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Results of a Great War

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Germany's surrender was signed on the night between May 8th and May 9th, 1945. The core part of the Second World War, the largest war in history, was over. The German army was not the only loser in this war. German industry also lost the battle fought in factories and on drawing boards. The Soviet Union won this battle, finishing the war with the largest tank force in the world. Unlike in the summer of 1945, this was a qualitative rather than merely a quantitative advantage. More importantly, German tank building hit a dead end, while Soviet tank building evolved down a road that later proved correct. Nevertheless, there were plenty of dead ends along the way. This article tells their story.

Within reason

Every tank building school had its own approach to development. Nevertheless, the initial concepts were often very similar, especially when it came to medium tanks. Germany, the USSR, USA, and Great Britain all started working on similar tanks in 1942-43. They weighed about 30 tons and ideally had a power to weight ratio of 20 hp/ton. However, most nations quickly departed from these guidelines.

The Germans went first. The VK 30.01 family of medium tanks started at a weight of 35 tons. Given the theoretical maximum power output of the Maybach HL 230 it was possible to keep the 20 hp/ton ratio, but it turned out that even the first VK 30.02 (M) prototypes weighed over 35 tons and the production Panther Ausf.D already weighed 45 tons. The ground pressure did not increase that much, but such a large increase in stress on the running gear and suspension did not go unnoticed. German reports often show photographs of torn road wheel tires and broken torsion bars.

A comparison between two next generation medium tanks.

The Americans also could not avoid the call for increased mass. They tried to stay within reasonable weight for longer, but their 30 ton medium tank turned into the 40+ ton Heavy Tank T26E3. This tank was only heavy when it came to its mass. The British failed to hit the 30 ton weight class at the start. The very first A41 "heavy cruiser", later known as the Centurion, weighed over 40 tons. Neither the American nor the British tank could boast powerful armour, and the power to weight ratio was even worse than the Panther's. The British situation only got worse, the American one improved with the Medium Tank M46 that entered production in 1949. The issue of armour protection was still an unresolved one.

Even the mass produced T-44 kept its weight within reasonable limits.

Soviet tank builders did not have the luxury of doing this. The prospective next generation Soviet medium tank was not built from scratch. Its running gear was based on the T-34. This tank already began to suffer from issues with its road wheels once its weight crossed the 30 ton mark. 35 tons, let alone 40, was an impossible weight for the next generation of tanks. Ideally, the mass would be no more than 30-32 tons. This strict limit forced Soviet designers to stay within the realm of reason. The T-44 did not make it to the war for several reasons, but its concept became a guide for Soviet medium tanks for decades. The experimental T-54 tank that entered trials in early 1945 already had a partially modernized suspension. This tank had thicker armour and weighed 35.5 tons, but didn't have any issues with road wheels.

The T-54 tank entered trials in the spring of 1945. It had superior armour and armament to foreign medium tanks, but considerably lower weight.

Another important factor was the possibility to develop the new generation medium tank further. The production T-44 had superior armour to the Centurion and Heavy Tank T26E3. It could not be penetrated frontally by even the 75 mm KwK 42 L/70 gun used on the Panther. However, the T-44's armament was obsolete by the end of 1944, and even the armour protection required an upgrade, since the Red Army's new benchmark was the 88 mm KwK 43 L/71 gun. The result was the T-54 tank. The weight increased as a result of the thicker armour and heavier gun. The Panther could not repeat this trick. Rearmament with the 88 mm KwK 43 L/71 would result in a weight increase of at least a ton, and the Germans were very well aware of the consequences of this by looking at the Jagdpanther, whose final drives crumbled with stunning regularity. As for armour protection, the very first vehicles in this series maxed it out already. Any meaningful increase skyrocketed the mass to over 50 tons, raising the ground pressure to over 1 kg/cm² and radically decreasing mobility. 

The Kirovets-1 tank entered trials in late 1944. It had the same mass as the IS-2, but more reliable armour protection.

