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D-25 Muzzle Brake

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"October 13th, 1943
#1610s

To the Deputy Chair of the GAU ArtKom, Major-General of the Engineering Artillery service comrade Zhevanik
CC: Chief of the Gorohovets ANIOP, Engineer-Lieutenant-Colonel comrade Grandilevskiy

RE: sending materials on the D-25 122 mm gun

I send you letter #1468/35s from factory #9 written on October 9th, 1943, with materials on the D-25 tank gun.

The D-25 tank gun was designed and produced by NKV factory #9 according to GOKO decree published on September 4th, 1943.


Trials of the experimental prototype of the 122 mm D-25 tank gun took place at the factory proving grounds from September 16th to September 23rd, 1943, when the gun fired 96 shots. The prototype was permitted to continue trials, and was sent to factory #100 in Chelyabinsk on September 25th for installation into an IS tank.

During trials, the D-25 muzzle brake was deformed. Due to the immediate need to install the D-25 gun in a tank, the prototype was sent to factory #100 with the deformed muzzle brake.

On October 10th, 1943, a new reinforced muzzle brake similar to the type used on the German Ferdinand assault gun was built and tested on a D-2 gun with six increased power shots. Another identical muzzle brake was tested on a D-2 gun with 39 shots, 30 of which were increased power, and 9 of which were regular. After checking the muzzle brakes against the reference, neither of them had any deformations. A new reinforced muzzle brake for the D-25 gun will be sent to the GANIOP on October 13th separately, as the tank with the D-25 gun was sent to the GANIOP from factory #100 on October 11th, 1943.

Regional GAU engineer, Engineer-Colonel Abramov."


Controlled Impact

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"Order to the Red Army Air Force #0194
September 23rd, 1944
Moscow

Commanders of the Air Armies report that fighter pilots still use one of the most complicated attacks, namely ramming, to this day. 

In many cases, ramming does not only destroy the enemy plane, but also leads to a loss of our airplane, and, often, the death of the pilot.

I order that:

It must be explained to pilots of the Red Army VVS that our fighter aircraft have excellent and powerful modern armament, which surpasses all German types of fighters. The use of ramming in air combat with enemy aircraft that have poorer characteristics is senseless. 

Ramming must be performed only in exceptional cases and as a last resort.

Commander of the Red Army VVS, Chief Marshal of Aviation, Novikov
Member of the VVS Military Council, Colonel-General Shimanov
Acting Chief of Staff of the VVS, Lieutenant-General Krolenko"

Tank Armies

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Despite its very young industry, the USSR was focused on building a large amount of tanks right off the bat. It might seem weird to focus on something like that so early on, but once you see the intelligence information at the army's disposal then everything falls into place.

This map maps the tank armies of European nations by the fall of 1931 (according to German sources). The data is as follows:
  • Sweden: 10 light "21" tanks
  • Finland: 32 Renault
  • Estonia:
    •  10 Renault
    • 4 Mk.V
  • Latvia:
    • 7 Renault
    • 10 Mk.V
  • Lithuania: 
    • 16 Renault FT
    • 12 Renault M.26
  • Poland:
    • 25 Char 2C
    • 100 Renault FT
    • 120 Renault M.27
    • 20 Renault NC-27
    • 10 "gas" Renault
    • 20 Mk.V
    • 5 A7V
    • 20 Carden-Loyd
    • 10 MP
  • Czechoslovakia:
    • 30 Renault
    • 50 convertible drive
  • Romania:
    • 75 Renault FT
    • 6 Schneider M.16
  • Yugoslavia:
    • 50 Renault FT
    • 20 Renault 27
  • Italy:
    • 100 Fiat
    • 40 10t Fiat 
  • England:
    • 20 heavy tanks
    • 100 Mk.V
    • 1 "heavy Vickers"
    • 25 SPGs
    • 220 light Vickers Mk.III
    • 10 light Mk.II
    • 5 light Mk.I
    • 200 Carden-Loyd
  • Belgium: 49 Renault FT
  • France: 
    • 2200 Renault 26
    • 1200 Renault radio
    • 1500 Renault NC-27 (by 1935)
    • 100 Mk.V*
    • 90 Char 2C
    • 10 (?) Char 3C or D
    • 20 Saint-Chamond
    • 62 Schneider-Lorraine
  • Spain:
    • 20 Renault FT
    • 5 Trubia 1925
    • 10 Schneider 16
In retrospect, of course, this map is terribly wrong. There were hardly hordes of French superheavy tanks wandering around in Europe, but that was the boogeyman of the time. 20 years later you see the exact same thing with IS-3 tanks reported everywhere in Korea, for instance. 

An Opponent for the Tiger

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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.


A new gun the easy way

Deputy People's Commissar of Defense, Marshall Kulik, raised the issue of the KV-1's gun being insufficiently powerful in mid-June of 1940. A decision was made during a meeting held on June 16th, 1940, to develop an 85 mm tank gun with the ballistics of the 52-K AA gun. The task of creating this gun, indexed F-30, was given to V.G. Grabin and his team. The gun was installed in the experimental T-220 tank, after which work on it stopped due to the development of the 107 mm ZIS-6 gun.

A second attempt to create an 85 mm gun for the KV-1 was made in late 1941. The U-12, designed by UZTM's design bureau under the direction of F.F. Petrov, did not even make it to the prototype stage. The third attempt, this time in spring of 1942, was also made in Sverdlovsk. The result was the same: the ZIK-1, meant for the KV-1 and T-34, did not proceed past the technical project stage.

The 85 mm S-31 gun in an IS-1 turret, May 1943.

The fourth and final attempt was made in the fall of 1942. The ZIS-25 gun was designed at factory #92. The gun was rejected, mostly because servicing he gun would have been far from ideal. The loader would have had the hardest time of all, since the 85 mm round was longer than the ZIS-5's 76 mm round. In addition, the KV-1 was no longer in production in the fall of 1942. The KV-1S took its place.

Thanks to all of these failed attempts, engineers in both Sverdlovsk and Gorky had extensive experience with 85 mm tank and SPG guns by April of 1943. However, both design bureaus underwent reorganization. F.F. Petrov's team was turned into the design bureau of factory #9, and factory #92's design bureau was moved to Kaliningrad, where it formed the Central Artillery Design Bureau (TsAKB). The existence of two artillery design bureaus, which often worked on similar projects, resulted in fierce competition. As it often happened, competition was good, and the GAU and GBTU had the freedom of choice. Often TsAKB and the design bureau of factory #9 had entirely different approaches to the same problem.

The TsAKB proposed this turret for the IS-1 (233) and KV-1S.

Officially, work on 85 mm tank guns began on May 5th, 1943, when GKO decree #3289 "On improving the armament of artillery armament of tanks and SPGs" was signed. The decree's text called for two KV-1S tanks and two IS-1 (233) to be armed with 85 mm guns.

Even though the decree gave the order to factory #9, TsAKB received an order for an 85 mm gun practically at the same time. They did not start from scratch, but developed the ZIS-25 further, especially since work on it never fully stopped. The return to the 85 mm gun happened in February of 1943. To continue his work, Grabin composed a request for tactical-technical requirements and documentation for the KV-1. In addition, he requested one KV-1 tank and one ZIS-5 gun to produce an experimental ZIS-25. The GBTU refused to give him a whole tank, since the TsAKB still had the KV-2 that was used to test the 107 mm ZIS-6 gun. A counter-proposal was made to send only the turret, and a KV-1S turret at that, since that is the tank that was presently in production. In addition, the TsAKB received documentation on the KV-1S and IS-1 (233).

Tactical-technical characteristics for a new 85 mm gun were composed by the GAU on March 26th, 1943. According to the requirements, the gun had to be capable of confidently penetrating 90 mm of armour from 500 meters. The gun would be installed not only in heavy tanks, but in medium ones, which caused protests from Grabin.

This work was done within the scope of the ZIS-25 program, since it satisfied the requirements. However, the order was sent not only to the TsAKB, but to factory #9. Because of this, decree #3289 was not a surprise for anyone. Work was already underway both in Sverdlovsk and in Kaliningrad when it was published. The requirement to defeat the Tiger only made the designers' work more complicated. To confidently penetrate its armour, the gun needed to have a barrel as long as the 52-K AA gun.

Installation of the S-31 gun into the stock KV-1S turret.

The chief of the 17th department of the TsAKB, P.F. Muravyev, as well as the chief of the 3rd department, Ye.V. Sinilshikov, headed the development of the gun, indexed S-31. TsAKB was not working on the same footing as factory #9. Petrov came to the conclusion that the turrets of the IS-1 and KV-1S were too small for an 85 mm gun, but the TsAKB worked with what they had. In addition, factory #9's specialists designed their guns based on old guns that they made themselves, while the TsAKB had to align their designs with what was already in production. According to the specifications, the new gun had to take most of its parts from the mass produced 76 mm ZIS-5 gun.

Cutaway diagram of the Object 238. This drawing differs slightly from the vehicle that was eventually built.

The experience with the ZIS-25 allowed the S-31 to be designed very quickly. An explanatory memo, as well as drafts of installation into the KV-1S and IS-1, were ready by May 14th. The initial vision of how the gun would be installed differed somewhat from what was eventually built in metal. This was especially true of the turret. The TsAKB did not demand that the size of the turret ring be increased, like factory #9 did, but the turret was still altered. The TsAKB considered the IS-1 a priority, but due to the same turret ring diameter the same turret could be used on the KV-1S. The turret bustle was enlarged, which allowed it to store 18 rounds of ammunition for the 85 mm gun. The commander's cupola and roof were altered to allow the loader to work with longer rounds. The cupola now stretched across the entire width of the turret. The turret also gained a turntable. According to the design, the tank would carry 76 rounds in total.

Perpendicular cutaway of the tank.

The design of the gun was an evolution of the ZIS-25. The gun had significant parts commonality with the ZIS-5: out of 449 parts, 350 were common, although some were slightly altered. The gun barrel, as requested, offered identical ballistics to the 52-K. The breech and semiautomatic mechanism were analogous to the design of the ZIS-5.

Through adversity

The project was reviewed by the GAU Artillery Committee on May 22nd. The turret, which was now not only larger, but also heavier, drew the most comments. The addition of a turntable made the crew's work easier, but also made it more difficult to access ammunition stored below. The fate of the turret was to be decided at a large meeting attended by representatives from the GBTU, People's Commissariat of Armament, GAU, the People's Commissariat of Tank Production, and the TsAKB.

There were also questions about the gun itself. Instead of the required maximum elevation of 30 degrees, the gun only elevated 25 degrees, but this was deemed acceptable. The fact that the requirements demanded a maximum of 350 mm of recoil, while the TsAKB's calculations showed that it would not be less than 520 mm, was much more problematic. The Artillery Committee instructed them to try and reduce the recoil length. To be fair, the recoil length of the 8.8 cm KwK 36 used on the Tiger was 600 mm, and that gun had the advantage of a muzzle brake.

Initially, the S-31 did not have a solenoid type firing mechanism. It was decided at the meeting that it should be added to the prototype.

Experimental Object 238 prototype, Chelyabinsk July 1943.

The fate of the new turret was decided at a meeting on June 7th, 1943. The Kirov factory was offered to design a turret based on the TsAKB's ideas. However, nothing of the sort was done in Chelyabinsk. By the time the decision was made no design work was happening anymore. The IS-1's fate was clear, and it was obvious that the tank would not go into production in its current form. In many ways this was connected with its turret, which was now being redesigned to fit the D-5T gun. The same turret was proposed for installation in the KV-1S by factory #9. This required a new turret platform, but resulted in the same turret being used by the IS and KV-1S. A third turret made no sense in this scenario.

In addition, the S-31 was far from perfect. It would seem that the GAU and NKV already had ideas about modernization, but the S-31 had no room for improvement. In addition, the D-5T was lighter and more compact. Its recoil length was only 430 mm. However, a final decision had not yet been made. The S-31 was installed in an experimental IS-3 (Object 237) and a KV-1S with a stock turret ring. Factory #92 was tasked with producing the TsAKB's guns, where they were indexed F-85.

View from the front. A late production KV-1S was used.

Work on installing the S-31 into the KV-1S' turret began in late May of 1943. Correspondence from the time indicates that initially work was being done to install the gun into both the stock turret and the IS turret. After the meeting in June, the S-31 with a new turret was cancelled, and the D-5T was installed in the IS-3 turret instead. The version with a new turret was jointly designed by factories #100 and #200, whereas the version with a stock turret was taken up by the Kirov factory's SKB-2. The KV-1S with a new gun received the blueprint index "238". In July of 1943 this index transformed into the official name of the vehicle: Object 238. The name "KV-85G" that appears in several sources was never used. This was a post-war invention. The lead engineer of the vehicle project was N.F. Shashmurin, G.N. Moskvin directed work on SKB-2's side, and Zh.Ya. Kotin oversaw the entire process.

