Monday 8 July 2013

T-50: Factory #174

The T-50 tank was meant to be a light tank for infantry support. It would replace the aging T-26 and the failed T-46 project. Here are the requirements given to factory #174:

"Tactical-technical Characteristics and Data on the Technical Project of the Order of the Labouring Red Banner Vorshilov Factory #174
  • Maximum mass: 13500 kg.
    • Turret: 1200 kg
    • Hull: 5590 kg
    • Suspension: 2644 kg
    • Transmission: 966 kg
    • Motor group: 760 kg
    • Equipment and armament: 1138 kg
    • Ammunition, fuel, grease, water, crew: 1200
    • Total: 13498
  • Crew: 4
    • Driver (hull front)
    • Gunner (turret left)
    • Loader (turret right)
    • Commander (turret rear)
  • Maximum speed (2000 RPM): 50 kph
  • At 1800 RPM:
    • 4th gear: 45.4 kph
    • 3rd gear: 30.15 kph
    • 2nd gear: 17.92 kph
    • 1st gear: 1.34 kph
    • Reverse gear: 6.08 kph
  • Maximum elevation angle: 44 degrees
  • Maximum downward slope: 45 degrees
  • Maximum tilt: 40 degrees
  • Fording depth: 1000 mm
  • Climbable vertical wall: 733 mm
  • Crossable trench: 2200 mm
  • Armament:
    • 1 45 mm gun (150 shells) + 2 DT machine guns (4000 rounds)
      • Elevation: 25 degrees
      • Depression: 7 degrees
      • PT-1 sight
      • TOS sight
    • Flamethrower (optional)
      • Fuel: 150 liters
      • Range: 90 meters
    • 1 PPD submachinegun (750 rounds)
    • 24 F-1 grenades
    • 3 ports for Nagant revolvers
  • Armour: homogeneous, manufactured by the Izhor factory, welded, sloped on all sides.
    • Turret side: 37 mm at 20 degrees (rear 15 degrees)
    • Upper front: 37 mm at 50 degrees
    • Lower front: 37 mm at 45 degrees
    • Lower side: 37 mm vertical
    • Upper side: 37 mm at 40 degrees
    • UFP: 37 mm at 56 degrees
    • Rear: 37 mm at 10 degrees
    • Bottom: 15 mm horizontal
    • Roof: 15 mm horizontal
    • Sloped roof: 30 mm at 63 degrees
  • Communications:
    • KRSTB radio
    • Flare launcher (20 flares)
    • Internal telephone TPU-3M for 3 people
    • Commander-driver light signals
    • 1 hatch in the turret for signals
    • 1 gun position indicator (driver console)
  • Vision devices:
    • Commander: 7 prismatic devices in a cupola with a hatch.
      •  Horizontal range: 360 degrees
      •  Vertical range: -45 - +20 degrees
    • Driver: 1 prismatic vision device covering the front sector
      • Horizontal range: 116 degrees
      • Vertical range: +/- 23 degrees
      • One spare device for driving with a damaged main device.
      • One device for looking left.
      • One device for looking right.
    • Gunner: PT-1 sight
  • Range: 300 km, 10 hours off-road
  • hp/ton: 22.2 (20 while driving the fan)
  • Engine: diesel V-3 (based on V-5)
    • Cylinders: 6
    • Positioning: linear
    • Engine power:
      • 300 hp at 2000 RPM
      • 250 hp at 1800 RPM"
There are a lot more very specific details if you need to know them, but the average reader should have a good idea of what the vehicle was like at this point.

The GABTU KA plans for 1941 expect factory #174 to have completed 220 radio-equipped T-50s, 230 regular T-50s, and 100 flamethrower-equipped T-50s, for a total of 550 brand new T-50 tanks by the end of 1941, to the tune of 163,900,000 rubles total. Additionally, they were also to produce 9,000,000 rubles worth of spare parts for the T-50.

Looking at it from the bureaucrat perspective, there's no simpler task: we give this tank factory money, the tank factory gives us tanks. Let's see what has to happen before even the first tank of the 550 comes off the assembly line.

"December 9th, 1940

We offer the T-50 project for examination and testing in factory and field conditions. Please return one confirmed copy to the factory for the management.

Factory director Markin."

The wheels of engineering start spinning. When comparing the Kirov factory prototype to their own, an engineer from #174 describes their superiority: their tank is shorter and narrower than the Kirov tank. The armour is heavily sloped: 40-50 degrees, providing immunity from 37-45 mm AT guns. Turret armour, sloped at 20 degrees, is only penetrable by 45 mm guns at 50 meters. Several gearboxes (5 gear, 8 gear, and an experimental planetary gear) were developed. While the tank only had two machine guns, the report describes the possibility of a third, with an optical sight (unless a larger radio was added, which #174 engineers were against).

Factory #174 built two prototypes, meant to travel 200 km in initial tests. The first traveled 121 km on January 13th, and had to be taken back to the factory to repair some defects. Meanwhile, the second prototype managed to travel 372 km. While the defects were being repaired, a problem arose.

