“Coming out of World War II and into Korea, the Army thought it needed three types of tanks – light, medium and heavy. At the end of World War II, the M24 was considered medium, but during Korea was reclassified as light. The problem for light tank design – indeed, all light armor – is if you want a light armor system capable of taking on enemy armor with upgraded ballistic protection, you need a bigger gun, which translates into a heavier vehicle. But it’s also nice to have something stealthier and more mobile. Throughout the Cold War, the Soviets kept upgrading their armor and armament and light tanks had a hard time keeping up.”
Korea also saw the introduction of a new light tank – the M41 Walker Bulldog – as a replacement for the M24. By the end of the Korean War, the U.S. had a large number of M48s in the field, along with the M41 and the M103 Heavy Tank – a variant of the M48 with a six-man crew, 120mm gun and two-piece cartridge that was the heaviest and most heavily armed U.S. tank until development of the M1A1 Abrams in the mid-1980s.
“These were to be grouped into heavy tank battalions to counter a major Soviet tank assault. It was similar to how the Germans used Tigers in WWII, but as we went through the 1950s, not many 103s were built (most were turned over to the Marines),” Cameron said. “But for the Army, the nature of the threat that led to the Heavy Tank design was found to be overrated. There had been exaggerated concepts of what Soviet tanks could do and, as people took a more realistic look at Soviet capabilities, the need for a heavy tank diminished. And the M48 became more versatile as the main battle tank (MBT) concept emerged.
“There also was a new look at the trend to light tanks. The M5 [Stuart, the Army’s standard light tank at the beginning of World War II], then the M24, then the M41 – the trend was the same as any other tank: Increasing gun caliber, heavier weight, heavier armament, heavier armor. As you moved through the 1950s, then, the Army began looking at a single platform instead of the light-medium-heavy triad.”
Perhaps the single biggest change in tank structure was how armor was incorporated.
“The big advance came in the change from a cast hull, which had its own problems because, when hit, even if you did not penetrate, the back side of the hull would splinter off and throw fragments into the interior,” according to Dr. Douglas Templeton, deputy associate director for ballistic protection at the Army’s Tank Automotive Research, Development & Engineering Center (TARDEC). “The M60 still used cast iron. The big change came in what evolved into the Abrams, with welded armor plate instead of cast.
“In addition, we moved into using aluminum as the availability became greater. Probably the world’s best armored vehicle is the U.S. M113 armored personnel carrier, introduced in the 1960s but still seen around the world. It’s an all-aluminum vehicle, basically a box on tracks, not as heavily armored as a tank, but still well-protected and extremely versatile.”
Editor’s note: This article was first printed in The Year in Defense: Review Edition in an abridged version as “Armor: Three Decades of Advances.” It is now appearing online in its original form, in four parts.