The American tank industry finished WW2 in a strange position. On one hand, the Americans achieved an impressive amount. Starting the war with a few hundred light tanks and a few dozen medium ones, the Americans quickly caught up and in some ways even overtook the leading tank building nations of the world. The Medium Tank M4 was one of the finest medium tanks in the world when it was built. The Americans also achieved great things in SPG development. However, the Americans were in a difficult position by the end of the war. The looming crisis was not so obvious in 1945, but if one digs a bit deeper then the situation in American tank building begins to seem a lot more dire.
Achievements of the arsenal of democracy
It's wrong to say that everything was bad with American tank building. Overall, the Americans came at least third and were leaders in some aspects. Before talking about problems, it's worth listing their achievements. This can also show where the problems came from.
|Like the Soviet T-34, the Medium Tank M4 remained the main American tank until the end of the war.
By 1943 the situation in American tank building was far from ideal, but better than what was happening to the Germans. The combat debut of the Medium Tank M4 took place in the fall of 1942. This tank became the second most numerous tank of WW2. It was an evolution of a chassis that came about before the war. The decision to avoid changing it was wise, as it allowed production numbers to remain high. The Americans showed that they were adaptable and capable of quickly compensating for any difficulties. Production initially relied on radial aircraft engines, but by 1943 a whole series of engines were in use. The USSR solved its engine shortage by building several factories that produced engines from the V-2 family. Meanwhile, the Americans used four different types of engines in their medium tanks (there was also a fifth one used on the M4A6, but its age was a short one). The cost of this was the need to build a different hull, but four different manufacturers (Continental, Ford, Chrysler, and GM) solved the engine problem.
Recall also that the Americans built 49,000 Shermans in 3.5 years, while the USSR had from 1940 to 1946 to build 61,000 T-34/T-34-85. Tanks from the T-34 family were built at six factories in total (seven if you include factory #183 in Kharkov), but the Medium Tank M4 was built at a dozen different plants. American tank factories were also not working just for themselves, but also for the British, as over 17,000 tanks were sent to the UK.
|M4A3E8, the peak of evolution of the Medium Tank M4. These tanks served for a long time after WW2 ended.
The Medium Tank M4 was the greatest achievement of the American tank industry. This workhorse had an impressive modernization reserve. Without much trouble the Americans installed a new turret on their medium tank, making a vehicle that was no worse than the T-34-85 and definitely better than the Pz.Kpfw.IV, its main opponent in 1943-45. The hull was also modernized, which improved the conditions in the driver's compartment, and the HVSS suspension solved the issue of increasing ground pressure. After the war it turned out that the Medium Tank M4 could accept even a 105 mm gun thanks to its 1750 mm wide turret ring, a record in its class. To compare, the Pz.Kpfw.IV expended its modernization resource by the end of 1942. The fact that the modernized M4 chassis was suitable for the next generation of SPGs was also important. Some of them entered service right at the end of the war.
|The Light Tank M24, the best light tank of WW2, served even longer.
The Americans were even more successful at building light tanks and SPGs. It helps that these tanks were not intended to be cheaper and smaller medium tanks, but rather used for reconnaissance and other special tasks. Development hit a snag with the Medium Tank M7, but went a different way after the desire to have thick armour cooled off. The Light Tank M24 ended up being not just the best light tank of WW2, but also a good platform for SPGs. These SPGs did not make it in time for WW2, but came in handy in Korea, where they achieved great results. The use of light tanks for SPG chassis became a priority for the Americans later on.
|Gun Motor Carriage M36, the best tank destroyer the Western Allies had at the end of the war. This vehicle was often used as a tank, since it was not much different from one conceptually.
Medium tank destroyers were also a successful direction. Tank Destroyer Command backed projects like the GMC M18, but practice showed that this was not the right move. Its armour was not even thick enough to protect from heavy machine guns. It was also impossible to install any gun heavier than the 76 mm M1 on this chassis. There were some experiments, but all ended as failures. On the other hand, the GMC M36 ended up being the best American tank destroyer. This vehicle was not built from scratch, but rather as a conversion of the GMC M10, M10A1, or the Medium Tank M4A3. This optimization allowed rapid production of these tank destroyers which were also often used instead of tanks,
|The Heavy Tank T26E3 ended up as the only new generation tank that managed to see battle.
