World of Tanks History Section: Object 212

The history of domestic SPGs began in September of 1931. During work on a "self propelled corps triplex", SU-7 and SU-14 SPGs were developed. SU-7 was designed to use a 152 mm gun, 203 mm howitzer, and a 305 mm mortar. The SU-14 was designed to use a 107 mm gun, 152 mm gun, and a 203 mm howitzer. After the arrests of N.N. Magdeisev (designer of the B-4 howitzer) and then P.I. Syachintov, who was in charge of the SU-14 project on August 7th, 1938, the "small triplex" was cancelled.

High powered SPGs came up again in late 1939. While storming the Mannerheim Line, the Red Army needed an SPG with a high caliber gun and at least light anti-shell armour. In the middle of December of 1939, the Kirov factory and factory #185 design bureaus received an order from the Military Council of the North-West Front to develop engineering tanks with anti-shell armour. Factory #185 started two projects at once. Work began on an SPG based on the T-100. Additionally, it was decided to equip the SU-14 with armour. You would assume that the already made SPG was the faster solution, but no, work only competed on March 20th, a week after the end of the Winter War. The creation of an SPG on the T-100 chassis was not fast either, resulting in a vehicle named T-100Y, armed with a 130 mm B-13 naval gun.

The Kirov factory took a different route. In January of 1940, a prototype of the KV heavy tank (serial number U-0) arrived from the front. According to orders from the Military Council of the North-West Front, the first 4 tanks, including U-0, were to be equipped with 152 mm howitzers to defeat pillboxes. An enlarged turret was rapidly developed as a result. Work on the enlarged turret was done by SKB-3, headed by N.V. Kurin. Initially, the 152 mm model 1909/30 howitzer was planned, indexed L-21. In metal, the assault KV was equipped with a shortened M-10 (indexed MT-1). By February 10th, the new U-0 passed gunnery trials, and by February 17th, U-0 and U-1 were sent back to the front. "KV with large turret" tanks first saw battle on February 22nd. By March 3rd, there were 4 tanks of this type on the front lines.

Due to the results of the Winter War, it was decided that the "bunker buster" theme would be continued. During the spring and summer of 1940, the Kirov factory and factory #185 continued designing heavy SPGs on the T-100 and SMK chassis. However, the final fate of these vehicles was decided by the end of June. Based on the results of trials, it was clear that neither tank will be mass produced, since the KV was more protected and weighed less. The "KV with a large turret" was an adequate interim solution for the bunker buster problem.

As mentioned above, the "KV with a large turret" was a temporary answer to the need for a heavy assault SPG. Kurin's tank was a hypertrophied support tank like the artillery BT-7 (frequently called BT-7A, but that index belongs to another tank). The vehicle on the KV chassis (indexed KV-2 in 1941) had the advantage of parts commonality with its base vehicle. However, it had many drawbacks. The chassis allowed for a limited power gun, while the military demanded that the Br-2 gun be used. Due to the limited size of the turret, loading the M-10T was no easy task. The presence of a rotating turret did not mean that the tank could shoot from any angle.

After the SMK and T-100 projects died, efforts were concentrated on the creation of a heavy tank that was a modernized KV. On July 17th, 1940, the Committee of Defense of the Council of People's Commissars issued decree #198ss on the creation of new vehicles on the KV chassis. According to the decree, the Kirov factory was to develop the following:

• Two experimental KV tanks (T-220) with 100 mm armour. One was to be armed with the F-30 85 mm gun, the other with the F-32 76 mm gun.
• Two experimental KV tanks with 90 mm armour. One was to be armed with the F-32 76 mm gun, the other with the F-30 85 mm gun.
• One experimental SPG with a Br-2 152 mm gun. 

The KV with 90 mm of armour received the factory index "150" (GABTU correspondence used the index T-150). It differed from its base vehicle in its 76 mm F-32 gun and a commander's cupola. It was planned that this tank, under the index "KV-3" will replace the KV-1.

The "220" tank was more distinct from the KV-1. The tank had a longer hull; the amount of road wheels increased to 7 on each side. The T-220 had a new turret, which housed the 85 mm F-30 gun. The tank used an 850 hp V-2F (V-10) engine. It was completed on December 5th, 1940.

The technical requirements for the 152 mm SPG were finalized by the end of August of 1940.

