Monday 31 July 2017

KV-1 Transmission Upgrade

"Transmission for the KV tank with a preselector gearbox

Variant 1

The main clutch, gearbox, both final drives, brakes, and the lines to these components are removed. Instead, two identical Wilson type gearboxes with preselectors are installed symmetrically in the transmission compartment on each side (photo #2).

Photo #2. Transmission diagram, variant 1.

Sunday 30 July 2017

M4A2(76)W: Emcha With a Long Hand

The Americans considered improving the firepower of the Medium Tank M4 back in September of 1941. A year later, experiments with installing the 76 mm T1 gun into the stock turret commenced. Even though the gun fit, the military was unsatisfied with this rearmament. A decision was made to equip the M4 with the turret from the Medium Tank T23, which did not enter production. This was not hard, since the turret ring diameter was the same.

Shortly before that, the M4 (known in the USSR under the nickname "Emcha") was equipped with wet ammunition racks. These modernized tanks, whose name received the suffix (76)W, went into production in January of 1944. Among them was the M4A2(76)W, the production of which began in May of 1944. The USSR received these tanks under the Lend Lease program.

Saturday 29 July 2017

M4A2(76)W Shipment

October 5th, 1944

We, the undersigned, Senior Assistant to the Chief of the GBTU TU Military Acceptance Department, Engineer-Captain comrade A.M. Davydov, and Technical Deputy to the Commander of the 27th Independent Training Tank Regiment, Engineer-Captain comrade Dudin, compose this act to state that the former had delivered and that the second had accepted tanks that arrived on the "Darma" on October 4th, 1944, and the "Neftedag" on October 2nd, 1944.

Friday 28 July 2017

M24 Chaffee: Test Drive at the End of Lend Lease

Starting in the second half of 1943, the approach to sending British and American Lend Lease armoured vehicles to the USSR changed. Instead of immediate large scale shipments, the Western Allies sent a few samples of new vehicles. If the tank or SPG was satisfactory for the Soviet side, full scale shipments followed.

The first vehicle to arrive on this trial basis was the Light Tank M5A1. By that point, production of light tanks in the USSR was wrapping up, so the American novelty never made it into service. Nevertheless, the USSR received another foreign light tank. This was the Light Tank M24, the best American light tank of WWII.

Thursday 27 July 2017

Dinger Tank

BTU HQ of the Voronezh Front
Reconnaissance Dept.
May 3rd, 1943

To the divisional HQ chief
Operational department only

Through POW interrogation, it was established that:

The German army is receiving a new "Dinger" tank. The mass is 65 tons, armament is one 100 mm cannon and two M-42 machineguns. The armour thickness (front and engine compartment) is 90 mm. The crew consists of 6 men.

This type of tank is being built in Austria, at a tank factory in Proll. Mass production began in the fall of 1942.

In addition, infantry units received a new type of anti-tank grenade. The grenade carries three magnets on the front of a round plate. The grenade is used as follows: a tank hunter attaches the grenade to the tank and pulls out the cord (the grenade is held on the tank with magnets), after which the grenade explodes.

Inform your subordinate forces of this kind of tank and anti-tank grenade, make it a priority to clarify data on the type of tank and anti-tank grenade.

Chief of the Armoured and Motorized Department of the Voronezh Front, Lieutenant-Colonel Sch[illegible]enko."

Lend Lease Truck Requirements

"People's Commissariat of External Trade, Technical and Industrial Imports
To comrade Pritvorov

When ordering trucks, keep in mind the following technical requirements that GABTU has for foreign vehicles:
  1. From the total, 70% must be two axle 4x4, 20% two axle 2x4, and 10% three axle 4x6. The cargo capacity must be 2.5-3 tons. One or two brands.
  2. All vehicles must be equipped with tools and spare parts, and have special Ground Grip type tires.

Tuesday 25 July 2017

Tanker Rations


On the supplies of Guards tank units, attached to the 64th Army by order of the Member of the State Committee of Defense of the USSR, comrade Malenkov,

As of March 6th, 1943, in days:

Monday 24 July 2017

New Heavy Tanks, 1943

"To the Chief of the GBTU TU 6th Department, Regional Engineer at the Kirov Factory
July 5th, 1943

I report on the experimental work performed at factory #100 during June of 1943.

