Friday, 27 January 2023

Overrated Soviet Medium Tank

Soviet tank building began to fall behind worldwide trends in the early 1930s. In part, this was because even prospective tanks were designed based on mid-1920s ideas while the rest of the world moved on. The UMM (Directorate of Mechanization and Motorization) created in November of 1929 found a solution to this problem. Fitting vehicles were purchased abroad in 1930-31. Initially the plan was to buy samples for familiarization, but all this changed after Khalepskiy's commission went abroad. It was obvious that Soviet tanks in development were incapable of reaching required characteristics and mass production would be accompanied with a mass of troubles.

The T-28 was the best known original Soviet tank of the 1930s.

The foreign T-27 went into production instead of the domestic T-17 tankette, the T-20 and T-19 light tanks were edged out by the T-26. A new class of tanks arose: fast tanks. The BT fast tank replaced the T-24 tank, which was quickly taken out of production. There were also tanks that either had no foreign analogues or such analogues could not be purchased. These were large (heavy) and maneuver (medium) tanks. In a way, the adoption of the BT tank was a necessary evil, since the fast tank could not entirely replace the maneuver tank class. Development of a successor to the T-24 continued. The result was the T-28, the best Soviet tank of the early 1930s without a foreign ancestor.

Many myths are associated with this tank.

The T-28 tank that appeared in 1932 was a true achievement for the Soviet tank building school. It was not built without foreign influence, but it was overall a quite original vehicle and the best in its class at that. There was a lot of trouble with developing medium tanks abroad, while the T-28 was successfully produced in a series of over 500 units. This success gave birth to some theories, the most popular of which is that the T-28 should have been modernized instead of developing the T-34. This is a strange assertion, as the T-28 was a medium tank in mass only. Its replacement (as well as the replacement of the T-35) was the KV-1. In this article, let us explore what the T-28 was supposed to be and what role it played in the armaments system of the Red Army.

From maneuver tank to breakthrough tank

To start, let us remember what a maneuver tank is and where it came from. Not every medium tank of the era was a maneuver tank. Colonel John Fuller was the ideologue behind this class of vehicle, having developed a theory of a mobile medium tank. This tank had a high speed, thanks to which it could embed itself deep into enemy territory. His work led to the Medium Tank Mark D, the first maneuver tank. The vehicle was not successful, but it started a whole class of armoured vehicles. Analogues of the Medium Tank Mark D were built in the UK, USA, Germany, and the USSR. Not all of its descendants were quite as fast as the original. Fuller wanted a speed of at least 40 kph. The Medium Tank Mark D** reached a speed of 49.6 kph, a feat for the 1920s.

Medium Tank Mark D, the ancestor of maneuver tanks.

The concept of the maneuver tank solidified by the mid-1920s. The mass of these tanks was about 16 tons. The armament consisted of a 47-76 mm gun and several machine guns. Experiments with multiple turrets began in the early 1920s. Several nations reached this concept independently. The mobility of machine guns in ball mounts was low and it could be increased by putting them in small turrets. Initially, this was either a turret in the rear that could also fire at aircraft or an enlarged commander's cupola. The ineffective machine guns flanking the Medium Tanks Mk.I and Mk.II evolved into two turrets, which became a signature feature on British tanks.

Medium Tank A6, the first "three headed" tank. Many tried to imitate this tank, even if the original was unsuccessful.

An important point in this story is that not every medium tank of the time was a maneuver tank. Britain's next tank of this class was the Medium Tank A6. Before that, they developed the Medium Tank Mk.I and Medium Tank Mk.II. These tanks were not initially medium tanks. They were envisioned as light tanks, but then "promoted" due to an increase in weight and size. Fuller himself continued to call them light. There is no such thing as a miracle, and just renaming a tank won't make it jump into a different class. This was the reason for the weak armour of the Medium Tanks Mk.I and Mk.II. Fuller was also dissatisfied with their mobility. The minimum acceptable speed for a maneuver tank was 20 mph (32 kph), preferably more. The mass was also too high at 16 tons. Many nations of the time (Germany and briefly the USSR) also wanted their maneuver tanks to cross water obstacles. Fuller and his Medium Tank Mark D aimed for the same.

T-24, the first Soviet production "maneuver" tank. There are some who also insist that this tank should have been left in production.