The SPG that the Kirov factory was tasked with received the index of "212". The chief engineer for this project was T.N. Golburt. The 212 was reminiscent of the SU-14-1, especially when it came to the layout of the fighting compartment. The chassis was a reworked T-220 suspension, with an engine in the middle and drive wheels at the front. The front also housed the driver's compartment. The fighting compartment was in a large casemate at the rear of the hull. On one hand, this design increased the size of the SPG. On the other, it increased crew comfort. The rear position of the casemate also reduced the distance that the Br-2 stuck out past the vehicle's hull.

2 million roubles were issued to this project. 100,000 went into the development of the technical project, 25,000 to the design of a model, 300,000 on blueprints, 75,000 on blueprint edits, 1.1 million on the production of a prototype, 100,000 on trials, and then 300,000 on repairs. The cost of the armament was not included in this sum.

The first prototype was due on December 1st, 1940, but serious corrections had to be made due to faults found during the design process. According to a GABTU report on experimental works, some components for the 212 were produced by January of 1941. Also, the technical project was completed, and sent to the Izhor factory for the production of a hull. By then, 1.5 million roubles have been spent. Work was going slowly due to higher priority of the T-150 and T-220, as well as other problems.

The hull for the new SPG was received only on March 5th, 1941. According to reports, assembly was stalled due to a lack of ready components. By the spring of 1941, the 212 project was dropping in priority at the Kirov factory. The factory received an urgent order for a heavy tank that inherited the T-150's index of "KV-3". The project, indexed "223", was developed on the T-220 chassis, with a front plate thickened to 120 mm and a new turret for the 107 mm ZiS-6 gun. The mass was estimated at 68 tons. The design of this vehicle began after learning of a new German heavy tank. Due to this load, work on the 212 stalled starting in the second half of March of 1941. April and May reports on experimental work state "No changes" in the row titled "self-propelled gun on the KV chassis". 

After Germany's attack on the USSR, designs were reconsidered. Work on some designs was accelerated. Others, either in the initial stages or not compatible with the realities of modern war, were cancelled. According to the most common version of this story, this was the fate of the 212, but it did not happen quite this way.

According to order #253ss of the People's Commissariat of Heavy Production, the KV-3 was transferred from the Kirov factory to the Chelyabinsk Tractor Factory (ChTZ). Engineers, technologists, and materials were sent to Chelyabinsk. One KV-3 made it to the front, another, without a turret or components, was sent to Chelyabinsk. In February of 1942, this KV-3 was assigned to the experimental OP-2 plant. As for the 212, until the start of August of 1941, it was still at the Kirov plant. Only then was it transferred to the Ural Factory of Heavy Machine Building (UZTM in Sverdlovsk, modern Ekaterinburg). 

Meanwhile tank production had no time for the KV-3, nor a bunker buster on its chassis. The Kirov factory was evacuated to Chelyabinsk and renamed Kirov Factory in Chelyabinsk (ChKZ), and the Izhor factory that made KV armour was sent to Sverdlovsk. UZTM was renamed to Izhor factory, and only got its name back on January 4th, 1942. UZTM was also loaded with Ordzhonikidze factory #37 and Kalinin factory #8 setting on up its territory. Factory #75, which was producing the V-5 engine was moved to Chelyabinsk, and began working on the much more necessary V-2. The situation with 152 mm guns was no better. The last Br-2 was produced by Barricade factory #221 (Stalingrad, modern Volgograd) in 1940.

Bunker busters fell out of priority, but not for long. In November of 1941, work restarted on many prototypes referred to in the SNK report "On self-propelled artillery" from May 27th, 1941. Nearly all of these projects remained in the requirements stage until 1942, there was not even a possibility of a design. Most factories tasked with designing the SPG were either busy with setting up manufacturing in the buildings where they were evacuated to in the summer and fall, or loaded with more urgent requests. Nevertheless, the list of experimental works for 1942 once again included the KV-3, scheduled for completion on May 1st, 1942. The same was true for a "two-stroke 1200 hp diesel engine" (due on October 1st, 1942), "charging the V-2 engine to 1200 hp" (due on July 1st, 1942). In March of 1942, the topic of "152 mm SPG on the KV-3 chassis (bunker buster)" resurfaces. The KV was indicated as its chassis, and the oscillating part of the Br-2 its armament. Factory #100 was listed as responsible for the chassis. Factory #8 was responsible for the gun. 1.5 million roubles was issued for this project. A prototype was expected by July 1st, 1942. However, the KV-3 was dead and buried in spring of 1942, and different vehicles were considered candidates for a bunker buster chassis.

