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Torsion Bar Trials

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"Methodology of Torsion Bar Trials

The trials were split into stages:
  • Motion trials of torsion bars.
  • Lab tests of materials (static and spring fatigue).
  • Lab static destruction tests of torsion bars (by twisting).
  • Analysis of various layouts of torsion bar suspensions and issues connected with them.
1. Motion trials of torsion bars

The Pioneer tractor and T-38 were used as test beds, both with torsion bars.
Pioneer tractor. Fig. 1: side view

Fig. 2: view from the front
Fig. 3: view from the rear

26 torsion bars of various brands, types, and production conditions (see Torsion Bars section, page 64) passed trials.

The motion trials were performed in winter and summer conditions. Ground: frozen fields in the winter (see fig. 19), road paved with large stones in the summer.

The terrain was picked in such a way that the torsion bars would be twisted to their limit as often as possible at the set speed (15-30 kph)."

Fig. 19. Pioneer tractor in winter conditions.


ZIS-5, Take One

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"May 30th, 1941
To the Central Committee of the VKP(b)
Comrade Zhdanov

According to USSR SNK and Central Committee Decree #1216-502 issued on May 5th, 1941, two experimental T-44 tanks built by factory #183 are supporsed to be armed with the 76 mm ZIS-5 or 57 mm ZIS-4 gun. The main characteristics of these guns is shown in the following table:

Gun model
Caliber in mm
Muzzle velocity, m/s
Shell mass, kg
Penetrates armour
At 0 degrees
At 30 degrees
Thickness in mm
Distance in m
Thickness in mm
Distance in m
F-34
76.2
662
6.3
60
Up to 1000
50
Up to 1000
ZIS-5
76.2
813
6.5
90
Up to 1000
70
Up to 1000
ZIS-4
57
992
3.14
90
Up to 1000
70
Up to 1000

The penetration of the ZIS-5 and ZIS-4 is equivalent. Since the ZIS-5 HE shell weighs more than the ZIS-4 shell, its explosive action is significantly better. The F-34 gun's HE shell is equivalent to the ZIS-5, but the F-34 has lower penetration.

Despite this, arming the T-44 with the ZIS-5 76 mm gun is unreasonable because:
  1. The ZIS-5 is not in production. Factory #95 built one prototype to install in the KV tank.
  2. The 76 mm ZIS-5 gun was designed to use the shells of the 76 mm 3-K gun. The 76 mm 3-K gun has been out of production since July of 1940 and is still only used at the corps level.
    As such, supplying T-44 tanks with ammunition would be very difficult, as supplies would have to go from the corps.
  3. Various types of guns (F-34, ZIS-4, ZIS-5) will make it difficult to train crewmen, and supply the guns with parts, tools, and ammunition.
Keeping this in mind, I report that the decree of the USSR SNK and Central Committee regarding the armament of the T-44 must be altered in the following manner:

"Arm one experimental prototype of the T-44 with the 57 mm ZIS-4 tank gun, and one prototype with the 76 mm F-34 tank gun".

The machineguns and ammunition must be left as they were.

Marshall of the Soviet Union, Kulik
GABTU Chief, Lieutenant-General of the Tank Forces, Fedorenko"

The One Without the Rifle Follows

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"Moscow, Kremlin
To Comrade Poskrebyshev

Operational group of the Western Front HQ, Kransodar
#0702/op
December 21st, 1941, 11:30

I ask you to report to the People's Commissar that out of all the weapons bought in Iran (10 million rounds, 100,000 rifles, 600 handheld and 300 mounted machineguns as of December 21st), 21,600 rifles and one million rounds of ammunition arrived to Qazvin.

The shortage of arms on the Western Front, including the three newly forming divisions and one brigade, is 126,000 rifles, 4,750 handheld machineguns, and 2,460 mounted machineguns.

I ask that all weapons bought in Iran be left for the Western Front, which will allow us to arm the newly forming divisions and brigade with domestic weapons and equip rear line units with Iranian weapons.

D. Kozlov
Shamanin"

Via kris_reid.

T-60 in Difficult Times

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On July 20th, 1941, the State Committee of Defense (GKO) passed decree #222ss "On the production of 10 thousand light tanks". Interestingly enough, the tank that was supposed to be built did not exist even on paper. The tank, later named T-60, was designed in a little over a week. The first tanks were built in September of that year, and full fledged mass production began in October. The Molotov Gorkiy Automotive Factory (GAZ), Kharkov Tractor Factory (HTZ), and factory #37 were tasked with producing these tanks. Meanwhile, reports coming in from the front indicated that the tank was in need of modernization. What problems did the tankers reveal, and how did Soviet engineers try to solve them?

Applique armour and thickening

The first work on modernization of the T-60 was on improving its armament. In August of 1941, during the trials of the ShVAK 20 mm autocannon (accepted into service under the name TNSh), it was stated that it is only slightly more powerful than the DShK machinegun. In September of 1941, a program was launched to install a 45 mm gun into the T-60's turret. The work dragged on. As a result, the design bureau designed the 37 mm ZIS-19 cannon that was even tested in the T-60's turret, but the project did not advance past that. No doubt, improving the armament was important, but a tank designed for reconnaissance and infantry support could do without.

T-60, late 1941 production. By that point issues with headlights were not as pressing, so tanks were built with a full array of electrical equipment.

The protection of the tank was a completely different story. The T-40, which served as the basis for the T-60, had armour thick enough to protect it from rifle caliber bullets. The T-60 and T-30 had their armour thickened to 20 mm in the front and 15 mm along the sides. Theoretically, this could resist high caliber machineguns.

However, the Germans had no high caliber machineguns. Their main weapon against tanks was the 3.7 cm Pak, which was gradually being replaced with the 50 mm Pak 38. The German Pz.B.39 was also an effective weapon. 20 mm Flak 30 and Flak 38 autocannons were also frequently used against tanks. The T-30 and T-40's armour was insufficient against this wide variety of anti-tank weapons.

The same tank from the front. You can see the simplified tow hooks and lack of main clutch foundation rivets on the lower front plate. At some factories, it was welded on. 

On November 13th, 1941, Stalin signed GKO decree #893 "On increasing production of T-60 tanks at the Molotov Gorkiy Automotive Factory". According to the decree, the factory had to put out 30 tanks per day by December 25th. Stalin added a note "with thickened armour (to 35 mm in the front and front of the turret)" to the printed text.

This addition was no accident. The factory's design bureau had been working on improving the T-60's armour since early November. A tank with applique armour was tested on November 9th through 11th. The goal was to establish the consequences of improving the tank's armour, which increased the mass of the T-60 by 360 kg (the total mass of the tank was 6150 kg). Tank #37790 was equipped with 10 mm thick applique armour plates, which protected the turret all around, the front plate, the driver's cabin, and the rear bottom plate.

The text of GKO decree #893. Stalin personally introduced a correction regarding the thickness of the arrmour.

During the trials, the tank drove along the Gorkiy-Vyksa-Murom-Gorkiy route, 457 km long in total. The trials showed that the tank retained the maneuverability characteristics of the T-60, with the fuel consumption and water and oil temperature remaining within acceptable levels. The load on the torsion bars also remained acceptable, and other components worked normally. The verdict was as follows: "The applique armour of the T-60 hull and turret with 10 mm armour plates is acceptable and recommended for production."

In parallel with work on applique armour, the design bureau developed a variant of the T-60 with thicker armour. This design included the simplifications that GAZ introduced in late November of 1941. A cast drive sprocket without a removable crown was designed for this tank, as well as an idler without a rubber rim.

Aside from armour, the modernized tank had a new turret. The air intake on the front was moved to the turret hatch, which improved the protection of the turret from the front. This project remained an experiment, but several of its elements were later implemented at other factories.

Applique armour approved on January 20th, 1942.

On November 16th, a meeting was held between GAZ and GABTU representatives. A decision was made to thicken the front plates to 35 mm and the driver's cabin and rear to 25 mm. The thickness of the turret armour was increased to the same level.

Decision and implementation are two different things. Out of GAZ's subcontractors, only factory #176 (Dzerzhinskiy Murom Locomotive Factory) took into account the orders for modernization. The first set of applique armour was finished on November 19th. In total, GAZ received 47 hulls and turrets with applique armour (12 in November and 35 in December) in 1941. Decree #1062ss, signed by Stalin himself, had to be issued to urge the other factories to mosey. 

"Comrade Malyshev's NKTP must:
  1. Produce T-34 tanks with applique armour that increases the thickness of the front armour to 60 mm starting on January 15th, 1942, and, as of February 15th, tanks with 60 mm thick front armour.
  2. Produce T-60 tanks with applique armour that increases the thickness of the front armour to 35 mm starting on January 15th, 1942, and, as of February 15th, tanks with 35 mm thick front armour."
On January 5th, Malyshev sent out a letter to his factories, which confirmed the indicated deadlines. On January 12th, 1942, a meeting with GAZ management and the chief of the GABTU 1st Armoured Directorate (BTU), Military Engineer 1st Class I.D. Pavlov. At this meeting, the applique armour for the T-60 was finally approved and the documentation was sent out to each factory.

Factory #176 in Murom was doing well when it came to applique armour. The factory continued to prepare for full scale production of hulls and turrets with applique armour, which would start on January 15th. In total, factory #176 produced 113 sets of hulls and turrets in January, and 125 in February.


The modernized turret of the T-60 could have looked like this. As you can see, the air intake in the front of the turret was moved up to the hatch.

Other subcontractors took their time with installing applique armour. As of January 9th, factory #177 in Vyksa did not even begin to work on it. As a result, not a single hull with applique armour arrived in January. The only difference was that plates that used to be 13 mm thick were thickened to 15 mm. The same situation occurred in February.

Factory #178 (S.M. Kirov factory in Kulebaki) encountered production issues. The factory was overloaded with orders. In addition to making T-60 hulls, it also cast turrets and front plate connectors for the T-34, as well as armoured seat backs for LaGG-3 fighters and front armour for NKL-26 aerosans. Due to a shortage of oxygen, factory management made the decision to switch to thicker armour in lieu of applique armour. There were plans to begin installing applique armour on January 29th, but in reality the first hulls with applique armour produced at this factory were only accepted by mid-February.

T-60 at the GAZ courtyard, February of 1942.

Overloading of the factory led to the reduction of the amount of hulls produced to 75 units in February and 75 in March. It's worth noting that factory #178 was also exploring production of a cast turret for the T-60. This turret was round, like the T-40 and T-30 turrets, and the walls were 28-30 mm thick. The design discussed with GAZ, but it was never put into production.

In April of 1942, factory #178 worked on casting a driver's visor that was 36-39 mm thick. This component was problematic, since it cracked during trials. According to a report from April 11th, factory #178 made a test batch of visors, which was enough to equip 15-20 tanks.

This tank had reinforced armour.

Starting in January of 1942, GAZ itself began to produce hulls and turrets. Production was organized at the MSTs-8 plant. Factory #112, "Red Sormovo", and the Kuznetsk Metallurgical Factory (Stalinsk, modern day Novokuznetsk) provided the metal. According to plans, GAZ would produce 140 hulls in January, but actual production was only 50 hulls. The result of this discrepancy was poor supply of materials and low quality of steel, especially from factory #112. The lack of metal meant that only 42 hulls were delivered in February, with a target of 325.

On January 3rd, GAZ assembled the first T-60 hull with applique armour (7 were finished in January in total), and the first hull with thickened armour was finished on January 29th. 

Another tank in the GAZ courtyard. The hull has thickened armour, while the turret has applique armour. 

The last factory that was roped into producing T-60 hulls was factory #180 (Saratov train car repair factory), where the Izhor factory was partially evacuated in 1941. Initially, T-50 hulls would be produced in Saratov, but after the tank was removed from production, orders came in to prepare for producing the T-60. Due to a delay in preparations, production of T-60 hulls and turrets only began on February 2nd, 1942.

Factory #180 made hulls and turrets with thickened armour from the very start, producing 50 units in February. Interestingly enough, the February batch was made from leftover amour from the T-50, so the rear plate was 20 mm thick instead of 25, the floor was 8 mm thick instead of 6, and the front was 37 mm thick instead of 35. An unfortunate issue was that most hulls ended up with cracks (68% of production). Similar complaints were made regarding factory #177's hulls.

Immunity of the T-60's armour after reinforcement.
a) against 12.7 mm DK bullets, any distance, in a 120 degree arc.
b) against 14.5 mm B-32 bullets, any distance, in an 80 degree arc.
c) against 37 mm shells from 650 m, in an 80 degree arc.
d) against 45 mm shells from 700 m, in a 40 degree arc.

As trials at the Red October factory showed, the effort involved in organizing production of applique armour and thicker hulls paid off. The T-60 was now invulnerable from to front to large caliber bullets from all distances. The effective range of the 3.7 cm Pak dropped to 650 meters. Even though the gun was already being replaced by the spring of 1942, the T-60 still had a good chance of meeting on on the battlefield. In addition, the Soviet tank was no longer vulnerable to the PzII from the front. In short, the modernized T-60 was a much more dangerous enemy for the Germans and their allies after the modernization.

One of the characteristics of a tank with applique armour was the rough gun mantlet.

By March of 1942, five factories were backing the production of GAZ T-60s. Ironically, that is when clouds gathered over the T-60, and GAZ was at fault. The issue was that work on modernizing the T-60 ended with the development of the GAZ-70 light tank, which was accepted into service with the index T-70 on March 6th, 1942. According to GKO decree #1394, the first 20 tanks were already due in March. Subcontractors, with the exception of factory #180, switched to production of T-70 hulls and turrets in April of 1942. Even though no T-70s were assembled in March for a number of reasons, the T-60's days were numbered.

GAZ T-60 with applique armour, seen from the left.

Even though the T-60 was being taken out of production, modernization continued. By February, a large amount of equipment that was lost during simplification returned. As for the spring production tanks, the T-70 influenced their design. The most notable feature of these tanks was a modernized exhaust system with a new muffler, borrowed from the new tank. The new exhaust system and stamped road wheels became the trademark of late production Gorkiy T-60s, which easily distinguished them from tanks produced at other factories.

T-60s were given mufflers in March-April of 1942.

In March, GAZ produced 320 T-60s (20 of them without turrets), and 138 more in April (14 without turrets), after which production of this type of tank ceased. As of July 1st, the factory had 13 T-60 tanks with serious manufacturing defects left. The last 5 tanks were sent to the 1st Gorkiy Tank Academy on August 15th. In total, the Molotov Gorkiy Automotive Factory built 2913 T-60 tanks, half of the overall number.

Kirov instead of Tashkent

On October 9th, 1941, GKO decree #752ss "On the evacuation of factory #37, KIM, the Podolsk factory, and tank production of the Kolomna factory". According to the decree, factory #37, KIM, and Ordzhonikidze Podolsk factory were sent to Tashkent. TashSelMash (People's Commissariat of General Production's Tashkent Agricultural Equipment Factory) would serve as the base for these factories. As for the Kolomna factory, the second subcontractor for T-40 and T-30 tanks, itw ould be moved to Kirov, to the People's Commissariat of Railways 1st of May Kirov Machinebuilding Factory. The hull production lines and their staff were sent there.