The combination of the S-31 and the stock KV-1S turret was finally approved in mid-July of 1943. According to calculations, the mass of the tank increased to 44 tons, but its mobility would remain at the level of an ordinary KV-1S. The gun easily replaced the ZIS-5, since it was designed with its components. In addition to a new gun, the Object 238 had a slightly different gun mantlet, but the existing mantlet was preserved in practice. Another change was a redesigned ammunition rack, which now held 8 rounds. Unlike the mantlet, it was built in metal. The overall amount of ammunition was reduced to 55 rounds.

Object 238 from the side. In addition to a new gun, the tank had no differences compared to production KV-1S tanks.

Despite the fact that the design of the "238" was ready by May 25th, all further work was stalled for nearly 2 months. The tank that had the IS-3 (Object 237) turret and D-5T gun had a higher priority. That tank was indexed Object 239. According to the NKTP's orders, work on modernizing the KV-1S was of lower priority than Object 237. Another reason for the delay was the lateness of factory #92 in delivering the guns. It was proposed that Object 238 would be ready by July 1st, but the deadline was not met. However, two of these tanks were built for some reason, as evidenced by a report from factory #100 regarding experimental work performed between July 10th and 20th, 1943. Only one vehicle was used in trials.

The same vehicle from the rear.

The first trials of the Object 238 were performed at the Gorohovets proving grounds from August 2nd to the 4th. The trials were comparative: in addition to the Object 238, one Object 239 and two Objects 237 with different guns took part. The precision of all four was identical, but then the 238's shortcomings started showing themselves. The smaller turret ring made working in the stock KV-1S turret, which was already a source of complaints, even more difficult. As a result, the rate of fire of the Object 238's gun was 5-6 RPM, while the Object 239 fired at 10-12 RPM. The S-31 also proved itself unreliable.

Issues with the tank version of the S-31 were not significantly different from the SPG variant. The cramped turret only exacerbated them. The result was predictable: Object 239 with the turret from Object 237 was accepted for service. GKO decree #3891ss "On production of KV tanks with an 85 mm gun (KV-85)" was signed on August 8th, 1943.

Diagram of crew and component placement in the Object 238's turret.

One of the two Objects 238 survived to this day. This vehicle is mostly a mass production KV-1S tank (#30751) produced in July of 1943. The only difference is a new gun. It is not known what was done with this tank. It has road wheels taken from the KV-1 and "foreign" return rollers. The track links were taken from the T-10, and bars are welded onto the air intakes.

Last try

Work on 85 mm guns did not cease at TsAKB after the victory of the D-5T. More than that, discussions of producing the TsAKB's turret continued until the fall of 1943. However, no work was done. Nevertheless, Object 238 was not the last KV-85 from the TsAKB. The next attempt was made a year later thanks to continuing work on medium tank guns.

KV-1S with the S-28 gun, August 1944.

As mentioned above, the initial requirements for the 85 mm gun were to use it in both heavy and medium tanks. Despite Grabin's protests, the S-31 was also compatible with the T-43 medium tank. After factory #183 modernized the T-43, it received a turret with a 1600 mm turret ring. This was done to allow it to carry an 85 mm gun. Due to the loss of the S-31, the altered T-43 turret used a D-5T gun.

Nevertheless, work on this topic did not go to waste. Muravyev and Sinilshikov designed several more tank guns in the second half of 1943. Among them was the S-50 "triplex", which could use 57 mm, 76 mm, or 85 mm barrels. LB-1 and S-53 85 mm guns followed.

The same vehicle from the side. A winter-spring production KV-1S tank was used.

Initially, the S-53, which was tested in a T-34 with a stock 1420 mm turret ring, showed itself no better than other guns of the TsAKB. It did not pass trials, Nevertheless, this gun was a lucky break for the TsAKB. Initially, the modernized T-34, called T-34-85, used the D-5T gun. This was logical, as this was the same gun used on the SU-85, KV-85, and IS-85. On the other hand, the KV-85 was out of production, and the days of the IS-85 (IS-1) were numbered. It was replaced by the IS-122 (IS-2) with a much more powerful 122 mm gun. The S-53 was trialled again in late January-early February of 1944, after which a decision was made to put it into mass production.

Overall view of the S-28 with gun mantlet.

After many defects were discovered in the S-53, the gun was improved by the TsAKB, after which it received the index ZIS-S-53. The gun was tested in April of 1944, the discovered defects were corrected again, which was confirmed in July of 1944. The ZIS-S-53 was put into production, but in August of 1944 another tank with the same gun arrived at the Leningrad ANIOP. This was a KV-1S, and the gun it carried was indexed S-28.

Unlike the Object 238, its mantlet was seriously altered. The mantlet was the same as on the ZIS-S-53, with the whole system fitting comfortably into the gun port on the regular KV-1S turret. The biggest advantage of this design was that the firepower of the KV-1S could be easily improved. In addition to the gun, other components of the turret were changed. Racks for 85 mm ammunition were added in the bustle and on the right. The overall capacity was 40 rounds. The racks in the hull still needed work.

S-28 from the rear.

Trials of the S-28 took place from August 8th to August 20th, 1944. A.S. Chasovnikov represented the TsAKB at the trials. Based on his work, he was a specialist in rearming tanks. Chasovnikov was also one of the authors of the ST-1 and ST-II projects. The presence of a representative from the Main Tank Repair Directorate, Engineer-Colonel Gavrilov, also hinted at the goal of this design. It would seem that tanks already in service would be rearmed.

Overall, the trials were successful. It turned out that the crew conditions in the turret differed little from those in the T-34-85. However, there were some complaints. The field of view of the TSh-15 sight was small, the rack in the turret broke during testing, the rate of fire was only 4-6 RPM, and the precision was deemed unsatisfactory. In addition, it was proposed that a ventilation fan should be added to the turret. Nevertheless, the overall verdict was positive.

Ammunition racks. One of the slots in the side rack was torn off during trials.

Despite the results of the trials, the S-28 remained a prototype. The career of the KV-1S was coming to an end in the summer of 1944. These heavy tanks were replaced by the IS-2. The T-34-85 would have surpassed the KV-1S armed with an S-28 gun in effectiveness anyway. Too much time and effort would have to be put into rearming existing vehicles. It was easier to gradually replace the KV-1S with new tanks.

The Future of Tanks

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"Theses of the report by the commander of the Armoured and Mechanized Forces in the Group of Soviet Forces in Germany, Marshal of the Armoured Forces Rotmistrov, titled "Tanks of the Soviet and Foreign Armies Presently, and the Potential of Their Development"
March 24th, 1947

Overall conclusions regarding the tanks of WWII and the potential of its development:
  1. Due to the thickening of armour and gun calibers, light tanks are departing from the battlefield. The amount of medium and heavy tanks is increasing.
  2. The protection armour offers is, chiefly, increased by increasing its thickness. 200 mm thick armour will be very common soon. Ground pressure and acceptable width for railroad transport will be the limiting factors in increasing the thickness of the armour any further. In the future, it will be important to change the quality of the armour. Simply increasing the thickness of the armour is a dead end. The protection must be increased not by adding more armour, but by improving its qualities and using composite armour.
  3. The effectiveness of tank guns grows linearly with the increase of the caliber and barrel length. Guns are designed to fire directly at long ranges (1-2.5 km), which dictates their caliber and muzzle velocity, which also raises the requirements for observation devices.
    The penetration of guns increases, mostly, by increasing the muzzle velocity and the gun caliber, and the muzzle velocity is increased by lengthening the barrel. It is obvious that increasing muzzle velocity by lengthening the barrel any further is unrealistic. It is possible to improve in this category by creating improved explosive substances and the qualities of the shell itself (mechanical qualities) and the design of the gun barrel.
    For example, guns with conical 28.20, 42/28, and 75/55 mm barrels appeared, which increased the speed of a subcaliber round to 1200-1400 m/s.
    To illustrate the impact of a high muzzle velocity and mechanical toughness of the shell on its penetration, it is sufficient to demonstrate this example. Shells for the 90 mm gun of the American T26E4 tank equipped with a tungsten carbide core are capable of penetrating 355 mm of armour from 275 meters.
    The caliber is also approaching its limit, as increasing the caliber rapidly increases the weight and size of a shell, which means that loading becomes more difficult and less ammunition can be carried.
  4. The engine group is not mature in the sense of the range of power outputs an reliability. The power output range is a weak point, which slows down the modern development of tanks.
  5. Observation devices, turret traverse mechanisms, and gun stabilizers demand more attention than they are currently given. Precision and agility of tanks depend primarily on the maturity of these components. 
Maximum weight of a heavy tank

Since the main tanks on the battlefield are tanks with powerful armour and armament, it is important to determine the limits of thickening the armour of such a tank. If we postulate that the tank must not be taken apart into pieces and must be transported via railroad without any complications, then the limits of the tank's weight are defined by the acceptable width for railroad transport, ground pressure, and the ratio of the length of the contact surface to its width, which dictates the agility of the tank.

If we assume that long range transport will be achieved by special towed platforms, then the width restriction can be increased, thus increasing the maximum weight of a tank. The thicker the armour, the smaller the dimensions of the engine-transmission group must be. Ultimately, they determine the maximum thickness of the tank's armour. The thicker the armour, the smaller the useful volume inside the tank, and less space is left for the engine and transmission. For a tank with powerful armour, a T-34-like shape is inevitable. 

Assuming the maximum acceptable width is 4 meters (such a tank will be transported by towed platforms), the weight of the tank can be increased to 100 tons, and the thickness of the armour to 350-450 mm.

If we build super-powerful tanks with the restriction of the railroad width, then the maximum weight of a tank can be 97 tons.

Given the present methods of tank layouts, the thickness of a tank's armour cannot be more than 350-450 mm if it is to be transported by railroads. It is obvious that even with modern tank guns (100-128 mm in caliber) further increase in muzzle velocity can achieve penetration, if not of the plates themselves, then their joints, from 1.5-2 km. After that, a leap must occur in the quality of armour and guns. It will soon be impossible to simply grow the length of a barrel or the thickness of armour. Quantity must be turned into quality. In the meantime, 300-350 mm thick armour will allow the creation of a first class breakthrough tank in modern conditions."

PzIII Armour in British Hands

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I previously shared how the PzIII did in Soviet hands. In summary, the 30 mm plate proved far too brittle under fire from a 45 mm gun, shattering into pieces from just one hit. Curiously, British trials find the exact same thing.

Under attack from 2-pounder AP shot, the first projectile chips off the edge, but the second shatters the plate and causes severe cracks. When the remaining pieces are tested, they too crack into pieces after one or two shots with APC shells at 20 and 30 degrees. The British had more than just one hatch, however, and also observed the welding seams coming apart after the shots. The velocities matched those for 1200 yards in the test with AP and 1000 yards with APC. 


However, things get even more interesting after. In trials against a later model PzIII, one with 50 mm of front armour, the 2-pounder can get a shot through the front plate from 100 yards, although the projectile shatters. Interestingly enough, in Soviet trials, the 2-pounder only managed to penetrate the upper edge of the StuG's upper plate (also 50 mm thick) once from 100 meters. The testers were unable to reproduce this penetration from 50 or 100 meters. The Soviet conclusion is that the 2-pounder cannot penetrate 50 mm of armour at any distance, whereas the British are content with its ability to penetrate the German tank from 100 yards. The British also establish that the 2-pounder can defeat a PzIII from the front from 300 yards with HV ammo, but the Soviets didn't have any available.

Soviet Schurzen

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I posted some information on Soviet protection research before, which included experiments spaced armour. Here is another such experiment, performed in the summer of 1943 at factory #112.


A drawing of the extra armour includes armour for the turret, but the prototype does not have it. Only the sides of the hull are equipped with additional armour.



The armour did not enter production. However, "everything old is new again" rang as true then as it does now, since the idea of skirt armour returned in 1945, this time to combat Panzerfausts. The additional armour was 6-8 mm thick and positioned 600 mm away from the main armour. A hit from a Panzerfaust created a 30 mm breach in the screen, but did not penetrate the main armour.

Reused Tank

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"Female soldiers fight the enemy exceptionally well. Senior Sergeant Voyevodina's 45 mm gun crew consisting of Komsomol members Rofanova, Zibirova, Bartinkova, and Abramova opened direct fire at enemy strongholds on the left flank during a battle for a settlement. The enemy moved into a counterattack, but the women were out of ammunition. Spotting a knocked out tank up ahead, the brave women crawled forward to it. Having entered the tank, they opened fire from cannons and machineguns at the enemy. The counterattack was defeated. 2 cannons, 9 strongholds, and over 70 fascists were killed. In this battle, crew commander Voyevodina and private Zibirova died the death of heroes."


Lee and Grant: American Generals in British Service

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The United States was seen by Britain and France as a giant factory that could aid them in production of military hardware back before the First World War. That is what ended up happening, although American produced vehicles did not arrive in time to fight. However, during WWII, the expectations of America's European allies were met, especially when it came to tanks. However, the trans-Atlantic tank factories didn't work like the British expected them to. Instead of building British tanks under license, the Americans provided their own designs. This article describes the General Lee and General Grant tanks, the first mass produced American medium tanks that were used by the British army.