It would be wrong to write off the Panther entirely. A number of its characteristics stood out among all medium tanks until the end of the war, but it also had a number of built-in defects, and the tank's future was in doubt. The only reason it kept a lead was because the Allies were late with their answers to it for various reasons. The USSR and USA also modernized their existing vehicles, which may not have fought the Panther on equal footing, but were far from helpless. Also, about 16,000 T-34-85 tanks were built in 1944-45 compared to 4850 Panther. Considering that the tank's main objective is not just fighting other tanks, this ratio did not promise the Germans anything good even without accounting for the equally numerous Medium Tank M4.

The Kirovets-1 was followed by the IS-3 with even tougher armour. As later developments showed, it was thick enough to withstand fire from even the 105 mm L7 gun.

The situation with heavy tanks was even sadder for Germany, again due to diverging philosophies. The USSR began traditionally with growing the KV-1's armour thickness. The result was widespread issues with reliability of heavy tanks by early 1942. The result was the 42 ton KV-1S, followed by the IS-85 in late 1943 which was then succeeded by the IS-2 with an even more powerful gun. The IS-2 only weighed 46 tons, just slightly heavier than a Panther.

The Germans went a different route, building the 68 ton Tiger Ausf.B, a successful execution of an absolutely mad order. The tank was far too large and far too heavy with armour that was not remotely as invulnerable as it appeared when development began. The result was questionable reliability and zero room for modernization. The IS-2, especially the tanks that went into production starting in August of 1944, was not that far behind the new Tiger. Production of the IS-3 tank began in April of 1945, which was slightly heavier than the IS-2 but with far superior protection. This tank was late to the war by a hair, but even with the IS-2 alone the situation was bleak for German heavy tanks. The IS-2s ended up taking fewer losses despite being far more common on the battlefield. 

The Object 704 heavy SPG was a great success, but fate was not on its side.

Self propelled artillery was in the same boat. Soviet SPGs surpassed the enemy in both quality and quantity, especially in heavy SPGs. There was also a promising future generation with the SU-101 and Object 704. While the former had issues with overheating, the latter had a good chance at mass production. Like the tanks, Soviet SPGs stayed within reasonable weight limits while German SPGs ran out of options in 1944. The Germans managed to lead themselves into a dead end that would have been difficult to escape.

When you can't stop

One may read the above chapter and assume that everything was going great in Soviet tank building at the end of the war. This was not the case. There were more than enough problems, which will be described later. However, it would have been incorrect to study Soviet tank building apart from that of other nations. The USSR was undoubtedly ahead of the pack as the only nation who organized production of a new generation of heavy tanks that were reliably protected from the main types of German armament. There were also other successes compared to German, American, and British tank builders.

Quality of welding was a problem for Soviet tanks, T-44 included.

A large amount of effort was put into improving protection of medium and heavy tanks. Equal armour all-around was common in the early war, but by 1943 the frontal armour was the thickest. This was a tendency that appears and disappears all over the world, but WW2 solidly cemented it, although the GBTU periodically tried to make side armour at least close to the front armour in protection since about half of all hits came at the side of the hull and turret. The IS-3 was one such attempt. Its side armour, especially the upper hull and turret, was close to that of the IS-2's front and even surpassed it in some places. These cases are an exception. Simple calculations showed that parity would result in excessive weight.

Type of steel was another issue. It caused problems with early IS-3s, but was solved in the spring of 1945.

Recall that armour protection is afforded not only by its thickness. The quality of the armour and welding seams also played a role. There were often issues with the latter. For instance, in penetration trials of the 88 mm Pak 43 L/71 against a production T-44 tank the upper front plate withstood hits from the gun, but the lower front plate fell off as the welding seams were destroyed. The alloy and manufacturing process also had an effect, and so thickness did not always guarantee protection. Turrets of the IS-3 and IS-6 prototypes that cracked after several hits can be used as examples. 

While the IS-6 also had a poor turret shape, the IS-3 suffered from the composition of its armour's alloys as well as cracks in the armour. The production manufacturing processes were different, so one can't evaluate the IS-3's protection based on the prototype turrets. The result of IS-6 trials also had an effect on the development of the T-54 tank. Factory #183's design bureau used it as a starting point for their turret, but after the news arrived they changed directions, moving closer to the IS-3. The tank was then simply overloaded with armour. The T-54 model 1946 was removed from production in February of 1949. The T-54 model 1949 had 20 mm thinner armour, which cut half a ton off the tank's weight. The turret and running gear were also changed.