Production of T-60 tanks at factory #38, March-April 1942. The tanks already had stamped road wheels, likely from GAZ.

The decision made on October 9th was quickly revised. Decree #811ss "On evacuation of factory #37, KIM, and Podolsk factory" was issued on October 19th, according to which the factories were being evacuated to Sverdlovsk. Nevertheless, the idea of setting up production in Tashkent lived on. In early November of 1941, the Secretary of the Central Committee of the VKP(b) of Uzbekistan, U.Yu. Yusupov, and the Deputy Commander of the Middle Asia Military District, Major-General P.S. Kurbatkin made such a proposal.

Several organizations were moved to Tashkent during evacuation. For example, production of Li-2 transport aircraft was set up here in 1942. In addition, the Kharkov Tank Academy was moved to the nearby Chirchik. The L.M. Kaganovich Tashkent Locomotive Repair Factory and NKPS casting and mechanical factory allowed production of tanks to be organized.

GABTU was interested in this proposal. On November 10th, GABTU chief Fedorenko pitched it to Malyshev. A GKO decree on the organization of tank production in Tashkent was drafted that same month. Discussion of organization continued for a month, but a decision was made to not move forward on December 16th. The reasons included the insufficient equipment of the mechanical casting factory with tools and a lack of armour. Instead of tanks, armoured trains were built in Tashkent.

Turning down production of tanks in Tashkent didn't mean that no new production of T-60 tanks would be set up. Production of T-30 hulls was evacuated from Kolomna to Kirov, in accordance with GKO decree #752ss. By the way, the tank was never called T-30 at this factory: it was referred to as T-60 or "T-40 non-amphibious".Cast turrets designed at the factory's design bureau under direction from M.N. Schukin accompanied the hulls. The factory organized at the 1st of May Kirov Machinebuilding Factory was named the Kuybishev factory #38. Ye.E. Rubinchik became the director of the factory. In May of 1942, Rubinchik was moved to factory #112, and his post was taken by K.K. Yakovlev, formerly the chief engineer. The new factory received its own design bureau, headed by Schukin.

This is a typical tank produced by factory #38. As the summer of 1942 neared, cast road wheels designed at STZ were replaced with stamped wheels, produced in Kirov.

Initially, the purpose of factory #38 was the same, supplying other factories with hulls and turrets. However, it was quickly discovered that this factory was powerful enough to do more than just make hulls. A decision was made to build the tanks at factory #38. The factory received a quota for 200 tanks in January of 1942. Prefab armoured plates were supplied by the Nizhniy Tagil and Chusovoy metallurgical factories. STZ supplied road wheels, GAZ supplied engines, the Yaroslavl Tire Factory supplied rubber rims. The first tank built in Kirov was finished on January 10th, 1942. According to the contract signed by factory #38, the cost of one tank was 75,000 rubles.

For a number of reasons, the preparations of factory #38 for tank production ran late. Even though most of the production lines were prepared by the start of 1942, the work was not fully completed. By early February, the assembly plant bay, compressor station, and furnace were not completed, and some plants were not yet launched. In addition, in the confusion of the evacuation, some equipment was sent to Sverlovsk, Molotov (current day Perm), and Kazan instead of Kirov. Precious time had to be spent to bring it to its original destination,

Failure by subcontractors to meet goals also impacted production. For example, GAZ did not send enough engines, cast, or stamped parts. Factory #38 had 50 engines by February 1st, but 30 of them were not fully equipped with electrical equipment. There were shortages of other electrical equipment, a lack of radiators, ball bearings, and other parts. As a result, instead of 200 tanks, only 4 were delivered, and these weren't really T-60s, but T-30s, made from hulls that were already available.

A number of factory #38's tanks received mufflers similar to those used on T-70 tanks starting in March of 1942.

Realizing that the quota didn't match the factory's capabilities, GABTU reduced the volume of orders for February to 75 tanks. This time, factory #38 not only completed the plan, but overcompleted it, delivering one extra tank. Starting in February, the tank's main production consisted of 060 tanks, even though some 030s were delivered. All tanks built at the factory were referred to as T-60s, so it's only possible to determine which tank was which by looking at serial numbers (T-30s built at factory #38 had serial numbers in the format of 2###, while T-60s had 2#####). At least 10 T-30s were built in February. They also pop up in later batches. Overall, approximately 49 tanks of this type were built in Kirov. It's very likely that some of the T-30 tanks had cast turrets, and not impossible that some of the T-60s did too.

As for Kirov T-60 tanks, their design was almost identical to the ones from Gorkiy. The difference was only in road wheels: the ones installed in Gorkiy were stamped, the ones installed in Kirov were cast at STZ.

On March 9th, 1942, GKO decree #1417 "On the organization of T-70 tank production at factories #37 and #38" was issued. Unlike factory #37, which dug in their heels, Kirov began preparing for production of T-70 tanks. In March, the factory built hulls for 5 tanks and cast 2 turrets. Since the factory did not have enough electricity for casting, welded T-70 turrets were used. Production of T-60 tanks continued in parallel.

Despite some difficulties, 160 tanks were produced in March, with a quota of 150 tanks. In April, small tank production hit its peak: 163 tanks of all types were delivered. In May, mass production of T-70 tanks began, which reflected on production of T-60 tanks: only 109 were delivered that month. At the same time, Kirov tanks received a modernized T-70 type exhaust system, same as in Gorkiy.

One of the last batches of T-60s coming out of factory #38. There is a T-30 among them.

According to a report by the factory #38 military representative, 22 T-60 tanks were built in June over quota, 10 of them without turrets (these tanks were intended as chassis for M-8 rocket launchers). According to documents, the factory continued shipping T-60 tanks in July. For example, on July 25th, train #15258 took 9 T-60 tanks and 1 T-30 (serial number 2071) to the 1st Gorkiy Tank Academy. In addition, judging by serial numbers, some T-60 tanks could be found in shipments of T-70s. The last T-60s put out by factory #38 had the old exhaust system, but stamped road wheels. This was possible thanks to the production of stamped road wheels in Kirov. The idlers were still cast. Until the very end of production, factory #38 used both hulls and turrets with applique armour as well as thickened armour.

A demonstration of the mixed deliveries at factory #38. The tank with a 4 digit serial number is a T-30, not T-60.

To wrap up, it's worth mentioning that factory #38's production data is a mess. For example, the military representative reported 4 tanks as complete in January, but other documents account for 5 tanks. In June, GABTU's documents recorded 2 delivered T-60s, but the military representative talks of 22 tanks, 10 without turrets. Starting with May of 1942, factory #38 began supplying factory #113 with chassis for M-8 rocket launchers, but this is not recorded everywhere. If you add T-60 tanks masquerading as both T-60s and T-70s, the result is total confusion.

The number of hulls sheds some light on this issue. In total, 567 hulls and turrets were welded at Kirov, of which at least 524 were used to make T-60 tanks, and at least 10 chassis for M-8 launchers.

T-60 From Stalingrad

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The T-34 tanks built in Stalingrad became one of the symbols for the battle there. The last tanks produced where went straight into battle from the factories, crewed by factory workers. T-60 tanks were less noticeable contributors to the breaking of the backbone of the German blitzkrieg. At the outskirts of the city, in Krasnoarmeysk, the T-60 tank remained in production at factory #264 for less than half a year. However, by volume of production, this "unplanned" factory was second only to the Molotov GAZ.


Building tanks at a shipyard

Two significant moments occurred in the history of Krasnoarmeysk (former Sarepta German colony until 1920). First of all, the settlement was joined to Stalingrad. Second of all, construction of a shipyard began. The Krasnoarmeysk shipyard specialized in civilian ships, but plans to give it military orders were made in the late 1930s. In 1940, it was reformed into factory #264 of the People's Commissariat of Shipbuilding. The new direction of the factory was Project 1124 armoured motorboats, also known as "river tanks". 

However, soon the factory became connected with real, land tanks. When STZ began preparing for T-34 production, a decision was made to involve the shipyard into building hulls.

Hull assembly at factory #264, winter 1942. You can see that the sides of the hull are welded.

After the start of the Great Patriotic War, production of T-34 hulls became factory #264's most important task. In September of 1941, it was reassigned to the People's Commissariat of Tank Production. In the meantime, it kept producing armoured motorboats.

In late September, the factory changed its production even more. The evacuation of the Kharkov Tractor Factory, which was working on HTZ-16 armoured tractors and T-60 tanks, began on the 17th. Some of the equipment was overtaken by Germans, some ended up in the Altai in Rubtsovsk, and was used to form the Altai Tractor Factory. The rest of the equipment and HTZ's workers ended up in Stalingrad.

There is information about production of HTZ-16-like tractors at STZ after the evacuation, but that information is incorrect. A proposal was made by factory #264 engineers to build a similar vehicle using STZ-5 tractors, but it was rejected. Instead, the factory would produce T-60 tanks. This response was dated September 5th, 1941. It was hard to think that the proposal would turn into an order just a month later.

Assembly of a turret. Just as with the hull, the use of rivets is minimal.

The trains that arrived from Kharkov began unloading in unfinished buildings, without heating, warehouses, or conveniences. October and November were spent on organization of production. HTZ's design bureau ended up in Krasnoarmeysk along with their equipment. One factory became home to two. For a while, factory documentation for the T-60 tank still carried the HTZ stamp. Engineer Frolov became the chief designer at the newly formed design bureau.

On November 9th, GKO decree #876ss "On the rebuilding of tank factories evacuated from Kharkov, Moscow, and Leningrad". According to this document, the installation of equipment at factory #264 had to be complete by December 1st. The first 30 T-60 tanks were expected in November, and 150 in December. Starting on January 15th, 1942, the factory would produce 10 tanks daily. Despite a number of problems, preparations for T-60 production were complete by December, but no tanks were finished at factory #264 in November. The biggest cause of delays was that the first three engines only arrived at the factory on November 29th.

An idler without a rubber rim, one of the characteristics of a Stalingrad T-60. The design was composed in late 1941, but the blueprint still carries HTZ's stamp.

One should not be surprised that a shipyard was chosen to build tanks. The first Soviet tanks were built in the 1920s at the Red Sormovo factory, and factory #112 was organized there by 1941. There are many examples of using shipyards to build tanks in history.

The organization of the tank building is a completely different question. Paradoxically, factory #264, STZ's supplier of T-34 hulls, never built its own T-60 hulls. The Red October factory became factory #264's subcontractor for T-60 hulls and turrets. The factories were located more than 35 km apart, and this decision seems strange from the point of view of logistics.

Many-faced tank

At the start of production, factory #264 had 37 sets of hulls and turrets. In addition, there were 13 hulls without turrets from the October Revolution Voroshilovgrad factory. These hulls, with 20 mm thick armour, were given applique armour at factory #264. According to plans, 100 hulls and turrets should have come in from the Red October factory, but only 7 arrived. One of them was rejected, the rest had to be fixed up. 

Supplies from STZ were in no better shape. 39 radiators and 91 fuel tanks were received in December, and there were delays in shipments of track links and other components. Some parts had to be produced at factory #264 using various improvisations.

Despite all of these difficulties, the first five T-60 tanks drove out of the factory on December 8th, sent to the 21st and 22nd Reserve Tank Training Regiments. In December of 1941, factory #264 delivered 45 tanks. The factory became the second largest producer of this necessary tank, behind the Gorkiy factory.

T-60s from factory #264 looked like this. The angular driver's air intake and idler without a rubber rim are indicative of the manufacturer.

Red October's products deserve a separate mention. Even though the T-60 was mostly welded, its hull also had riveted connections. For example, halves of the sides were riveted together. There were also enough rivets in other places: they were used to attach the main clutch, connect the floor plates, hatch hinges, etc. There were also many stamped parts, some of them with a very complex shape. The production setup at Red October resulted in welding used instead of rivets, which was sometimes very rough.

Several toolbox variants were designed in December of 1941. Some of them entered production.

Production of the T-60 was going slowly, mostly because of subcontractors. Only 101 tanks were delivered in January of 1942 instead of 240. Hulls that came in from Red October often had to be refined locally. In addition, instead of 200 hulls, only 92 were received in January. STZ also fell though on deliveries of several important components, such as fuel tanks and radiators. Problems with supplies from STZ were so dire that some tanks had to be produced without certain components. For example, at least 11 tanks were delivered in January without oil radiators. A lack of heating equipment at factory #264 meant that tanks were painted with white nitrocellulose enamel instead of a casein, chalk, and lime whitewash.

Other factories had to be relied on to supply factory #264 with missing components. The Gromov factory #469 (Gorkiy), a producer of radiators for factory #37 and GAZ, received an enlarged order in mid-February.

GABTU considered these problems temporary. On January 30th, an agreement was signed between GABTU and factory #264 for delivery of 650 tanks. According to this document, the price of a fully equipped T-60 tank was 81,000 rubles. A radio version was also discussed, and the cost of one would be 82,700 rubles. However, not a single T-60 with a radio was built. The cause of this was the shortage of radios.

Aside from the octagonal turret hatch, one can recognize this as a factory #264 tank by the characteristic toolboxes.

Problems with subcontractors plagued the factory. 67 tanks were finished in February instead of the 200 planned, and the expectations for March were for 250 tanks. However, factory #264 was not at fault: instead of 200 hulls, Red October delivered 61 in the first half of February and 159 in February in total. The biggest issue was the "engine hunger". Effectively, the number of tanks that factory #264 could finish was equal to the number of engines they had.

In March, STZ's failure was more critical. The situation with radiators was especially bad: only 35 were received in March out of 350, ten times less than planned. Instead of 670 gas tanks, 170 arrived that month, 133 brake ribbons instead of 600, 1257 road wheels (157 sets) instead of 5000.

Shipments of hulls from a new subcontractor began in March: factory #180 (Saratov). Unfortunately, a new supplier meant new problems. Saratov's hulls were chock-full of defects. The following fact illustrates how critical these defects were: factory #264 received complaints for 47 tanks from March 1st to April 4th. The complaints were regarding cracks in the hulls, and with factory #180, half of the hulls had defects.

A modernized T-60 hull that was never accepted for production.

Difficulties with T-60 production were only overcome in April. On April 9th, GKO decree #1571ss was issued, dictating that factory #264 had to produce 825 tanks in the second quarter of 1942. Of those, 660 were regular tanks, and 165 would be equipped with 9-R radios. The cost of a regular T-60 was 75,000 rubles, and a radio tank cost 77,750 rubles. However, as mentioned above, not a single tank was built with a radio.

The issues with hulls were resolves thanks to the factory's energetic actions. On April 16th, new conditions for acceptance of hulls and turrets were composed. Red October and factory #180 sent complaints to Moscow, but factory #264 was in the right. In addition, the factory began the practice of using hulls and turrets from different suppliers. Thanks to these decisions, Krasnoarmeysk overfulfilled the quota: instead of 250 tanks, 255 were completed in April.