Read more about the Object 212 and other SPGs on the KV heavy tank chassis in the book "SU-152 and other KV-based SPGs", published by Tactical Press.

Article author: Y. Pasholok.

Original article available here. 

World of Tanks History Section: M46 Patton

The most mass produced American tank in WWII was the M4 Sherman. Objectively, this was a very good design. Decent armament and armour, good maneuverability and speed. Most important of all, it was easily repaired. The Americans built 50 thousand Shermans throughout the war. However, in 1943, they first met Tigers and Panthers in Italy and Africa. After meeting with this zoo, American commanders' faces turned very pensive, and not very amused.

To help the Sherman, the M26 Pershing was developed toward the end of the war. It could fight with German tanks as an equal, but since the first Pershings appeared in February of 1945, they didn't have much time to prove themselves. Pershings fought as a part of the 12th tank group.

The Pershing was, in many ways, superior to the Sherman, but had its drawbacks. The Pershing had the same engine as the M4A3, but was 10 tons heavier. Because of this, it had poor maneuverability and off-road capability. Its 120 km range was laughable when held up to the standards of modern war. High command issued a verdict: the M26 needed improvement.

A new tank began development in 1948. The reason for this delay was that the Americans were enamoured with atomic bombs and the methods of their delivery. A war that could be swiftly ended by a handful of planes carrying such bombs seemed much more attractive than tank and infantry battles. However, the failing relationship with the Soviet Union rid the Americans of these illusions. You can't throw around atomic bombs in Europe all willy-nilly, civilization won't appreciate it. As for valuable targets in the USSR itself, just try getting to them. Americans had to come back to Earth and modernize the M26. However, the resources that were dedicated to this project were scarce.

In May 1948, the first prototype was shipped to Aberdeen. It had a more powerful engine and a more reliable transmission than the M26. It was suggested that the gun be replaced, but the same M3 gun ended up on the tank, with a few modifications. Prototypes were tested until July 1949, after which the tank was accepted for general production. It was named "Patton", after the American general Joe Patton.

The M46 was very similar to its predecessor, and serves as a good example of what can be achieved with very tight financial limitations. The Patton's superior engine and transmission did not fully get rid it of the Pershing's "illnesses" of poor maneuverability and range. Contemporaries remark that the Patton had difficulties with climbing hills. The new engine exhausted the gas tanks within 120 to 145 kilometers. This was not enough for any maneuvers. Additionally, the Patton's 44 ton mass could not be supported by a large number of European bridges. Its size was greater than both the European and Soviet railroad standards. This meant that whoever had to deal with the logistics would have a hard time; the tank could not be shipped everywhere.

The armour and armament were nothing special either. The 90mm gun was weaker than British and Soviet analogues. It was an effective weapon against late WWII tanks, but it had great difficulty with the tanks of the potential enemy. A T-54 Model 1949 was impenetrable with standard AP rounds, and subcaliber rounds could only penetrate it at short distances, at angles close to normal. The Patton's armour could not protect it from 100 mm shells, and 85 mm shells, while not guaranteeing penetration in the front, could easily penetrate the side. Without going too deep in the details, let us say that the only Soviet tank that the Patton was a deadly opponent to was the T-34-85. In order to defeat more modern armour, the Patton would have to work hard, taking up tactically superior positions and aiming for sides, rears, or use expensive subcaliber ammunition.

The only war the M46 fought in was the Korean war. In the fall of 1950, two American tank battalions with Pershings and Pattons supported the advance of American and South Korean forces. Here, what was described one paragraph above was proven: after engaging with 8 T-34-85s and one SU-76, Pattons of the 6th armoured corps defeated them with no losses. Over 12 battles where Pattons were used, 12 total T-34-85s were destroyed.

After more advanced M47 and M48s were built, M46 Pattons were removed from the regular army and transferred to the National Guard or reserves. A number of these vehicles remained in service in South Korea. In 1957, the M46 Patton was officially added to the list of obsolete vehicles. In the early 1960s, all M46 Pattons were either scrapped or handed off to serve as either museum exhibits or practice targets.

