Controversial Commander's Cupola

Three-man turrets appeared in the USSR back in the 1930s. The T-28 and T-35 tanks already had a dedicated commander. The problem was that his abilities were limited. He only had a periscope at his disposal, which had a limited field of view. The KV-1 tank that came to replace the T-28 and T-35 kept the overall layout of the fighting compartment. As before, the commander sat in the front right and had a periscope to look through. It was clear by 1940 that this was not enough. Nevertheless, it took a while for engineers to arrive at a classic commander's cupola.

The commander's cupola on the KV-1S tank appeared a full two years after the start of the KV tank family.

Failed Modernization of the KV-1S

Evolutionary development is a common sight in tank development. The fact that engineers do not seek to make work for themselves should not be mistaken for laziness. This is often a necessary requirement set by the customer, especially when it is necessary to keep up the rate of production. For this reason, revolutionary projects were often vetoed from above. This happened with the KV-13 and T-34M in 1942 when both were put away until better days.

Object 238 on trials, August 1943.

First KV-1S

 "To the Chief of the GBTU BTU, Major General of the Tank Forces, comrade Korobkov

I report that the Kirov factory presents two KV-1S tanks for trials.

First tank: #10279

1. Engine: V-2KF #A-1401 650 hp at 2100 RPM
2. Cooling system:
1. Water radiators designed for the KV-3 tank
2. Oil radiator from the RZT aircraft
3. Gearbox: 8 speed with demultiplier, blueprint 21gr
4. Main clutch: four disk, blueprint 110gr
5. Fan with stamped blades and milled diffuser, blueprint 902gr
6. Shifting gate blueprint 119gr and control rods blueprint 117gr

Second tank: #10334

1. Engine: V-2KF #4ML-1669 650 hp at 2100 RPM
2. Cooling system:
1. Water radiators: production with additional radiators - blueprint 903gr.sb.8
   
2. Production oil radiator with extra radiator, blueprint 902gr. Air intake with deflectors.
3. Gearbox: 8 speed with demultiplier, blueprint 212gr
4. Main clutch: four disk, blueprint 210gr
5. Fan blueprint 219gr
6. Shifting gate blueprint 219gr and control rods blueprint 217gr
7. Final drive blueprint 15gr (normal drive sprocket with 16 teeth)

By April 21st, 1942 trials of tank #10334 had started. It drove for 99 km on a highway. Linkage cones for 2nd, 3rd, and 4th gear control rods cut off.

Tank #10279 went on an initial run today (April 22nd) but was not accepted for trials since the air intakes on it are still wooden models.

The vehicles are not ready for checking the cooling system.

Senior Assistant to the Chief of the 5th Department of the BTU, Military Engineer 2nd Class [Signature]"

CAMD RF F.38 Op.11355 D.870 p.170

Heavy Without Alternatives

One can often encounter brainstorms about how individual vehicles or even entire tank building schools ought to have evolved. Most of these brainstorms are done by people that are far removed from the field of history, but sometimes even notorious historians take part in this exercise. Among Soviet tanks, the T-28 is a popular character in alternative history. Modern improvements to this tank know no bounds, but the fact that the T-28 was replaced by the KV-1 and not the T-34 is often ignored, as is the fact that a replacement for the T-28 by the name of T-29 already existed. 

Object 237 accepted into service with the Red Army as the IS-85 (IS-1).

The IS-85 heavy tank was accepted into service with the Red Army on September 4th, 1943. This was the finale of the program aimed at developing a successor to the KV. One can often hear claims that if the KV remained in production and was modernized then it could be made into a heavy tank that was no worse than the IS-85. You may laugh, but these claims were not just made by alternative historians. Attempts to preserve the KV-85 were made at the highest levels, even in 1944. Nevertheless, the KV had to make room on the assembly line for its successor. Read on to find out why this happened and why there was no alternative to the IS tank.

Planetary Turning Mechanism Trials

 "January 7th, 1943

#11

In October and November of 1942 factory #100 designed and tested a planetary turning mechanism designed by Engineer Lieutenant Colonel A.I. Blagonravov.

We attach the report on the first stage of trials held with a KV-1S tank and ask you to approve it.

By now, the total length of trials reached 1085 km, of those 135 km was travelled towing a tank. Once the tank with a planetary mechanism even towed two tanks with a combined weight of 75 tons without issue.