The same fate awaited the modernized turret. After complaints from Red October and factory #180, this idea was shelved.

In parallel with solving production issues, the factory's design bureau was also working on improving the tank's design. In February, an improved turret was developed. Like the GAZ modernization, the air intake in the front was moved to the hatch. The improved designs were approved on April 15th, but production was never implemented because of Red October's complaints. Nevertheless, individual components from the project ended up on production tanks.

Two variants of toolboxes were designed in December of 1941. The first variant, named 060-21-Sb.12, was similar to the small toolbox designed at GAZ in August of 1941. The second, 060-21-Sb.13, was very similar to the T-34's toolbox. Factory #264 began using these toolboxes in the spring of 1942. The most common layout was 060-21-Sb.13 on the left fender and 060-21-Sb.12 on the right. There was also a variant with 060-21-Sb.12 toolboxes on both fenders. In addition, the factory still used regular toolboxes.

Road wheels with internal shock absorption went into production in April of 1942.

Even though the modernized hull and turret were not approved, the T-60s produced in Krasnoarmeysk changed in the spring of 1942. Red October left their mark with changes made to the hull and turret to simplify production. The most characteristic part was the octagonal turret hatch, a distinguishing mark of factory #264's tanks. This hatch was produced in two variants: with its sides bent at 45 degrees (like on regular hatches) or at 90 degrees. The turret roof had to be redesigned to support the installation of a new hatch. In addition, the driver's air intake was simplified, and became angular. As with the turret hatch, there were two variants of the air intake.

Around this time, another distinguishing feature of factory #264's tanks appeared. These were road wheels with internal shock absorption, designed in December of 1941, but implemented in April of 1942. The military initially rejected them, but, since issues with rubber threatened tank production, the design came up once again.

A knocked out tank equipped with road wheels that have internal shock absorption, summer of 1942.

Simplified hulls and road wheels with internal shock absorption were characteristic features, but not mandatory ones. In April of 1942, factory #264 began receiving hulls from the subcontractors that used to produce hulls for GAZ. Cast road wheels from STZ didn't go anywhere, and stamped road wheels kept arriving from Gorkiy.

As a result, factory #264's tanks could come in over 300 different variants by the summer of 1942. For example, photographs show tanks with a thickened hull, turret with applique armour, stock toolboxes, and road wheels with internal shock absorption. The driver and turret hatches could also be different types. This mish-mash had a positive effect: due to a mix of components from different factories, production could be increased.

Hulls instead of tanks

Factory #264 built 275 T-60 tanks in May of 1942, which met quota. However, this was a difficult feat. A shortage of radiators meant that 102 tanks were built with reversed radiators. GAZ sent engines intermittently, which meant that the factory did nothing for five days. Issues with rubber liners and supplies of track links also remained. Despite these issues, the factory built 311 tanks in June, with a quota of 311 tanks.

T-60 from the 3rd Guards Tank Brigade. A typical late production tank with an octagonal turret hatch and driver's hatch with an angular air intake. The hull and turret were not built at Red October or factory #180.

The increase in production gave hope that the quota for 325 tanks set for July by GKO decree #1880ss issued on June 5th, 1942, will be met. However, the T-60 was completely obsolete by then. On July 3rd, decree #1958ss "On production of T-34 and T-70 tanks" was issued. According to this decree, factory #264 would cease production of the T-60 on July 5th to concentrate on production of T-34 hulls. This was the correct decision, since he T-70 was already in production, and STZ needed T-34 hulls like air. Nevertheless, factory #264 shipped 51 T-60 tanks in July. Due to intermittent shipments of engines from GAZ and track links from STZ, assembly of the last T-60s was completely on June 26th.

Most July production tanks were sent to equip Stalingrad and Voronezh Front forces. Some T-60 turrets were used to make bunkers. Despite all of its difficulties, factory #264 reached second place in T-60 tank production. In total, 1174 tanks were built at Krasnoarmeysk.

Stalingrad T-60s fighting in the North Caucasus. All three tanks are from the same factory, but they have three different types of road wheels.

After the Battle of Stalingrad, factory #264 was reformed into repair factory #264, since it suffered from bombing the least. Aside from repairs of Soviet tanks, the factory repaired captured ones. In 1944, the factory built ISU-152 casemates and also components for the T-44. Later, it returned to its original purpose: shipbuilding.

Several years ago, the factory, now called JSC "Volgograd Shipbuilding Factory", remembered its glory days. On April 30th, 2011, a T-60 tank was recovered from the Dobraya river in the Surovikino region of the Volgograd oblast. The tank was knocked out in the winter of 1942 during fighting for Stalingrad. A number of signs indicate that it's obviously a factory #264 tank. It took several months to decide the tank's fate. On August 8th, it was sent back to where it came from. The shipyard restored the tank fully, and now it takes place in events dedicated to the Battle of Stalingrad.

Soviets vs M48 Patton

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Fig. 2 Tactical diagram of complete penetration and satisfactory penetration limits when firing at an M48 tank with domestic 85 mm sharp tipped capped armour piercing shells.
Muzzle velocities higher than stock were tested at 100 meters with an increased charge.
  1. Complete penetration limit of the lower front plate.
  2. Rear plate integrity limit of the lower front plate.
  3. Complete penetration limit of the upper side of the hull.
  4. Rear plate integrity limit of the upper side of the hull.
  5. Complete penetration limit of the lower side of the hull.
  6. Rear plate integrity limit of the lower side of the hull.
On the resistance of the hull to 85 mm sharp tipped capped armour piercing shells, it can be said that:
  1. The upper front plate, 110 mm thick at an angle of 60 degrees, cannot be satisfactorily penetrated with an 85 mm shell fired at 800 m/s at any angle.
  2. The lower front plate, 80 mm thick and an angle of 54 degrees, can be penetrated at 0 degrees at a velocity of 780 m/s, which corresponds to a range of 200 meters. However, a complete penetration of this part of the hull is not guaranteed, and can only be achieved with shells at a muzzle velocity of 820 m/s.
  3. The upper sides of the hull, 80 mm thick at an angle of 45 degrees, can be penetrated at 90 degrees at a velocity of 720 m/s, which corresponds to a range of 850 m. The limit of satisfactory penetrations in these conditions is equal to 680 m/s (1250 m). The range of safe maneuver of this part of the hull is 52 degrees*.
  4. The lower sides of the hull, 80 mm thick at an angle of 30 degrees, can be penetrated at 90 degrees at a velocity of 600 m/s, which corresponds to a range of 2200 m. The limit of safe maneuvering of this part of the hull is 38 degrees.
*) Safe maneuvering angles are calculated from satisfactory penetrations only.

Fig. 3 Tactical diagram of compete penetration limits when firing at an M48 tank with domestic 100 mm armour piercing sharp tipped and blunt tipped capped shells.
Muzzle velocities higher than stock were tested at 100 meters with an increased charge.
  1. Penetration limit of the upper front plate with blunt tipped shells.
  2. Penetration limit of the lower front plate with sharp tipped capped shells.
  3. Penetration limit of the lower front plate with blunt tipped shells.
  4. Penetration limit of the upper sides with sharp tipped capped shells.
  5. Penetration limit of the upper sides with blunt tipped shells.
  6. Penetration limit of the lower sides with sharp tipped capped shells.
  7. Penetration limit of the lower sides with blunt tipped shells.
Fig. 4 Tactical diagram of the satisfactory penetration limits when firing at an M48 tank with domestic 100 mm armour piercing sharp tipped and blunt tipped capped shells.
Muzzle velocities higher than stock were tested at 100 meters with an increased charge.
  1. Satisfactory penetration limit of the upper front plate with sharp tipped capped shells at an angle of 0 degrees.
  2. Satisfactory penetration limit of the upper front plate with blunt tipped shells.
  3. Penetration limit of the lower front plate with blunt tipped shells.
  4. Penetration limit of the lower front plate with blunt tipped shells.
  5. Penetration limit of the upper sides with sharp tipped capped shells.
  6. Penetration limit of the upper sides with blunt tipped shells.
  7. Penetration limit of the lower sides with sharp tipped capped shells.
  8. Penetration limit of the lower sides with blunt tipped shells.

    On the resistance of the hull to 100 mm blunt tipped and 100 mm sharp tipped capped armour piercing shells:
    1. The upper front plate cannot be penetrated with the 100 mm gun with a muzzle velocity of 895 m/s with the specified types of shells at any angle. However, if the muzzle velocity of the 100 mm gun is increased to 1000 m/s, the specified part of the hull could be penetrated by the blunt tipped shell from angles in the +30 to -30 degree range. The sharp tipped capped shell cannot deliver unsatisfactory penetrations to this part of the hull even at this speed.
    2. The lower front plate can be penetrated at an angle of 0 degrees with a blunt tipped shell with a velocity of 660 m/s (range of 2500 m) or a sharp tipped capped shell at a velocity of 750 m/s (1450 m).
      At the stock muzzle velocity (895 m/s), the lower front plate can be penetrated:
      1. With a blunt tipped shell, in the +55 to - 55 degree range.
      2. With a sharp tipped capped shell, in the +38 to -38 degree range.
        The limits of satisfactory penetration at 0 degrees with blunt tipped and sharp tipped capped shells are equal to 610 m/s and 700 m/s respectively.
    3. The upper sides can be penetrated with blunt tipped or sharp tipped capped shells at +/- 90 degrees at velocities of 570 m/s and 625 m/s respectively (3600 and 2950 m). The limits of satisfactory penetration are equal to 535 m/s and 560 m/s. The safe maneuvering angles equal to:
      1. With blunt tipped shells: +/- 25 degrees
      2. With sharp tipped capped shells: +/- 34 degrees
    4. The lower sides can be penetrated with blunt tipped or sharp tipped capped shells at +/- 90 degrees at velocities of 495 m/s and 475 m/s (4500 m and 4800 m). The limits of satisfactory penetration are equal to 470 m/s and 425 m/s. The safe maneuvering angles equal to:
      1. With blunt tipped shells: +/- 19 degrees
      2. With sharp tipped capped shells: +/- 28 degrees

    Fig. 5  Tactical diagram of complete penetration and satisfactory penetration limits when firing at an M48 tank with domestic 122 mm blunt tipped armour piercing shells.
    Muzzle velocities higher than stock were tested at 100 meters with an increased charge.
    1. Penetration limit of the upper front plate.
    2. Satisfactory penetration limit of the upper front plate
    3. Penetration limit of the lower front plate.
    4. Satisfactory penetration limit of the lower front plate.
    5. Penetration limit of the upper side.
    6. Satisfactory penetration limit of the upper side.
    7. Penetration limit of the lower side.
    8. Satisfactory penetration limit of the lower side.
    On the resistance of the hull to 122 mm blunt tipped armour piercing shells:
    1. The upper front plate cannot be penetrated by 122 mm shells at 781 m/s at any angle. At a velocity of 900 m/s, this part of the hull can be penetrated within +/- 18 degrees.
    2. The lower front plate can be penetrated from an angle of 0 degrees at 590 m/s (2600 meters). The limit of acceptable penetration is 540 m/s (3400 m). At 781 m/s, this part of the hull can be penetrated within +/- 53 degrees.
    3. The upper side can be penetrated at 435 m/s (5300 m). The angle of safe maneuver is +/- 26 degrees.
    4. The lower side can be penetrated at 390 m/s (6100 m). The limit of acceptable penetration is 315 m/s (7400 m). The angle of safe maneuver is +/- 20 degrees.
    Conclusions:
    1. The armour protection of the American M48 medium tank is increased compared to previous designs (M46 and M47). This increase is achieved due to variable armour thickness height and perimeter wise, and due to highly sloped armour of the hull and turret, which was achieved by widespread use of casting.
    2. Domestic 100 mm and 122 mm guns are effective measures against the American M48 tanks. Out of the two types of 100 mm shells (blunt and sharp tipped), the blunt tipped is more effective.
      However, neither the  100 mm blunt tipped shell with a muzzle velocity of 895 m/s nor the 122 mm blunt tipped shell with the muzzle velocity of 781-800 m/s can penetrate the upper front plate of the M48 tank.
      In order to penetrate this part of the hull at 0 degrees, the 100 mm shell must have a velocity of at least 940 m/s, and the 122 mm shell - 870 m/s.
    3. Domestic guns with a caliber of 85 mm or less are ineffective against the armour of the M48 tank. It can be assumed that any part of the hull can be penetrated with 85 mm HEAT shells.
      The resistance of the armour of the American M48 medium tank to HEAT shells is not included in this article. Data regarding the resistance to HEAT shells will be published separately."

    French Tanks in German Service

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    "Use of French Armoured Vehicles by Germany

    A series of low altitude photographs of large tank parks at Gien and La Brosse gave valuable information regarding the types of French armoured vehicles in use by Germany.

    a) FT 17/18 tank

    The fact that at least 1000 of these tanks were seen in other depots and on railroad platforms standing on reserve routes, ready for shipment, leaves no doubt that the Germans are ready to use them in large volumes.

    The FT 17/18 tank is a French light tank used in the previous war. Its characteristics are as follows:
    • Mass: 6-7 tons
    • Armour: 6-22 mm
    • Armament: one machinegun or one 3.7 cm cannon
    These tanks are equipped with modern engines and can be used for training, law enforcement within Germany or occupied countries, or for export to Germany's allies. It's possible that the Germans will use them as bunkers, dug into the ground or protected by sandbags.

    b) Somua S 35 tanks

    Photographs show the presence of Somua S 35 tanks, which as, as is already known, present in German tank units.

    Specifications of this tank were given in attachment 1 of the weekly Bulletin of the Ministry of War #106, August 27th, 1941

    c) Panhard 178 AM armoured car

    Photographs revealed additional information regarding the use of the Panhard 178 AM in combat. This armoured car is a standard vehicle used by the French army, and is considered satisfactory. The characteristics of this armoured car are as follows:
    • Mass: 8 tons
    • Armour (maximum): 18 mm
    • Armament: one 2.5 cm cannon and one machinegun
    The size of the Panhard 178 is about the same as that of German light four-wheeled armoured cars.

    Approved by Engineer-Captain Kommissarov"

    On the Way to the SU-122

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    "To factory #8 director comrade Fratkin
    CC: Chairman of the NKV Technical Council, regional GAU KA engineer at factory #8, Engineer-Colonel Kascheev

    RE: development of self propelled howitzers.

