In 1962, the US Armor Association launched a competition for the design of a next generation of Main Battle Tanks (MBTs) to replace the M60 Gun Tank in light of advanced Soviet vehicles which were being developed. The goal was to gather ideas as to how people thought the tanks of 1965-1975 might look and left the various designers a lot of freedom in terms of armament and propulsion. Many designs were sent in from around the world but one very close to home came from a serving US soldier, David Bredemeir, based at Fort Knox, the home of the US School of Armor at the time. This design was to eschew conventional suspension, layout, and armament and produce a missile carrier capable of destroying any future Soviet threat. Named the ‘M-70’ (no connection to the MBT-70), presumably for the anticipated in-service date, this vehicle provides a semi-professional glimpse at some of the thinking of the era.
The basic layout of the M-70 was a long slender tank. The engine, a “long slender gas turbine”, was positioned alongside the driver at the front. The turbine would power the front-mounted transmission.
The M-70 was not to be a conventional gun tank. Bredemeir eschewed the conventional cannon approach for his design and put the offensive capability for the tank in the hands of anti-tank guided missiles. This design choice was based upon the logic that it would be able to fire before an enemy tank could and to ensure a first-round hit each time. The result was that the tank was to carry a battery of 8 anti-tank guided missiles (ATGM) in each ‘fender’, the sponsons along each side above the tracks. As the missiles traveled slower than a conventional shell, they could be fired in the general direction of the enemy even without aiming, with this process then being picked up by means of the guidance as the vehicle stopped. There would then be time to guide the missile onto its target before the corresponding enemy tank had had time to stop, aim and fire its main gun. Another launcher was retained in a rotatable turret at the back of the vehicle and between 50 and 60 missiles could be carried. Storage was facilitated for them, as their fins were all spring-loaded to fold down. Of those 50-60 missiles, 20 were to be stored in the turret.
Various types of missiles were proposed, including smoke, chemical, heat-seeking, and even atomic rounds, guaranteeing these missiles were capable of taking on even the heaviest of enemy armor. The heat-seeking missiles also enabled this tank to counter enemy aircraft and it could track them itself too with a built-in onboard radar. A machine gun was mounted on the commander’s cupola.
The M-70 was to use a three-man crew consisting of commander, gunner, and driver, although the gunner also served as a radar operator. When the gunner was busy loading the missile tube, the commander could take over his duties. Of the three crew, the driver would be at the front, leaving the commander and gunner in the turret at the back. The gunner, situated on the left, would be able to operate the missile launch-tube centrally as well as the radar, and when he was otherwise engaged, the commander could take on the gunner’s duties. The commander sat in the turret on the right-hand side and had his own cupola with a machine gun.
Being lower than the M60 Gun Tank would give the M-70 a higher chance of survival on the battlefield, as it would be less likely to be hit. It also meant a lighter and more maneuverable tank but it still needed armor. The result was that the M-70 was to be made out of aluminum. This, in turn, would keep the overall weight down to 20 to 25 tons (18.14 to 22.70 tonnes)
The suspension for the M-70 was a ‘two-stage’ system, with the tracks and road wheels divided in half and connected together via a single leaf-spring holding them to a beam that ran the full length along each side. Each of those beams was then connected by a pivot arm at the front and back of the tank to a connector on the opposite side. The hull itself was not mounted directly to these track units but held via coil springs from each end of the beam instead. Only the driving axles for the sprockets would directly link the hull to the tracks units. This double-spring system was felt to provide maximum comfort. Small road wheels would spread the weight of the tank along its track and also serve to keep the overall height of the vehicle down.
During the 1960s, faced with the enormous growth in power of anti-tank guided missiles, many were speculating it meant the end of the conventional tank. Likewise, the potential of ATGMs outstripped the anti-armor potential for large caliber guns with the advantage of being significantly smaller and lighter. Many countries would consider and even develop ATGM-based tanks during the Cold War, but just like the US Army, they were constrained by budgets, thinking, and a conservative attitude of trying to keep developments relatively simple. The M-70 offered superior firepower to the M60 in a much smaller vehicle but in 1962, this gun-launched missile concept was already underway on the M551 Sheridan. It was never to work satisfactorily for that tank and the M-70 offered little to warrant development.
Armour Magazine January-February 1963
|Total weight, battle ready||20 to 25 tons (18.14 to 22.70 tonnes)|
|Crew||3 (Commander/Gunner, Gunner/Radar Operator, Driver)|
|Propulsion||Petrol turbine (fuel tanks under turret at the back)|
|Armament||ATGM launchers, 50-60 shells (incl. 20 in turret)|