KV-1S Planetary Turning Mechanism

 "January 7th, 1943

In October and November of 1942 factory #100 developed and built a planetary turning mechanism designed by Engineer Lieutenant-Colonel A.I. Blagonravov. The report on the trials performed in the KV-1S tank is attached, we ask you to review it.

SU-152 Regiments

 "State Committee of Defense Decree #2889ss
February 14th, 1943
Moscow, Kremlin

Topic: on the formation of heavy SPG regiments within the Reserve of the Supreme Command

The State Committee of Defense decrees that:

1. 16 heavy SPG regiments are to be formed according to TO&E #08/175 including 310 personnel and 12 152 mm self propelled ML-20 gun-howitzers each.
   The formation of regiments is assigned to the Commander of Artillery of the Red Army, Marshal of Artillery comrade Voronov, and the Military Council of Armoured and Mechanized Forces of the Red Army (Colonel General of the Tank Forces comrade Fedorenko and Lieutenant General of the Tank Forces comrade Biryukov). The following deadlines are set:
1. By February 28th, 1943: 1 regiment
2. By March 25th, 1943: 5 regiments
3. By April 25th, 1943: 5 regiments
4. By May 25th, 1943: 5 regiments

85 mm Gun Upgrade

 

"In order to make loading of the S-31 tank gun in the KV-1S and IS-1 tanks comfortable, the following must be done:

1. Increase the distance from the bore axis to the roof to 470 mm (280 mm on the IS-1) as ramming an 85 mm shell at face height is difficult and impossible if the gun is depressed.
   On most modern foreign heavy tanks and on our SPGs the space between the bore axis and the roof ranges from 400 to 500 mm.

Tank Brigade Experience

"To Deputy People's Commissar of Defense, Lieutenant General Fedorenko

Experience in battle, especially the experience of the [91st Tank] Brigade between August 21st and 29th, 1942, shows that the KV tank lost its advantage over the T-34 in protection, as the same caliber of gun can penetrate both the KV and T-34. The KV has a significantly different weight and dimensions than the T-34, is less maneuverable, and is thus inferior to the T-34.

KV-1 vs KV-1S

"Proposal on improvement of the design of the KV tank

1. It is necessary to improve the reliability of the V-2K diesel to 500 service hours. The components and assemblies of the running gear and transmission last for this time, but the tank goes out of service after 150-200 hours exclusively due to the engine. The latest engines break even earlier, 80-100 hours. The weakest parts are:
1. Valve foundation (it unseats itself, tearing the valve and piston)
2. The hold-down studs work themselves out and penetrate the cylinder bank head (there were cases where this happened after 30-40 hours).
3. The piston rings are worn out quickly, and while the crank and connecting-rod assembly can keep working for 150-200 hours the engine consumes 1 kg of oil per 1 km.

Soviet Tank Observation

From "Observation from Modern Tanks"

Engineer-Major L.S. Tolokonnikov

Vestnik Tankovoy Promyshlennosti (Tank Industry Herald) 1944 #10

"Presently, tanks use simple observation devices

1. Observation slits with protective glass and without.
2. Mirror observation devices (periscopes).
3. Commander's cupolas with observation slits or periscopes.
4. Observation ports.

Optical (aside from sights) and mechanical observation devices are completely absent. until a new type of tank observation device is discovered, further improvement of observation from tanks, protection of the observer, and convenience of observation can only be increased by improving the design of existing devices, increasing their quality, positioning them more rationally, and improving their attachment inside the tank.

This article will examine only a portion of the issue, that is the position, amount, and observation angle of modern tanks, domestic, captured, and allied (25 in all).

High Caliber Convertibles

History often repeats itself. This well known fact is often confirmed in tank building. For instance, Soviet SPGs, especially heavy ones like the SU-14, were created in order to mechanize artillery. The requirements changed during the process of their creation. The Red Army was in need of an assault gun that was capable of direct fire and had shell-proof armour. The 212 SPG and subsequent vehicles were designed according to this concept. Work resulted in the creation of the SU-152. However, one day the Red Army once more found itself in need of a self propelled gun with an open fighting compartment equipped with a 203 mm B-4 gun.