    Regarding the issue of designing a 122 mm self propelled M-30 or U-11 howitzer on the T-34 chassis, in accordance with the NKTP, I report that:
    1. The turret platform of the T-34 tank can be extended to span the length of the hull, and the sloped sides can be placed vertically.
    2. The fuel tanks can be located in the engine compartment. As a last resort, the shape of the fuel tanks can be changed
    3. It is not permitted to change the hull of the T-34 tank or  the layout of the engine and transmission.
    In addition, it is also necessary to consider the following:
    1. It is desirable to carry 50 rounds of ammunition on board, but mandatory to have at least 30.
    2. The increase in mass of the SPH must not be greater than 3% of the mass of the T-34.
    3. In both variants, the M-30 and U-11 oscillating parts must be used without changes. THe only changes permitted are in the parts that mount to the hull.
    4. The recoil mechanisms must be armoured, and the system must be balanced.
    Due to the urgency of the issue of SPGs, I ask you to finish the development no later than June 15th with the aim of presenting the projects to the Artkom by June 20th for joint review by the NKV and NKTP.

    Along with the 122 mm self propelled howitzer, I ask you to present the draft of the installation of the 152 mm ML-20 gun-howitzer into the KV-7 hull.

    Deputy GAU Chief and Artillery Committee Chair, Major-General of Artillery Hohlov
    GAU Military Commissar, Regimental Commissar Vasilyev"

    CAMD RF 81-12038-90

    Tetrarch Delivery

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    "Contents: delivery of supplies to the USSR by the south route
    December 27th, 1941

    To: General Panfilov
    CC: General Fedorenko

    I received a report that the light tanks which we delivered through Persia arrived in Zanjan, where they are being transferred to Soviet authorities.

    I am being told that training of Soviet personnel with these tanks will happen in Zanjan. I am also being told that an officer of the British Mission in Tbilisi is being sent to Zanjan to help.

    I would like to know if everything is going well or if you have some issues that demand my attention.

    Lieutenant General [signature]
    British Military Mission
    Moscow"

    Big Gun for a Small Turret

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    In June of 1940, the Red Army GABTU began working on modernizing the KV-1 heavy tank. Even though production had not yet fully began, the military already had issues with the tank. This is a fairly ordinary scenario, especially considering the fact that tank development sped up with the start of WWII. According to the GABTU, the KV-1 needed more armour and, more importantly, a more powerful gun. It's hard to argue with the latter, since the Red Army's heavy and medium tanks, KV-1 and T-34, ended up with the same gun.

    ZIS-5: three guns under one name

    Work initiated by Council of Commissars and VKP(b) Central Committee decree #1288-495ss issued on July 17th, 1940, took two directions. In the first case, the aim was a 76 mm gun with ballistics of the 3-K AA gun. This project resulted in the creation of the T-150 heavy tank. The second variant was an 85 mm gun with ballistics of the 52-K AA gun. It was quickly obvious that a gun of this caliber doesn't fit into the KV-1, which resulted in the transformation of this project into the T-220 tank.

    Reports from factory #92 made it clear that the F-27 was not just a paper gun.

    Both tank guns were designed at factory #92, headed by V.G. Grabin. The F-34 was chosen as the foundation for the new gun with 3-K ballistics. This choice was no accident. Initially, the KV-1 was accepted into service with the F-32 gun, which had the same penetration as the L-11 gun on tanks produced in 1940. For this reason, the more powerful gun F-34 with ballistics of the 76 mm USV divisional gun (another design by factory #92) was designed using the F-32 base. The order for this gun was given in February of 1938, alongside the launch of the F-32 program. This gun was suitable as a stating point for a new system, although the gun mantlet had to be reworked.

    The new gun based on the F-34 was indexed F-27 at the factory. Don't be surprised at this "wandering" of indices, this was normal for factory #92. For example, the 85 mm gun launched at the same time was called F-30 and the 107 mm, later pitched as armament for the KV-3, KV-4 and KV-5 tanks, was called F-42. The 57 mm anti-tank gun, known as the ZIS-2, was initially called F-31, even though it appeared after the F-42.

    KV-1 with the ZIS-22 gun, February 1941.

    A myth was spread about the F-27 gun, alleging that it was designed in early 1939 and work did not move past the design stage. However, volumes of correspondence in the archives prove that this was far from the truth. Design work on the F-27 and F-30 began simultaneously in June of 1940. Regular reports on the status of tank and anti-tank guns coming from factory #92 indicate that the gun did not stay on paper. Even more, work on the F-27 progressed faster than on the F-30. The working blueprints were sent to production by July 23rd. The F-30 ran into many problems, the biggest of which was that it did not fit into the "small turret", the turret of the KV-1.

    As of September 21st, the F-27 was completed, and installed in a T-28 tank. It went through five stages of trials in total, firing 122 shots. The results were satisfactory. The F-30 fired 68 shots by then, which revealed drawbacks of its design.

    When the F-27 fired 60 shots on September 26th, problems with the recoil system were discovered. The factory worked on various design defects throughout November. As a result, the work was late, and the F-32 gun was installed in the T-150. In total, the F-27 program cost 260,000 rubles.

    Gun mantlet for the ZIS-22, designed at the Kirov factory.

    This turn of events did not mean that work on the F-22 ceased. By January 15th, 1941, the first gun was improved and prepared for shipment to the proving grounds. A second prototype was also built and installed in a KV-1. After that, it was discovered that the foot trigger didn't work and that the gun was unbalanced.

    By that point, work on the F-30 stalled, since factory #92 designed the 107 mm F-42 gun on their own initiative. This gun looked a lot more promising than the F-30. As for the F-27, this gun vanished from was no longer mentioned after the end of the winter of 1941. The reason was simple: it was renamed. Factory #92 introduced a new system of indices that confused many researchers. The F-27 was now called ZIS-5. This index was picked for a good reason, as the full name of the factory was "State Order of Lenin factory #92 named after I.V. Stalin".

    On February 19th, 1941, Deputy People's Commissar of Defense, Marshall Kulik, signed an order on the trials of various guns in KV tanks. Item 4 on the list was as follows: "Install the ZIS-5 gun (F-27 with AA ballistics) into the KV tank (experimental prototype with 90 mm armour). The Kirov factory must deliver the turret for this tank by March 1st, 1941"

    The "experimental prototype with 90 mm armour" is the T-221 tank, which was still awaiting assembly. As for the turret, it was eventually sent to factory #92. However, by that point, the issue of armament was up in the air. On March 11th, 1941, intelligence passed on information about heavy tanks that entered production in Germany. As a result, the tank development program was adjusted. The T-150, which would enter production as the KV-3, was no longer needed. Work began, first on the 223 heavy tank, which eventually also received the index KV-3, then the even heavier KV-4 and KV-5.

    Nevertheless, work on the ZIS-5 continued, albeit with difficulty. Another tank appeared that could be armed with it: the T-44 (A-44) tank designed at factory #183.

    Gun mantlet designed by the factory #92 design bureau. It turned out to be more reliable and easier to produce.

    The ZIS-5 fell out of favour by May of 1941. As strange as it sounds, its downfall was the 3-K AA gun. The problem was that production of shells for it ceased in June of 1940, when it was replaced by the 85 mm 52-K. The 3-K and F-34 used different shells, which would have complicated supplies of tank units. Another issue was that the penetration of the 3-K and the 57 mm ZIS-4 (tank version of the ZIS-2) were similar. As a result, work on this version of the ZIS-5 ceased by the end of May.

    KV-1 with the ZIS-5 gun, July of 1941.

    However, that doesn't mean that work in this direction ended. Factory #92 had a refined system with the same caliber and similar barrel length. It was called F-22, and unlike the 3-K, it fired the same ammunition as the F-34 did.

    In parallel with work on the ZIS-5, the installation of the F-34 in the KV-1 turret was surrounded with drama. In Kulik's aforementioned order, this was item #1. The F-34 was delivered to factory #92 on February 2nd, 1941. The reworked gun was indexed ZIS-22. It had a direct connection with the F-27: the F-34 barrel was installed in the existing F-27 mount. The trials program was signed on March 3rd, but the itself arrived only in April. After that, the project stalled. The issue was that the gun mantlet was made of structural, not armour, steel.

    Kulik added oil to the fire. In the spring of 1941, the KV-3, KV-4, and KV-5 were now the priority, so the letter from the Kirov factory requesting replacement of the gun mantlet with an equivalent made from armour steel was met with a short reply: "Unnecessary, the ZIS-6 gun is on its way."

    The Kirov factory did not agree with the design of the gun mantlet, but took its time with its own version. Meanwhile, the Sword of Damocles in the form of the disappearing stockpile of F-32 guns loomed over Kirov and Chelyabinsk factories. The new gun mantlet design was sent to GABTU only on July 17th, 1941. The design of the mantlet was very peculiar.

    The same tank on trials, end of August 1941.

    The design bureau of factory #92 had to resolve that problem, and redesigned the gun mantle with Kirov factory's permission. Work clearly began before July 17th, since the factory reported that the work was completely on July 20th. There was, however, a twist: the gun installed on the KV-1 had the ballistics of the F-22 divisional gun. As the accompanying note mentioned, the replacement of the F-34's barrel with a 51.5 caliber long one could boost the muzzle velocity to 780 m/s. This speed was possible with an increased propellant load. In other words, Grabin was trying to pitch a second iteration of the F-27.

    One advantage of this gun was that it used the same ammunition as the F-34. Factory #92's gun mantlet turned out to be better, although the overall design was similar to the Kirov one. The gun mantlet was composed of two parts, held together with bolts. Unlike the design from Leningrad, all parts of the Gorkiy design were cast. Special slots were added, which made the design more resistant to hits from the side.

    The design of the gun was good, overall. The issue with it was that the F-22 had been out of production for two years.

    Even though the gun, which inherited the ZIS-5 index from the F-27, was ready by late July, the KV-1 only arrived for trials on August 29th. Two days before that, factory #92 inspected and marked the system. The reason was that the Gorohovets proving grounds didn't have the necessary equipment.

    Designer I.M. Lependin represented factory #92 at the trials, and A.S. Schneidman represented ChTZ. Schneidman used to work on KV armament at the Kirov factory, but was moved to Chelyabinsk by August of 1941. The gun had a barrel length of 50.8 calibers (3866) and a muzzle velocity of 687 m/s. 612 shots were fired in total, and the tank drove for 170 km.

    The minimum gun depression of -2 degrees did not impress the military.

    Overall, the ZIS-5 passed the trials. However, Grabin's claim that the gun could achieve a muzzle velocity of 780 m/s was questioned by the commission. The issue was that the recoil resistance when using an increased charge was twice as high as calculated. Nevertheless, the robustness of the system was satisfactory.

    At the same time, the effort required to elevate the gun increased. This was caused by the fact that the gun was slightly unbalanced. The commission also did not like that the gun depression dropped from 5 to 2 degrees. The designers were tasked with resolving these drawbacks.

    Third variant of the ZIS-5, the one that entered production.

    According to the records of the Artillery Committee, the gun was accepted into service as the "76 mm tank gun mod. 1941", indexed 52-PT-354V by the GAU. However, the ZIS-5 with F-22 ballistics did not enter service. The issue was with production: the F-22 was not produced since 1939, and it would take time, and more importantly, resources, to resume production at factory #92. F-34 and USV guns were needed like air, and production of F-22 barrels was a costly proposition. ChTZ was also in need of guns right now, instead of in the distant future. Only 13 F-32s were available as of September 1st, 1941. These factors killed off the long 76 mm gun.

    Production ZIS-5, from the rear.

    A somewhat different gun went into production. The stockpile of F-32 guns at ChTZ dried up, and the issue of putting the F-34 into production was very urgent. The issue was solved simply: the F-22's barrel was replaced with the F-34's. The T-34 and KV-1 had equal firepower once more, but there was no other choice.

    The issue of the gun mantlet still remained. Since factory #92's design no longer met the requirements, ChTZ's design bureau pitched in. A 90 mm thick cast mantlet was ready by mid-September. The idea of a two-piece design was rejected. A special access door was added to maintenance of the recoil system. This mantlet was put into production. By the end of September, the issue of the KV-1's armament was solved.

    ZIS-5 gun mantlet designed at ChTZ.

    The first 17 ZIS-5 guns, initially called F-34 in letters, were shipped in September. The name ZIS-5 finally entered use in November. The name ZIS-5 can refer to three guns with a common ancestor.

    As for factory #92's gun mantlet, it was later used to re-arm the Matilda III tank, but work did not move past the prototype stage.

    It fits!

    This conclusion to the chapter of installing a more powerful 76 mm gun didn't mean that the whole story was over. Recall that, until the fall of 1941, the KV-1 was considered a temporary measure that would be replaced by the KV-3. In the fall, it was clear that this idea would not work. Interestingly, factory #92's design bureau designed a 107 mm ZIS-6 gun mount with a coaxial 45 mm gun. It's unlikely that this was the factory's idea, it's more likely that someone at the top decided to grow a KV-4 out of the KV-3. When the reality that the KV-3 would not enter production at Chelyabinsk set in, another idea appeared: to make a KV-3 out of the KV-1. Of course, the ZIS-6 was not considered as an option, especially since it never entered production. However, an 85 mm gun was once again seen on the horizon.

    The Ural Heavy Machinebuilding Factory (UZTM), the new home of evacuated Izhor factory and factory #8, picked up the development of these systems for a time. Due to the relocation to Sverdlovsk, UZTM was renamed to "Izhor factory" for some time, but Stalin signed GKO decree #1107 on January 4th that returned the old name. Earlier, on December 27th, 1941, GKO decree #1077ss "On building NKV factory #8" was signed. However, production of tanks at Sverdlovsk began deploying even before that.

    Production of ZIS-5 guns began at Sverdlovsk, which supplied ChTZ (ChKZ after 1942) with tank guns. New faces joined the design bureau, including L.I. Gorlitskiy. The Gorlitskiy-Petrov duo was in charge of designing new guns for the KV-1.

    ZIK-1 tank gun. This gun, designed for the T-34 and KV-1, was the first design of factory #8's design bureau at Sverdlovsk.

    The factory's design bureau began working on two guns for installation into slightly modified KV turrets in December of 1941. The first one, a 122 mm howitzer with ballistics of the M-30, was indexed U-11. In the context of this article, the second gun, the U-12, looks much more interesting. This was an 85 mm gun with 52-K ballistics. A new recoil system was designed, which reduced the recoil length from 850 to 450 mm. Like the U-11, the U-12 needed slight modifications of the front of the turret and a new gun mantlet.

    According to UZTM's post-war report, the gun was designed and even installed in a tank. However, unlike the KV-9 with the U-11 gun, this tank does not appear in any other documents. There are also inconsistencies with the designers. The UZTM report says that it was designed by V.N. Sidorenko, S.Yu. Rykovskiy, A.D. Zaets, and others. In reality, the work was directed by F.F. Petrov, and L.I. Gorlitskiy was his deputy. However, there are often inconsistencies in UZTM reports, especially for the period of 1941-1942.

    ZIK-1 barrel. It was somewhat shorter than on the 52-K or U-12, but the penetration characteristics were not that much lower than of those guns.

    Alas, no drawings of the U-12 have been found to date. However, there are some drawings of another gun, which was left out of UZTM's historical reports. This gun is the ZIK-1, a design by the factory #8 design bureau. This bureau, led by F.F. Petrov, was created in February of 1942. As for Gorlitskiy, he headed the UZTM's design bureau. This resulted in two design bureaus in direct competition with each other on two different floors of the same building.

