Video: Three Way Heavy Tank Contest

In 1939, the Red Army had not one, not two, but three whole heavy tank designs. Find out how they competed and who the winner was in my latest video.

1942 Lineup

"Wundsdorf Tank School

March 1st, 1942

Which Russian tanks will you encounter in 1942?

A significant amount of obsolete tanks:

1. Ford armoured reconnaissance car
2. T-37 amphibious tank
3. T-26 light tank
4. BT (Christie) light tank
5. T-28 heavy tank
6. T-35A heavy tank

Modern tanks:

1. T-60 light tank
2. T-40 amphibious tank
3. T-34 heavy tank
4. KV-1 heavy tank
5. KV-2 heavy tank

Leaning by Doing

"December 13th, 1939

#212472

To the Assistant of the Chief of the General Staff of the RKKA, Corps Commander comrade Zaharov

RE: your #57129s/s

It is not possible to perform battlefield trials of the KV, SMK, T-100, A-20, A-32, T-40, A5, A7M tanks or the BA-11 armoured car in 1939, as the experimental KV, SMK, and T-100 tanks are currently undergoing proving grounds trials.

Experimental prototypes of the A-20, A-32, T-40, A5, A7M tanks, and the BA-11 armoured car passed proving grounds trials, and the factories are now making changes to blueprints based on the results of the trials, in order to produce pilot batches.

Only tanks and armoured cars produced in 1940 will be sent to battlefield trials. 

Modernized T-28 tanks will not undergo battlefield trials, and will be issued to regular Belorussian Military District units. 

The modernized T-26 tank has a new suspension, but the turbocharged engine has not yet arrived, and therefore battlefield trials will be postponed until 1940.

The SBT bridgelayer tank will be transferred to battlefield trials in December of 1939.

On the orders of Assistant Chief of the ABTU, Corps Commander Pavlov Panfilov

On the orders of Military Commissar of the ABTU, Brigade Commissar Kulikov"

RGVA 31811-3-1632 p.62

Experimental Tank Guns in 1940, part 2

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.

German Intel: Red Army Tanks

Naturally, before you invade a country, you need to be aware of what their army is like. This is a German intelligence bulletin listing the tanks that were known to be in the Red Army. Black rectangles mark especially vulnerable areas.

"BA Ford" armoured car

This is a BA-10 armoured car. The German document correctly identifies it as being armed with one 45 mm gun and two machineguns, although the hull MG is very much overexaggerated in the drawing. The armour is also listed correctly (6-10 mm). The speed is a little low (50 kph instead of 52). The mass is listed as 5-7 tons, which is also a bit high (actual mass was 5.1 tons). The vehicle is shown to be vulnerable to armour piercing bullets at 250 meters and 20 mm shells at 700 meters.

Amphibious Tank T-37

The T-37 is correctly named, but its armour is overestimated (10 mm instead of 8) and so is the speed (45 kph instead of 40), but the rest seems about right. The vulnerability of the vehicle is the same as the BA-10.

Amphibious tank T-38

The data on the T-38 is largely the same as on the T-37, except it's 100 kg lighter (it was actually heavier, at 3.3 tons). The armour is still listed as 10 mm, even though it's still thinner (9 mm). Vulnerability is, naturally, the same.

Vickers-Armstrong's T-26A tank

This is the two-turreted T-26 mod. 1931 or 1932. The document can't decide, ascribing the tank an armament of one 37 mm gun and two machineguns, whereas in reality tanks with two turrets had either two machineguns or one 37 mm gun and one machinegun. The armour is listed as 14 mm, which is in between the mod. 1931's 13 mm and mod. 1932's 15 mm. The mass (8.55 tons) is more than either of the modifications (8 and 8.4 tons respectively). This tank is listed as invulnerable to armour piercing bullets, but still vulnerable to 20 mm shells at a range of 550 meters.

Vickers-Armstrong's T-26B Tank

This is the most common T-26, T-26 mod. 1933. Armour is too thin (14 mm instead of 15 mm) and mass is a bit high (9.55 tons instead of 9.4). Vulnerability is the same as the above tank.

Vickers-Armstrong's T-26B Flamethrower Tank

This is a KhT-130 chemical tank, the Red Army's most common flamethrower tank on the T-26 chassis. Data is the same as on the "T-26B".