The trick is that nearly none of the 1920s maneuver tanks went into production. The only exception was the Soviet T-24, and even then the UMM quickly understood that the value of this vehicle was limited. To make matters worse, HPZ was not ready for its production. Delivery of the T-24 began in October of 1931, half a year after the tank's fate was decided. Only 24 vehicles were delivered, at most 5 of which received any armament. Some nations solved the lack of maneuver tanks in the same way as the British did. The Japanese Type 89 was first a light tank and only later became a medium. The French had their own way of doing things, but even their Char D medium tank grew out of the Renault NC light tank. Soviet BT tanks were also something in between light and medium tanks. The German Z.W. (Pz.Kpfw.III) was also an evolution of a light tank.

The TG-1 tank was supposed to replace the T-24, but its trials ended unsuccessfully.

Work on maneuver tanks continued even after the decision was made to build the BT tank at HPZ. HPZ itself tried to build a maneuver tank on a widened BT chassis with a bigger turret. This work was cut, since something similar was already being designed at the Special Design Bureau (science prison) led by N.A. Astrov: the PT-1 tank. Some don't consider it to be a medium tank, but unfairly so. Essentially, it was a Soviet analogue of the Grosstraktor, but lighter and more mobile. Even the placement of the crew was the same (the commander was in the front right of the hull). Before pulling the trigger on the BT tank, the army was thinking about another alternative, the TG-1. This tank was classified as a "powerful tank", although Eduard Grotte himself planned it as a 18-19 ton maneuver tank. Since it grew to 25 tons, it was treated as a vehicle of a different class. Even though the trials were not successful, the TG-1 didn't die. Work on reworking the vehicle continued, and it led to the creation of the T-35. This seems strange, since the T-35 looks nothing like the TG-1, but such was the evolutionary path.

35 ton T-35 and 16 ton T-28 prototypes, offshoots of the maneuver tank program.

In total, there were four maneuver tanks in the USSR in 1931. The dying T-24, the overgrown TG-1, the future PT-1, and the main character of this article: the T-28. Work on this tank began in the summer of 1931 at KB-3 of the VOAO. It was directed by S.A. Ginzburg himself. O.M. Ivanov also played a key role in its development. Work later moved to the Bolshevik factory and then followed when the factory's tank branch was moved out on its own to factory #174 on February 16th, 1932. The work was directed by N.V. Barykov, who previously supervised the work on the TG-1. Ginzburg headed the OKMO (Experimental Design Machinebuilding Department). Ivanov became the lead engineer on the T-28 project. The tank is commonly associated with the Vickers 16-tonner or Medium Tank Mk.III. In fact, the only thing the two tanks shared was the layout with three turrets. One might just as well call the German Nb.Fz., another typical maneuver tank of that generation, a Medium Tank Mk.III copy. The T-28 had much more in common with the Germans. The running gear was taken from the Grosstraktor, the engine used in production had German roots, and the crew was laid out according to the German concept. Soviet engineers managed to meet the 16-17 ton weight limit. The question was: what next?

The initial T-28 matched the requirements of a maneuver tank.

The Red Army's system of armaments began to slip in 1932. This was the result of additional development programs launched in the second half of 1931. A torrent of correspondence resulted in corrections to the new developments. Only the T-26 and BT were left unchanged, but even they were not ignored by designers. These metamorphoses were more clearly seen by 1933. The PT-1 had two land-based offshoots: the T-29-4 and T-29-5. The first initially weighed 16 tons and the second 18 tons, but later calculations showed that the mass would be 17.1 and 20.1 tons respectively. As for the T-28 and T-35, the tanks that initially weighed 16 and 35 tons respectively were clearly going to be larger than planned. Their duties also changed. The production T-28 tank grew to 21-23 tons and lost the designation of "maneuver tank". By 1935 it weighed 25 tons. This was not a surprise. The production T-28 tank was 870 mm longer, 290 mm wider, and 180 mm taller than its prototype. The turret was enlarged and the number of crewmen in it grew to 3. The engine also changed. The experimental T-28 and the production tank were very different vehicles.

This is what the production tank looked like.

The overloading was not something extraordinary. The same thing happened to all maneuver tanks of that generation. The 15 ton mittlere Traktor turned into the 23 ton Neubaufahrzeug, which had the worst mobility of all its cousins. None of the British 16 ton class tanks met that weight limit either. What's worse, the requirements for high mobility were dashed by issues with the suspension. The same problem arose on the A7, the alternative to the Medium Tank Mk.III. The British and Germans went along the path of building lighter tanks: the A9/A10 and B.W. (Pz.Kpfw.IV) respectively. British Cruiser tanks had a lot in common with Fuller's maneuver tanks. The USSR went in a different direction.