Foreign and domestic

The first country to use American weapons in WWII, primarily aircraft, was France. 7000 American trucks also laboured on the ground. After the fall of France, the American "center of gravity" shifted towards supplies for Britain. The British had a very serious problem at the moment: with the defeat of the British Expeditionary Force, the vast majority of tanks were lost in France, which resulted in a  critical shortage of armour. The British were not sitting idle, but the rate of production was not particularly impressive for wartime.

The solution was to be production of tanks abroad, like during WWI. Canada had the most developed industry out of all the Commonwealth nations, and production of the Valentine tank was organized there. However, it was obvious that the United States were to be the main production base. The French were also planning to organize production of the Char B1 bis there. However, these plans were never realized, since France quickly lost the war.

A model of the turret designed by Carr for the British version of the Medium Tank M3. The developed turret bustle is visible.

The British were planning on suggesting the Infantry Tank Mk.IIA for production under license. This was the best British tank at the time, but domestic industry was having significant difficulties with its production. Only 152 tanks were built from the fall of 1939 to July of 1940. The rate of production increased slightly in the second half of the year, but not by much. 1 tank per day was not a lot for wartime, especially if 6 companies were working on it. It's not surprising that the War Office turned to the American government with the proposal to organize production of the Infantry Tank Mk.IIA. A delegation was sent for negotiations, lead by Michael Devar, the head of British Timken Ltd and accompanied by L.E. Carr, a tank specialist from the Department of Mechanization.

The same turret from the front. It was significantly larger, despite the same turret ring diameter. The tank's height was decreased from 3120 mm to 3022 mm by removing the commander's cupola.

An attempt to organize production of the Infantry Tank Mk.IIA in the USA was unsuccessful. Trials of the tank at Aberdeen in early September of 1940 disappointed the Americans. The tank was slow, put in motion by a pair of weak bus engines, and had poor armament. Its only advantage was thick armour.

The fact that production of the Medium Tank M3 recently started made the Infantry Tank Mk.IIA an even weaker prospect. An agreement was signed with Chrysler Corporation for production of 1000 of these tanks. These tanks would be built at the new Detroit arsenal, construction of which began on September 9th. It had slightly thinner armour than the Infantry Tank Mk.IIA, but surpassed it in all other ways. It's not surprising that the Americans rejected the British infantry tank.

The first Medium Tank M3 built to British specifications by the Pressed Steel Car Company. July 15th, 1941.

As a result, the British Tank Mission could only agree to purchase American tanks. One of the mission's objectives was the adaptation of American tanks to British standards. Carr set out on this task. It was impossible to radically alter the tank, but the vehicle did undergo some changes. For one, the British were categorically opposed to the design of the turret. It was too small, and its commander's cupola was poorly designed. The limited amount of space was inefficiently used. Carr didn't want to settle and designed his own turret. It was also cast, but was significantly different from the initial design. The cupola was removed, and replaced with a hatch with a periscopic observation device. A turret bustle was introduced, and the radio was moved there. Since the Medium Tank M3 was not yet ready, Carr experimented with a Medium Tank M2A1.

Generals' names

The first contract for a British variant of the Medium Tank M3 was awarded to Baldwin Locomotive Works. The same company received an order for M3 tanks for the American army. The factory was to build 685 tanks for the British. Later, an order for 1000 more tanks was made. It was split in half: 500 tanks for Pullman-Standard Car Manufacturing Company, 500 for Pressed Steel Car Company, which also worked on train cars. The first Medium Tank M3 that was built to British specifications was completed by Pressed Steel on July 15th, 1941.

Grant I tanks at the Pullman-Standard Car Manufacturing Company.

The British did not stop there. The war promised to be a long one, and British manufacturing capacity was not limitless. Some new British designs, such as the Cruiser Tank Mk.V (Covenanter) proved controversial. The planned output of medium tanks to equip the British and American armies was so high that Tukhachevskiy himself would have been jealous. The reality, of course, was different. Far fewer than 70,000 medium tanks were built in 1942-43, but the output was impressive nevertheless. 

Due to the increase in demand, the Americans supplied the British with both variants of the Medium Tank M3. However, these vehicles were still different from American ones, since they were equipped with British pattern Wireless Set No.19 radios.

Finished tanks on their way to the customer. All they had to do was cross the Atlantic, which was not always successful.

Supplies of both variants of the Medium Tank M3 to Britain began towards the end of 1941. There were some changes to the nomenclature of British tanks by that point. New names began appearing in August, and were officially approved on September 22nd. The problem was that the existing system of indexes became too complex. Because of this, the British migrated to using names instead. For instance, the Infantry Tank Mk.IIA* became the Matilda III. As for American tanks, they received names of American generals.

Overall requirements for the Grant I and Grant II.

The choice of names for the Medium Tank M3 was driven by British humour. The American version of the tank was called General Lee I, in honour of General Robert Lee, the commander of the Confederate army during the American Civil War. As for the British version, it was named General Grant I, after the commander of the Union army, which achieved victory over Lee. Later, closer to the fall of 1942, the names were shortened to Lee I and Grant I. The names "M3 Lee" or "M3 Grant" were never used and exist as a result of inaccurate analysis by some historians. 

A typical Grant I. The tank has no sand shields, but already has WE210 tracks.

As mentioned above, real supplies of the Lee I and Grant I began towards the end of 1941. Monthly shipments passed the 200 tank mark by the end of the year, and were up to 400 tanks in April. Shipments for May remained at that level, and then began to radically decrease. Production of the Medium Tank M4A1 replaced the Medium Tank M3. The British eagerly awaited this new tank, named General Sherman II, or simply Sherman II. The last of the Lee I/Grant I tanks reached Great Britain in July of 1942. Overall, 2653 tanks of both types were received.

The same tank from above. The turret is noticeably larger than the one used on the Lee.

Shipments of the Medium Tank M3 did not end there. One of the services that Carr rendered was help in designing a power plant that used two GM 6-71 diesel engines, the result of which was the General Motors 6046. It was used by the Medium Tank M3A3 and Medium Tank M3A5, indexed Lee V and Grant II respectively. The M3A3 was built as an ordinary american tank, while the M3A5 underwent modernization similar to the Grant I. These modernized tanks were built by Baldwin Locomotive Works. In total, the British received 47 Lee V and 185 Grant II. It's likely that these were the tanks sent across the ocean in March of 1943.

Various names for American tanks in the British army as of October 1942.

The registration numbers turned out to be quite interesting. Since the initial prediction was for a much greater number of tanks than were built, a much larger range of numbers was reserved. 36 Lee tanks (T.22668-T.22703) were followed by 1686 Grant tanks (T.23504-T.25189) and 1214 Lee tanks (T.25290-T.26503). The amount of reserved numbers already surpassed the real amount of shipments, but that was not the end. 650 Grant tanks followed (T.29141-T.29790), 550 Lee/Grant (T.39231-T.29780), 9 Lee tanks (T.74594-T.74502), 100 Lee/Grant (T.78847-T.78946), 2465 Lee tanks (T.138946-T.141410) and then a block of 791 Lee tanks (T.144100-T.144890). The reserved space allows one to estimate the planned amount of production. The appearance of the Sherman, a far superior tank, put a stop to them.

No worse than British tanks

The appearance of the Lee I and Grant I coincided with a difficult time for British tankers. Despite a numerical advantage, British tanks began to fell behind the tanks of the Afrika Korps starting with the second half of 1041. Their 2-pounder gun was insufficient against German tanks equipped with 50 mm of armour. The reliability of most British tanks left much to be desired, and those that were sufficiently reliable and had good enough armour (Matilda and Valentine) were too slow. This was the reason why the British did not perform too well in North Africa.

Loading Grant I tanks in Britain for shipment to North Africa, February 1942. The tanks are equipped with sand shields for desert operations.

British documents show that the tanks were classified as Cruisers. This is partially due to superior mobility compared to infantry tanks. The American tanks were not as fast as the Crusader, but the difference was not that great. The Crusader's top speed was only 3 kph higher, but the American tanks surpassed it in armour and armament, and, more importantly, reliability. Another interesting fact can be gleamed from photographs: the Lee and Grant never received the 75 mm M3 gun, and stabilizers were rarely installed.

Late production configuration: additional fuel tank, stowage boxes, mud shields in between bogeys, the 37 mm M6 gun is equipped with a stabilizer.

Like other British tanks that fought in the desert, the Lee and Grant received some modifications. They arrived in Africa in their initial configuration and were slowly changed over time to suit the needs of the British. By late 1941, tanks were equipped with extended fenders with additional sand shields. Later tanks were also equipped with mud shields in between bogeys. Additional fuel tanks were also added.

Another improvement that was added in the fall of 1941 were improved tracks, named Rubber Standard, but better known by their catalogue number WE210. Unlike T41 tracks, they had grousers, and were also reinforced, which improved their reliability in the desert. Despite all these improvements, the tanks were still equipped with additional stowage in the desert. This was a pretty common phenomenon. British tanks underwent similar modifications.

Typical stowage of a Grant I tank in the desert.

The first Grant I tanks arrived in Egypt by January 31st, 1942. Before the tanks went into battle, their crews were thoroughly trained. Unlike Stuart tanks, which differed little from British models, the American medium tanks required extensive training. The concept of a tank with its main gun in the hull demanded some changes to how the tank behaved on the battlefield. The 37 mm gun in the turret caused few issues, but the 75 mm M2 gun in the hull was not easy to use. Its traverse range was limited, and the sights took some getting used to. Unlike the weapons of British tanks and the Light Tank M3, the M2 gun used a periscopic sight. The sighting grid was an unfamiliar sight, and, what's worse, only had markings for AP shells. A lack of a scale for HE shells was a traditional shortcoming of American tank sights.

The presence of HE shells was already a blessing, but there were some issues with them. Some Russian authors like to draw attention to Tsarist stock used by the Red Army. The same situation was not uncommon in other armies of the world. The British were no exception. The M2 used ammunition from the French Canon de campagne de 75 mm modèle 1897. The British had extensive stocks of ammunition for it since WWI. The issue was that the shells didn't get any newer with time. Accidents during training with this ammunition were common.

Training time, spring of 1942. The fenders are not painted the same colour as the rest of the tank.

AP shells were a separate issue. All Grant I tanks were equipped with 75 mm M2 guns with similar ballistics to the Soviet L-11 76.2 mm gun. This gun was better than the 2-pounder, but should not be overestimated. The M72 shell could penetrate 52 mm of armour from a kilometer away. This was not so bad, but the British could have used better performance. Fate smiled upon the British: among German stocks captured in 1942 were 7.5 cm Pz.Gr. shells used by PzIV tanks. The shell with a tracer and a ballistic cap piqued the interest of Australian Major Norty. He proposed to implement a conversion, removing the German shell from its casing and inserting it into an American one. After a consultation with Major Jarrett, the American ordnance advisor, trials were performed, to excellent results. Another bonus was that the German shell had a bursting charge, while the American round was just a solid shot.

This triggered a mass conversion of German ammunition, which continued through the spring of 1942. 17,000 rounds were converted in total. The Americans developed their own shell based on the German one, the M61. Penetration from 1000 meters improved to 65 mm. These shells appeared in the summer of 1942. Before then, usage of converted German ammunition was widespread.

The same tank. A signal flag on the antenna is visible.

Service in the desert brought many surprises with it. For instance, the rubber-metallic tracks wore down quickly. The WE210 track links were more long-lived, but even they did not reduce the need for fully metallic track links. The result was the T37 and T47 track link, but they did not make it to the Lee/Grant.

Another issue with American tanks were their engines. In addition to their need for high quality gasoline, there were some reliability issues. Some instances of burning up after only 25 hours of use were recorded. The issue turned out to be with poorly working air filters and incorrect usage. The solution was quickly found by replacing the filters with better ones and improved training.

Lee I during combat. Many tanks were equipped like this.

British leadership initially considered the use of General Grant I tanks to be temporary. In February of 1942, Major General Galloway predicted that both the American tanks and the Valentine would be replaced by the Crusader III. Sir Galloway turned out to be an optimist. The reliability of the Crusader raised many questions. Despite all the growing pains of the American tank, the time spent between refurbishments was significantly longer. In addition, the Crusader had no HE shells. Only the Crusader CS, armed with a 76 mm howitzer, had them, but not AP shells. The combat effectiveness of the Grant and Lee tanks was much higher.

As a result, the strategy of American tanks in combat changed by late February. The 22nd Brigade replaced their Stuart tanks with refurbished Crusader I and II tanks, and the Grant I became their main tank. The British still hoped that the Grant I will be replaced by the Crusader III equipped with a 6-pounder gun.

Repairs of a Grant I tank. The armour of American tanks proved too much for German 50 mm shells.

