Friday, 23 June 2017

T-60 in Difficult Times

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.

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