenades; one [[AN-M8 smoke grenade|AN-M8 HC]] and one [[M34 grenade|M34 WP]].{{sfn|Hunnicutt|1990|p=134}} 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 Company|Continental Motors]] AVCR-1100 diesel engine, {{convert|1,475|bhp|abbr=on}}. This was paired to a German [[Renk]] electro-hydraulic [[transmission (mechanical device)|transmission]].<ref name="500 Germany" /> The top speed was {{convert|50|km/h}} and the range was {{convert|645|km}}. The top reverse speed was the same as its top forward speed.<ref name="500 Germany" />

In 1969, the American team decided to eventually replace the diesel engine with an Avco-[[Lycoming Engines|Lycoming]] [[AGT-1500]] [[gas turbine]] engine on the production model.{{sfn|Else|2008|p=67-68}}

;West German variant
The [[Mercedes-Benz Group|Daimler-Benz]]/[[MTU Friedrichshafen|MTU]] MB 873 Ka-500 four-stroke diesel engine on the German variant was heavier and larger than the American [[Continental Motors Company|Continental Motors]] engine. The choice of this engine required some changes to the [[chassis]]. The engine was paired with a [[Renk]] HSWL 354/2 hydraulically operated gearbox with four gears and two reverse. The top speed was {{convert|72|km}} and the range was {{convert|580|km}}.<ref>{{cite book |last1=Spielberger |first1=Walter J. |title=Waffensysteme Leopard 1 und Leopard 2 |date=2003 |publisher=Motorbuch-Verlag |isbn=3-613-01655-9 |pages=370–399}}</ref>