A number of M46 tanks survive to this day, including one at the Kubinka museum.

Original article available here.

Suspensions

"T-28 Characteristics:

1. Mass: 28000 kg
2. Suspension type: half-side long bogeys
3. Base: L=5870 mm, L1=325 degrees, L2=262 degrees
4. Stabilization angles: a0=4 degrees, a1=64 degrees 30', a2=57 degrees 30'
5. Number of road wheels: 24
6. Wheel travel: 113.5 mm
7. Spring potential energy per ton: 9.6
8. Modulus: 0.238 I/cm^2
9. Effective hp per ton: 18

Note: this is not the reinforces suspension.

Evaluation of the tank:

On the robustness of the suspension.

The miserly potential energy reserve of the springs makes it easy to receive harsh blows, and destroys the suspension. Bumps 250-300 mm tall are already critical for the tank in third gear at 25 kph. 

The damage touches all elements of the suspension: balancers, levers, caps, everything up to the rivets. Since harsh blows on striking terrain are local, the carrier and road wheels, too. The overall load is comparatively small, but that should not be a cause for considering the existing robustness reserve sufficient. When the tank gets off a bump, all road wheels hit simultaneously, which deforms a series of parts. This phenomenon softens the overload. 

On shaking:

The short travel of the road wheels, large number of wheels, small potential energy reserve of the springs, and a long base result in short amplitudes of linear and angular shaking, with a large period. In terms of comfort of firing on the move, the vehicle presents a good platform.

On crew workspace:
The seats of the commander and driver are not designed for fast movement on off-road terrain.

Conclusion: 

The main idea behind the T-28's suspension is that a road wheel will share its force with other wheels in the bogey. This idea is present in the design, but only works in practice on relatively small bumps, as the wheel travel is miserly and harsh shaking happens on bumps that are 200 mm tall. When the vehicle falls at an angle, the bogey doesn't work, and the blow is very harsh to the first wheel. The kinetic energy of the entire tank, minus the first carrier's spring, is absorbed through elastic deformation of the suspension elements. 

Installation and removal are very difficult. When the outer candle breaks, the tank's skirt armour hits the ground, and makes movement impossible. In order to climb over a steep obstacle, the fenders must be removed. An advantage of the suspension is the calm movement, resulting in high precision fire on the move. A disadvantage is that half of the road wheels do not participate in the softening of the blow due to deformation of the springs. The aforementioned stresses decrease deformation and increase the harshness of the blow. 

It is reasonable to maintain the smoothness of the travel while switching to a simpler, more robust suspension.

T-29 Characteristics:

1. Mass: 28500 kg
2. Suspension type: individual candle
3. Base: 3765 mm
4. Stabilization angles:  65 degrees 40', 60 degrees
5. Number of road wheels: 4
6. Road wheel travel: 170 mm
7. Spring potential energy per ton: 33
8. Modulus: 0.224 I/cm^2
9. Effective hp per ton: 24.9
10. Inertia radius relative to the perpendicular axis: 2.22

Evaluation of the tank:

On the robustness of the suspension:

Due to the high energy reserve of the springs, as well as the tires, which are not counted here, the T-29's suspension is sufficiently robust, as the blow is felt far after all other tested vehicles. 

The T-29 can travel on bumps up to 0.6 meters tall at 3rd gear with almost no danger to the suspension (at 30-35 kph).

The spring stem is a weak point, as their cut is insufficient. The effective horsepower is sufficient for fast off-road movement.

On shaking:

The large spring travel of the wheel results in significant (compared to the T-26 and T-28) angular shaking, the amplitude of which is determined, in the event of a non-harsh blow, by the angle of the tank relative to its center of mass, until the full compression of the spring, in which case the harsh blow is determined by the stabilization angle and inertia. The large reserve of potential energy of the springs and tires results in large (like on BT tanks) amplitude of shaking for linear vibrations (on lower gears, the amplitude is lower than the height of the bumps on higher gears, it is higher), since the compression of the springs and rubber can throw up the vehicles to significant heights. The shaking of the T-29 is such that there is a reason to preserve this suspension design, but attempt to reduce it, with maybe a shock absorber.

On crew workspace:
The seats of the commander and driver are not designed for fast movement on off-road terrain.

Conclusions:

The T-29 suspension type was chosen correctly.