Vickers-Armstrong's T-26C Tank

This is the last model of the T-26, T-26 mod. 1939. The mass is too low again (9.7 tons instead of 10.25), armour is still too thin at 14 mm. The armament is identified correctly. The vulnerability of the tank is the same as above.

BT (Christie tank)

Despite the Germans being aware that there are different kinds of BT tank, they are all rolled into the one BT entry. The mass is listed as 10.5 tons to 12 tons, and is a little off again, as the BT-2 weighed in at 11 tons and the BT-7 went up to 13.9 tons. Armour is listed as 6-16 mm; too thin for the BT-7, which went up to 22 mm. Armament is listed for all BT models, including the BT-7 with a 76 mm gun. The vehicle is vulnerable to 20 mm shells at 400 meters. 

T-28 Medium Tank

Here we have the classic T-28 with a KT-28 gun. Unlike with the T-26, there is only one T-28 model listed in the guide. The mass is a bit too high (28 tons vs. 25). Vulnerability is listed as 300 meters with the 20 mm gun, 700 meters with the Czech 37 mm gun, 450 meters with the German 37 mm gun, 1400 meters with the 50 mm tank gun, and 1500 meters with the 50 mm AT gun. The side is vulnerable at 500 meters to the 20 mm gun and at any range to any other gun.

T-35A Heavy Tank

The drawing might not look like it, but yes, this is the T-35. Armament is identified correctly, even though the drawing seems to be missing three turrets. Vulnerability is the same as in for the T-28.

T-35C Heavy Tank

The SMK (the only new Soviet tank the Germans seemed to be aware of) has been rolled into the T-35 family, which is not too absurd if you don't have very good intel. The drawing is of the early SMK with the T-35 suspension, but the tank already lost its third turret. This information is likely based on the SMK that was bogged down in Finland, as there was not much opportunity to examine the other two prototype heavy tanks.

The vulnerability of the tank is not too shabby either: impervious to bullets or 20 mm shells, vulnerable to 37 mm guns at 100 meters, and to 50 mm guns at 450 meters. The Germans bust out the heavy artillery here, noting that the tank is vulnerable at 500 meters to the 105 mm mod. 1918 cannon firing mod. 1939 shells.

And that's it, no T-34, no KV-1 or KV-2. Those tanks were indeed surprises for the German intelligence.

Kirov Factory Experiments, 1937

"Tanks

1. Development of a project and working blueprints for a tank destroyer on the T-28 chassis with 4 turrets, each with a DK 12.7 mm machinegun, and one turret with a 45 mm cannon and a 7.62 mm DT machinegun.
Work begins in the 1st quarter, will end in the 2nd quarter of 1937.
SKB-2 chief comrade Efimov is responsible for the project. Cost in 1937: 70,000 rubles.

2. Development of a project and working blueprints for a breakthrough tank with the following armament: one 76.2 mm turret with limited traverse, two turrets with 45 mm guns and DK machineguns, commander's cupola with all-round vision.
Work begins in the first quarter, will end in the 4th quarter of 1937.
SKB-2 chief comrade Efimov is responsible for the project. Required funds: 350,000 rubles.

Armour will be 60 mm thick, cemented. The hull and turret will have sloped armour. The mass of the tank will be 40 tons. The engine will be an 800 hp diesel, provided by ABTU. The speed will be 40 kph. Fuel range: 350-450 km.

Factory director (signature)."

V. Lehn Collection

The first vehicle is, of course, hilarious, but the second is much more reasonable. One 76 mm gun, two 45 mm guns, 60 mm of sloped armour: some of you may have recognized the SMK breakthrough tank. The tank lost one turret when Stalin inspected the design, and another in the process of making the "budget" KV that ended up winning the role of the Red Army's heavy tank after a trial by fire in Finland. Looks like the tank's history reaches as far back as 1936.

Birth of the KV

"History of the development of the KV tank

The KV tank began development according to the decisions of the Main Military Council on December 9th, 1938. Tactical-technical requirements were set by RKKA ABTU and confirmed by the People's Commissar of Defense on February 19th, 1939. The final revision of the requirements and permission to build the tank was given on February 27th, 1939, by the decision of the Commissar of Defense in the Council of People's Commissars #45ss and #118ss from May 15th, 1939.