The British plans were changed after the first use of the Grant I in battle. On May 26th, 1942, the German Afrika Korps and its accompanying Italian allies began Operation Venice. At that point, the British 1st and 7th Armoured Divisions had 167 Grant I tanks. Battles erupted around Bir Hakeim. The battle, known to the British as the Battle of Gazala, resulted in their loss. The defeated British army retreated to El Alamein. The garrison of Tobruk surrendered on June 21st.

The analysis of the battles revealed interesting results. The Grant I was slower than the Crusader, as expected. The narrow range of the 75 mm gun was also criticized. However, the Grant I had a lot more advantages. The thick armour of the American tank was much more reliable, and German 50 mm guns could only penetrate it at close range. Most PzIII tanks used by the Afrika Korps were equipped with 5 cm L/42 guns. The Crusader was vulnerable to these weapons from a much greater range.

The power of the 75 mm gun was deemed good, and the 37 mm M6 gun also had superior penetration to the British 2-pounder. The American tank that was considered a temporary measure in early 1942 turned out to be the best tank the British had at the time. The Battle of Gazala was the combat debut for American tankers in North Africa. Three of their crews fought in the 1st Royal Tank Regiment, claiming 9 enemy tanks.

The Grant I turned out to be the best British tank in the spring-summer of 1942.

After the fighting at Gazala, the British decided to send more American tanks to Africa, including the Lee I. 170 tanks of this type fought at El Alamein. The Crusader III finally turned up on the battlefield, but the rearmament with domestic vehicles was not to be. The Sherman II made its debut in this battle as well. This tank retained the best features of the Lee and Grant, but also had the advantage of a 75 mm gun in a fully rotating turret. The new American tanks triggered a wide range of position responses from the British, if not outright joy.

General Montgomery and his command tank, fall of 1942.

The Battle of El Alamein was the swan song for a large number of tanks, including the Lee/Grant. They were gradually replaced with arriving Shermans. There were almost no tanks of this type by the landings in Italy. However, some remained. This had to do with the large internal volume of the tank that made it suitable for conversion into command tanks. The 75 mm gun was removed and a fake barrel was put in its place. The fighting compartment was also changed. These tanks served for a lot longer. 

The best known Grant I command tank was named Monty. This was the personal tank of General Montgomery, which he used starting with El Alamein. The general continued to use it during the Italian campaign. This tank survives to this day in the Imperial War Museum in Duxford.

A Grant I command tank in Italy, May 1945. The fake gun is visible.

Some command tanks were converted towards the start of the Italian campaign. Since the Sherman became the main tank of the British army, the tanks had to look like them. The sponson and its bulge were removed. The turret was altered, and a dummy 75 mm gun barrel was added to it. These tanks served in Italy until the end of the war.

CDL Tank M3 coastal defense tank.

Other British versions of the Grant I also deserve a mention, primarily the CDL Tank M3. This vehicle was designed as a part of the Canal Defense Light program. It carried a number of changes to allow fighting during the night. A powerful spotlight replaced the turret. Initially this spotlight was used on the Matilda tank, but there was an issue. The tank was designed to resist a German invasion, but its armament consisted of only one BESA machinegun.

The CDL Tank M3 name was retained into 1944.

The installation of a turret with this spotlight into the Medium Tank M3 was a much more rational choice. Requirements for the CDL Tank M3 were drawn up in May of 1941. This tank retained its primary armament and could therefore fight the enemy on its own. The first tanks were ready by the end of 1941, and these were the first American tanks to be adopted by the British army. The names Lee and Grant did not apply to them. Even in documents dated 1944 they are still called CDL Tank M3.

According to research by John Fuller, 1850 Medium Tanks M3 were converted. British and American companies performed the conversions. There was a difference between the two: American-built tanks had Browning M1919A4 machineguns in the turret.

Australian Grant I tanks. Their career continued until the end of the war.

While the British stopped using Lee and Grant tanks by the spring of 1943, the situation on the other side of the world was different. The Australians put their own tank into production, the AC 1 Sentinel. It is often called a variant of the Medium Tank M3, but it is a different vehicle, although similar. Nearly all Grant II and Lee V (232 tanks from 234) were sent to Australia. 266 Grant I and 239 Lee I tanks also ended up there. 20 more drowned on the way, along with their ships.

The arrival of these tanks was met with enthusiasm. The combat effectiveness of these tanks was much higher than that of the Matilda, especially in terms of firepower. Nevertheless, these tanks were included into the strategic reserve in case of a Japanese invasion. Many Lee tanks had their cupolas removed and replaced with a hatch. A large number of Lee/Grant tanks were used in agriculture after the war, which explains the large amount of well preserved specimens in Australia.

Lee I in Burma, 1945.

Another theater of war where the Lee served for a long time was Burma. The tank was good enough to keep fighting the Japanese. It's not surprising that these tanks remained in service until the very end of the war. Even though the Shermans began arriving in late 1942, their predecessor continued to fight, at least in secondary operations. This is evidence that the Lee/Grant was an adequate vehicle from the point of view of combat performance. At the very least, they were better than British tanks of the same class, which, aside from the Matilda and Valentine, vanished from the battlefield in the summer of 1943.

Uparmour

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"Order of the People's Commissariat of Medium Machinebuilding of the USSR #268ss
Moscow
June 29th, 1941

In accordance with the decree of the USSR SNK, I order:
  1. To the director of factory #174, comrade Markin:
    1. Produce two experimental T-26 tanks (one 1939 production with a conical turret and sloped turret platform, the second 1938 production with a conical turret and vertical turret platform) with 25-35 mm thick applique armour by July 25th, 1941.
    2. Develop blueprints, have them approved by the GABTU, and send them to the Izhora factory by July 8th, 1941.
  2. To the director of factory #183, comrade Maksarev:
    1. Produce four experimental BT-5 and BT-7 tanks with 30-35 mm thick applique armour by July 25th, 1941.
    2. Develop blueprints, have them approved by the GABTU, and send them to the Mariupol factory by July 8th, 1941.
  3. When producing experimental T-26 and BT tanks with applique armour, develop a full set of armoured parts, a technological process for installation of armour, and a complete set of instructions for installation and removal.
  4. This decree orders:
    1. The People's Commissar of Shipbuilding to supply on the day of receiving the blueprints:
      1. Two sets of armour to factory #174 from the Izhora factory for T-26 prototypes according to factory blueprints.
      2. Four sets of armour to factory #183 from the Mariupol factory for BT-5 and BT-7 tanks according to factory blueprints.
    2. The People's Commissar of Defense (GABTU):
      1. To supply the People's Commissar of Medium Machinebuilding with tactical-technical requirements for T-26, BT-5, and BT-7 tanks developed jointly with factories #174 and #183 within five days.
      2. Supply within five days:
        1. Factory #174 with 2 T-26 tanks.
        2. Factory #183 with 4 BT tanks.
      3. Perform thorough trials of T-26 and BT tanks with applique armour and, jointly with the People's Commissariats of Medium Machinebuilding and Shipbuilding, establish the optimal method of armouring the aforementioned tanks in 1941 by August 10th, 1941.
  5. The following will track the progress of this order:
    1. At factory #174: lead engineer of the tank department, comrade Savin.
    2. At factory #183: lead engineer of the tank department, comrade Grigoryev."

Tough IS-2

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"During the fighting for Roben, having broken enemy resistance by the end of March 23rd, 1945, the brigade approached Roben proper. On the night from March 23rd to March 24th, units of the brigade occupied the eastern outskirts of Roben. During the night and the day of March 24th, the brigade fought to clear Roben from enemy submachinegunners. By 12:00 on March 24th, Roben was cleared completely.

The enemy occupied the dominant terrain to the north-west and west of Roben and opened fire with artillery, not letting our tanks group up on the western outskirts of Roben for further action.

The brigade commander made a decision: leave the assigned SPGs for covering fire, move around Roben with the main forces, and head to Bratsch.

The brigade left Roben to complete the task. By that point, the enemy had concentrated infantry and up to 16 armoured vehicles south-west of Roben. When our tanks left Roben, they counterattacked. infantry from the 24th and 26th Guards Motorized Brigade did not hold and left Roben. On the corps commander's orders, the tanks turned back and suddenly attacked Roben from the south and south-east, knocking the enemy out. The positions were restored by 17:00. Until the end of the day, the brigade fought south-west and west of Roben. By 21:00 of March 24th, the brigade completely concentrated in Roben. During the night, the brigade did not fight, but performed refuelling, restocking, and maintenance. 

IS tank with 16 dents from enemy shells. The tank commander, Guards Junior Lieutenant Neelov, destroyed 3 enemy tanks, 2 enemy SPGs, and 7 enemy guns with this tank.

Our IS-2 tanks fought actively in these battles. Brave tankers went into attacks time and time again, crushing with their tracks and shooting up enemy strongholds.

Tank commander Guards Junior Lieutenant Neelov distinguished himself in these battles. With his crew, he was constantly in battle from the start of the offensive on March 15th. Time and time again, he entered uneven battle against the enemy. Having been wounded, Guards Junior Lieutenant Neelov did not leave the battlefield, and was only sent to the hospital during battles for Rusin, when he was severely injured. Guards Junior Lieutenant Neelov destroyed 3 tanks, 2 SPGs, 7 guns, and up to 100 enemy soldiers and officers. His tank had 16 dents from enemy artillery shells, but did not leave the battlefield even once. 

The brigade destroyed many tanks and SPGs during the battles for Rusin and Roben. Many were also captured intact."

Intact enemy SPG captured at Roben.

Knocked out enemy SPG at Rusin.

Hide Your Guns

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The need to hide artillery appeared long ago, but the military took development of camouflage paint schemes seriously only on the cusp of the 19th and 20th centuries. Progress in observation methods and increased movement of all sorts of forces played an important role. Widespread use of firearms and the introduction of aircraft dispelled the romantic notion of tight formations and colourful uniforms. There was a sudden need to quickly hide equipment, especially large equipment such as tanks, guns, and automobiles, but not at a cost to mobility. How did the Red Army deal with camouflage during the Great Patriotic War?


For a long time, typical camouflage was applied in a single tone of various shades of khaki, olive drab, and other varieties of green, but this was ineffective. WWI gave a significant push to the development of camouflage patterns. Manuals for painting camouflage were developed during the interbellum period based on wartime experience and then improved based on experience in WWII. This issue did not go unnoticed in the USSR.

85 mm U-10 divisional gun, UZTM, Sverdlovsk, 1941. The edges of camouflage spots are clearly visible. The darkest is 6K, the medium is 4BO, and the lightest is 7K.

The Main Artillery Directorate of the Red Army developed various instruction manuals, guides, and memos regarding the painting of camouflage patterns on equipment directly by army units, at military bases, at repair yards, or at factories. These documents described the process of painting summer and winter camouflage on cannons and tractors.

Three-tone summer pattern

This type of camouflage was developed for spotted backgrounds (forest, shrubs, fields with exposed earth, etc). Three colours were used. Green 4BO paint, matching most types of vegetation, was the dominant colour. It covered 45-55% of the surface of the object. Yellowish-earth 7K matched the colour of freshly ploughed soil, dirt roads, etc. It covered 15-30% of the object. Finally, dark brown 6K matched the colour of soil in shade, tree bark, etc. It also covered 15-30% of the surface.

Samples of camouflage colours. Keep in mind that the paint chips changed colour during storage and are additionally altered during the process of photography and reproduction on your monitor.

Spots in camouflage patterns had to match the shape of naturally occurring backgrounds, and have a distinctive uneven outline. Large characteristic parts (gun shields, barrels, wheels) were covered in spots of various colours that broke the silhouette apart. Protruding parts were coloured in dark paint.

An example of spots and their position relative to edges. Left: correct (spot #1 is closed, spots 2-5 are open), right: incorrect (spots #1 and #2 are identical in colour and shape, spot #3 is parallel to the edge).

An interesting detail is the requirement for edges of the spots. Camouflage paint performs differently at different ranges. To put it simply, camouflage makes no sense at very long or very short distances. In the first case all colours blend into one, in the second all spots are noticeable and don't blend into their background. Camouflage is most effective at medium distances, and each distance has its own optimal size for spots. At 300-600 meters, the size of spots should be 8-40 cm in width and up to 80 cm in length. At 500-1000 meters the dimensions of the spots increase to 15-80 cm and 200 cm respectively.

Long range artillery has a greater range from which it can be spotted than battalion level artillery. The spots on these guns should be larger, and their borders more defined. For smaller calibers it is more important to hide at close range. Blurred edges make camouflage more effective at close ranges, but makes it less effective at long ranges. Because of this, guns 20-76 mm in caliber were painted with blurred spots, and guns with higher calibers were painted with hard edges.

Guns captured by Germans: 76 mm F-22, 57 mm ZIS-2, and others. The borders of colours are clearly visible.