The robustness of the suspension and convenience of maintenance are superior to the T-28.

The shaking of the vehicle is adequate. There is reason to reduce it by adding shock absorbers.

T-35 Characteristics:

1. Mass: 50000 kg
2. Suspension type: paired, with two degrees of freedom
3. Potential energy of the spring per ton: -
4. Modulus: 0.034 I/cm^2

The vehicle was not trialled. The conclusions are given as a result of calculations and logical reasoning.

Conclusions:

The T-35 suspension allows for larger springs, allowing for a more favourable spring potential energy reserve than other paired suspensions, like the T-18 and T-46.

Summary:

As expected from theoretical calculations, and confirmed by experiments, starting at 20 kph, tanks start losing contact with the ground when traversing bumps longer than their suspension travel: jumping. As a result of this, there is a strike when the tank hits the ground. The tank's movement will be characterized in two ways when moving on off-road terrain at high speeds:

1. Non-stop jumping: losing contact with the ground and landing. Let's call this type of movement glissade. 
2. Non-stop hard strikes from hitting bumps and falling, which leads to harsh overload of suspension elements. 

Therefore, vehicles meant to travel quickly off-road should have a high reserve of potential energy in their springs compared to static load. 

On evaluation of suspension designs:

Out of the two tested suspension designs, T-29 and BT, the T-29 is more correct."

World of Tanks: Today in History: IS-3

In 1943, the Kirov factory in Chelyabinsk (ChKZ) developed a heavy tank armed with the 122 mm D-25T gun. This tank was indexed IS-2 (or IS-122, by the gun's caliber). The tank was not very well balanced when it came to armament and protection. The gun was indeed powerful, but its armour was not impervious to German anti-tank guns. This issue of protection was more or less resolved with a straightened front plate. Protecting the turret in this way was difficult due to design limitations.

In December of 1944, the Kubinka proving grounds saw the first prototype of the "Kirovets-1" tank designed in Chelyabinsk, which had improved armour compared to the IS-2 tank. The tank passed trials in a satisfactory manner, but the commission remarked that the tank was equivalent in many ways to the currently produced IS-122. Additionally, the engineers were tasked with removing a number of defects (for example, reliability of the ventilation system).

In the fall of 1944, at factory #100, a group of engineers led by G. Moskvin produced their own modernized heavy tank. As with the Kirovets, they put a lot of thought into the protection of their vehicle.

The People's Commissariat of Tank Production suggested that the best parts of both designs be used, On December 16th, 1944, an order was issued, describing further work on the "complete and improved" heavy tank.

On February 20th, 1945, work on the "Object 703" completed, and it was sent to Kubinka for trials. The full set of technical documentation for this tank, already indexed IS-3, was signed on May 21st of that year. The tank was too late for the Great Patriotic War.

A little over 2300 IS-3 tanks were built. Due to its characteristic two-piece upper glacis plate, it was nicknamed "pike". Tanks of this type were sent to heavy tank and SPG regiments of the Soviet Army. 52 IS-3 tanks from the 2nd Guards Tank Army took part in the parade through Brandenburg Gate on September 7th, 1945.

Original article available here.

T-29 Blueprint Delays

"To the chief of the Main Directorate of Military Production, comrade Pavlunskiy

Spetsmashtrest chief comrade Army Commander Neim

Director of the S.M. Kirov Experimental Vehicle Factory comrade Barykov

Director of the Kirov Factory comrade Ter-Asaturov

After military trials of the experimental T-29 prototype in the end of 1935, the Experimental Kirov Factory began developing blueprints for production of the first batch of T-29s at the Kirov factory. In March of 1936, these blueprints were submitted for approval.

On April 11th, ABTU representative brigade-engineer comrade Sviridov, along with Kirov factory representative and KB chief comrade Ivanov, and deputy director of the Kirov factory comrade Ginsburg composed their conclusions on the blueprints, which included required changes, the need for which was identified in factory and military trials, but were not included in the blueprints by the factory (the trials were held in the third quarter of 1935). Additionally, new changes were identified. These conclusions were approved by factory director Ter-Asaturov and experimental factory director Barykov. Work on changes to the blueprints was split between the Kirov factory and the experimental factory, as agreed by the two directors. 