    The acronym "ZIK" is decoded as "Zavod imeni Kalinina" (Kalinin factory). Factory #8 received this name at its old location. Work on the ZIK-1 began in March of 1942 and was completed in mid-April. This gun was an attempt to fit an 85 mm barrel into the ZIS-5 gun. In order to achieve this, the barrel had to be shortened to 3400 mm (40 calibers). Even in this condition, the gun was significantly more powerful than the ZIS-5. In addition, the ZIK-1 could fit into a T-34 turret. Nevertheless, the gun remained on paper.

    85 mm ZIS-25 tank gun. As you can see, the 85 mm gun can fit into the KV-1 turret, but with some nuances.

    A conceptually similar gun was developed at factory #92 starting in October of 1942. The gun project, indexed ZIS-25, was led by engineer D.I. Scheffer. Lependin, who previously headed the ZIS-5 project, also worked on this gun. The main idea of this project was the unification of the 85 mm gun with the ZIS-5, which was already in production. According to the project, only 47 new parts would have to be made.

    The barrel was also shorter than on the 52-K, which lowered the muzzle velocity to 757 m/s. According to calculations, this was enough to penetrate 75 mm of armour at 30 degrees from a kilometer away. To compare, the ZIS-5 could penetrate 49 mm in these conditions. The mass of the gun grew by 250 kg in comparison with the ZIS-5. As with the ZIK-1, no changes had to be made to the KV-1's turret or gun mantlet for installation.

    The same gun from the rear.

    The ZIS-25 project was sent for approval on November 5th, 1942. The reply from GABTU was mixed. Admitting the positive qualities of the gun, its authors fairly pointed out that the rate of fire of the KV-1 with this gun would decrease to unacceptable levels, around 2 RPM. The turret didn't get any larger, but the 985 mm 52-K round was 336 mm longer than the ZIS-5's. The loading process became more difficult.

    Technically, GABTU was not opposed to producing the ZIS-25, but they demanded that measures be taken to increase the rate of fire to at least 5 RPM.

    The gun was never built in metal. On November 5th, 1942, GKO decree #2477ss created the Central Artillery Design Bureau. Work on the ZIS-25 stopped, but the concept was not abandoned. In the spring of 1943, work on this gun served as the foundation for the S-31 gun. However, it was still plagued with the same issues. TsAKB did not learn from past mistakes and wanted to install it in the rather small KV-1S turret.

    Howitzer KV

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    So called artillery tanks, or support tanks, appeared in the mid-1920s. The British pioneered the concept, equipping their Medium Tanks Mk.I and Mk.II with 94 mm howitzers. Similar tanks were also built in other countries. The USSR was no exception. The first work on artillery tanks in the USSR began in the early 1930s. The BT-7 Artillery was the best known vehicle of this type. The KV-2 can also be placed into the artillery tank category, with some leeway. The artillery tank concept was rejected by the USSR before the start of WWII. Nevertheless, the KV-9 was designed in early 1942, a tank that fully fit into the category of support tanks.
    A child of the gun famine

    Histories of the KV-9 are usually based on the post-war UZTM (Ural Heavy Machinebuilding Factory, Uralmash) report on its activity during the war. According to it, the design of a 122 mm artillery system was done "under factory initiative, with the goal of creating a more powerful tank gun than the L-11 or F-34 that our tanks used at the time." Various historians added fuel to the fire, claiming that the design of a 122 mm tank howitzer began in 1939, and a second attempt was made in the spring of 1941.

    In reality, there was no interest in the M-30 as a tank gun in 1939 or especially in 1941. At the time, GABTU focused on increasing penetration, not high explosive action. The M-30 was not good in this department, especially considering the lack of armour piercing shells for it. Unsurprisingly, the gun was never considered for use in a tank.

    Production of M-30 howitzers at UZTM. The existence of a production line influenced the choice of an alternative weapon system for the KV-1.

    The summary of UZTM's work is viewed by many as a main and completely trustworthy source, but this is unwise. It was written in 1945, and some events ended up distorted through the lens of time and wartime chaos. It's enough to say that this document omits a large number of vehicles that were designed, mostly SPGs.

    One of these distortions happened with the KV-9. The Artillery Committee journal entry dedicated to the testing of the KV-9's 122 mm howitzer shows how much this report reflects reality.

    "In the fall of 1941, when the KV was being put into production at Ural factories, the issue of insufficient supplies of artillery systems was raised. Production of F-32 guns at the Kirov factory in Leningrad ceased, and the last producer of tank guns was factory #92 in Gorkiy, which mostly produced the F-34 gun for the T-34, and only began production of 76 mm tank guns mod. 1941 (ZIS-5) with 40 caliber barrels in October.

    It was necessary to produce tank guns somewhere close to tank production in order to ensure continued production of KV tanks. It was necessary to consider the production of local factories first when solving this problem, since it was necessary to begin production of tank guns as quickly as possible. Based on this requirement, the NKTP technical council ordered the Uralmash design bureau to design and produce a prototype of a 122 mm mod. 1938 howitzer (M-30) into the KV-1."

    As you can see, there is no mention of improving firepower in the entry. The Artillery Committee document reflects reality more closely. The first 17 ZIS-5 guns arrived at the Chelyabinsk Tractor Factory (ChTZ) in late September of 1941, and full fledged production began in October. ChTZ produced 27 tanks instead of 65 in September and 87 instead of 100 in October. Guns weren't the only limiting factor: there were also issues with supplies of V-2K engines and a large amount of rejected gears. Uralmash was also partially at fault: a report for October mentions that the factory did not produce enough gun mantlets.

    The issues with engines, a direct consequence of the evacuation of factory #75, was partially resolved by organizing production of V-2 engines at the Ural Turbine Factory. On December 13th, factory #76 was organized here, and the first V-2K engines were shipped even earlier, in November. The Ural was starting to grow its own tank production center.

    U-11 gun system, dated December 15th, 1941

    Where did the M-30 as an alternative to the ZIS-5 come from? The answer to this question comes from the requirement to use the capabilities of local factories. Uralmash began producing M-30 howitzers in 1940. F.F. Petrov, the gun's chief engineer, arrived from Molotov (modern Perm) to organize production. He remained at Uralmash as the head of the design bureau. As you can see, there was no other choice for an alternative to the ZIS-5. The myth about improved firepower came from a different project, U-12. It was built from the 52-K 85 mm AA gun, production of which was evacuated from Kaliningrad (modern Korolev) to Sverdlovsk, along with the factory #8 design bureau.

    Emergency backup

    According to the Artkom historical report, the gun design was ready by late November of 1941. The factory design bureau's chief, F.F. Petrov, headed the project. L.I. Gorlitskiy, evacuated from Leningrad in October of 1941, was his deputy. These two men later became key figures in designing Soviet medium SPGs. V.N. Sidorenko, a veteran of Uralmash's gun production, was the chief engineer on the project. Engineers A.V. Usenko and N.V. Kurin also worked on the system, the latter of which also came from Leningrad. The project was curated by Zh.Ya. Kotin. In addition to overall direction of work on the KV, Kotin was the Deputy People's Commissar of Tank Production at the time.

    Reorganization of UZTM's production lines which made factory #8 a separate entity. The production of ZIS-5 tank guns at this factory put an end to the mass production of the U-11.

    The project presented at a meeting with Kotin came in two variants. The first variant of the U-11, had minimal changes to the oscillating part of the M-30. Sadly, there are no remaining images of this variant, but it was similar to what ended up in ZIK-11 and SG-122. Instead of a pedestal mount, the howitzer was installed in a frame and protected with a mantlet. This variant was simpler to produce, but it was completely unsuitable for a tank gun. For starters, the gun had a very complex and massive mantlet. The overall layout of the turret was altered, and its balance was thrown off. It's not surprising that this variant was rejected.

    The second variant of the U-11 was more difficult to produce. The M-30's barrel and breech remained, while the pipe was changed and the recoil mechanisms were designed anew. However, even from a production standpoint, it wasn't as bad as it could have been. The overall design was quite simple, and the components that had to be manufactured were tailored to the factory's capabilities. The most important thing was that the turret did not have to be changed significantly,

    KV-9 at the factory, January 1942.

    As a result of the meeting, the more compact and appropriate variant was selected.

    "The technical meeting made a decision that can be summarized as follows. The Uralmash design bureau will create a technical project based on the draft and produce one prototype. Considering the lack of armour piercing shell, size of the ammunition and limited amount of space for it, drastic drop in rate of fire, and other negative consequences, the technical meeting made it clear that this option is viewed as a reserve, emergency measure."

    It's not hard to see GAU's opinion of the project. The main reason for it was that the peak of the "gun famine" had passed. In addition, after the evacuation of factory #8 to Sverdlovsk, the ZIS-5 would be produced not only in Gorkiy, but at UZTM. This decision was finally confirmed by GKO decree #1070ss "On building NKV factory #8". The launch of production was late, but Chelyabinsk tanks were equipped with Sverdlovsk guns starting in January of 1942. Compared to this, the new gun with a lower rate of fire, unclear penetration, and a need to change the turret was less attractive.

    The same tank from the front.

    Despite such grim conclusions, the U-11 project moved past the draft stage. Technical documentation was ready by December 15th, 1941. A.S. Schneidman was involved from the ChTZ side as the man responsible for the KV's armament. The gun fit into the turret, but the gun port, mantlet, and observation devices were changed. The calculated maximum gun depression of the U-11 was -3.5 degrees. The recoil mechanisms did not allow for making it any greater.

    KV-9 from the left.

    The U-11 was built in metal and tested on a stand by the end of December of 1941. Later, when the gun mantlet was finished, the system was sent to Chelyabinsk to ChKZ. Tank #4996, built in Leningrad and put through refurbishment, was selected as the recipient. According to documents, the tank fought in the 121st Tank Brigade before it ended up in Chelyabinsk. The U-11 was installed into a cast KV turret with the rear machinegun still in place. Overall, the gun fit into the turret, but the gun depression was even less than on paper: -2 degrees. The ammunition capacity was planned at 50 rounds, but in reality was slightly less, at 48 rounds. To compare, the stock ammunition capacity of the ZIS-5 was 114 rounds. The amount of ammunition carried for the machineguns was also less: 1943 instead of 3000. The converted tank was given the index KV-9.

    False start

    Overall, ChKZ's treatment of the KV-9 was neutral, if not cold. The factory's design bureau had no direct relationship to the project. In addition, SKB-2 had two projects of higher priority: KV-7 and KV-8. The KV-7 was designed at Stalin's personal request, and factory #200 built 20 hulls before it was even tested. Finally, the tank was rejected and sent to be refined, and the factory had many unused hulls lying around. All of this slowed down work on the KV-9.

    The same tank, showing maximum gun elevation.

    On January 23rd, 1942, the test program of the "122 mm gun on the KV-9" was finalized. 206 shots would be fired, 150 of them with an increased power shell to test robustness and 30 to determine precision. A 50 km march was also planned to test the travel lock, convenience of mechanisms, loss of calibration, reliability of the ammunition rack, and crew comfort. Order #012 was signed on the next day, instructing that the trials would be done at the Kopeysk proving grounds from January 26th to February 5th. The order also formed the trials commission.

    The turret is turned backwards.

    In practice, the trials shifted, and were performed from February 2nd to 11th. 210 shots were fired, 171 of them at the factory proving grounds with proof and increased power shells. The recoil length of 560-580 mm was considered normal. Air samples taken to establish the concentration of gases in the turret were also within norm. Firing at a 5x5 meter target at a range of 1 km was a success: all shells hit the target. Trials to measure precision when shifting fire were also successful: at a range of 600 meters, all 1.25x1.25 m targets were hit.

    In addition, trials were held at factory #200 to determine penetration. Since the M-30 had no armour piercing shells, they were taken from the A-19 122 mm corps gun. 4 shots were fired at a cast KV-1 turret from a range of 100 meters. The propellant charge was increased with every shot (from 2100 to 2400 grams), and the muzzle velocity went up from 525 to 573 m/s. The first and fourth shells penetrated the turret and ended up inside, the second and third ricocheted, knocking out a plug.

    These were impressive results, but there were also complaints. In addition to the poor gun depression, the rate of fire was only 2 RPM. There were also complaints about the loader's station. The commission demanded that the gun mantlet be improved. There were also other drawbacks.

    The turret is turned to the left.

    Despite the drawbacks, the commission's conclusion was positive:

    "
    1. The KV-9 tank with the M-30 howitzer passed trials and can be accepted into service with the Red Army.
    2. When building an experimental batch of KV-9 tanks, it is necessary to make all changes regarding the drawbacks of the prototype, paying special attention to the armour of the gun and the ammunition racks.
    3. Since the 122 mm M-30 tank howitzer trials gave good results, the commission considers it necessary to accelerate mass production of the KV-9."
    Factory #8, which was separated from UZTM in February of 1942, began preparing for the initial batch of U-11 tank guns. In the meantime, some serious discussions broke out between the GAU and the NKTP. The Artillery Committee's review of the trials revealed a nuance. When firing armour piercing shells, the pressure inside the chamber reached 3500-4000 kg/cm² at a stock value of 2350 kg/cm². This was unacceptable, and intensive firing of these shells could result in failure of the breech. When an acceptable propellant load was used, the muzzle velocity was only 432 m/s. As a result, the penetration of the U-11 was worse than the ZIS-5. The only advantage of the U-11 was the high explosive performance. The GAU Artillery Committee considered it unnecessary to install the U-11 into the KV-1, reminding the NKTP that this was built on their own initiative.


    Damage of an armour piercing shell after hitting a KV-1 turret.

    On April 2nd, 1942, trials of high explosive shells against armour plates were performed. The M-30 gun was used instead of the U-11, since their ballistics were the same. Trials against a 76 mm plate showed that it it not damaged when hit by a 122 mm HE shell. The trials stopped here. This meant the end of the KV-9. The issue of mass production was no longer mentioned.

    A number of researchers claim that the KV-9 was not put into production because of excess weight. As you can see, that is not the case. An attempt to reanimate the KV-9 was made in October of 1942, but that attempt was unsuccessful.

    Paper reserve

    By the time the trials of HE shells against armour were performed, factory #8 began production of the pilot batch of U-11 guns. As a result, the story of the KV-7 repeated itself. This time, instead of 20 hulls, there were 10 howitzers with no purpose. A decision had to be made regarding what to do with these systems.

    U-22, an attempt to install the U-11 into a T-34 turret.

    When work with a heavy tank went badly, a decision was made to turn to the T-34 medium tank as a platform. Mass production of the T-34 at factory #183 in Nizhniy Tagil had just begun in the spring of 1942. NKTP approved the cooperation of factories #8 and #183. The resulting system was indexed U-22 and differed slightly from the initial design. The turret had to be altered slightly to fit the larger weapon. The mass of the "artillery tank" was 30.7 tons, which was about the same as that of a regular T-34.