There were other nuances. For instance, factories and military bases painted new or refurbished vehicles with grated pigments of three different colours (4BO, 6K, and 7K) according to the aforementioned requirements. The positioning and pattern of spots was dictated by diagrams, although it was recommended to cycle through 2-3 variants of positions to increase the variety. Before painting, a primer coat of iron oxide was applied (40% dried or grated iron oxide, 55% oil varnish, 5% dessicant #64). Primer could be applied either by airbrush or by paintbrushes. If possible, it was recommended to dry the paint for two hours at a temperature of 80 degrees.

The first layer of paint (brushed) was composed of:
  • 6K: 100 parts thick milled paint for 40 parts oil varnish.
  • 7K: 100 parts thick milled paint for 25 parts oil varnish.
  • 4BO: according to technical conditions for single-tone camouflage.
When applying the paint via airbrush it was thinned with white-spirit until it reached the necessary consistency.
ML-20 152 mm gun-howitzer crossing a river on a pontoon. Camouflage with hard edges is visible.

Notably, paint was only applied to areas where it was marked. Spots were not painted over one another. The second layer of all colours was diluted with oil varnish and gasoline or white-spirit to thinner consistency than the base layer. The viscosity was picked experimentally. 

The painting process at repair bases was similar to the factory process, but took into account the possible lack of materials or instruments. If the vehicle was already painted in 4BO, the coloured spots were painted on top, leaving the top layer intact. Chalk was recommended as a marking between colours.


Diagram for painting guns 20-76 mm in caliber (except AA guns). The edges of the spots are blurred.

Diagram for painting AA guns greater than 37 mm in caliber. The edges of the spots are hard.

Diagram for painting corps level artillery. The edges of the spots are hard.

Diagram for painting artillery of the strategic reserve of the Supreme Command. The edges of the spots are hard.

Typical diagram for STZ-5, S-2, S-35, S-60, STAZ, HTZ, and NATI tractors (top) and Voroshilovets tractors (bottom).

The paint was distributed in the form of a thick paste with the recommendation to dilute it with equal parts oil varnish and gasoline in the amount of 25-40% of the weight of the paste. It was acceptable to thin the paint with gasoline or kerosene only, but one can assume that the paint applied in this way would not hold very well. The desired consistency of the paint was thin enough to allow it to be painted with a brush. One layer of paint was applied, using about 100 grams of paint per square meter. If blurred edges were desired, pure gasoline or kerosene was applied to the edges of the spots while they were still wet along a 1.5-3 cm wide strip.

Winter camouflage patterns

Many techniques used for winter camouflage of vehicles discussed previously were also applied to artillery, such as the principles of mixing certain colours, applying spots, etc. However, artillery camouflage had its nuances. The difference in the technical process and simplification of ingredients between the instructions issued in 1941 and 1942, caused by difficulties in supplying units with paint, is also interesting.

122 mm M-30 howitzer during trials of the ZIS-42 halftrack, 1942. The hatched winter camouflage is visible.

Paint in 1941 instructions:
  • "B" dry white paint prepared according to GAU requirements #2918: recommended
  • White glue paint: acceptable
  • White rosin-gasoline paint: acceptable
Paint in 1942 instructions:
  • "B" dry white paint prepared according to GAU requirements #2918: recommended
  • White glue paint: acceptable
  • White chalk: additional materials
One can make the conclusions that the GAU and GABTU didn't come to an agreement about what materials to use for winter camouflage. Unlike for armoured vehicles, the use of lime for painting artillery was not recommended. Zinc, titanium, lead, or lithopone paint was forbidden.


Painting equipment in solid white was permitted on featureless snow cover.

"B" paint and white glue paint were diluted to the consistency of sour cream with water. The mixture was applied while warm and dried in 1-2 hours. White rosin-gasoline paint could be applied at a temperature as low as -20 degrees Celsius and would dry in 6-8 hours. White chalk was recommended in the 1942 instructions as an additional and simplest material for camouflage. It was used to apply camouflage in extreme cold or touch up small spots and hatching if nothing else was available. Chalk was also used to colour wheel rims, tires, and other elements, as well as during the preparation of positions or after moving the gun, when it was necessary to prepare the main layer of camouflage.

In 1941, the process of applying spots was as follows. When applying paint to previously camouflaged guns or vehicles, green areas are covered in white completely, and rhomboid hatching is applied to yellow and brown spots. Application of only horizontal or vertical lines was forbidden. On dark brown spots, 1-1.5 cm wide lines were applied every 6.5-10 cm. On yellow spots, every 3.5-5 cm.

Recommendation for painting an AA gun with a forest or shrubs in the background.

If the gun was positioned out in terrain that was fully covered in snow, it was acceptable to paint the equipment completely white or reduce the distance between lines. 

When painting over single colour camouflage (4BO), an imitation of three colour camouflage was used. Spots were marked in chalk, just like for summer camouflage. Then, the green parts were completely covered with white, and spots that corresponded to brown or yellow were covered in hatching with various line thicknesses. With 1-1.5 cm wide lines the distance between them was 8.5-13 cm on dark brown spots and 2.5-4 cm for earth yellow spots. This technique imitated three shades of colour by varying the tightness of the hatching.

Paint was applied with brushes, cotton packing, or simply rolled up rags. Special attention was taken to not cover moving parts of guns, bronze, copper, or anodized surfaces. 

Winter camouflage of battalion, regimental, and divisional artillery, 1941.

Winter camouflage of AA guns, 1941.

Winter camouflage of corps artillery, 1941.

Winter camouflage of artillery of the strategic reserve of the Supreme Command, 1941.

Winter camouflage for STZ-5, S-2, S-35, S-60, STZ, HTZ, NATI tractors (top) and Voroshilovets and Komsomolets tractors (bottom).

As mentioned above, the instructions that were reworked and issued in 1942 had significantly different materials and methods of application to make application cheaper and faster. Instructions to methodically apply hatching were replaced with simpler techniques.

As before, when applying paint over three-tone camouflage the green was covered completely in white. However, the brown and yellow spots were not hatched. They were covered in fine dashes and small spots that matched the patterns of the terrain. The lower parts of gun shields and trails were painted white regardless of the colour of summer camouflage. Chalk was used to apply the extra spots and dashes.

Soviet 203 mm B-4 howitzer crew, Poland, 1945. Winter camouflage with white spots can be seen.

The technique used for white paint was analogous. All surfaces were split between green, "yellow", and "brown". Green areas and lower parts of gun shields and trails were painted in white. Spots marked as yellow and brown were covered in stripes, dashes, and spots to match their surroundings. Gun commanders and their crews had the freedom to choose a camouflage pattern based only on their imagination to match their surroundings.

The issues of removing the winter camouflage come spring or transition to an area without snow were also addressed. Partial removal of white paint from yellow and brown spots was allowed, and even recommended, upon entry into an area with less snow. The camouflage was later restored if necessary. Rags, water, and kerosene were used. In the cold, the paint was removed with hot water, rags, and wooden scrapers. Gasoline was allowed as a solvent only during warm weather.

Winter camouflage of battalion, regiment, and divisional artillery, 1942.

Winter camouflage of AA guns, 1942.

Winter camouflage of corps level artillery, 1942.

Winter camouflage of artillery of the strategic reserve of the Supreme Command, 1942.

Winter camouflage for STZ-5, S-2, S-35, S-60, STZ, HTZ, NATI tractors (top) and Voroshilovets and Komsomolets tractors (bottom).

In conclusions, one can see that the camouflage applied during the first years of the war changed to become simpler and cheaper, while remaining an effective way to hide equipment from sight.

To be continued.

Replacement Engines

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"Order of the People's Commissar of Medium Machinebuilding of the USSR #319ss
Moscow
July 11th, 1941

To carry out State Committee of Defense Decree issued on July 9th, 1941, "On the facilitation of production of T-34 tanks at the Krasnoye Sormovo factory, I order that:
  1. The director of the Molotov Gorkiy Automotive Factory must provide Krasnoye Sormovo with M-17 engines for the T-34 tank in the following amounts:
    1. August 1941: 15
    2. September 1941: 80
    3. October 1941: 160
    4. November 1941: 230
    5. December 1941: 260
      supply them evenly throughout the month.
  2. The director of factory #183, comrade Maksarev, must deliver to the Krasnoye Sormovo factory 5 sets of all T-34 parts in their completed state and 5 sets of rough stock.
Deputy People's Commissar of Medium Machinebuilding, S. Akopov."

T-64A's Birthday

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"Central Committee of the CPSU and the Council of Ministers of the USSR

Decree

May 20th, 1968

On the installation of a more powerful set of armament into the T-64 tank.

The Central Committee of the CPSU and the Council of Ministers of the USSR decree that:

In agreement with the proposal of the Ministry of Defense of the USSR and the Ministry of Defense Industry of installing into the T-64 tank a new 125 mm smoothbore D-81 gun with armour piercing subcaliber, HEAT, and HE-fragmentation shells, two-plane stabilizer 2E23, TPD-2 rangefinder sight, and a PKT coaxial machinegun with main characteristics in accordance to attachment #1.

The T-64 tank with new armament will be called T-64A."

Short-Term Queen of the Desert

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The Matilda is arguably the most famous British tank of WWII. This fame is well deserved. At the time of its appearance this slow moving but thickly armoured tank was the best the British industry could give its troops. However, its service with the British army was brief. By mid-1942, these tanks began to leave the stage to make room for American tanks.


Bigger infantry tank

The British tank forces slowly began to wake from their five year stasis in 1934. In many ways, this became possible due to the work of Sir Percy Hobart, who became the inspector of the Royal Armoured Corps in 1934. At the same time, Lieutenant General Sir Hugh Ellis took the post of Chief of Ordnance. The 1930s were a time of experiments, and this applied to the British armoured force in full. New management brought with it new ideas that radically changed the face of British tanks fairly quickly.

The Medium Tank A7E3 laid the foundation for the new infantry tank.

The overall system of British tank forces in the mid-30s followed worldwide tendencies. The backbone of the force was composed of medium tanks. However, their development lagged behind. A worthwhile replacement for the ageing Medium Tanks Mk.I and Mk.II was never found, and only three Medium Tanks Mk.III were ever built. The British were slowly transitioning from tankettes to more effective light tanks. These vehicles became the most popular pre-war British tanks.

The British were closely following developments in other countries while working on their light tanks with bulletproof armour. This was especially true for France, which had the largest tank fleet in the world. The French also had many issues with their tank development, but they took a different path. Instead of mobility, they placed their bets on armour, taking into account their experience in WWI. The symbol of the French tank industry in the early 1930s was the Renault NC. Even though it was never adopted into service by the army, it was widely advertised.

The first experimental Infantry Tank A12E1, summer of 1938.

The Vickers-Armstrongs and Carden-Loyd companies received an order for a tank similar to the Renault NC in 1934. This tank would have 25 mm of armour, a top speed of 16 kph, and either a 7.62 or a 12.7 mm machinegun. Further development of this concept resulted in the A11 tank, or the Infantry Tank Mk.I.

In parallel, requirements for a larger tank were developed. Its armour and top speed were the same, but it would be armed with a more powerful weapon. The 2-pounder 40 mm gun that was under development at Vickers-Armstrongs and the Royal Arsenal Woolwich at the time was proposed as such a weapon. This gun was designed to replace the 3-pounder 47 mm gun whose penetration was already lacking. 25 mm of armour was too much for this gun, while the new gun could penetrate 37 mm of armour at 60 degrees from 457 meters.

The exhaust pipes were moved up as far as possible to increase fording depth.

Unlike the Infantry Tank Mk.I, Vickers-Armstrongs did not receive the order for a medium infantry tank. The development remained at Royal Arsenal Woolwich. This was not the first such work done at the arsenal. One can imagine that the A12 was revenge for the competition with Vickers since the start of the 1920s.

Work on a gun tank stalled. The first drafts appeared only in September of 1936, when the A11E1 was already entering trials. In the meantime, requirements were increased. The A11's armour had to be 60 mm thick, and the project that was now called A12 had to have 75 mm of armour.

The V-shaped front hull that migrated from the Infantry Tank Mk.I was concealed by toolboxes built into the sides.

There is information that the A12 project was initially called Matilda Senior. This is a rather interesting discussion. This index was never used in correspondence. However, some influence from the A11 can be seen. The characteristic V-shape in the front of the hull indicates that the designers were familiar with the Leslie Little's work.

However, the Arsenal had no shortage of experience with tank design. This was true for the suspension as well. One should not forget that assembly of experimental A6 medium tanks happened here, as did the development of the A7 medium tank. The A12 was born from these developments. There are also claims that the "Japanese suspension" from the Japanese-built Medium Tank Mk.C was used. In reality, the same suspension was used by Vickers on a number of export vehicles. A similar suspension was also used on the A6. Woolwich did not reinvent the wheel and used a number of tried and true ideas. This was also true for the suspension covered with spaced armour.

The power plant, made from two AEC A183/A184 engines, repeated the concept that was tested on the A7E3.