In May of 1936, RKKA Armament Chief, Army Commander 2nd grade comrade Khalepskiy urgently requested these blueprints to get them signed at ABTU.

Three months elapsed since April 11, 1936. Currently, neither the Kirov factory nor the experimental factory have provided ABTU with updated blueprints. I know that the Kirov factory is working on correcting T-29 blueprints, but the experimental factory does not do its duty, and works slowly, delaying the production of T-29 tanks at the Kirov factory. I ask that your factories:

1. Provide ABTU with corrected T-29 blueprints for signing.
2. Develop final requirements for production and acceptance of T-29 vehicles. 

Please give your factories the proper instructions.

ABTU chief, RKKA Division Commander Bokis

Comrade Koshkin! Please give an answer.

Ginsburg, July 28th, 1936

Answer: all work will be done by August 14th, 1936, of which ABTU has been informed.

Koshkin, August 10th, 1936"

A-20 in Combat

The A-20 prototype lost out to its fully tracked competitor in 1939, and was prepared for a calm retirement at the Kubinka proving grounds. However, the war caused a deficit in the Red Army's armoured forces, and everything with a gun on it was sent into battle. This included the A-20. The vehicle was handed over to the 22nd Tank Brigade, and was deployed on November 28th, 1941.

Location of units of the 22nd Tank Brigade, November 28th, 1941, 21:00 

An empty rhombus marks a T-30 tank. A rhombus with a diagonal line marks a T-34 tank. A rhombus with a vertical line marks the A-20 tank. A rhombus with a dot marks the T-50 tank. A car marks a command company vehicle.

CAMD RF 326-5068-4

"Operational update #42 as of 12:00 on November 29th, 1941, in Ivanovskoye, which is 2.5 kilometers south-west of Pavlovskaya Sloboda. Map 100,000

1. Elements of the 22nd Tank Brigade, from 11:00 on November 28th to 21:00 on November 28th relocated towards the Pavlovskaya Sloboda region. No combat occurred at night.
2. Two infantry companies, two tank destroyer companies (understrength), and an AT gun battery (5 guns) moved from the Pavlovskaya Sloboda region to the Zhevnevo region (9375) and took up defensive positions.
3. The tank regiment has 4 T-34s, 2 T-30s, 1 T-50, and 1 A-20, and is located on the south outskirts of Pavlovskaya Sloboda. An inspection of the tanks was held the morning of November 29th. 
4. AA units are deployed west of Pavlovskaya Sloboda, and are ready to open fire.
5. The reconnaissance company has been contacting forward units during the night.
6. The brigade HQ is located in Ivanovskoye.
7. The command company and medical staff are located in Timoshino.
8. Communication with other units is maintained through telephones and through couriers. Radio contact is maintained with motorized infantry. Telephone contact is maintained with the 5-A operative group. 
9. The second echelon is established at Zhavoronki."

I don't have any data on the combat the A-20 took part in, but it is known that the T-50 was withdrawn from this unit and returned to Kubinka with a dent from a ricochet in its turret, so it is likely that the A-20 did see some combat.

Gun Production

Some useful numbers from CAMD RF 38-11369-1, production of tank guns in the Soviet Union from 1941 to 1945. Keep in mind that a lot of these are multi-purpose guns. Clearly the model 1931 corps gun A-19 was produced before 1944, but this table only counts those that went into an ISU-122.

The columns are as follows: Name, 1941 (6 months), 1942, 1943, 1944, 1945 (4 months) and Total. The guns are ShVAK, 45 mm tank gun, F-34, ZiS-5, ZiS-3, D-5, S-53, D-10, D-25, D-25S, M-30, and ML-20, and total.

"But wait", some keen-eyed readers may exclaim, "these numbers are all wrong! Only 34355 F-34s? Less than 20,000 85 mm guns? Wikipedia tells me that there were over 35,000 T-34s and nearly 50,000 T-34-85s, not to mention all other vehicles that used these guns!"

Did they go into battle with no gun, in some kind of bizarre Enemy at the Gates type arrangement? Of course not. Every vehicle had a gun, with ample spares. The discrepancy comes from the definition of "produced". A vehicle that came out of the factory counts as produced regardless of how it came in: as raw materials or as a heavily damaged tank. Where a German bureaucrat would keep track of a single tank regardless of how many times it was knocked out and sent back to the factory, without counting it as a loss until it could no longer be repaired, a Soviet one would count it as a loss if it could not participate in battle, and the factory would count the tank as produced once more. A tank could last throughout the entire war, and if it required major repairs (even due to noncombat damage like engine wear), it would count as multiple casualties and multiple tanks.