    Factory #183's howitzer T-34.

    The project ended up at the Artillery Committee in July of 1942. The response was as expected:

    "The project installs a 122 mm U-11 tank howitzer into a new T-34 turret, with preservation of the existing turret ring. Considering that the fighting compartment only fits two people, which is not enough to properly service the gun, this project is of no interest and must be declined. Since the installation of this gun into the larger KV turret did not result in satisfactory comfort of service and rate of fire, the development of this project is nonsensical. 

    In order to avoid further unproductive waste of time and effort, the Artillery Committee considers it prudent to consult the GAU on further work that stems from personal initiative."

    It's hard to argue with the artillerymen. If the KV-9's rate of fire was only 2 RPM, it would be even lower here. A number of researchers considered this vehicle to be the ZIK-10 SPG, but the letter specifically refers to a tank. 

    One of the last photographs of the KV-9, spring of 1942.

    This was not the last attempt of finding a home for the U-11. In August of 1942, factory #8's design bureau, led by Petrov, designed the ZIK-10 SPG that had the same U-11 as its armament. Even earlier, in July of 1942, factory #592 designed the SG-122U SPG with the same gun. These designs did not move past the drawing board, even though the GABTU kept trying to find a use for the rather good U-11 gun. As for the KV-9, it was parked at ChKZ's courtyard in June of 1942. In December of 1943, the tank was scrapped.

    New Gun for the T-34

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    "On arming the T-34 with an 85 mm gun instead of the 76 mm F-34 gun

    In order to improve the artillery armament of the T-34 tank, the State Committee of Defense decrees that:
    1. The 85 mm tank gun designed by TsAKB (comrade Grabin) is accepted into service and named "85 mm tank gun model 1944 (S-53)".
    2. T-34 tanks, starting with January of 1944, will be armed with the 85 mm tank gun model 1944 (S-53), installed with the stock turret ring, instead of the 76 mm F-34 gun.
    3. Implement the following plan for transferring to producing T-34 tanks with 85 mm guns in NKTP factories:
      1. January: 25
      2. February: 100
      3. March: 300
      4. April: 800
        and then, starting with May, produce only T-34 tanks with 85 mm guns.
    4. The NKO (comrades Yakovlev and Fedorenko) must supply tank factories with, and the NKV (comrade Ustinov) must produce the following amount of 85 mm guns for rearming T-34 tanks and SU-85 SPGs on the T-34 chassis:
      1. January: 270
      2. February: 400
      3. March: 650
      4. April: 1000
      5. May: 1650
    5. To ensure the production of T-34 tanks and SU-85 SPGs on the T-34 chassis, approve the following plan to transition to production of 85 mm tank guns instead of 76 mm F-34 tank guns:
    Factory
    System
    January
    February
    March
    April
    May
    92
    76 mm ZIS-3
    1100
    1100
    1100
    1100
    1100
    57 mm ZIS-2
    200
    200
    200
    200
    200
    76 mm F-34
    1150
    1000
    700
    400
    -
    85 mm S-53
    35
    150
    300
    600
    950
    13
    76 mm F-34
    400
    200
    -
    -
    -
    85 mm S-53
    -
    50
    150
    250
    400
    8
    85 mm AA gun
    200
    200
    200
    200
    200
    85 mm D-5
    35
    50
    100
    150
    300
    9
    122 mm M-30
    300
    300
    300
    300
    300
    85 mm D-5
    200
    150
    100
    -
    -
    122 mm D-25
    40
    70
    125
    160
    160
    152 mm D-1
    15
    15
    15
    15
    15
    Chair of the Committee of Defense, I. Stalin"

    Truck Amphibian

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    "Towing barges with a ZIS-5 truck

    When crossing deep rivers, drivers of the Nth Front successfully used a ZIS-5 truck to tow a barge. Equipped with special wheels, the truck could easily tow 12 ton barges at a speed of 4 kph (see figure).

    To build wheels with wooden paddles, we usually took two wheels from a ZIS-5 truck (per tugboat) and 50x50 mm edge irons. Six pairs of metal spokes were welded onto each wheel, and bolts 0.5 cm in diameter were used to attach wooden paddles. The spokes were connected with rods 10-15 mm in diameter.

    The tugboat was built as follows: a ZIS-5 truck with the truck bed and muffler removed drove up on two connected half-pontoons, with the driveshaft in between them and the channels of the frame resting on them. The frame was fastened to the pontoons, and the wheels with paddles were attached. A regular rudder was attached to the frame. A team of six could build a tugboat in 1.5 hours.

    Experience showed that wide rivers, especially in open terrain without wood to build bridges, can be crossed with tugboats of this design. If the wheels are built in advance, a tugboat can be built quickly and travel to the needed location either by land or by water.

    Engineer-Major M. Bolot"

    KV Tank Markings

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    "To the chief of the "Balance" operational department

    In order to more easily control and identify fighting and transport vehicles, the Commander of the Army's Armoured Forces gave the following order:
    1. For tank units, introduce the following identification marks:
      1. 1st TC and 8th G.TBr: Rhombus
      2. 26th TC: Circle
      3. 4th TC: Square
        drawn on in white paint on the side and rear of the turret. The size of the marks is 50 cm, with a 5 cm thick outline.
    2. Assign the following letters to brigades:
      1. 89th TBr: А
      2. 117th TBr: Б
      3. 159th TBr: В
      4. 3rd G.TBr: Г
      5. 44th MSBr: Д
      6. 29th TBr: Е
      7. 157th TBr: Ж
      8. 216th TBr: З
      9. 14th MSBr: И
      10. 45th TBr: К
      11. 69th TBr: Л
      12. 102nd TBr: М
      13. 4th MSBr: Н
      14. 22nd MSBr: О
      15. 1st G.TP: П
      16. 2nd G. TP: Р
      17. 4th G.TP: С
    3. Each tank should have a sequential number. The numbers should be as follows:
      1. 1st TC: 1-210
      2. 3rd G.TBr: 210-180
      3. 26th TC: 230-490
      4. 4 TC: 490-700
        Each brigade should have 70 numbers reserved, starting with the number of the brigade. The letter code should be the numerator and the number code should be the denominator inside the outline.
    4. For wheeled transport, establish the following ranges:
      1. 1st TC: 1-600
      2. 3rd G.TBr: 600-750
      3. 26th TC: 750-1200
      4. 4 TC: 1200-1600"
    The resulting markings looked like this:


    The Other M-30

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    "Technical data of the M-30 303 mm HE (chemical) rocket

    Parameter
    Tested variant
    In production
    Total weight
    82 kg
    76 kg
    Mass of explosive (nitrol)
    27 kg
    21 kg
    Mass of poison (Yperite)
    24 kg
    21 kg
    Volume of explosive or poison chamber
    18 L
    16 L
    Range
    2550 m
    3000 m
    Notes: 
    1. The shell can be used with a chemical or explosive payload without any conversion.
    2. The rocket part and propellant are used from the existing M-13 rocket.
    Rocket in a launcher

    M-30 rocket


    Pz.Kpfw.I Ausf. B: All Grown Up

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    The creation of the PzI light tank did not come easily for German tank building. The tank was redesigned several times while still in the development stage, starting out as a 3 ton tank with a 20 mm autocannon, and ending up as a 5 ton tank, where nothing larger than a pair of MG-13 machineguns could fit into the turret. Even though the PzI entered production and became a mass produced tank, easily numbering over 1000 units, the German tank forces were not completely satisfied with its characteristics even before production began. Modernization was only a matter of time. What results did it bring?

    Bigger engine

    The Germans have no one to blame but themselves for the metamorphosis of the PzI during its creation. This was a chronic issue with the Wehrmacht; the only case where the initial requirements, especially the mass, coincided with the final product was with the B.W. support tank (PzIV). This happened not because of the military, but because of Krupp's engineers, who were initially only responsible for designing a turret for Rheinmetall's chassis. It just so happened that Krupp managed to push through a whole tank along with their turret. This tank ended up being the most numerous in the German army, remaining in service until the late 1960s.

    As for the Kleintraktor/La.S., later indexed PzI, its creation can be considered a canonical example of a typical situation where the German military demanded that its engineers do the impossible. A 3.5 ton, 3.5 meter long hull was supposed to fit three crewmen, a 20 mm autocannon, an engine that provided 17 hp/ton, and reliably protect from rifle bullets. Even though the idea of a three man crew and a 20 mm autocannon were discarded during development, the tank's mass kept growing.

    NL 38 Tr engine. Its installation meant a redesign of the PzI.

    Meanwhile, the limited dimensions of the hull reduced the number of engines that could be installed in it. Krupp engineers had to take an opposite engine from a truck and beat it into shape. It's not surprising that issues with the engine began immediately. The first chassis only had a top speed of 34 kph. Tanks from the first series (1.Serie/La.S.) had improved engines, which increased the top speed to 37.5 kph.

    Meanwhile, the mass of the chassis reached 4 tons, and the tank still had to get a turret, a turret platform, armament, and ammunition. Finally, the mass of the PzI Ausf. A reached 5.4 tons, and the power to weight ratio dropped to 11.1 hp/ton. Formally, the top speed remained the same, but there is no such thing as miracles. Engine trouble was common in these tanks.

    The German military started thinking that things weren't exactly going to plan in the summer of 1932. On August 18th, Krupp received a letter from the 6th Department of the Armament Directorate, ordering them to urgently work out the possibility of installing the Büssing-NAG Typ G engine. This 3.92 L 65 hp 4-cylinder inline engine was installed on the Büssing-NAG G 31 family of trucks. Krupp's designers looked into the issue and replied with a distressing verdict. Installation of a water cooled engine required a complete redesign of the engine compartment and an increase in mass of 250 kg.

    Despite all this, the issue of a new engine remained. Krupp initially decided to deal with it on their own. Work on a prospective 80 hp V-shaped 8 cylinder air cooled engine began in October of 1932. The first stage of the project was completed in November of 1932, and it was already clear that a hull redesign was still necessary. The hull needed to be 220 mm longer, mostly in the engine compartment. The output of the potential engine increased to 85 hp.

    At the same time, the idea of installing another Büssing-NAG engine came up, this time an 80 hp one. In 1933, another competitor arrived on the scene, this time from Adler.

    La.S.-May chassis. The suspension modifications are shown.

    Finally, with the help of Ernst Kniepkamp, a new engine was found. A key employee of the 6th Department was working on halftracks. The 6 cylinder 90 hp 3.5 L NL 35 engine was designed at Maybach for one of them, the 5 ton Büssing-NAG BN L5. It served as the foundation for the 3.8 L NL 38 engine, which output 100 hp.

    The idea of using this compact engine that showed itself well in a halftrack was reasonable. A tank version of the engine was ready by the end of 1935, indexed NL 38 Tr. This engine was chosen as the "heart" of the PzI.

    Even though the new engine did not take up much space, a redesign of the hull chassis was still needed. One of the weaknesses of the PzI Ausf. A was its suspension. The installation of a new engine was sufficient reason for a redesign, especially since the engine was lengthened anyway. The number of road wheels increased to five per side, and a new idler was installed, lifted above the ground. This modification made the chassis, indexed La.S.-May, more stable. This later made it possible to develop SPGs on its platform.

    PzI Ausf. B chassis diagram.

    As for the fighting compartment, it was left mostly unchanged. The rear wall was altered since, the new engine compartment resulted in a new engine deck. The observation devices were removed from the back wall, since there was no more space for them. The turret platform lifting eyes were changed, and the bolts received bulletproof caps. The turret was changed even less. The lifting eyes were moved from the sides to the top, and the rivets were altered.

    To training tanks and back again

    According to plans from January 15th, 1936, the share of tanks with Maybach NL 38 Tr engines was not great: only 325 out of 1500. The final number was even smaller, since 72 tanks with the La.S.-May chassis were going to be used for commander tanks. Only 253 tanks out of the 5th series (5a.Serie/La.S) were left with new engines. 30 tanks with serial numbers 10478-10537 were assembled by Daimler-Benz. The biggest share fell to Henschel: 107 tanks with serial numbers 12501-12608. The second largest contract was filled by MAN: 66 5a.Serie/La.S. with serial numbers 13501-13566. Finally, Grusonwerk built 50 tanks with serial numbers 14501-14566.

    5a.Serie/La.S. tanks in Poland, September 1939.

    Production of the 5a.Serie/La.S. began in the summer of 1936. The precise date is currently unknown, but it likely happened in July or August. By October, 52 tanks were delivered to the army. Meanwhile, a contract for a second batch of La.S.-May chassis was on the horizon. These tanks were indexed 6a.Serie/La.S. On the outside, these tanks were distinguished by the reinforcement beam in the rear and three rivets on the driver's observation hatch.


    146 tanks from 6a.Serie were built in total. Daimler-Benz received a small order for 30 tanks yet again, with serial numbers 10538-10567. The biggest order went to Henschel, which assembled 48 tanks with serial numbers 12609-12656. MAN and Grusonwerk received contracts for 34 tanks each, 13567-13600 and 14687-14720 respectively. The date of the start of production is unknown, but it's known when it ended. In May of 1937, all tanks were ready, and 58 were awaiting delivery. By then, tanks with the Maybach NL 38 Tr engine received the index PzI Ausf. B.

    PzI Ausf. B, 6a.Serie/La.S. The rivets in the driver's observation hatch are shown.

    Production of the PzI officially ended at this point. This is caused in part by reports from Spain about their use. These reports were not complimentary for the machinegun tank. It turned out that these tanks could not effectively fight T-26 tanks received by the Republicans. A tank armed with, at the very least, a 20 mm autocannon, was necessary. Such a tank, the La.S.100, was designed by MAN engineers and put into production in the fall of 1936.

    Better known as the PzII, this tank replaced its machinegun-armed predecessor, further production of which seemed pointless. In reality, production of "number one" continued, although these vehicles were no longer officially called PzI Ausf. B.

    Schulfahrzeuge, a learning tool for German tankers.

    PzI tanks from the very first production run (1.Serie/La.S.) never received turret platforms or turrets, and were reclassified as training tanks. The military liked the idea so much that, in addition to proper tanks from 5a.Serie/La.S., Grusonwerk received a contract for 120 5b.Serie/La.S. vehicles.

    Officially, they were called Schulfahrzeuge, or "school vehicle". This was simply a PzI Ausf. B with a railing instead of the turret platform. The engine deck was also slightly different: the lifting eyes were moved from the sides to the top, and it was made from mild steel.

    These training tanks received serial numbers 14567-14686. A batch of 60 6b.Serie/La.S. tanks with serial numbers 14721-14780 followed, also built by Grusonwerk. The seventh series (7b.Serie/La.S.) was built by Henschel, who built 70 tanks with serial numbers 15201-15240. Finally, the eighth series (8b.Serie/La.S.) was split up between three companies. Damiler-Benz built 21 tanks with serial numbers 16001-16021. Henschel built 37 tanks, with serial numbers 16101-16137. The last 17 training tanks with serial numbers 16201-16217 were built at MIAG. In total, 295 Schulfahrzeuge were built.