The factory began working on the design on February 1st, 1939. The chief engineer of the project was Nikolai Leonidovich Dukhov. The technical project and a model were provided for inspection on April 7th, 1939. The model commission, chaired by deputy ABTU chief, military engineer 1st grade comrade Korobkov, with the following suggestions:

1. Hull and turret:
1. Increase the thickness of the rear plates to 75 mm and the front sloped plate to 60 mm.
2. Test the hull, turret, and hatches by firing at them.
3. Install a guard against hand grenades outside the turret and under the turret bay.
4. Move the turning mechanism of the turret forward to make it more convenient. 
2. Armament:
1. Place machinegun ammunition in the turret first, and then use the remaining space for shells.
2. Simplify the gun mantlet.
3. Follow the Commissar of Defense's order and install a removable AA machinegun in addition to the forward facing machinegun. 
4. Provide a means for every crew member to open fire from personal weapons.
3. Engine:
1. Lower the engine by 50 mm.
4. Transmission:
1. Robustness calculations should use a 660 hp M-17F engine with M=330 kg-m. Dynamic calculations should use the 580 hp V-2F engine with [missing handwritten figures make the rest of the paragraph meaningless]
2. From the gearboxes provided, #3 (planetary gearbox with a reductor) should be the main variant. In parallel, develop a simple gearbox. The gearboxes should be able to replace each other. Lower the engine axis by 50 mm. The side friction clutch should be the same type as on the SMK, with a diameter of 500 mm.
3. The final drive should be of the same type as on the SMK. Change the design of attaching the inner gears to make it easier to produce. 
5. Suspension:
1. Increase the length of the foundation to 4600 mm, with the width of 700 mm and ground pressure of 0.6 kg/cm^2.
2. Use an SMK-style track (stamped). The space between the wing and track must be no less than 20 mm.The track spur should be at least 70 mm away from the hull.
3. Develop two kinds of idlers and drive wheels: one with rolling bearing, one with a sliding bearing.
4. Use SMK-style road wheels and idlers, with armoured bearings, according to the technical requirements. Place the torsion bars in armoured covers.
6. Observation devices and equipment:
1. Give the driver mirrored devices for looking left and right, as well as a periscope in a hatch as a backup.
   The radio operator should have a mirrored observation device for looking left.
   The turret needs devices to look forward, back, left, and right, as well as a backup periscope.
2. Place the radio left of the driver, as stated in the technical requirements.
3. Provide a spare parts and instruments container for the tank.
4. Add small hatches for throwing hand grenades from the tank.
5. Develop a project for servo-controls, and present it to ABTU for approval.

Working blueprints were delivered to the Izhor factory on May 20th, 1939. The approximate processing time was one week. On May 28th, 1939, the following list of changes was provided to ABTU.

1. The tank hull is 50 mm lower.
2. The turret is 60 mm lower.
3. The rear plate was thickened to 75 mm.
4. A planetary gearbox is being developed.
5. The foundation length was increased to 4.4 m.
6. The diameter of the brake drum was decreased to 500 mm.
7. A 700 mm wide track was developed.
8. Mirrored observation devices are being developed.

May 25th: factory #75 receives an order for two V-2 tank engines. The first is due by June 10th, the second by July 1st. 

June 4th: the 75 mm armour plates are tested at the Izhor factory against the 76 mm 40-caliber gun with the muzzle velocity of 650 m/s. The homogeneous armour with hardness of 3.5-3.6 successfully resists these shells at 200 meters. At 50 meters, the armour forms bumps 25-30 mm deep, and occasionally forms cracks.

June 5th: ABTU instructs the factory to:

1.  Use the V-2 engine only, and not use the M-17 engine anymore.
2. Change the air intake and exhaust. Install a coaxial 45 mm gun.

June 10th: the factory begins production of a simple gearbox, final drive, suspension, tracks.

September 1st: the first tank was assembled. After travelling 7 km, due to poor assembly, the clutch between the gearbox and final drive disconnected. This defect was temporarily solved by sleeve welding. A variant with a cam-bearing sleeve is in development.

September 2nd: the tank travelled 45 km at factory trials. The following was discovered.

1. The 4 small oil reservoirs in the tank aid foaming of the oil, as a result of which it escapes the reservoirs. A decision was made to throw these reservoirs away and use the rear left 120 L gas tank as an oil reservoir.
2. Due to the 45 mm and 76 mm L-11 guns installed in the tank, the position of the crew was not finalized.
3. The mechanism for tightening tracks is inconvenient.
4. The mirrored observation devices are not installed.

September 5th: the tank was sent to Moscow to show to the Government."

CAMD RF 38-11355-934