Blockade KVs

In the fall of 1941, Leningrad was surrounded by a blockade of German and Finnish forces. Its warehouses burned, its food stores ran low, its citizens were starving, but it was still home to the Kirov factory, and it had to keep working no matter what.

The following is a telegraph conversation between G.M. Malenkov and A.A. Kuznetsov.

"November 19th, 1941

Kuznetsov here.

Malenkov here. Hellow. As you can see, the evacuation of Kirov factory equipment is delayed. We have a question for you. Is it possible to, in short time, revive KV production in Leningrad? Comrade Zaltsmann told us that you have about 300 sets of stamped armour, and enough unstamped armour for 200 sets, as well as diesel engines, and it is also possible to find M-17 engines. How much KV armour do you have? Do you have a lot of manufactured components? Zaltsmann says about 50 units. What are your thoughts on restoring KV production in Leningrad in general?

Hello, comrade Malenkov. Kuznetsov here. My reply: I don't know how many diesels we have right now, I have no data, and the supplies are being used to restore KVs coming back from the front. Whatever M-17 engines were had were placed in KV tanks when we were not receiving diesels. We have 30 assembled KV hulls, and the Stalin factory is working on assembly, but our equipment was packed up for shipment, and we cannot produce components. As for manufactured components, we have enough for about 30. We have nothing against KV assembly at the Stalin factory. Keep in mind that Izhor factory equipment, including steel rolling equipment, has been evacuated, and the production of more hulls is no longer possible. The Martin ovens and steam powered equipment are not working due to a lack of fuel oil and constant artillery fire (the front is 3 km away). It is possible to unpack equipment and get it working at the Stalin factory, but keep in mind that most workers tasked with assembling KVs have been evacuated. That is all.

Is it possible to discover how many diesels you have, and how many M-17 motors? If it is difficult right now, we will speak tomorrow on these issues. Also, answer these questions: are you building mortars? What kind? How many guns are you building, how many machineguns, and what kind?

Answer: On the issue of KV production and remaining diesel and M-17 engines, allow me to reply today. I will wait for your call.

Good.

As for mortars, we produce 50 mm, 80 mm, and 122 mm, 70-80 per day total. Also regimental guns, 18-20 per day. The front is fully supplied with mortars and regimental guns, if anything, we are overproducing them. If you send us a Douglas [transport plane], we can send out the extras regularly.

How many guns and mortars do you have in reserve that you can supply us with?

I do not have that data right now, allow me to answer along with data on KV production.

What about machineguns? Do you make Maxim guns?

We make Maxim guns using spare barrels for other machineguns. We can only make 1-2 per day. We make 180 PPDs per day.

Do you remember how many 122 mm mortars you make per day?

At least 20-25. On some days, up to 40, but factory #7 that made these mortars was damaged by bombs, and the production decreased, but in the next 3-5 days, repairs will be made, as we are doing all that is possible to rebuild the factory. That is all.

Have you thought about production of KVs with the equipment of Kirov and Izhor factories, given that the equipment has been moved to Ladoga, but not further? You can put it anywhere you deem optimal, but we must know exactly how many diesel engines and how many M-17 motors you have, as well as how much armour you have in stores. Think about it this evening, and we will talk on the wire. Have you started producing rifles?

We have not started producing rifles.

I hear progress at the front is slow, is that true?

True, in fact, there is no progress at all. Advancing units are cut down.

Have you moved even one KV across?

We are attempting to move KVs tonight, having organized three crossings with our best civil engineers. They proved themselves with their crossings for medium tanks, which transported 14 tanks at once.

Good, that is all."

According to everything I could find, there were indeed no remaining M-17 engines in Leningrad. The Kirov factory in Chelyabinsk was in possession of 100 such engines, 22 of which were installed in a tank. Of those, 19 were sent to the army, 2 to a training battalion, and one to reserves (CAMD RF 38-11355-886).

Factory #371 documents hold more information on what it is they actually did.

"6. Production of KV components.