Long Living KV-1S

"Award order

1. Name: Ivan Agapovich Podkosov 
2. Rank: Guards Lieutenant
3. Position: Commander of the "Papanin" tank, 80th Guards Idritsa Order of the Red Banner Order of Suvorov 3rd class Heavy Tank Regiment
   is nominated for the Order of the Red Star.

Visibility from Tanks

"Engineer-Major L.S. Tolokonnikov

Obsevartion from Tanks

...

T-34 tank: the mechanic-driver observes through two mirror periscopes. The periscopes are affixed to the driver's hatch. Periscopes are made from transparent plastic. From the outside, they are covered with armoured covers, from the inside with a transparent plastic shield. The periscopes are angled towards the sides to increase the field of view. There is a backup for observing the road in front of the tank. The commander of the tank observes through the commander's panoramic sight and the telescopic sight. Two observation slits with two layers of armoured glass are located along the sides of the turret. The loader and hull gunner observe through their machinegun ball mount sights.

An Opponent for the Tiger

The capture of two Tiger tanks by the Red Army on January 18th, 1943, had a significant impact on Soviet tank building. Trials of one of the tanks revealed an unfortunate fact: the F-34 76 mm gun, the main weapon of Soviet tanks, could not penetrate the side. The reaction to this result was swift. Designers were tasked with developing a more powerful tank gun immediately. It was to be installed in the KV-1S heavy tank.

Visibility

Here's a rather interesting analysis of the Tiger's commander's cupola by British tankers. It's no secret that the British weren't huge fans of German observation devices, but here is a pretty thorough list of its deficiencies, backed by a handy diagram.

KV-1S: From Temporary to Permanent

State Committee of Defense decree #1878 "On the improvement of KV tanks" was signed on July 5th, 1942. This was the starting point for the creation of a lighter variant of the KV, named KV-1S. Two prototypes were built by July 27th, and mass production began in Chelyabinsk by late August. The KV-1S was not as much of a legend as the KV-1, but this was the tank that defeated the Germans at Stalingrad and Kursk. Its creation and production was, in many ways, a necessary evil, but the KV-1S remained in production for a year, and remained on the front lines until 1944. This article covers its production and use in combat.

KV-1S OP

"Conclusions regarding Engineer-Colonel comrade Barykov's proposal

Comrade Barykov proposed:

1. The installation of 45 mm guns instead of 76 mm guns into some KV-1S tanks. The freed up space is to be used for housing a forward observer. He will have two observation periscopes and a place to put his map.
   To disguise the 45 mm gun as a 76 mm gun, an armoured sleeve will be installed over it.

Less Armour, More Mobility

The gradual increase of a tank's mass is a normal and logical occurrence. Mass grows, first of all, due to thicker armour. During WWII, the thickness of tank armour grew several times over. However, there was one case where designers had to sacrifice armour. This case was the Soviet KV-1S tank, which was, in many ways, a necessary compromise, taken to resolve serious issues with the KV-1's reliability. The vehicle left a mark in the history of Soviet tank building. The KV-1S appeared as a result of a change of perspective in Soviet heavy tank doctrine. Mobility started to play a more important role. The new tank was not just a lighter KV-1, but had a large amount of new technical solutions. What is the history of the KV-1S, and why was its journey into production so difficult?

KV-1S Costs

"To the Director of the Kirov factory, comrade Makhonin

Regional GABTU engineer at the Kirov factory, Engineer-Lieutenant-Colonel comrade Kozyrev

Notice #B1-521

October 16th, 1942

1. In accordance with GOKO decree #2392ss issued on October 10th, 1942, the Kirov factory must produce and deliver KV-1S and KV-8S tanks to the GABTU in the 4th quarter of 1942, in the amounts and according to deadlines outlined in the attached ledger.
   Prices, requirements, and list of equipment is given in the same ledger.
2. The overall price of deliveries between October 1st and December 31st, 1942, according to the attached ledger, is 177,000,000 (one hundred and seventy seven million) rubles.
3. The cost of a KV tank, 295,000 rubles, is established by USSR SNK decree #638-328ss issued on May 6th, 1942.
   The cost of a tank is determined as free-on-board at the station, including container and packaging.
4. In all else, the conditions established in agreement #B1-081 on February 7th, 1942, remain in effect.
5. This notice is an inseparable addendum to agreement #B1-081, signed on February 7th, 1942.

Attachment: ledger on two pages.

Deputy Chief of the GABTU, Major-General of the Tank Forces, Korobkov