The most attention was paid to Objects 237 (experimental IS tank) and 239 (KV-1S tank with an IS tank turret and 85 mm gun).

Saturday 22 July 2017

SG-122: Assault Gun on a Foreign Chassis

Work on SPGs, especially heavy ones, stopped in the USSR after the start of the Great Patriotic War. This was largely caused by the fact that the factories were busy with other orders. In addition, many factories were evacuated eastward. Only light SPGs were put into production at the start of the war, and these were largely improvised.

Meanwhile, due to the number of factories that switched from making artillery tractors to tanks, the artillery branch was forced to revisit SPGs towards the end of 1941. Experience gained in battle and a number of other factors meant that the new generation of SPGs that was built in 1942 was radically different from pre-war designs. This is especially true for medium SPGs, which became assault guns instead of tank destroyers. The SG-122 was one such SPG, built on the chassis of a captured German SPG.

Friday 21 July 2017

Superheavy Trophy

The German superheavy Maus tank left a mark in the history of tank building. This was the heaviest tank in the world, developed as an assault tank, practically invincible to enemy fire. In many ways, its fate was the same as the fate of another giant, the French FCM 2C, which holds the title of the world's largest tank to this day. Like the French heavyweight, the German tank never saw combat. In both cases, the tanks were blown up by their own crews. Another similarity was that the tanks became the subject of a careful study.

Thursday 20 July 2017

Br-19 152 mm Gun

"To the Chief of the 3rd Department of the USSR NKV 85 Gorkiy St
In response to #5488s and 5255s-41

CC: Factory #221 director, Stalingrad
In response to #2890s-41

CC: Chief of the 2nd Department of the GAU UVNA, 2nd NKO Building

CC: GAU Regional Military Engineer at factory #221, Stalingrad

September 2nd, 1941

RE: Br-19 system

The Br-19 152 mm gun showed satisfactory precision at proving grounds trials, and the elevation mechanism worked flawlessly.

Considering the positive results of the trials and the advantages of the Br-19 over the 152 mm Br-2 gun in its lack of balancing mechanism, I consider it possible to put the gun into production to replace the 152 mm Br-2.

In connection with this, I ask that you instruct factory #221 to develop copies of blueprints and technical documentation for the Br-19 gun and send it by November 1st, 1941, through the GAU regional engineer to the 1st Department of the GAU UVNA for approval.

GAU UVNA Chief, Colonel Sorokin
GAU UVNA Military Commissar, Regimental Commissar Kozlov
1st Department of the GAU UVNA Deputy Chief, Komarov
3rd Section of the 1st Department of the GAU UVNA Chief, Yudov"

Wednesday 19 July 2017

Tuesday 18 July 2017

T-34 with U-11

"To the director of Kalinin factory #8, comrade Fratkin, Sverdlovsk
CC: NKTP Technical Department Chief, Engineer-Colonel Ginzburg, Sadovo-Sukharevskaya 9.11.
CC: NPTK Technical Council Chair, comrade Satel, 35 Gorkiy St.
July 20th, 1942

The design sent to us for review in letter #1430s of a 122 mm U-11 howitzer in a T-34 turret, designed under the initiative of factory #8, was reviewed by the Artillery Committee of the GAU.

The design describes the installation of an experimental U-11 122 mm tank howitzer into a new T-34 tank turret, while maintaining the existing turret ring. Since the proposed fighting compartment only fits two men to service the gun, which is insufficient for the howitzer to work normally, the project is not of interest and is rejected.

Considering that the installation of this howitzer in the larger KV tank turret resulted in insufficient comfort of service and rate of fire, the development of this project is nonsensical.

In order to avoid unproductive waste of effort and resources, the Artillery Committee consider it prudent to seek approval from the GAU before projects are started.

Deputy GAU Chief and ArtKom chair, Major-General of Artillery, Hohlov
ArtKom Military Commissar, Regimental Commissar Vasiliev"

Here is the proposed design.