Factory #174's light tank, a victim of the GBTU's constantly growing requirements.

Protection requirements often led development programs into a dead end. One nameless light tank developed by I.S. Bushnev's group at factory #174 in 1943-44 died this way. This tank would have become a spiritual successor to the T-50 tank with 75 mm of armour and a 76 mm gun with 3-K ballistics, but the GBTU wanted an 85 mm D-5T and 90 mm of front armour. Yes, you read that right: protection from the Pak 43 for a light tank.

This "pumping up" continued until 1945. The GBTU had its own vision of a light tank. They still considered a light tank to be a smaller and lighter medium tank. This was no longer possible in 1943-45. The result was an absence of not only a next generation light tank, but also a chassis for light SPGs. The SU-76M ran out of modernization reserves in 1943. This is why the vehicle didn't have a roof. It had to be removed to lighten the chassis. Nevertheless, the GBTU continued to wish for a 25 ton light SPG that could withstand a frontal hit from the 88 mm Pak 43. The end result was predictable. Meanwhile, across the Atlantic, the Americans understood the situation perfectly and built the Light Tank M24 with a family of SPGs on its chassis. The 25 mm thick armour did not appear to be an impediment to this platform, but its mobility was high and it was a good match for a reconnaissance vehicle role.

This tank could have replaced the IS-3 in production, but the NKTP knew full well how it would end. The IS-4 was therefore postponed to 1946-1949.

The same protection requirements almost led to disaster in the spring of 1945. Both the GBTU and ChKZ considered the IS-3's protection to be insufficient. They were seriously suggesting putting the Object 701 into production instead. Only the NKTP knew full well the status of Soviet tank production and managed to defend the IS-3. The future showed that production of the IS-3 was the only correct outcome. The Object 701 weighed just under 55 tons in 1944 and reached 56 tons in 1945. The production IS-4 tank accepted into service on April 29th, 1946, already weighed 60 tons. Production and usage turned into a large drama that was not fully solved even with the modernization carried out in the 1950s.

The IS-3 also had issues, but for other reasons. The tank was put into production "as is" without time to work out bugs. Nevertheless, it was actively used for decades and two modernization programs radically improved its reliability. Its fate was completely different from that of the IS-4. One can only marvel at the claim of inferior protection, as the IS-3 turned out to be better protected than the IS-4. This protection was proven in battle, as the front hull of the tank was impenetrable for the 105 mm L7 gun, a more powerful weapon than the Pak 43. Meanwhile, the IS-4 ended its career as a part of border fortifications.

The result of excessive protection requirements. The working conditions inside the SU-101 were worse than the original concept, the mass increased, reliability dropped, but desired protection of the sides was still not achieved.

A similar situation took place with SPGs. The desire to make a vehicle impervious to the Pak 43 from the front and partially from the sides gave a predictable result. The SU-100M2 (a starting point for the future SU-101) weighed 31.6 tons. The changes requested by the GBTU drove its weight up to 34 tons, 3 tons more than the T-44. This was one of the reasons that the engine overheated. That was just a part of the problem. The desire to protect the sides of the vehicle from the Pak 43 resulted in a significantly narrower fighting compartment. Penetration trials showed that reliable protection of the sides was still not achieved. The vehicle became the best protected medium SPG built during the war, but that was what ruined it. It was unclear why a tank destroyer with a fixed casemate needed to have such protection of its sides. To top it off, work was shunted over to factory #174 alongside a new chassis. As a result, the SU-100's successor only arrived on March 15th, 1954, when it was no longer needed. The armament of this vehicle was almost identical to the armament of the SU-102, and the front armour was almost identical to what was available 9 years earlier. The side armour was only 5 mm thicker than that of the SU-100M2.

The requirement for side armour also affected the Object 704, although not as much. The death of the Object 704 was not due to this, but the desire to have a more powerful gun and the same vehicle on the Object 701 chassis.