From the first days of the war, and until February 1942, the factory produced individual components of the KV tank. These components were:

• Turret
• Gearbox
• Side reductors
• Main friction clutch

The turret armour plates were mechanically processed, welded, and the final assembly was processed again. Supplier factories also supplied the factory with blueprints and armour plates. For other aforementioned components, their parts were produced locally. Final assembly took place at the Kirov factory.

7. Assembly and repairs of KV tanks.

From February 1942 to the end of 1943, the factory produced new KV vehicles and repairs, mainly major repairs. Most components were produced and assembled at our factory. Some components, such as the hulls, engines, tracks, were supplied by other factories. The amount of newly produced vehicles was small. The factory was mostly concerned with repairs. Over 200 vehicles were repaired over the indicated period, most of them passing through major repairs. These vehicles included burned up vehicles, the repair of which was difficult, as such vehicles have all control mechanisms, engine parts, and transmission parts destroyed, and they must be replaced. Our factory fixed all vehicle components, with the exception of engines, which were repaired at the Kirov factory."

As time went on, production increased.

"Order of the People's Commissar of Tank Production #559s
Moscow
July 29th, 1942

On the delivery of KV parts and assemblies to factory #371 (Leningrad)

To fulfil the GOKO order #2118 from July 28th of this year, I order that:

1. In order to produce 25 KV tanks in August, the director of the Kirov factory (comrade Mahonin) must deliver 25 sets of KV parts and assemblies above quota to factory #371 (Leningrad), before August 5th of this year, according to the attachment.
2. The director of the Kirov factory (comrade Mahonin) and chief of the NKTP transport department (comrade Kosolapov) must consider that the GOKO order decreed that:
1. NKPO (comrade Hrulev) must supply means for transportation of the aforementioned items until the Lavrovo station on the Oktyabrskaya railroad.
2. The command of the Leningrad Front must supply means for transportation of the aforementioned items to factory #371 (Leningrad).
3. The director of factory #255 (comrade Moroz) must supply the Kirov factory with:
1. GT-4563A generator: 25 units
2. RRT-4576 relay regulator: 25 units
   for the transport to Leningrad above quota.
4. The director of the NKTP dispatch service, comrade Vorobeichik, is tasked with control over the execution of these orders.

Deputy People's Commissar of Tank Production of the USSR, P. Sernov"

CAMD RF 38-11355-959

Caliber Breakdown on the Eastern Front

More interesting data from Igumnov's thesis, percentage breakdown of damage to tanks vs the caliber responsible. From left to right: 20 mm, 37 mm, 47 mm and 50 mm L/42, 50 mm L/60, 75 mm, 88 mm, 105 mm, 128 mm, Panzerfausts, and Unknown. 

The rows are as follows: 

Before September 1942

Stalingrad Operation, fall-winter battles of 1942-1943

Central Front, Orel Operation, 1943

1st Belorussian Front, summer operation of 1944 (June-September)

1st Belorussian Front, winter operation of 1945 (January-March)

1st Ukrainian Front (January-May 1945)

4th Ukrainian Front (January-May 1945)

1st Belorussian Front, Oder-Berlin (1945)

2nd Guards Tank Army in the Berlin Operation

Inside the Maus

Out of the two prototypes the Soviets recovered, they were able to assemble one "full" tank (hull from the turretless prototype, turret from the turreted prototype) and put it on display at Kubinka. This enterprising gentleman managed his way inside, and took some photos to demonstrate exactly how much exists in the exhibit. Let's take a look.

Here is the Maus from the outside, in case someone didn't know what it looks like.

Driver's compartment. Vodka bottle can be used for scale :)

Spare road wheels inside the tank. The article author theorizes that these came from the other Maus, since this one has all of its wheels accounted for.

A lone road wheel in the engine compartment.

Oil tank bay. The tank itself is gone. 

Inside of the fighting compartment. This was supposed to fit a commander, a gunner, both loaders, most of the ammunition, battery charger, and a power supply for the turret turning mechanism. A snug fit, by any measure. 

Closer view of the turret ring and ammunition storage.

Floor to the rear. The pipes lead to the electric motors. 

Gun breech.

Another view of the gun and the turret ceiling. The hatches and observation devices have been removed.

Gun and turret front.

Grille on top of the engine compartment.

Left side of the turret.

As you can see, there isn't much left inside. What wasn't damaged by the explosion and fire was removed prior to the tank being put on display.