Monday 17 July 2017

Experimental Guns, 1941

"Experimental works
at the Order of Lenin Molotov factory #172, 1941

According to contract #3-84 signed on March 18th, 1941, the factory is working on the following systems and parts:

1. 152 mm gun, 203 mm howitzer, and 280 mm mortar on a unified mount (M-70)

The technical project was completed in March of 1941. In August of this year, it was reviewed by the NKV Technical Council, along with a GAU representative. As a result, the factory received several directions regarding the technical project and the permission to begin development of working blueprints, which were completed to 40%, after which the factory ceased work under orders from the NKV. Until the end of the year, we did not work in this area.

According to the agreement, the factory was supposed to deliver working blueprints and the prototype by March of 1942, but it appears that the factory cannot do that.

Sunday 16 July 2017

Small, But Fierce

One of the distinguishing characteristics of German tank building in WWII was an aim to use up obsolete vehicles, including those which used to be the backbone of the German tank force. If a German tank became obsolete, that didn't mean that it would be scrapped. Some tanks were sent to training units, other were modernized. Obsolete tanks, especially light ones, were often converted to SPGs or engineering vehicles. This was the fate that awaited the PzI, Germany's first mass produced tank, which was already obsolete at the start of WWII.

Saturday 15 July 2017

Pz.Kpfw.I Ausf. F: Pocket Tiger

Coming up with tank ratings is a hobby of many tank experts, as well as people who consider themselves as such. As a rule, the creators try to determine the best tank. While some kind of systematic approach was developed over the years, picking out the worst tanks is usually more complicated. Often, creators of lists of the worst tanks make their choices according to no set system and end up naming a number of tanks that didn't earn such a shameful label.

If we consider the tank's characteristics, the time of its appearance on the battlefield, and combat effectiveness, then one of the worst tanks of WWII was the German Pz.Kpfw.I Ausf. F. Conceptually similar to the British Infantry Tank Mk.I, it entered service in the middle of the war, with very questionable characteristics.

Thursday 13 July 2017

Wonder Weapons

Colonel Kurt Stressner was captured by the Red Army on January 12th, 1945. His interrogation deals with many interesting topics, but one section is probably the most interesting:

"Presence of new weapons and chemical substances

I don't know anything about new weapons, either through official channels or personally. It's possible to redesign the V-2 so that it could be used to strike targets on the front lines precisely. The V-1 is shaped like a plane and is aimed at the target along a horizontal trajectory, and hits the target very imprecisely. They say that it hits 2-3 km from the target. The V-2 has a vertical trajectory and hits 500-1000 m from the target. Time consuming calculations are required. The V-2 can strike tall objects in an area 3-4 square kilometers in size. Both of these weapons can only be used against cities, that is why they cannot be used on the Eastern Front. They say that there is also a type of weapon being developed that is based on decay of atoms. This kind of weapon is desirable, but unlikely.

The use of chemical weapons on German soil is impossible due to the small spaces on which the battles take place."

Wednesday 12 July 2017

T-37 Modernization

"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

Tuesday 11 July 2017

T-37 and T-38 Applique Armour

"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]"

Monday 10 July 2017

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.

Oscillating part mass
Top speed (kph)
Practical rate of fire RPM
Horizontal range
Vertical range
Max. range (km)
Muzzle velocity
Shell mass (kg)
152 mm M-10 tank howitzer in the KV tank
53 tons
Up to 20
Penetrates 90 mm of armour at 1000 m
122 mm corps gun for the KV tank
54 tons
Up to 20
Penetrates 130 mm at 30 degrees at 1000 m (calculated)
85 mm SPG on T-34 chassis (tank destroyer)
26 tons
Up to 40
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
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
Up to 20
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
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
Up to 50
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.

Sunday 9 July 2017

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

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.

Friday 7 July 2017

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

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?

Thursday 6 July 2017

The Other M-30

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

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
2550 m
3000 m

Wednesday 5 July 2017

KV Tank Markings

"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.

Tuesday 4 July 2017

Truck Amphibian

"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).

Monday 3 July 2017

New Gun for the T-34

"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.

Sunday 2 July 2017

Howitzer KV

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.

Saturday 1 July 2017

Big Gun for a Small Turret

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.