The history of the other prospective SPG, the Kirovets-2 or Object 704, was no less strange. This vehicle did not suffer from overheating and also turned out to be more reliable than the early experimental IS-3s. It also suffered from the need to protect the side of the hull from the Pak 43, although to a lesser extent. The sloped sides made the loader and breech operator's jobs harder and also ate up some space where ammunition could be stored. This was noted in trials reports. Nevertheless, the vehicle was quite successful and suitable for mass production. It was one of the best protected vehicles in its class at a mass of only 48 tons. Unfortunately, the GBTU was already thinking of using the Object 701 as a chassis. As a result, the next heavy SPG, the Object 268, only entered trials in 1956. Like the SU-122-54, there wasn't much of a need for it by then. There was no significant difference between the two vehicles even though they were designed 11 years apart.

This is how the Soviet military envisioned the next generation of heavy tanks by late 1945. One question remains unanswered: who is this 65 ton monster supposed to fight?

The situation in the USSR was somewhat different than the one that was taking place in the USA, Great Britain, and Germany. Soviet tank building took a lead, but instead of stopping to analyze its own tanks and compare them to enemy and allied ones, the GBTU continued to "pump up" its vehicles. The Maus tank discovered in May of 1945 only added fuel to the fire. The first information about this tank triggered a review of the heavy tank program. The IS-7 was essentially a countermeasure to the German superheavy tank that died in 1944. Heavy SPGs to fight Maus-class vehicles were also designed. Work continued from late 1945 to February of 1949. The result of this work deserves a separate article, but one can only say that it mostly led to a dead end. A "reset" took place in 1949. The only saving grace was that the USSR's former allies weren't doing much better.

One step forward, two steps back

Even though the overall situation with tank building in the USSR was not too bad by the end of the war, there were some considerable problems. Not all of them had to do with the GBTU's desire to do battle with a phantom enemy. Any tank or SPG is a complex system of assemblies and components. In addition to armour it needs a powerful engine to give it sufficient mobility, a reliable suspension, good observation devices, powerful armament, etc. While the USSR managed to catch up and take a lead when it came to a number of these, there were still some aspects which Soviet tank designers could not deal with even in the immediate aftermath of the war. Once again, these issues were not unique to the USSR and could also be observed in other nations.

V-12, the only high power tank engine put into production.

Let's start with one of the biggest issues: the engine. Work on creating a more powerful engine than the V-2 began in 1940. These engines were essentially modernized V-2s with mechanical superchargers. This work did not move past experiments. Work on a tank variant of the M-50 engine was also conducted. It was dropped with the start of the war. An attempt in 1942 to create a 700 hp version of the V-2 failed. There were also complaints about the 600 hp V-2K, especially when it came to reliability. The improved V-2-IS engine appeared in 1943. Its power was reduced to 520 hp, but reliability improved.

The V-2-IS served as a starting point for the V-2-44, thanks to which Soviet medium tanks finally got a more powerful engine. The problem was that the IS-2's power to weight ratio was considered insufficient even in 1943, and so work began on a modernization of the V-2-IS. The problem was that the V-11, the most successful of these engines, still only put out 520 hp. The V-16F engine proposed for the Object 257 had insufficient reliability even at 600 hp. The only real success was the V-12 (a reincarnation of the 850 hp V-2SN but reduced in power to 750 hp). This engine was used on the Object 701 alongside a supercharger from the AM-38 aircraft engine.

V-2-44, later V-44, later V-54. This wartime engine was used on Soviet medium tanks for decades after the war.

Work on new engines continued, but most did not progress past experiments. Descendants of the V-2 engine remained in Soviet medium tanks for decades. This situation was not exclusive to the USSR. The British stayed with the Meteor, an engine that was designed in 1942, and its descendants long after the war. The Americans only developed a new successful engine with the Continental AV-1790 in 1948. Everyone had their own issues with engines by the end of the war.

Plan for experimental work on tank and SPG armament for 1946. In practice, all of these programs continued into the 1950s.