While the suspension looks suspect, a number of components migrated wholesale from the A7E3 tank, built at the Royal Arsenal Woolwich. That tank was yet another failed attempt to build a replacement for the Medium Tank Mk.II. Even though work on that tank stopped in 1937, it had a great influence on British tank building. Components designed for this tank can be found in many later vehicles. This was also true for the A12.

The most characteristic reused component was the powerplant with two AEC engines that was tried out on the A7E3. This system has a good reason for existing. The British had a lot of issues with tank engines, and a pair of AEC bus engines partially resolved the issue of engine supplies. The A12 was equipped with the 6.75 L AEC A183/A184 engine. The Wilson planetary mechanism was also taken from the A7E3, as were the tracks and a number of other elements. Therefore, one can only say that the A12 was a further development of the A11 with a number of caveats.
The suspension as well as the chassis in general was a further development of past Vickers and Royal Arsenal Woolwich designs.

A significant change in the A12 from previous Royal Arsenal Woolwich designs was that it only designed the tank. The Vulcan Foundry Limited company from Lancashire was charged with the production. Contract T/3951 for two prototypes costing 30,000 pounds Sterling was signed in 1937.

Initially, the British military was uncertain in their choice of armament for the new tank. One variant had two machineguns in the turret, but it was rejected. The main variant was one 2-pounder gun in the turret with a coaxial Vickers machinegun. This type of mount was also used on the Medium Tank A7E3.

As for the turret, it was designed anew. Like on the A7E3, it fit three people, but it had nothing to do with the arsenal's past designs. The turret and hull were designed in tight cooperation with Vulcan to ensure that it was within the company's power to build it. As a result, the A12 was the first British tank that used widespread casting. The A11 only had a cast turret, while the A12 also had a large portion of its hull cast. Otherwise, the design was standard for British tanks of the time. It was assembled on rails using rivets. 

The Infantry Tank Mk.II turret went into production like this. However, the variant with a Vickers gun did not last for long in production.

The first experimental prototype, indexed A12E1, was sent to the Mechanical Warfare Experimental Establishment (MWEE) on April 11th, 1938. The tank received registration numbers T.3421 and MHM 786. The tank was on a completely different level than the A11. While it was still slow, the top speed of 24 kph on a highway and 15 kph off-road was leaps and bounds over the 12.9 kph that was the limit of the Infantry Tank Mk.I.

More importantly, it was a full fledged fighting machine that combined thick armour and adequate armament for the time. However, there was one caveat. Like with the 3-pounder gun, the 2-pounder did not have an HE round. British doctrine dictated that the tank's machinegun was enough to fight infantry, and the cannon was only for fighting tanks.

Joint trials of the Infantry Tank Mk.II and Infantry Tank Mk.III in early 1940.

Trials at MWEE were successful. The tank confidently travelled a distance of 1000 miles. However, issues of traction were discovered even at this early stage. In August of 1938, the A12E1 was sent to Lulworth. On December 15th, a new prototype arrived at Farnborough, indexed Infantry Tank A12E2. The prototypes spent winter-spring of 1939 at Vulcan factories, where they were repaired and modernized. However, it was clear by June of 1938 that the tank will go into production. The tank was accepted into service as the Infantry Tank Mk.II.

The many faces of Matilda

The first contract for 140 Infantry Tank Mk.II tanks, T5115, was signed in June of 1938, but the company was not the only producer of this tank. The situation Europe was starting to heat up, and Great Britain was not ready for war with Germany. The widely known policy of appeasement had one end goal: to win time for British industry to move to wartime footing.

It's nor surprising that in August of 1938 contract T5694 was signed for 40 more Infantry Tanks Mk.II. It was given to the Ruston & Hornsby Ltd. manufacturing company. Nearly at the same time, contract T5653 was signed with John Fowler & Co. for another 40 tanks. London, Midland, and Scottish Railway company (LMS) was next. Contract T5741 ordered 120 more tanks. Another railway company, North British Locomotive Company (NBL) from Glasgow received contract T6904 for 50 tanks. The last producer in this list was the Harland & Wolff Ltd. shipbuilding company from Belfast. Contract T6905 signed with them ordered 130 Infantry Tanks Mk.II. This impressive list of manufacturers shows how seriously the War Office treated this tank.

Infantry Tank Mk.II in production. The factories had trouble spinning up production at first, but the overall production rate was high thanks to six factories working on the tank at once, at least for British industry.

Vulcan had the lead role in further development of the A12's design. They composed technical documentation that was then sent to the rest of the factories. It's not surprising that Vulcan was the first to complete the tank. Over a year went by between the initial contract and putting the Infantry Tank Mk.II into production. Preparation for manufacturing and finding subcontractors for components took all this time. In addition, Vulcan carefully reviewed the results of trials and introduced changes into the tank's design. In part, the complex exhaust system was replaced and a number of hull components were simplified. 

One of the first Infantry Tanks Mk.IIA.

The launch of the Infantry Tank Mk.II coincided with the start of WWII. The first tanks rolled out of the factory in September of 1939. One of the consequences of the trials was a "lifted" suspension. The cause of this was that the spaced armour clipped the ground while driving off the road.

According to some documents that were obtained by the Red Army's GABTU, 24 tanks were built during the first quarter. These included the Infantry Tanks Mk.II that were built at LMS starting with December of 1939. 27 more tanks were built in the first quarter of 1940. The situation only changed in the second quarter. Production at Harland & Wolff and Ruston & Hornsby began in March, NBL joined in in May, and John Fowler in June. As a result, the number of produced tanks increased to 101.

September 1940, trials at the Aberdeen Proving Grounds.

The Infantry Tank Mk.II did not last long in its initial configuration. The BESA tank machinegun was accepted into service with the British army in 1939. This was a British adaptation of the Czechoslovakian ZB.53 mounted machinegun. Unlike the Vickers gun with a massive water cooling jacket, the BESA was air cooled. The new machinegun was installed on the new tank starting with the spring of 1940, which demanded a change to the turret and gun mount. 85 Infantry Tanks Mk.II were built in this way, 55 of them at Vulcan (T.6729-T.6783) and 30 at LMS (T.6909-T.6938).

As with other tanks that received the BESA machinegun, the index was changed. The improved tanks received the index Infantry Tank Mk.IIA. This version was produced until the summer of 1941, and these were the tanks destined to become the "Queen of the Desert".

The stamped tracks with additional grousers were not uncommon. This photo was taken in early 1941 in Africa.

After the British Expeditionary Forces received a crushing defeat in France, the British army lost a large amount of tanks, including 23 Infantry Tanks Mk.II. In total, British industry delivered 356 infantry tanks in 1940. The British were seriously afraid of a German landing, and their rates of production were not a cause for optimism. In July of 1940, Great Britain turned to the United States with a proposal to produce the Infantry Tank Mk.IIA overseas. To demonstrate the vehicle, tank T.7861 from the 7th Royal Tank Regiment, "Grampus", was sent to the US, accompanied by Junior Lieutenant Knott.

After trials at the Aberdeen Proving Grounds, the Americans refused to produce the tank, proposing their own Medium Tank M3 instead, which were currently under development. The British tank was sent to Canada, where it is preserved to this day at Base Borden.

The tank played its part, however. The Americans took note of the dual diesel powerplant. With the aid of Carr, a member of the British commission, a similar component was made with American GMC diesel engines. Thus was born the General Motors 6046, which was used on M3A3, M3A5, and M4A2 medium tanks. The latter were actively used in the British army under the name Sherman III, which received 5041 such vehicles.

The appearance of Ford tracks did not entirely force out initial models.

The story with tracks deserves a separate mention. As mentioned above, stock track links behaved poorly off paved roads. Nevertheless, they were put into production at Ruston & Hornsby. The mistake revealed itself in the winter of 1939-40, when it turned out that the grip on icy roads and snow is very poor. To resolve this issue, grousers were welded onto every track link.

The mobility was improved, but another issue surfaced. It turned out that this track has a lifespan of less than 500 km. An improved design with one large spur and one small was introduced. This design had a greater lifespan, but was less common.

Three types of tanks on one photo. The first has Ford type track links with additional grousers.

Five types of track links entered trials in March of 1941. In addition to the aforementioned types, the Lepaz T.D. 1195 was introduced. The tank with these track links had the lowest speed, 17.7 kph, but had the best traction. The most balanced design was the Ford cast track link, also known as the Ford Box. The average speed of the tank was reduced from 20.6 to 20.1 kph, but it had very good traction. After some improvements, this design was used as the main track link.

Nevertheless, Ruston & Hornsby track links were still used on a portion of the tanks. Many of them can be seen on photos of tanks sent to the USSR. According to correspondence, another type of stamped track links that also went into production was also developed.

 Leyland E148/E149 engines, the main feature of the Infantry Tank Mk.IIA* or Matilda III.

The look of the tank changed with time. By the summer of 1940 the "lifted" suspension was no longer in use, and instead of one headlight two were used. The front and rear mudflaps that quickly broke off during use were removed. However, the Infantry Tank Mk.II changed most radically in the spring of 1941. A pair of  Leyland E148/E149 diesel motors was used instead of AEC A183/A184. These 6.8 L 95 hp engines also came from buses.

The difference between Matilda II and Matilda III exhaust systems.

Production of tanks with Leyland engines began in May of 1941. They received the index Infantry Tank Mk.IIA*. These tanks can be distinguished by a new exhaust system and accompanying changes to the rear of the tank. The new model didn't stop some factories from producing the old one. For instance, tank number T.10459 currently on display at Bovington was produced at NBL on May 28th, 1941. This is a Mk.IIA tank, even though production of the Mk.IIA* already began.

One of the first Matilda III tanks on maneuvers, May 1941. As you can see, this tank still used old track links.

The Mk.IIA* had a large number of changes, including the name of the tank. This was due to the simplification of the names of the tanks that coincided with the start of American Lend Lease aid. This happened in May-June of 1941, when the Infantry Tank Mk.II received the name "Matilda". This name was the cause of many arguments, and in many historical publications, including very reputable ones, this tank is named incorrectly. The new name structure was as follows:
  • Infantry Tank Mk.II - Matilda I
  • Infantry Tank Mk.IIA - Matilda II
  • Infantry Tank Mk.IIA* - Matilda III
However, old indexes were still sometimes used.


Matilda III CS on maneuvers, September 1941. The Parrish-Lakeman Mounting AA mount seen here was installed on infantry and cruiser tanks starting with 1941.

The name wasn't the only thing that changed. The design kept changing as the tank was produced. Leyland E148/E149 engines were replaced with the Leyland E164/E165. The running gear also changed. Instead of support rollers, later model tanks used rails. The gun mantlet was altered somewhat as a result of battle experience. A bulge above the driver's vision port reduced the changes of him being hit with shells. The antenna mount changed after the Wireless Set No.19 entered use.

In addition, the Matilda III CS was introduced in June of 1941, armed with a 76 mm howitzer instead of a 2-pounder gun. It could only fire smoke and HE shells.

Additional fuel tank introduced on the Matilda III.

A major change to the look of the Matilda III was introduced at the tail end of its production. Since the main theater of war at the time was North Africa, the cruising range had to be increased. At first, crews added holders for fuel cans on their own. Near the end of production tanks were equipped with a 135 L external fuel tank in the rear. The fuel tank was linked to the fuel system. Later, a significant number of Matilda II tanks, such as the one in Bovington, was modernized to the level of the Matilda III.

Production of the Matilda IV, 1942. The main feature of the new variant, a lowered commander's cupola, can be seen.

A new version of the tank, named Matilda IV, entered production in the fall of 1941. Another noticeable change was added to all those that preceded it. The height of the vulnerable commander's cupola was reduced. Another change was the engines: the Leyland E164/E165 was replaced with the E170/E171. Most tanks of this type were equipped with Ford tracks, although there are some with Ruston & Hornsby designs.

This variant was the most common, encompassing 60% of the tanks of this type. Most Matilda IV tanks ended up in the USSR and in Australia, and not in the British army. The tank was produced in two variants: with a 2-pounder cannon and a 76 mm howitzer (Matilda IVCS).

A model of the A24 cruiser tank turret with a 6-pounder gun on the Matilda. The failure of this project put an end to this tank.

The Matilda V was the last variant to be produced. It didn't look any different than the Matilda IV from the outside. All the changes were on the inside. The tank received a Westinghouse servo mechanism, which made driving easier. Like the Matilda IV, these tanks largely went to the USSR and Australia. The British were disappointed with the tank by the end of 1941. It was clear that the 2-pounder gun is no longer powerful enough. As an experiment, the model of the A24 cruiser tank turret was installed on the Matilda, but the experiment was considered a failure. No attempt was made to install the 6-pounder gun into the stock turret, which is odd, given that the Soviets managed to install the 76 mm ZIS-5 gun into the turret of the Matilda III.