Important detail: the T-28 was classified as a medium weight tank. Its designation by 1935 was "quality reinforcement tank".

If you read documents on the T-28 carefully, you will see that it's called a medium tank only when it came to mass. There were two classifications: by mass and by purpose. The T-28 was classified as a "quality reinforcement tank" when it came to the latter. This classification was introduced in 1935 when the tank was issued to troops. It was allocated to heavy tank regiments within the Reserve of the Supreme Command along with T-35 tanks. On December 12th, 1935, the heavy tank regiments were reformed into heavy tank brigades. The name "heavy" should already suggest something. It did not mean that only heavy tanks were included in the unit. The independent heavy tank brigade included 54 T-28, 16 BT, 18 T-26, and 3 KhT-26. Nevertheless, this TO&E should demonstrate that the tank was no longer considered a maneuver tank.

An example of ABTU Chief Komkor D.G. Pavlov himself referring to the T-28 and T-29 as heavy tanks. 1938.

The "quality reinforcement tank" was essentially a heavy tank. Both the T-28 and its potential replacement, the T-29, were referred to as heavy tanks in 1937-38. Both tanks were criticized for thin armour for a tank with this designation, but what could be expected of a tank that was designed back in 1931? The T-28's armour was 30 mm thick, which was enough against light cannons in the early 1930s. Everyone took the British 47 mm 3-pounder gun as a golden standard, even though a 37 mm gun that could penetrate 40 mm of armour was already available by that time. The French were the first to do something about it, but with a nuance. The French built their Char B as a breakthrough tank whose armour had to resist anti-tank guns from the very start. It was impossible to simply attach this kind of armour to a maneuver tank, since the mass would radically increase and maneuverability would decrease.

The T-28 was used as a breakthrough tank both in the Winter War and in the summer of 1941. This applies to the types of units it was used in as well.

The statement that the T-28 was "the best medium tank" only suggests that the speaker is not familiar with the Red Army's system of armaments in the 1930s. It is enough to take a look at the composition of Soviet tank divisions. For instance, the 8th Tank Division of the 4th Mechanized Corps. On June 22nd, 1941, it had a large number of T-34 tanks (140 units). It also had 56 T-28s instead of KV tanks, since those were not yet available in sufficient amounts. Other tank divisions were in a similar state by the summer of 1941. The KV was supposed to gradually replace the T-28 tank, which would then be recycled as engineering vehicles. Plans to replace the T-28 and T-35 with new breakthrough tanks were made as far back as 1938.

What to upgrade?

As a rule, arguments that the T-28 should have remained in production instead of the T-34 cite the allegedly superior characteristics of "the best medium tank", although their authors often include caveats like replacing the suspension, thickening the armour, etc. The proposal to improve a tank designed in 1931-32 and put into production in 1933 to remain competitive in 1940 is staggering. It was certainly an achievement for the early 1930s, but how can one say that it's better than another tank of a different class developed so much later? Let's take a look.

Suspensions of the Grosstraktor and T-28. At first they both weighed 16 tons, but then something went awry.

The first issue with the T-28 was its suspension. The suspension came from the German Grosstraktor nearly wholesale, with some simplifications. The Krupp suspension had a road wheel in the front to absorb shocks when the tank ran into vertical obstacles. The T-28 didn't have it, and so the hit came at the first bogie from the side. This was half the problem. Both the Grosstraktor and T-28 started out at 16-17 tons, but the production tank weighed 25 tons. The results of this kind of growth were obvious. The use of steel rims on T-28 wheels was necessary, since in some cases rubber tires would be destroyed even when driving on even ground. Off-road, the running gear would begin to break at speeds of 15-18 kph. A T-28 tank tested in 1937 lost the rubber on 20 of its wheels after 102 km of driving off-road at an average speed of 21.8 kph.

The T-28's suspension made it a stable firing platform, but it couldn't drive fast on uneven terrain.