Armament was another sore spot. The D-10 100 mm gun became the priority for Soviet SPGs and then even medium tanks in 1944. This was a good gun with an optimal balance of characteristics for medium class vehicles, but not without its nuances. For one, penetration in trials against German tanks turned out to the less than what the 122 mm D-25T could achieve, and that gun was already considered insufficient by late 1943. Tactical-technical requirements for a 100 mm SPG with a muzzle velocity of 1000 m/s were composed on February 25th, 1945. The work dragged on. The D-46 gun created to satisfy these requirements never made it past the prototype stage, neither did the later D-54. The D-10 remained in service for a long time. The D-25T shared its fate. The 122 mm BL-13 gun with increased muzzle velocity did not make it past the prototype stage either. Various iterations of the D-25T remained in production until the mid-50s when it was finally replaced with the M-62. Weapons meant for heavy SPGs were also in the same boat.

For various reasons, none of the high caliber anti-tank guns that started development in 1943 ever saw mass production.

Again, everything needs to be viewed in context. The Americans finished the war with the 90 mm M3 gun that had lower penetration than the D-10T. Attempts to replace the gun proved fruitless until the M60 was accepted into service. The British finished the war with the 76 mm 17-pounder and only built the 84 mm 20-pounder, their analogue of the 88 mm Pak 43, by the end of the 1940s. The next jump in armament only came in the late 1950s with the 105 mm L7. Guns for the next generation of heavy tanks came long after the war. The former Allies arrived at the same conclusion as Soviet designers. There was no need to chase after long medium caliber guns that the Germans loved. The optimal solution was a 120-122 mm gun with ballistics of an AA gun.

The need to maintain high rates of production meant that the USSR's main tank factories continued building the T-34-85 rather than the T-44.

Finally, there was another issue that affected medium tanks specifically. As mentioned above, the rising requirements meant that even the prospective T-54 tank was already at its weight limit. Factory #183 had other restrictions when it came to building tanks. For instance, an attempt was made to redesign the T-34 chassis in 1941, but the most conservative variant of the T-34M was chosen in the end to make production easier. This tendency is very clear in A.A. Morozov's work.

The same mindset applied to the T-44 tanks. Experiments with road wheels went nowhere and the production tank still used the same 830x150 mm wheels. The same concept migrated to the T-54, even though the wheels were wider and the swing arms were incompatible with the T-34 and T-44. The diameter of the road wheels was reduced to 810 mm for mass production, but no radical new concept was put into production. Introduction of any new components such as a pinwheel gear drive sprocket took a lot of effort. This was not only due to Morozov's conservatism, but also the fact that the new medium tank was a high priority. Introduction of a radically new vehicle would threaten production volumes. This is why production only began at factory #75 that did not contribute to T-34-85 production.

The T-44 and T-54 were threatened by the need to keep up high rates of production. Reusing T-44 components and rising requirements meant that the T-54's weight limit was reached at the start of production. The T-54 model 1946 ended up being an intermediate step.

Another issue with the medium tanks was that there was no competition. Heavy tanks were designed by two competing design bureaus, for instance the Kirovets-1's competitor was the IS-2U. The T-44 and T-54 had no alternatives. It's a mistake to think that this was only the case in the USSR. The Americans followed the same concept when it came to medium tanks. Development was led by the military, who considered it necessary to polish their chosen platform to perfection and then scale it up. People who are upset that the T-34 traces its lineage back to the BT tanks should remember that the Medium Tank M4 descends from the Light Tank T2, a vehicle developed in 1933. At least the USSR didn't try to inflate a medium tank into a heavy one like the Americans with the Heavy Tank T29

Result of the "brain drain" of the late 1940s. The Object 730 had armour that was slightly better than the IS-3, but with the same D-25T gun. This was a compromise, but it's hard to expect a different result. It took even longer for other nations to build a new generation of heavy tanks.

In conclusion, tank building all over the world was in a crisis in 1945. Development of various components (especially guns and engines) could not keep up with rising requirements. This coincided with weapons of medium tanks and SPGs reaching the weight limit these platforms could support. As a result the Americans stopped building tank destroyers in 1946. There was no longer a need for them, as a tank could have the same armament. Experience from the war was also reviewed. Many nations took until the 1960s to draw conclusions from it. 

Original article by Yuri Pasholok.


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