Harland & Wolff received a contract to produce 75 tanks in March of 1942. This was the last contract to be issued. The last tank was delivered in August of 1943. 2987 Matilda tanks were produced in total.

15 minutes of fame

The first unit to use the Infantry Tank Mk.II was the 7th Royal Tank Regiment. As of May 10th, 1940, it had 23 tanks of this type. The British were clearly preparing for a positional war, since the characteristic feature of the 7th RTR's tanks was a tail analogous to those used on Renault FT tanks. It was designed to lengthen the tank during crossing of wide trenches. The reality of the May-June campaign was far from what the British predicted. The German Blitzkrieg was fully realized. The Germans took a risk, but it paid off. A sudden offensive by German tank divisions left the Allies unprepared.

Knocked out Infantry Tanks Mk.I and Mk.II, Arras, late May 1940.

The combat debut of the Infantry Tank Mk.II happened on the same day as that of its older brother, the Infantry Tank Mk.I. On May 21st, 1940, tanks of the 7th and 4th Royal Tank Regiments counterattacked elements of the German 7th Tank Divison and SS division Totenkopf. Machinegun and gun tanks fought side by side.

The attack was successful, but not for long. British engineers built a tank that could resist anti-tank guns, not taking into account heavier artillery. 88 mm Flak 18 guns were reclassified as dual purpose guns back in 1938. In addition to aircraft, they would be used against long term fortifications. In reality, their main ground targets were British and French tanks with thick armour. The German gunners enjoyed a great success: two thirds of the British tanks were lost.

This tank has a lifted suspension and the characteristic tail.

The fighting in France was a death sentence for the Infantry Tank Mk.I. As for the Infantry Tank Mk.II, that was a whole other story. Despite the mixed results, it was clear that this was the best tank that British industry could provide. The reliability of this tank was markedly superior to that of the Cruiser Tank Mk.IV. In addition, German 88 mm guns weren't that common on the battlefield.

Tanks of the 4th Royal Tank Regiment in North Africa, 1941.

The Infantry Tank Mk.II waited for a second chance for half a year. Italy entered the war on June 10th, 1940, but fighting in North Africa developed very slowly. After the critical part of the Battle of Britain had passed and it was clear that the Germans would not land on the island, the British could move reinforcements to North Africa. Among them were Infantry Tanks Mk.IIA of the same 7th RTR that had such a poor debut in France.

5:00 am on December 9th, 1940, marked the start of Operation Compass, which resulted in a sound beating of the Italian forces. Tanks of the 7th RTR had their revenge. The Italians had nothing to defeat these thick-skinned tanks. Even the achievements of Tiger battalions pale in comparison to what the 7th RTR achieved here. This is when the tank received the nickname "Queen of the Desert". Its domination was absolute. 

The sad end to Operation Battleaxe. The rear of the tank has a rack for fuel canisters.

The luck of the British came to an end towards the middle of 1941. The first German units of what would eventually become the Afrika Korps began landing at Tripoli on February 14th. It was headed by Erwin Rommel, who already had experience in fighting infantry tanks. His next meeting with them took place in June of 1941. All the players were the same: his opponents were once more the 4th and 7th Royal Tank Regiments.

The countermeasure was the same: using AA guns in an anti-tank role. Large open spaces of the North African desert made the gunners' job simpler than in France. Slow British tanks made for good targets. The experience of the 4th RTR in Operation Battleaxe was a disappointing one: out of 100 tanks the regiment lost 64.

A victim of the German 88 mm gun. A good hit could knock the turret off.

British industry put out 316 Matilda III tanks in the 3rd quarter of 1941, which allowed units to be filled up with infantry tanks. Nevertheless, the British military was already doubting the tank's future on the battlefield. The results of Operation Crusader, which took place from November 18th to December 30th, 1941, added plenty of food for thought. The Matilda suffered heavy casualties once more. It turned out that thick armour alone in North Africa solves very little. The Allies decided to place their bets on cruiser tanks, as well as American light and medium tanks. During the Battle of Gazala which began on May 26th, 1942, only the 4th and 7th RTR had Matilda tanks. By October of 1942 the Matilda was off the front lines.

Repair dump, late 1942. By that point, the Matilda was relegated to the second lines.

North Africa became the last theater of war where the British used Matilda tanks for their primary purpose. It was just one of the many tanks to be filtered out by the sieve of North Africa. Only the Churchill, which had a very mixed debut, managed to defend the honour of British tank industry. This tank was quite handy during the fighting for Tunis. The Matilda was later used for training, never again leaving the island. Other nations, however, used the Matilda for much longer.


Canadian Sten

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The Sten Gun earned a reputation for being cheap and shoddy, but trials showed that it wasn't all that bad.


Seems acceptable. Let's compare it with the results of Soviet submachinegun trials. The numbers will be a little off, since the British were firing at 91.4 meters instead of 100, and taking the line from the center of the rectangle to the corner will (in most cases) result in an R100 that is larger than if a circle would be drawn around the points of impact, but the results will at least be comparable.

Sten #1 gives an R100 of 17.8 cm when firing single shots. This is around the same as the PPSh and Suomi submachineguns, around the middle of the pack. The mean point of impact is off by 28 cm to the right and 10 cm down. This is quite bad indeed, among the worst of the results. 

In bursts, the radius is 21.1 cm, which is quite good. Only the Neuhausen performs better. The mean point of impact is off by 6.35 cm right and 21.6 cm down, which is actually really good as well.

Sten #2 is a little less reliable, jamming up every time full auto is attempted (but firing off 6 mags initially without issues). It also has issues with dispersion. R100 in single fire is 22.9 cm, significantly worse than its brother and any of the other submachineguns. The mean point of aiming is off by 2.5 cm to the right and 12.7 cm up, however, which is pretty good.

Firing in bursts, the picture is reversed. Sten #2 has an R100 of 35 cm, around the same as the PPSh and Suomi. The mean point of impact is off by 22.9 cm left and 28 cm down, which is the worst result.

The Stens jump all over the place, doing rather average overall. However, considering that the other guns were produced in peacetime, while the Sten was a wartime design and produced by relatively inexperienced hands, the end result is actually quite impressive.

Mix and Match

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"Order of the People's Commissariat of Medium Machinebuilding #301ss
Moscow
July 6th, 1941

On the order of introducing design and technological changes to tanks and artillery tractors

Further developing paragraph 4 of order #253ss issued on June 26th, 1941, I order that:
  1. The leading factories, which develop all blueprints and design documentation, are as follows:
    1. KV-1 tank: Kirov factory
    2. T-34 tank: factory #183
    3. T-50 tank: factory #174
    4. V-2 engines: factory #75
  2. ChTZ, STZ, Krasnoye Sormovo, Uralturbomash, factory #37, HTZ, and all subcontractors that produce tanks, assemblies, components, and engines must produce their goods according to the blueprints of the lead factory.
  3. Changes to the technical documentation to meet orders of the SNK and Central Committee of the VKP(b) can only be done by the main factory, after approval by the customer.
  4. ChTZ, STZ, Krasnoye Sormovo, Uralturbomash, factory #37, HTZ are permitted to make design changes to components and assembly only with the permission of the lead factory's director and chief designer.
  5. Changes that impact the approved tactical-technical characteristics of tanks, engines, and artillery tractors can only be made with the permission of the People's Commissar.
  6. Control over the execution of this order is to be carried out by NKSM lead engineers:
    1. KV-1 tank: A.P. Petrov
    2. T-34 tank: N.I. Masalskaya
    3. T-50 tank: I.V. Yurasov
    4. V-2 engine: I.A. Moskalevskiy
    5. Artillery tractors: comrade Komov
People's Commissar of Medium Machinebuilding, V. Malyshev"

Compare and Contrast

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An interesting document was posted the other day on the War Thunder subreddit.


While very interesting on its own, there is one particular part of the trials that popped out at me.

The armour penetration of the HESH round is given as 150 mm at 60 degrees, which is exactly the same as the figure obtained by the Soviets in trials of a captured tank. Unfortunately there was no data on the HE-frag effect of the shell, as it would have been interesting to compare that.

The same poster also posted another interesting diagram of how the penetration changed with the impact angle.


More MKb.42 Impressions

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"Operational research department, 3rd Shock Army

Information Summary #01
January 1944


The model 1943 carbine-machinegun is designed to be used by infantry divisions that fight in forests. Two divisions in the Volkov and Holmsk directions had these weapons. Submachineguns have proven to be ineffective in the forest due to poor penetration. Machineguns are too heavy and not maneuverable enough. It is hard to aim and see when firing from the ground, and uncomfortable to fire from trees. machinegun-carbine combines the maneuverability of a submachinegun with the penetration of a machinegun. The system is well balanced and mobile. Firing in bursts has very light recoil. It is light and comfortable to use. One drawback is that it uses a special round with a shortened casing. Despite that, it has the penetration of a rifle at 400 meters. The magazines (30 round capacity, 7 are carried by each rifleman) are comfortable to use.

The weapon is gas-operated, tilting bolt. The effective range is 100-800 meters. Rate of fire: 500 rounds per minute."

Pershing With A Long Hand

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The opinion that America could win the war with tanks it already had in production was common at the start of 1944. This attitude backfired in the summer of 1944, when it turned out that even the M4A1(76)W with the 76 mm M1 gun was only a partial solution to fighting German tanks. American tanks were taking heavy losses from German Panthers on the battlefield. Another big surprise was the appearance of a new German tank in July of 1944, the Pz.Kpfw. Tiger Ausf. B, also known as the Tiger II. It turned out that no American tank gun was capable of penetrating it from the front. A search for a worthy opponent for these armoured monsters resulted in the creation of the T26E4 Super Pershing and some other variants of the Pershing with long-barreled cannons.

Tank destroyer, American style

The German Tiger II that was rammed by Lieutenant Gorman's crew near Caen was a nasty surprise for the Americans. It was not known how many tanks of this type the Germans had, but it was clear that American tanks and tank destroyers didn't have any reliable weapon against the Tiger II. Even the Heavy Tank T26 and the Gun Motor Carriage T71 (standardized as the Gun Motor Carriage M36 in July of 1944) were not enough. Their 90 mm M3 gun was close to the ballistics of the German 8.8 cm Flak 18 and was not capable of penetrating the front of this tank.

90 mm T15 gun, a concept inspired by the Germans. The requirements make it clear that this is the American analogue of the Pak 43/KwK 43.

The American answer to this new threat did not take long. General Electric proposed a modernization to their Heavy Tank T1E1 (although these tanks were never standardized, they were referred to as M6E2 in the letters). The proposal was to install a 105 mm T5E1 gun into a modified Heavy Tank T26 turret. A draft of such a modernization existed earlier. A plan to install a turret from a T26 tank (which was considered medium at the time) onto a Heavy Tank T1 was made in January of 1944. The project was worked on in the early spring of 1944, but the work was cancelled on March 7th. Nevertheless, this was the starting point for the creation of the Heavy Tank M6A2E1.

Initially, it was proposed that 15 tanks of this type would be built. On August 18th this tank was cancelled, since the M6A2E1 turned out to be too heavy and clumsy. Nevertheless, the project became a sort of mobile laboratory for the development of the gun and turret for another project, the Heavy Tank T29. The American Ordnance Department wanted a larger Heavy Tank T26.

This tank and the Heavy Tank T30 that appeared later (the difference was in its gun, the 155 mm T7) had another issue. It would take time to build and design them. It's not surprising that Ordnance decided to start a third project. This was a specialized tank destroyer built out of the Heavy Tank T26.

A T26E1 tank converted to use the 90 mm T15E1 gun, Aberdeen Proving Grounds, 1945.

One advantage was that the Heavy Tank T26 chassis existed in metal. However, it was not possible to install a 105 mm gun in this turret. Another route was chosen. The Watervliet Arsenal in New York received an order to build a longer version of the 90 mm T14 tank gun. The new gun received the index T15. In addition to the barrel, which was lengthened to 74 calibers, the gun received a bigger shell casing. This allowed increased the muzzle velocity of the T33 armour piercing shell to 975 m/s and the T30E16 subcaliber shot to 1143 m/s. The result was an analogue of the German 8.8 cm KwK 43 L/71. After trials of the T15 on a towed carriage, the Watervliet Arsenal received an order for the construction of two prototypes of an improved version, indexed T15E1.

The gun received a counterweight and a spring balancing mechanism to deal with the added weight.

The T15E1 gun showed excellent results. The front armour of a Panther tank was penetrated at 2377 meters. This was about the same as the effectiveness of the Soviet D-25T 122 mm tank gun and significantly better than the 100 mm D-10T.

However, there were issues after the gun was installed. The first Heavy Tank T26E1 prototype, which was at the Aberdeen Proving Grounds, was chosen for trials. The gun was installed in January of 1945, and it took some effort. The longer barrel resulted in a significant shift to the center of mass. To compensate, a large counterweight was added to the back of the turret. The gun mount was not design for such a long and heavy barrel, so a balancing mechanism was added to the top. The tank, converted by the Wellman Engineering Company, entered trials on January 12th, 1945.