The Americans were the only ones among the Allies who managed to not only build a next generation medium tank, but use it in battle. This was the Heavy Tank T26E3 or M26. It took a great effort to create this tank, but recall that the T-44 was also mired in adversity and never made it to the front anyway. The British Centurion also came too late to fight. The T26E3 was not without issues, but it performed quite well in the last year of the war and served for some time after that. Many American tanks built in the second half of WW2 ended up with quite long careers. Many of them were only retired in the 1950s, and other nations continued to use them for much longer. The Light Tank M24 and Medium Tank M4 finally retired not too long ago.
Half a step behind
We did not start with 1943 by accident. This year was the most difficult for American tank building. Failures were experienced in several directions at one. For one, the heavy tank program hit a dead end. The Heavy Tank M6 was deemed to not meet modern requirements, and thus not built in large numbers. The program to create a new light tank ended with a new medium tank, as mentioned above. This delayed the debut of the new light tank by a year. This was not such a big problem, as light tanks were used for secondary objectives, but the medium tanks were a bigger issue. The Medium Tank T20 concept was solid, and the tank was modern for its time. Nevertheless, it paled in comparison to the Panther. The same can be said for the Soviet T-43.
|The late appearance of the T26E3 is simple to explain. The tank was the result of the fifth attempt to build a new vehicle, and the new tank was already pushing the limits of its chassis.
Reliability was the biggest issue of the Medium Tank T20 and its family. Various defects cropped up regularly. Each vehicle had its own Achilles' heel: an unreliable transmission, overloaded suspension, complex electrical system, etc. The result was a false start in the form of the Medium Tank T23 that was even accepted into service, but turned out to be too complicated for front line service.
Suspensions also caused a lot of headaches for the Americans. It was clear that the torsion bar suspension was optimal after they had the chance to inspect the Soviet KV-1 and German Pz.Kpfw.III. This suspension was relatively quickly introduced to light tanks, but medium ones were harder. The same was true for the Medium Tank T25E1 with its new 90 mm gun. Interestingly enough, the Medium Tank T26E1 was the most successful tank of the family, since it was built with a reinforced suspension from the start. The tank was now officially a heavy, not just because it weighed 40 tons compared to the Medium Tank T20's 30, but also because it had tougher front armour than the Tiger.
|In Korea the Pershing was famous for its amount of technical issues.
|The first battles showed that the Heavy Tank T26E3's armour is insufficient. It later turned out that it was impossible to improve it any further,
|Heavy Tank M6A2E1, a desperate attempt to build a heavy tank. This tank used the stock turret of the Heavy Tank T29.
|Super Heavy Tank T28, the heaviest and most useless American tank,
|The Heavy Tank T26E4, the only true American heavy tank to see front line service.
|Heavy Tanks T29 and T32, both unsuccessful attempts at building a heavy tank on the T26E3 chassis.
|Trials showed that the tank was quite unreliable. The 105 mm T5E1 gun was also not a reliable means of defeating the latest German tanks. The American heavy tank was still worse than the King Tiger.
|The Heavy Tank T30 had a more reliable engine, but its gun was not a good choice.
|Power pack with a Continental AV-1790-1 engine and CD-850 transmission, the best outcome of the Heavy Tank T29/30/34 program.
|Another outcome of the Heavy Tank T29/30/34 program: the T53 gun that evolved into the M58. This gun was later used on the Heavy Tank M103.
|A tank destroyer on the Medium Tank T23 chassis. This vehicle did not proceed past a model since the 90 mm gun could be used on the GMC M36. In early 1946 it turned out that tank destroyers were no longer needed.
|Chrysler K, an attempt to make a new heavy tank that was quickly cancelled.
|The Light Tank T37, one of the outcomes of Stillwell's Council. This vehicle later evolved into the Light Tank M41.
|The War Department Equipment Board launched the development of new tank engines.