    A captured PzI Ausf. B. Judging by the lifting eyes on the sides of the turret, this is an Umsatz-Fahrzeuge.

    As a rule, it is written that these tanks were built exclusively for educational purposes and did not participate in combat. This makes the PzI Ausf. B on display at Patriot Park look very interesting indeed. Its serial number, 16208, indicates that it was a training tank built at MIAG. Meanwhile, it carried a 5a.Serie/La.S. turret platform and a PzI Ausf. A turret. It is not known how many Schulfahrzeuge  were converted into tanks.

    Converted tanks had almost no differences compared to regular PzI Ausf. B tanks.

    While a tank from a museum might raise some questions, there is no doubt that PzI Ausf. B with serial number 14720 was not the last PzI with a turret and armament. After production of 6a.Serie/La.S., the military had an idea for an additional production run. This happened in rather interesting conditions. A number of PzI Ausf. A tanks outside of the aforementioned 150 1.Serie/La.S. were converted into training tanks via removal of turret platforms. This was done by the military, and the practice was rather widespread. Officially, conversion of the PzI Ausf. A into training tanks was permitted on October 2nd, 1937.

    As a result, a reserve of turrets and turret platforms formed. The logical idea of releasing an additional batch of chassis was voiced. This resulted in a series of tanks that were not, formally, called PzI Ausf. B, but were almost identical to them (aside from PzI Ausf. A turrets). These tanks were called Umsatz-Fahrzeuge, or "converted vehicle". Their exterior was identical to the tank on display at Patriot Park.

    Smoke grenade launchers like these were installed on tanks from the 101st Flamethrower Battalion. This unit had no PzI tanks, but similar launchers were often installed in neighbouring units.

    The first contract for Umsetz-Fahrzweuge, indexed 7c.Serie/La.S., was signed with Grusonwerk in October of 1937. Later, the issue of building an additional batch of Umsetz-Fahrzweuge, 8c.Serie/La.S., was raised. Growonwerk received an order for only 9 tanks with serial numbers 16301-16309. Henschel received a much larger slice of the pie: 86 chassis with serial numbers 16401-16486.

    The real number of La.S.-May tanks differs from the official number of 546 vehicles. One can count at least 546 tanks, and it is also not known how many PzI Ausf. B-like tanks were built from training tanks, like the one in Patriot Park.

    Commander's box

    The first command tanks on the PzI chassis were built in 1935. Overall, the idea of a conversion was deemed a good one. At the same time, experience showed that the leichte (Funk) Panzerwagen needed improvement. For starters, replacing the turret with an immobile casemate was just a half-measure. More space was needed inside for additional equipment. In addition, the commander's tank was completely unarmed, which could result in issues in battle.


    Kleiner Panzerbefehlswagen from 7a.Serie/La.S.. The tank does not yet have a commander's cupola, and the machinegun port is covered up.

    Discussion of a new series of commander tanks on the La.S. chassis began in the fall of 1935. On November 29th, during discussion of equipping tank units with new materiel, a decision was made to order 72 commander tanks. 47 of them would be built on the La.S.-May chassis. The tank received the name Kleiner Panzerbefehlswagen (small commander tank) and index Sd.Kfz.265. Its main difference from the PzI Ausf. B was the addition of a large casemate instead of the turret and turret platform. As with the leichte (Funk) Panzerwagen, the number of crewmen was increased to three.

    Thanks to increased volume, the crew's working conditions improved noticeably. Large two-piece hatches were built into the roof and left side. The appearance of a machinegun ball mount in the front of the casemate was also an important addition. Thanks to this, the Kleiner Panzerbefehlswagen could stand its ground in a battle with infantry. The radio equipment included a Fu 2 (EU) transmitter and a Fu 6 two-way radio. Stable voice communication was possible over a range of 4-6 km.

    Kleiner Panzerbefehlswagen with a commander's cupola of the first type.

    The 47 commander tanks were combined into the 5a.Serie/La.S. run. One tank, serial number 12521, was built at Henschel. Grusonwerk received about a third of the order, 14507–14510, 14515–14517, 14519, 14520, 14522–14528, 16 in total. The biggest order went to Daimler-Benz. They assembled 30 Kleiner Panzerbefehlswagen with serial numbers 10478–1497, 10506–10512, 10514, 10518, 10522. In addition, Daimler-Benz produced casemates that were installed by other manufacturers.

    This was not the end of Kleiner Panzerbefehlswagen production. Soon, an order followed for 112 7a.Serie/La.S. commander tanks. This time, Grusonwerk did not participate at all. Daimler-Benz built 44 tanks with serial numbers 15001-15044. Henschel was responsible for most of the order: 68 tanks with serial numbers 15101-15168. Production of the Kleiner Panzerbefehlswagen ended towards the end of 1937.

    The final form of the Kleiner Panzerbefehlswagen (right). Poland, September 1939.

    The Kleiner Panzerbefehlswagen underwent many conversions during its service. The most noticeable one is the introduction of commander's cupolas in place of the roof hatch. There were two types of cupolas, differing in hatches and peaks over the observation slits. In the end, all commander tanks were equipped with these cupolas.

    A tank for battle

    The combat debut of the PzI Ausf. B was in Spain, just like its predecessor. Thanks to an improved engine, the maneuverability of the tank increased. In addition, engineers managed to fix several design flaws. However, the improved maneuverability did not affect combat effectiveness. The tank was still armed with a pair of machineguns, and it was almost helpless against the T-26.

    Pz.I Ausf. B in Spain.

    The Germans knew the limitations of the PzI, but there was nothing to replace it with. Even though the military began receiving PzII tanks in 1937, these vehicles were transitional tanks. As for the PzIII, the tanks that were supposed to make up the core of the German tank forces, production was delayed. Only 10 PzIII Ausf. A tanks were built, and the PzIII Ausf. B-D were also few in number. As a result, out of 2553 tanks that fought in Poland, 973, or 38%, were PzIs.

    A third of the tanks used in Poland were knocked out.

    The result of a month of fighting was harsh. 320 tanks were knocked out, 89 were lost irreparably. The combat effectiveness of the PzI was low, and the saturation of the Polish army with anti-tank cannons and rifles drastically reduced its survival rate on the battlefield.

    The real nightmare for PzI crews began in the spring. As of May 10th, 1940, German units fighting in France had 554 PzI tanks. By the end of the brief campaign, 182 tanks of this type were irreparably lost. If the PzI could hope to do something against TKS tankettes, they were useless against French tanks, most of which had 40 mm of armour. The Germans could have predicted this situation, but could not discard the PzI. By that point, there were not enough PzIII tanks, and the Panzerwaffe needed every tank they could get.

    Out of 66 PzI tanks sent to Africa, there were only 11 Ausf. Bs. The situation on the Eastern Front was different. Ausf. A tanks did not end up here at all, but 337 PzI Ausf. Bs were available on June 22nd, 1941. By the end of August, 172 were written off. Several tanks were captured by the Red Army. Studies of the trophy ended with a technical description, as it did not cause any interest. The last PzI tanks disappeared from the front in 1943. By that point, they were only used as commander tanks.

    Despite their obvious drawbacks, some tanks survived until 1943.

    Overall, the PzI turned out to be a controversial vehicle. It was the first real mass produced German tank, but it was already obsolete as soon a it started production. The time of machinegun-only tanks was over by the mid-1930s. The Germans had a sober idea of the tank's abilities, indicated by a mass conversion of these tanks into training aids. After 1939, PzI tanks were used to build SPGs and other special vehicles, which deserve their own article.

    Pz.Kpfw.I Ausf. C: Kniepkamp's Latecomer

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    Putting the PzI Ausf. B into production was the correct decision, albeit a late one. The problem wasn't only that the concept of a light tank with machineguns for armament was obsolete. The 6th Department of the Armament Directorate was disappointed in the chassis developed by Krupp's engineers overall. Even though the power to weight ratio of the PzI grew from 11.1 to 17.2 hp/ton after modernization, there was no drastic improvement in mobility. 40 kph is not what was expected with such a boost. It's not surprising that, instead of developing the PzI Ausf. B further, the German military decided to develop a completely new tank: the PzI Ausf. C.


    In halftracks' footsteps

    The strange situation with German tank suspensions that happened in the late 1930s didn't just touch the PzI. Only the suspension of the B.W. (future PzIV) was relatively successful. Other tanks had issues in this department, in one way or another. Leaf springs proved less than reliable, and small road wheels experienced issues with rubber rims flaking off.

    A number of companies, especially Krupp, completely ignored the military's demands. For example, the request to use torsion bars was ignored several times. Meanwhile, Krupp developed its own torsion bar suspension, which performed poorly on the B.W.II Kp. In Sweden, the torsion bar suspension designed by Porsche K.G. used on the Landsverk L-60 tank performed well. 

    Eventually, the patience of the 6th Department had worn thin.

    Krauss-Maffei KMZ 100 halftrack. Its suspension later migrated to the prospective light tank.

    It was time for Heinrich Ernst Kniepkamp's finest hour. The talented engineer played an important role in the development of German tanks before, but now he held even greater power. In early 1937, Kniepkamp was put in charge of all prospective tank development.

    This is when the letters VK (Vollketten - fully tracked) appeared in the names of prospective German tanks. This designation was applied to all new designs. The letters were followed by numbers, which indicated the weight class.

    By 1939, the number was followed by another number indicating the number of the prototype, for example VK 6.01. Later, a code for the company that developed the design was added, for example VK 30.01 (P).

    As you can see, the initial concept of Krauss-Maffei's light tank differed little from the La.S.

    The new type of tank that Kniepkamp evangelized was radically different from what was under development at Krupp and other companies. The new chassis would have to have a torsion bar suspension, which proved itself on Swedish tanks. Another interesting factor is that his suspension design didn't include any return rollers. The large diameter road wheels with rubber rims performed their function. The influence of Kniepkamp's halftracks can be seen here.

    Another important addition was the use of track links with lubricated joints, which would allow a high speed of movement. An engine with maximum possible power and minimum dimensions would provide it. A semiautomatic transmission with servos would go with it. The new tank would be fast, but easy to control.

    Despite the similar index, the difference between the VK 6 and VK 6.01 was considerable.

    Nobody stopped Krupp from developing their own next generation light tank. In February of 1937, the company received an offer to develop a tank to match Kniepkamp's specifications. Krupp's engineers rebelled against the idea that someone else was choosing what parts they would use to build a tank. Of course, the infamous torsion bar suspension played its part in the conflict.

    Kniepkamp replied to Krupp's protests with a mention that the contract could go to any of 10 companies, giving until the 15th to think. It's possible that Krupp relied on their connections to help, but the attempt failed. The contract for an experimental chassis of the 3 ton class (VK 3 t) went to a newcomer: Krauss & Comp.-J. A. Maffei AG from Munich. This company had no experience with building tanks. However, its portfolio included the 8 ton Sd.Kfz. 7 halftrack, the suspension from which served as a starting point for building the new tank.

    Third time's the charm

    The change of contractors did not mean that the La.S. concept was radically altered. The chassis designed by Krauss-Maffei differed little, conceptually speaking, from the Kleintraktor chassis designed over five years before that. This is not surprising, since both Krupp and the 6th Department had a direct connection to the Kleintraktor.

    One of several experimental prototypes of the Pz.Kpfw.I n.A. built in 1941. The tank has early type tracks with rubber pads.

    Development of the VK 3 t chassis began in October of 1937, and it started to take shape by January of 1938. Krauss-Maffei's engineers did not create anything radically new. The chassis that didn't make it off paper was reminiscent of the La.S.138 chassis, further development of the PzII that turned into the PzII Ausf. D. Like MAN's design, the VK 3 t had 4 large road wheels (700 mm in diameter) per side, and its idler and drive sprocket were elevated above the ground. The chassis had the same torsion bar suspension.

    The layout of the tank was the same as that of the early PzI. The engine was in the rear, drive sprocket in the front. The engine was also the same as that of the PzI Ausf. B: the Maybach NL 38 Tr. Thanks to its high power to weight ratio and improved suspension, the new tank had an enormous calculated top speed for its time: 80 kph.

    The first production PzI Ausf. C tank, summer of 1942. Later, it will end up on the Eastern Front.

    The overall chassis concept was approved in April of 1938, after which the VK 3 t chassis turned into the VK 5 to light tank. Overall, the chassis was not changed, just its wheelbase increased a little. According to calculations, the top speed of the tank in 8th gear would be 77 kph.

    Meanwhile, further development of the chassis meant that the mass of the tank would grow. Soon, Krauss-Maffei's design was renamed to VK 6. The calculated top speed was reduced to 67.5 kph, and that's with the 115 hp Maybach HL 54 TRM engine, borrowed from the Sd.Kfz. 6 halftrack.

    The tracks were taken from another halftrack, the Demag D7 (Sd.Kfz.10). The VK 6 chassis was built in August of 1939, but its trials went poorly, mostly for technical reasons.

    The side armour was improved to 20 mm. The photo shows applique armour installed on the side of the hull around the suspension.

    Meanwhile, work took another direction in June of 1938. The new tank, indexed VK 6.01, was supposed to receive a 130 hp Maybach HL 61 engine and an 8 speed DSRG 134190 Maybach gearbox. Around the same time, the VK 6.02 was proposed, equipped with the same Maybach HL 61 engine. In October of 1938, a contract was signed between Krauss-Maffei and the 6th Department of the Armament Directorate for production of six experimental VK 6.01 chassis.

    Three-quarters view.

    The tank underwent serious changes in early 1939, as a result of which very little remained in common between the VK 6 and VK 6.01. The length of the hull was shortened significantly, but the wheelbase remained at 1600 mm. The length of the contact surface decreased from 2295 mm to 1736 mm. The number of road wheels increased to 5 per side, and they were interleaved like on halftracks.

    The number of track links dropped to 52 per side from 62, and their width increased from 240 to 260 mm. These were still Kniepkamp's track links, with a lubricated joint and rubber pads.

    The 150 hp Maybach HL 45 engine and 8 speed semiautomatic Maybach SRG 15319 transmission were installed to achieve a top speed of 80 kph. Considering the experience gained in Spain, the tank's armour was improved to 30 mm in the front. The sides were still 14.5 mm thick.

    Thanks to a cupola with periscopes, the commander did not suffer from blindness.

    While Krauss-Maffei's engineers worked on a new chassis for the light tank, work on its armament proceeded in parallel. The fact that a pair of machineguns was not a correct choice of armament was clear after the first encounter with a T-26 in Spain. At the same time, a 20 mm autocannon was too much for this tank.

    As a compromise, a very unusual tank gun was developed, which is associated with a very common misconception. In July of 1938, the Mauser company began working on a tank version of the MG 141 machinegun, which was a derivative of the MG 151.