"January 14th, 1941

The commission sent to test T-50 tanks at factory #174 reports that the requirements for placing observation and fire control devices in the turret were not met. The plant director, comrade Markin, states that new turrets will be ready in early February. This does not allow the commission to make a full report in times specified by your order from January 7th, 1941. I request that you order factory #174 to install new turrets with new armament as soon as possible.

Deputy GABTU Chief, Major-General of the Engineering Forces, Lebedev."

The vehicle traveled 36 more kilometers, and the commission waved their bureaucracy wand, and composed an act. The act, among many amazingly tedious things (as always, if you want the full record, just ask), contains the following:

"The tested tanks passed factory trials. Prototype #1 traveled 506 km. Prototype #2, 612 km. The director claims that all defects discovered during these trials have been removed.

Field trials have not been performed for the following reasons:
  1. Periscopes are not installed.
  2. PPD and their ammunition, flare launchers, flares, spare parts, tools, chemical and medical equipment are not installed.
  3. Caps of the air intakes are absent.
The director claims that he will have the above deficiencies addressed by January 17th, 1941. "

The report also mentions the improved turret (to be ready by February 15th, 1941) and extra fuel tanks, along with friction clutch dust covers (to be ready by January 20th, 1941). Stamped tracks are to be developed by March 1st, 1941. Issues with the hull layout have been noted and entered in new blueprints. The commission accepts the two prototypes for field and armament testing.

On January 15th, the defects were repaired, and the first prototype traveled another 349 km with only one minor defect (the driver's hatch bracket cracked). To compensate for its stellar performance in the first round, the second prototype managed only 73 kilometers out of the 200 it was supposed to. The vehicle traveled another 18 km after repairs. On January 16th, the first vehicle traveled 80 more highway kilometers, and 51 km on a dirt road. The second traveled 101 km (out of 300). By January 17th, the first prototype had 601 km of field tests completed, and the second had 506. 

The tests revealed a weakness in the tracks, and drive wheels. Reinforced ones were ordered. Both prototypes also exhibited a very hot gearbox (80-90 degrees). 

On January 18th, testing continued. Prototype #1 traveled 222 km off-road, and 221 km the next day. Due to the high speed of travel, the tracks continued to crack. 

At the same time, prototype #2 traveled 213 kilometers off-road on January 18th, and 243 on the 19th. The second prototype had better luck with cracked tracks, but was worse off when it came to overheating and various suspension defects. 

At the end of January 19th, both vehicles stopped testing. The T-50-1 traveled 1059 kilometers since tests began. The T-50-2 traveled 1031 kilometers. From January 20th to January 25th, the vehicles were fixed up by factory #174. 

Tests resumed on January 26th. A gas-oil leak was discovered in the first prototype, and the second developed a crack in a gearbox component.  After being towed back to the factory, the second prototype was found to have a number of other defects. Meanwhile, the first prototype continued testing, and traveled 1115 km by the end of January 26th, while the second only traveled 1063. 

Tests were suspended until January 29th. Malyshev approved Lebedev's request to increase the required test distance to 500 km. The new tanks, including the new turret, were to be ready by the February 15th deadline. 

The documents remain silent about the next few days, but a document dated February 8th describes track failure then testing the friction clutch reliability by going up really steep slopes. Prototype #1 traveled 2571 km by this point (including factory tests). The T-50-2, meanwhile, was still suffering from overheating. After traveling 923 kilometers, its gearbox failed. The exact amount it traveled was unknown, but both vehicles reached over 2000 km of field tests by February 6th. 

A February 21st, 1941, report claims that the gearboxes now last 1500-2000 km (out of the requested 3000), and tracks last 300-400 km. 

Tests in March revealed that the T-50-1 also had heating problems. The gearbox temperature reached 105 degrees. By March 27th, the T-50-1 traveled 4027 kilometers. The T-50-2, by this point, traveled 3245 km. 

From the end of March to the end of April, various new track types were tested on the new tanks. They proved compatible with T-26-5 tracks, but the tracks were not robust enough. On April 24th, 1941, a planetary transmission was ordered for the T-50-1 and T-50-2. 

On May 5th, a list of new additions to the T-50 project was compiled.
  • Increased inter-repair distance of 7000 km.
  • 2x23 mm MP-6 AA guns with an automatic AA sight
  • Mine roller
  • Smoke canister
  • Hydraulic gearbox
  • New 350 hp engine
  • Electrically controlled DT machine gun
  • Automatic engine starter, triggered by temperature dropping below acceptable levels
On May 19th, factory #174 was tasked with producing 5 pre-production samples of the T-50. The gearbox temperature of 115 degrees was still not resolved, but it seemed to work fine while running that hot. The track life requirement was 2000 km. On May 20th, the requirement for the amount of observation devices on the commander cupola was increased to 8. Many other minor changes were introduced into the blueprint of the mass produced vehicles. On May 22nd, a letter was sent recalling the T-50 tanks to factory #174. Solutions to existing problems (such as hot gearbox and engine) were found, and the factory wanted to perform tests on the actual tanks. 