The same tank in late March of 1945. The sides were not yet added to the gun mantlet.

These measures balanced the turret and somewhat increased the mass of the tank. Trials showed another problem. As mentioned above, the new gun had a longer shell casing. As a result, loading the tank became a chore. Fitting the 127 cm long shells into racks was also an issue.

The problem was resolved by loading the propellant separately. The converted gun was indexed T15E2. This gun was installed on a second prototype.

The same tank from the front. Additional armour improved protection, but drastically reduced mobility.

Trials held on March 1st, 1945, led to the Ordnance Committee to approve the tank for service under the index Heavy Tank T26E4 (OCM 26831). With all the changes, the mass of the tank increased to 42.9 tons. To compare, the mass of the T26E3 was 41.5 tons. The length of the tank increased from 8509 to 10312 mm.

A decision was made to send the T26E4 straight to the front lines after the limited standardization. There was not a lot of time to test the new tank, since it was clear that the war would end in a few months. The tank ended up in Europe by March 15th. It was sent to the 3rd Armored Division, which received the Heavy Tank T26E3 shortly prior.

Design of the spaced armour in the front of the hull.

The new tank was accompanied by Captain Elmer Gray from the Tank-Automotive Center. His new ward cost the captain a few gray hairs even before it entered battle. The tank arrived at the division with a few parts missing. The M71E4 telescopic sight was lost on the way, and thus an M71C sight from the T26E3 was taken. After some investigation, it turned out the sight was never lost, it was not there at all, and the tank was sent with an M71C sight. A firing table had to be hurriedly computed.

Another issue was that the ammunition for this tank was mistakenly sent to the 635th battalion with the experimental T8 gun. This was unfortunate, as the T8 used regular rounds used by the 90 mm M1 AA gun and M3 tank gun. The anti-tank gunners had no need for this ammunition, and it took time and effort to return it.

The gun mantlet after improvements.

While all of this was being ironed out, the experimental T26E4 ended up in the hands of the 3rd Maintenance Battalion. Further events are known thanks to the memoirs of Belton Cooper, who served in this unit. A separate chapter is dedicated to the path of the experimental tank. Cooper is credited with the creation of the name "Super Pershing". Cooper's description of the metamorphosis the tank undertook in March of 1945 is interesting.

[The original article had an excerpt from Death Traps here, which will not be reproduced for copyright reasons]

However, Cooper neglected to mention that he did not design the spaced armour. L.R. Price from the Aberdeen Proving Grounds, who was also responsible for the gun mount, directed the work. The result of Price's influence was that the applique armour was a little different from the type usually used by the 3rd Armored Division. The division did use doubled up applique armour, but this type of spaced armour was not used. The influence of a proving grounds specialist can also be seen in the counterweights installed on the gun mantlet.

The back of the turret.

The addition of the applique armour had a noticeable effect on the tank's characteristics. In addition to sagging torsion bars and a significant drop in speed the engine began to overheat. This is not surprising, as the tank's mass grew to 50 tons. The tankers were lucky that the road wheels did not start breaking up at such a weight. The load on the aiming mechanisms increased, and the issue with large rounds did not disappear. However, the tank had one advantage: firepower. A shot fired from 2400 meters during trials penetrated the 80 mm thick front plate of a Panzer IV/70, passed through the whole fighting compartment, punched through the rear armour, and buried itself in the ground.

The finale of the Super Pershing's fighting career. 3rd Armored Division tank park, summer of 1945.

The debut of the T26E4 happened in April of 1945. Cooper witnessed this event.

[The original article had an excerpt from Death Traps here, which will not be reproduced for copyright reasons]

A battle between a Tiger II and the T26E4 is sometimes mentioned, but there is no official confirmation of this fact. The real combat career of the Super Pershing matches Cooper's description. The applique armour was a mistake. Work to protect the tank took up extra time, which, from the looks of it, is what separated the American tank destroyer from its enemies.

Limited standard, limited use

While the first T26E4 was busy on the front lines, work on the second continued. It was built with the discovered drawbacks in mind. For one, it used the altered T15E2 gun with separate propellant. Second, the tank received a new and improved balancing mechanism. The springs were covered up. The chassis of the tank was also newer. A production Heavy Tank T26E3 (serial number 97, registration number 30119907) was used.

The second T26E4 pilot at the Aberdeen Proving Grounds, summer of 1945.

The conversion of the second T26E4, also counted as the first production tank, was completed by Wellman Engineering Company in June of 1945. By that point, the war in Europe was over, and the need for a tank destroyer has passed. Plans drafted in February of 1945 called for 1000 of these vehicles. They would fight alongside T26E3 tanks and perform the same role as the British Sherman Vc. Since the war was over, the order was reduced to 25 in the summer of 1945. The order was not fully cancelled since the Heavy Tank T29/T30 program was slipping, and the T26E4 had the most promising armament of all American tanks at the moment.

The altered balancing mechanism is visible from above.

The tank that arrived at the Aberdeen Proving Grounds in July of 1945 had not only a new gun, but a new balancing mechanism. The tank finally received an M71E4 sight. The hydraulic traverse mechanism was also changed to compensate for the heavier turret. The ammunition rack was also altered. The tank could now hold 54 rounds.

The same tank from the rear.

Trials performed in the summer of 1945 showed that the changes made to the design had a positive impact on crew performance. Nevertheless, some issues remained. Even moving to separate propellant did not spare the crew of troubles. The casing was still too long to work with. In addition, even the new balancing mechanism was not good enough. This protrusion could easily be damaged in battle. The testers' desires were collected and added to a report. Wellman Engineering Company got to work. As a result, the production T26E4 looked somewhat different than the second pilot.

Production T26E4, Aberdeen Proving Grounds, January 1946.

Another T26E4, this time a production sample, arrived at the Aberdeen Proving Grounds in January of 1946. This tank was also not new, it was converted from T26E3 serial number 83, registration number 30119394. This time, the tank looked more like an ordinary T26E3, since the balancing mechanism was changed again. The hydropneumatic system was installed inside the turret. The counterweight was also changed. Its mass increased to 1334 kg. The tank went into production in this state.

The new counterweight.

The final mass of the tank destroyer grew even higher, reaching 44.07 tons. The length of the tank changed after the alterations, to 10465 mm. Theoretically, the maximum gun elevation would be the same as on the T26E3, but it turned out to be a little less during trials: 18.25 degrees instead of 20. This change was deemed acceptable.

This tank was later trialled at Fort Knox.

Army trials at Fort Knox followed these tests. T26E4, registration number 30128151, serial number 1405, was sent to perform them. The objective of the test was to determine the vehicle's characteristics, crew comfort, and the tank's behaviour in conditions as close as possible to combat. On May 9th, 1946, while trials were still ongoing, the Heavy Tank M26 was reclassified as a medium tank.

The altered counteweight is clearly visible.

The aiming mechanisms of the altered T26E4 remained the same as on the M26. The increased weight of the turret had an effect, especially on horizontal aiming. The turret could rotate at a speed of 2.6 RPM instead of the usual 3.3. This had an impact on mobility of fire. The increased load on manual aiming was also problematic. The hydropneumatic balancing mechanism was different than the one used on the M26, which made it harder to service in the field.

Stowage containers with the lids open.

The T15E2 gun, or rather its ammunition, was also heavily criticized. The separate propellant required new ammunition racks, which made the radio harder to access. The opinion regarding convenience was the same as at the Aberdeen Proving Grounds. The long casing was a noticeable drawback. The separate propellant reduced the rate of fire as is, and this additional difficulty soured the impression even further. In addition, damage to the barrel and muzzle brake was noted during firing of AP shells. The commission considered the poor design of the shell as the cause.

A demonstration of how difficult it was to load the gun, even with separate propellant.

The impressions during mobility trials were also mixed. The barrel overhang reduced the tank's ability to cross obstacles. Vertical obstacles were especially serious, as it there was a serious risk to hit the ground and damage the gun. The aiming mechanism was considered insufficiently robust, and changes had to be made. Service time after 800 km of travel also increased.

The tank's gun often clipped the ground while crossing obstacles.

Specialists at Fort Knox concluded that the tank had a whole gamut of drawbacks. The rate of fire, mobility of fire, and obstacle crossing abilities were reduced compared to the M26. The verdict was largely the same as the one that the T26E4 earned on the battlefield. It's not surprising that the tank did not remain in service for long.

The situation with the gun in travel position was not much better.

Only one T26E4 survives to this day. It can be seen at Cantigny Park, Wheaton, Illinois. The other tanks ended their life as shooting range targets. However, the history of long-barreled M26 tanks does not end here. While the first T26E4 was still undergoing trials, work on its replacement was already underway.

Third time's the charm

Moving to separate propellant was a half-measure. The fact that it only partially solved the issue while adding a whole load of problems was clear. It's not surprising that work on a new tank gun began in June of 1945 in parallel with work on the T26E4. The gun was indexed T54, and Watervliet was charged with its development.

90 mm T54 tank gun, designed for the M26E1 tank.

Externally, the T54 gun was very similar to the T15E2. The biggest difference was the use of a single-chamber muzzle brake. This is not surprising, as the objective was to build a gun with identical characteristics to the T15E2. The breech and ammunition were altered more seriously. The issue of a long casing was solved the easy way. Instead of increasing its length, its diameter was increased. In his time, Gladeon Barnes did the same thing then designing a 37 mm shell casing for the M3 gun. Of course, there is no such thing as miracles, and a larger casing meant there was room for fewer shells in the racks. The Americans considered this issue less pressing. It was better to have fewer shells, but to keep the rate of fire at an acceptable level and rid the loader of headaches.

Comparing the sizes of 37, 75, 76, and 90 mm rounds. The furthest round to the right is used in the T54 gun.

A prototype of the T54 gun was ready by February of 1946. Success in trials gave the green light to convert two tanks. Martens Ferry Division, a subsidiary of the Blaw-Knox Company, was given the task. The vehicle, indexed M26E1, was based on the T26E4, among others. The turret was similar to the T26E4, but there were many changes in addition to the new gun. The recoil mechanism was changed, the .30 cal Browning M1919 was replaced with a more powerful .50 cal Browning M2HB. Instead of the M71E4 telescopic sight, the gunner received a different one, the M83C. Since the T54 used different rounds, the racks were redesigned. Instead of 70 rounds in the M26, the T54-armed tank had only 41, 5 of which were carried in the turret.

M26E1 tank, Aberdeen Proving Grounds, March 1947.

Two prototypes of the Medium Tank M26E1 were ready in early 1947. The first tank was sent to the Detroit Arsenal, the second to the Aberdeen Proving Grounds. Trials began in February of 1947 and showed significantly improved characteristics. The shorter casing made the round easier to load. The gun also showed improved precision. It took three tries, but the Americans received a gun that was precise, had high penetration, and was comfortable to use.

The same tank from the right. The significant overhang is noticeable.

Trials were finished by early 1949. By that point it was clear that the budget cuts after the end of WWII meant there was no chance for this gun to enter mass production. The military only had enough money to produce the M46 Patton, effectively the same M26, but with a new engine and a modernized M3 gun.

View from above, turret in travel position.

There were other reasons why the M26E1 did not enter production. In addition to a smaller ammunition capacity, the M26E1 had a number of issues similar to those discovered with the T26E4 during trials at Fort Knox. The excessively long barrel limited mobility. The installation of a large counterweight and a long gun increased the mass of the tank by several tons. Finally, the pressure on the aiming mechanisms increased. The result was not worth the effort.

The only country that managed to create a successful analogue to the German 8.8 cm KwK 43 L/71 was Great Britain. The 84 mm Ordnance QF 20-pounder turned out to be better than the American and German guns. The gun was shorter (66.7 calibers), and its design was more compact. In addition, the gun was installed on the Centurion tank, which had a large turret ring (1880 mm).

The turret of the M26E1 was very similar to the one used on the T26E4.

There was another reason why American long 90 mm guns were effectively useless. However, it's unlikely that the Americans knew about this at the time. The Soviet Union, America's greatest enemy after the end of WWII, had been designing tanks that were protected from the 8.8 cm KwK 43 since 1943. These included, for example, the T-54 and IS-3. Considering the similar characteristics of the KwK 43 and T15/T54, it's likely that the American guns would have proven ineffective. Thankfully, this theory was never put into practice.

A draft of a Heavy Tank T29 turret on the chassis of a Medium Tank T25E1.

To end off, let us mention a vehicle that the Americans did not build at all. The idea of installing the turret from the Heavy Tank T29 on a Medium Tank T25E1 chassis was worked on in 1948. Theoretically, this was possible, although the turret ring diameter would have to be increased. The advantage of this design was that the turret would not have to be redesigned.

The issue was that the turret of the Heavy Tank T29 was significantly heavier than that of the Medium Tank T25E1. Issues with an excessively long barrel did not go away. It's not surprising that the project was cancelled at the draft stage.

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