    Like the MG 141, the new design indexed EW 141 (Einbauwaffe, "built in weapon"), used 7.92x95 mm rounds from the Pz.B.38/Pz.B.39 anti-tank rifle. Here is where many researchers are mistaken. They consider the EW 141 a machinegun. In reality, it was a semiautomatic gun, a tank version of an anti-tank rifle.

    Thanks to a very powerful round, the EW 141 could penetrate 25 mm of armour sloped at 30 degrees at 100 meters. This was enough to fight lightly armoured targets. The EW 141 would be installed in a one-man turret. The contract for development of a turret platform and its production went to Daimler-Benz.

    The crew couldn't complain about a lack of stowage.

    On September 15th, 1939, a decision was made to build a pilot batch, which included 40 VK 6.01. In April of 1940, the tank received the index Pz.Kpfw.I n.A., or "new type of Pz.Kpfw.I". The first tanks from the pilot batch were expected in March of 1941, and the last ones in September. The appetites of Germany's army were impressive. In case the heavier VK 9.01 reconnaissance tank failed, 1000 Pz.Kpfw.I n.A. would be ordered.

    At this time, according to calculations, the tank weighed 6.4 tons.

    The right fender housed a battery of smoke grenade launchers.

    By the summer of 1941, the situation changed radically. According to a report from July of 1941, the Pz.Kpfw.I n.A. would only be used by airborne troops and expeditionary forces. Looks like the Germany military realized a simple truth: the prospective reconnaissance tank was already obsolete before the first tank came off the assembly line.

    In July, Krauss-Maffei finally delivered the first two experimental VK 6.01 chassis. By that point, a decision was made to improve the side armour with 5.5 mm applique plates, increasing the mass of the tank to 7.3 tons. The first chassis were tested with dummies instead of turrets and turret platforms.

    The production of the pilot batch of the Pz.Kpfw.I n.A. was delayed to October of 1941, but then this date was shifted further. Daimler-Benz was overloaded with orders for other tanks and could only begin production of turrets and turret platforms by the end of 1941. Work on the chassis at Krauss-Maffei was also behind schedule.

    In early 1942, a decision was made to convert two chassis for use in tropical conditions.

    Trials continued in the spring, and the sixth experimental VK 6.02 drove from Munich to Dachau without issues on May 21st. It drove on the highway on the way there, but off-road on the way back. Around that time, the tank was subjected to some changes that raised is mass to 8 tons. This weight gain was a death sentence for Kniepkamp's track links. Instead, small tracks without rubber pads were used. The number of track links went up to 89 per side.

    On July 1st, 1942, the tank received the index by which it is best known today: Pz.Kpfw.I Ausf. C, Sd.Kfz. 101. Mass production also began around this time. Five years went by between the start of development and mass production, during which the tank's mass increased by more than 1.5 times. But, as they say, what else is new?

    High speed training

    The new tanks received serial numbers from 150101 to 150140. The production of the pilot batch was delayed, since the companies responsible for production were busy with other tanks. The last tanks were completed in 1943.

    That was also the last production of the PzI Ausf. C, since it was clear that such a tank was no longer needed. It was no longer interesting as a reconnaissance tank, since the requirements for this kind of tank changed. The PzI Ausf. C's radio equipment was ill-suited for reconnaissance, and a one-man turret for a reconnaissance tank was also a bad idea.

    The Wehrmacht also had no need for ordinary light tanks, since production of those ended in the summer of 1942. The changing conditions of the battlefield left these tanks low odds of survival. SPGs were now being built using the chassis of PzII and Pz38(t) tanks. The PzI Ausf. C's chassis was unsuitable for this purpose, since it was impossible to fit a gun and a crew into the tiny fighting compartment.

    One of the few photographs of the PzI Ausf. C in service, taken in France.

    The lack of clear direction for these new tanks meant that their fighting career was very short. Two PzI Ausf. C tanks were included into the 2nd Battalion, 1st Tank Regiment, 1st Tank Division in early March of 1943. However, being sent to one of the Wehrmacht's oldest tank units didn't mean that the tanks would see combat. The division was located in Greece, and would not be sent to the Eastern Front until October.

    Aside from two PzI Ausf. C tanks, the 2nd Battalion received 8 PzI Ausf. F tanks, the fighting qualities of which were even more suspect. The division fought at Kiev as a part of the 48th Tank Corps, 4th Tank Army. The main enemy of the 1st Tank Division was the 3rd Guards Tank Army, led by General Rybalko. By November 20th, only one of the two PzI Ausf. C tanks remained in service, the first tank with serial number 150101. This tank did not last long either. On December 10th, an order was given to send this tank away for repairs. This was the end of the PzI Ausf. C's career on the Eastern Front.

    PzI Ausf. C captured in Normandy.

    The fate of the remaining 38 PzI Ausf. C tanks was decided in the summer of 1943. On July 28th, the 58th Reserve Tank Corps was formed in France, which included all reserve and training units. These tanks, with their questionable abilities for the mid war, were sent there. They were spread out among training units. The PzI Ausf. C was a much better training tank than the many captured French vehicles.

    The PzI Ausf. C continued its career as a training tank even in June of 1944, which the Western Allies landed in Normandy. In July of 1944, the reformed 58th Tank Corps and some of its PzI Ausf. C tanks did set out for Normandy. These tanks could not influence the course of the battle, since they had no advantages aside from speed. At least one tank was captured and studied. After the war, it was scrapped. This sad fate awaited all PzI Ausf. C tanks.

    The tank went through a lot. You can see that a pair of the outer road wheels is missing, as well as much of the stowed equipment.

    Krauss-Maffei's design became a victim of late tactical-technical requirements for a new tank. The technical qualities of the vehicles are hard to blame for its failure. The PzI Ausf. C was the fastest German tank, but its combat capabilities mean that it was obsolete before production even started. This was caused by requirements that described effectively the same early PzI, but with slightly more powerful armament and more speed.

    Looks like the Wehrmacht was too late to understand that the time of PzI-like tanks was long gone, and attempts to recreate the same tank at a higher technical level were pointless. A program launched by General von Brauchitsch, the commander of German land forces, in November of 1938, serves as more evidence for this thesis. This vehicle, worthy of a separate article, is a competitor for the title of the most useless tank of the war.

    Experimental Tank Guns in 1940, part 2

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    We saw some Soviet pre-war prospective guns in a previous article, let's take a look at the rest of the list.

    Name
    Mass
    Oscillating part mass
    Top speed (kph)
    Practical rate of fire RPM
    Horizontal range
    Vertical range
    Max. range (km)
    Muzzle velocity
    m/s
    Shell mass (kg)
    Effect/
    Notes
    152 mm M-10 tank howitzer in the KV tank
    53 tons
    1890
    Up to 20
    1-2
    360
    -3
    +12
    6
    436
    51.07
    Penetrates 90 mm of armour at 1000 m
    122 mm corps gun for the KV tank
    54 tons
    3200
    Up to 20
    2-3
    360
    -3
    +15
    13
    800
    25.2
    Penetrates 130 mm at 30 degrees at 1000 m (calculated)
    85 mm SPG on T-34 chassis (tank destroyer)
    26 tons
    1200
    Up to 40
    15
    360
    -5
    +45
    17
    800
    9.2
    Penetrates up to 88 mm at 30 degrees at 1000 m (calculated)
    130 mm SPG (B-13) for the SMK
    64 tons
    -
    Up to 20
    2
    6
    +12
    15
    870
    33.5
    Penetrates 130 mm of armour and 40 mm of iron liner at 4400 m. Ready by September 1st, 1940.
    152 mm SPG (Br-2) for the SMK
    64 tons
    4200
    Up to 20
    0.5
    6
    +12
    13
    860
    51.07
    Penetrates 130 mm of armour at 30 degrees at 5000 m and 150 mm of armour at 0 degrees at 1100 m. Ready by September 1st, 1940.
    55-60 mm anti-tank gun
    1000 kg
    -
    Up to 50
    15
    60
    +25
    13
    At least 1000
    Up to 3
    Penetrates 70 mm of armour at 1000 m at 30 degrees (calculated)
    76 mm anti-tank gun based on the USV or F-22
    Up to 1800 kg
    1200
    Up to 50
    15
    55
    +45
    15
    813
    6.5
    Penetrates 70 mm of armour at 30 degrees at 1000 m. Uses shells from the mod. 1931 AA gun. Ready by October 1st, 1940

    The first entry is pretty self explanatory: this is the KV-2. By this time, 4 KV-2s have been assembled, but it has not gone into production quite yet, so it still shows up on the experimental list. The second entry is quite interesting: some kind of proto-IS-2. It's interesting to see such a powerful gun in a rotating turret so early in the war.

    Next, we have something my readers should already be familiar with. The 85 mm gun on a T-34 chassis is the U-20 tank destroyer

    Now here's something a little more obscure. Fans of Soviet tank history will know that the T-100, SMK, and KV faced off for the title of the Red Army's next heavy tank during the Winter War. By the summer of 1940, when this list was composed, the KV had already won. However, it seems that the SMK wasn't quite dead yet. Two SPGs, one with a 130 mm gun and one with a 152 mm gun, are still being pitched. The tank may have never moved forward, but the idea of SPGs with these guns remained. The 130 mm S-26, based on the B-13, was used in the ISU-130 SPG. The 152 mm Br-2 on a self propelled chassis was a long-lived dream of Soviet artillerymen, with several attempts, like the U-19, and S-51.

    The 55-60 mm anti-tank gun is another familiar sight. This is, quite obviously, the ZIS-2. The 76 mm anti-tank gun, however, is more interesting. There were attempts to build guns for the KV (ZIS-5, first iteration) and T-34 (S-54) with the ballistics of this gun, so it's only logical that a towed version would also be made. This particular implementation looks similar to the Pak 36(r), with the existing F-22 being adapted for a more powerful round.

    T-37 and T-38 Applique Armour

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    "To the Deputy People's Commissar of Tank Production, comrade Goreglyad
    CC: factory #37 director

    The question of adding applique armour to T-38 and T-37 tanks during their repair and turning them into land tanks has arisen.

    I ask you to instruct factory #37 to develop blueprints for applique armour for the T-38 and T-37 with calculations of change in mass and other parameters.

    GABTU BTU Chief, Military Engineer 1st Class, Korobkov
    GABTU BTU Military Commissar, Regimental Commissar [illegible]"

    To the Chief of the Production Department of the People's Commissariat of Tank Production, comrade Gnesin
    CC: GABTU BTU Chief, comrade Korobokov

    Re: applique armour for the T-37 and T-38 tanks

    Development of blueprints for applique armour for T-37 and T-38 tanks is underway at repair base #2, as instructed by the GABTU BTU in letter #148864s sent on September 19th, 1941.

    As the hulls of the tanks are not the same, blueprints for applique armour can only be produced for one type of tank within the deadline you have given us.

    We must also inform you that the maximum acceptable increase in weight for the T-38 tank is 400-500 kg. As for the T-37 tank, this kind of increase in weight can cause breaking of the differential, which can be observed even at the tank's regular weight.

    Factory director Frezerov
    Deputy chief of the 22nd Department, Astrov"

    "On October 1st, 1941, in the presence of Repair Base #2 Chief, Brigade Engineer comrade Burakov, Military Engineer 2nd Class comrade Nenarokov, Major comrade Efimov, Military Engineer 3rd Class comrade Lisin, and Military Technician 1st Class comrade Zavidonov, penetration trials of the T-37 tank with applique armour were performed at the Kuskovo proving grounds.

    Main armour thickness: 8 mm
    Applique armour thickness on the hull: 7 mm
    Applique armour thickness on the turret: 6 mm

    A DT machinegun was used to fire at the tank from distances of 200, 150, 100, and 50 meters in single shots with 7.62 mm armour piercing bullets at 90 degrees.

    The results are attached.

    Conclusions: the T-37 tank with applique armour cannot be penetrated with a 7.62 mm armour piercing bullet."

    Via Yuri Pasholok

    T-37 Modernization

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    "Report on the modernization of the T-37 tank
    1. After the modernization, the T-37 becomes purely a land tank.
    2. The following components are removed:
      1. Hull buoys
      2. Propeller with transmission
      3. Rudder, carrier, and drive
      4. One DT machinegun magazine rack (15 slots remain)
      5. Gunner's turning seat
    3. The hull of the tank has 6 mm of armour added to the sides. The side armour is attached right to the hull and covers the space from the bogey mounts to the rivets on the edges of the hull. The front and rear of the hull has sloped armour installed. The armour plates are attached using bulletproof rivets and electric welding. The part of the hull that protrudes above the radiator is shielded from four sides with 6 mm armour. 3 armour plates are added to the front, 2 to the sides, and one on the ventilation cap. The left plate and cap plate are bent to follow the shape of the parts they are installed on. The upper horizontal parts of the hull and the floor also have applique armour. Additional 6 mm plates are welded onto the observation port cover and the left side of the hatch edge. Mudguards are installed along the length of the hull on the buoy carriers.
    4. The turret has 6 mm of armour added to the sides. The front of the turret is converted similarly to the T-40 turret, and the DShK machinegun is installed, with no DT. The machinegun has no elevation mechanism, but has a shoulder stock. Aside from the existing travel locks, a stopper was added to the turret to fix it in place while shooting. A travel lock was added for the DShK machinegun. The DT machinegun opening is preserved, but closed with a plug. The DT remains in the tank, in case it needs to be removed and taken from the tank, or, in an emergency, installed in its old location. This kind of placement was caused by the fact that the old location made it difficult for the gunner to enter or exit the turret and made his station cramped. A special mount was added for the DShK ammunition box. A rack with 10 boxes was added instead of the second driver's seat.
    5. In the event that the current armament and 15 DT magazines remain, the turret can receive applique armour without any design changes.
    6. The mass of the T-37 tank increases by 350 kg after completing the work, stemming from these calculations:
      1. Applique armour weight: up to 400 kg
      2. Armament, ammunition, and mounts: up to 120 kg
      3. Removed components and parts: 170 kg
    7. Additional work to modernize the T-37 tank (with re-armament):
      1. Cutting and mechanical: 252 hours
      2. Smithing: 8
      3. Lathing: 18
      4. Milling: 4
      5. Planing: 3
      6. Welding: 42
      7. Installation: 146
      8. Total: 473 hours
        Note: Major repairs of a T-37 tank take 573 hours. The modernization adds an extra 79% to the time it takes to repair the tank.
    8. Additional work to modernize the T-37 tank (without re-armament);
      1. Cutting and mechanical: 173 hours
      2. Smithing: 4
      3. Lathing: 12
      4. Milling: 2
      5. Planing: 1
      6. Welding: 26
      7. Installation: 96
      8. Total: 316 hours
        Note: Major repairs of a T-37 tank take 573 hours. The modernization adds an extra 55% to the time it takes to repair the tank.
    Base Chief, Brigade Engineer Burakov
    Base Military Commissar, Senior Battalion Commissar, Gagloyev
    Technical Assistant to the Base Chief, Military Engineer 2nd Grade, Sharashov"

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