Due to setbacks at the Izhor factory, which was supposed to deliver 35 armoured hulls to factory #174 (but delivered zero), no T-50 tanks were built in May. Even if the Izhor factory had been on schedule, the order would not have been fulfilled. Instead of 25 V-4 engines that were to be delivered by factory #75, factory #174 received only 4. Next month, things did not get better. Instead of the 40 engines due in June, factory #75 delivered only one by June 13th.

In mid-June, the new reinforced tracks were tested. Between June 7th and June 12th, the new tracks traveled 657 km on both the T-50-1 and T-50-2. The track was deemed unsatisfactory. New "KV-style" tracks were in development. The temperature of the gearbox in the T-50-2 remained between 90 and 105 degrees during these tests. 

On June 17th, there were not enough V-4 engines to begin production. Relations between factories #75 and #174 were rather tense. Factory #48 was assigned as a subordinate to factory #75 in an attempt to get production started, but, due to mismanagement, its resources were used very inefficiently. 

On June 20th, the T-50-2 was undergoing long range tests. The T-50-1 was at ANIOP, testing the gun.

On June 27th, having familiarized themselves with Pz 38(t) tanks, the Red Army deemed it necessary to increase the armour of the T-50 tank to:
  • 50 mm front armour
  • 50 mm turret armour
  • 30 mm roof armour
At the cost of the tank's weight increasing to 14.5 tons, it would become invincible to 37-45 mm guns. T-50 tanks with this new armour layout were expected to enter production by September 1st, 1941, at least according to Timoshenko. Marshal Kulik considered it feasible to begin production on January 1st, 1942. 

Requirements for the new tank were given to factory #174. The prototype tank was due on November 1st, 1941. Both the upper and lower front plate, as well as all turret armour, was increased to 50 mm. 

On June 30th, the new "KV-style" tracks arrived. They fared much better than the T-26-5 tracks. After traveling 406 km, only 9 track links showed signs of damage. Chrome-steel tracks traveled 600 km, and none of them showed any cracks. However, the chrome-steel track links showed more wear at the pin wells, so preference was given to KV tracks. More powerful fans were ordered to keep the engines cooler. The rear torsion bars finally showed their age: the right broke down after 3429 km, the left, after 3603 km. Subsequent torsion bars were made of higher quality steel.

By July 3rd, a number of improvements was made, such as making the optical devices more resistant to bullets and shrapnel, increasing the robustness of the driver's hatch, thickened gun mantlet, and a more robust turret ring.

On July 10th, another enumeration of resolved defects was performed. Among them was the overheating gearbox. It could now withstand a 2000 km march. The due date for final production vehicles was established to be August 1st, 1941. 

By July 12th, only 10 V-4 engines were manufactured, out of 65 that were supposed to be. However, this was mostly due to the shifting priorities of wartime production. In total, out of 2150 requested engines, 2169 were built. 

On August 9th, another series of defects was resolved.

By September 15th, 1941, out of the 620 scheduled T-50 tanks (the numbers were increased due to the start of the war), only 37 tanks were produced. Due to the evacuation of factory #174, the manufacturing of these tanks stopped completely. However, by this point, the tank seems to have started performing rather well: 

"The first, however short, experience of using the T-50 in combat showed that its parameters match technical requirements. This tank needs to be the most numerous tank used by the Red Army. The GABTU KA requested that comrades Malenkov and Malyshev arrange for the beginning of mass production in 1941, and deliver 500 vehicles before the end of the year. Additionall, GABTU KA requests that 5000 T-50 tanks be produced in 1942, with increased 55 mm front, rear, and side armour, and a planetary transmission."

On October 14th, the Red Army is no longer satisfied with comparing the T-50 to the light Pz 38(t), and compares it to the medium PzIII. In this comparison, it is noted that the top speed of the T-50 grew to 52 kph. 

Fedorenko later revised the request to a somewhat more reasonable 300 units. By December 24th, 1941, factory #174 (evacuated to Chkalov) completed 10. Out of the lofty goal for 620 T-50 tanks by the end of 1941, factory #174 completed only 47.

With the aid of other factories, 65 T-50 tanks were built by the end of January of 1942. The project was scrapped, and the resources used to produce the T-50 were redirected to the T-34. The T-50, despite all of its advantages, was almost as complicated to produce as a T-34, and not as versatile.


  1. > There are a lot more very specific details if you need to know them

    Can you provide that source? I need it :)

    1. The source is in this document pack:

      Sadly, there are no archive numbers on most of them.

  2. Reading about the development of various German tanks (even the "successful" designs) yields similar tales of woe and inefficiency. National stereotypes do not hold up well under the mess of bureaucracy and wartime realities, it seems.