This was not news. The Red Army was aware of the running gear problems back in 1934. At first, attempts were made to solve the problem of low mobility the easy way. The first method was simple: a more powerful engine. The British did the same thing on their 16-tonners. The T-28A tank entered trials in 1935. Most of its wheels had metal rims a top speed of 68 kph. However, it suffered from exactly the same problems. Another potential solution was the T-28B with a convertible drive. The tank was supposed to be lightened to 21 tons, although it's unclear how. The third solution was the T-29, which was officially chosen as the T-28's successor in 1935. Development of the T-28 ended here. The T-29 suffered from a number of issues itself: an overloaded suspension, issues with the fighting compartment (the army suddenly noticed that the turret only fit 2 people and that it was going to be hard to put in one that fit 3). The T-28 coasted along, waiting for the T-29 to enter mass production. This never happened. The SMK didn't enter production either. This was the reason for the T-28's long career. It lasted for such a long time not because it was a perfect tank, but because its successors were even more unfortunate.

T-28A, an attempt to accelerate the T-28. The tank was indeed faster, but the suspension was unsuitable for this speed.

Now, on to the fighting compartment. One of the favourite ways of upgrading the T-28 tank is mounting different guns on it. It seems simple, since even the 85 mm F-30 gun was installed in it! Unfortunately, one must remember that the T-28 was designed for either the short 76 mm PS-3 or KT gun. There are no miracles when it comes to armament. Yes, the F-30 fit into the tank, but it was only used as a test lab.

The gun fit, but that didn't mean there was enough space left for the crew.

Even installing the F-32 was only possible by shifting the loader's seat to the left. The F-30 required even more interesting changes. Recall that development of the T-220 began when the factory #92's design bureau complained that the KV-1's turret was too small for this weapon. The gun could fire, but there were problems with crew placement and loading. In the T-28's case, the turret could only fit two crewmen with this gun installed. Brainstorming T-28 gun upgrades is an interesting hobby, but not a practical one.

Fighting compartment of the T-28 tank at the Central Museum of the Armed Forces before restoration work began. Imagine that the shell catcher is raised and the larger L-10 gun is installed. The fighting compartment was not as roomy as some people think.

The overall situation with the T-28's turret is no less interesting. Initially, the T-28 was supposed to have a coaxial machine gun, but on the prototype the main gun and turret machine gun were already separate. Someone very clever (possibly Tukhachevskiy) decided that the machine gun should be aimed separately. This machine gun was aimed by the commander. The KV-1's turret was a direct evolution of the T-28, and even though this tank had a coaxial machine gun the commander stayed where he was. As a result, he could only see forward and a little bit to the sides. The loader moved to the right. Even though the KV-1's turret received observation periscopes, it was still blind. What's there to say about the T-28? The separate commander gave the T-28 some advantages over the T-34, but not many.

A production T-28 tank cost three times as much as a BT-7. Annual production crossed the 100 unit mark only twice.

Let's talk about production costs. When the T-28 was introduced into production, it cost 250,000 rubles, as much as two BT tanks. The cost during production climbed to 370-380,000 rubles while the BT remained at 120,000. The impact of this is clear. Would the Red Army really want 100 T-28s instead of 300 BTs? To compare, in 1936 the Kirov factory delivered 105 T-28 tanks and factory #183 delivered 1050 BT-7s. The peak of production was 131 units built in 1939, after the Great Terror. The author doesn't consider executions to be an effective problem solving strategy, but it remains a fact that all 101 T-28s built in 1936 had defects. Only 39 tanks were delivered in 1937 since all of the ones from the previous year had to be refurbished.

T-28 tanks with applique armour were still vulnerable in the summer of 1941 while the reliability of the suspension dropped as expected.

The improvement of armour is another topic that is often raised. The T-28 tank received additional applique armour that some claimed increased its level of protection to that of the T-34. However, applique armour is not the same as a thicker monolithic plate. This modernization also increased the tank's weight to 32 tons, which the suspension did not take lying down. The applique armour also did not cover all of the tank's plates. One also had to remember the T-29CN, T-115, and similar projects. Their mass ranged from 32.5 tons (T-29CN) to 35 (T-115) or even higher. Some variants reached a mass of 40 tons. Keep in mind that even though these tanks were called breakthrough tanks, they only had light armour, less than 60 mm thick. 

The 35-38 ton T-115 tank introduced to replace the T-28 and T-29 was classified as a heavy breakthrough tank. The KV-1 was built instead.

The "best medium tank" could be created by removing the machine gun turrets, replacing the suspension, changing the layout of the turret, and thickening the armour. The result would be... a KV tank. Some aspects of the T-28's design such as the hull shape and turret layout can be easily seen in it. The replacement tank played the same role as the T-28, just as planned. Theories that the T-28 was a better medium tank than the T-34 will continue to remain theories.

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