[WWII] Soviet tank development

The soviets started the war (in my opinion) with some of the best tank guns available in mass production, the 76.2mm guns such as the T-34s F-34 and KV-1 ZIS-5 were among the best anti tank guns carried by a tank at the times, when you consider what rest of the world had in the form of 75mm low velocity guns (which mostly never fired Armour piercing ammunition until later on) on French CHAR b1 and the M3.

You have to be careful here my friend... at the start of the war tank armour was pretty thin and pretty much everyone had settled on two main tank calibres. The first was an anti armour calibre and started at 37mm as a common calibre and increased to 47mm and 50mm by the start of the war. The T-34 was considered revolutionary because the thickness of its armour together with its steep angling made it pretty much resistant to all "Anti tank" calibres. Calibres outside that range generally didn't have anti armour shells, so to reliably kill it you needed an extraordinary weapon... which was either a 105mm heavy artillery weapon or a high velocity anti aircraft weapon like the 88mm.
The second calibre was anti personnel and was generally a very short stubby gun in the 3 inch calibre range.

The Soviets were no different to anyone else in this regard, in fact their heavy tanks generally had a central 76.2mm main gun for anti personnel use and up to four 37mm and later 45mm guns in individual turrets around the main turret for anti tank use.

The breakthrough of the 76.2mm gun of the T-34 was that it had a bit of extra barrel length to give it modest anti armour capability.

The key here is that they had tanks for supporting infantry, which were armed with machine guns and 76.2mm short barreled guns with HE shells, and they had tanks for fighting other tanks armed with 45mm guns.

In the T-34 they had a single gun with the HE power for supporting infantry and taking out enemy positions, that could also deal with most of the armoured vehicles it would come across too... a fully multi purpose gun.

For example, the T-34s excellant 76.2mm gun did not get replaced until the 1944 with the 85mm (various calibers from 51 to 54 caliber barrels i think.

That is true but the small numbers of German tanks that required an 85mm gun did not make such a change a priority. By 1944 it was necessary.

It should be kept in mind that for every 85mm shell fired at a Tiger or Panther that same tank probably fired 100 or 500 HE shells at MG positions or concrete pill boxes, or other hard target or light armoured vehicle. If used correctly a T-34 wasn't supposed to find German tanks and take them on one on one. Its real job was to find a thin or weak point in the German line and punch through and attack rear units and HQs and take on vehicles in staging areas... or trucks taking fuel and munitions and food to the front.

There was a very long barreled hyper velocity flat trajectory 57mm gun developed for the T-34 to make it into a better anti tank platform, but however the STAVKA cancelled it probably because implementing such a gun could potentially delay production of existing tanks not to mention all the efforts of testing it and setting up new logistic chains etc.

Actually a few were made, but its HE shell was ineffective and its anti armour projectile used fairly exotic materials and was expensive... and meeting targets that required that sort of penetration performance was actually very rare, so they didn't make very many of them.

The 85mm gun on the T-34/85 was a very powerful gun, but many say its potential was not exploited due to poor ammunition.

That is rubbish. In direct comparison with the high velocity 75mm gun of the Panther it was almost as effective as an anti armour weapon without the over bore problems that led to short barrel lives for the German guns, while having a much more effective HE shell than the German weapon... which was much more useful.

Soviet anti tank rounds in general had tendancy to shatter on impact, possibly dew to quite conservative design based on older designs of anti tank penetrators not able to keep up to date with advances in modern rolled homogeneous armour, usually caused by high stresses in the penetrator.

There were lots of failings in ammo terms... German armour was often made too brittle and often shattered itself. Most of the Soviet anti tank ammo was capped with harder materials to improve penetration... which didn't always work.

Needless to say conservative = T-34 which was produced in enormous numbers actually won the war. Having a more exotic design using expensive materials would probably have been pointless as basic ammo in the tank is better than expensive and exotic ammo they can't make to the standard required to make it effective. Considering they made less than 2,000 tigers and less than 6.5 thousand Panthers, yet made about 65,000 T-34s or more suggests to me who got it right.

The IS-2 tank was also considered to fit the excellent 100mm D-10 gun from the su-100 which had better ballistic performance than the D-25T 122mm gun on IS-2, but was droped in favour of the potential problem with logistics and offsetting production (as new machine tools had to be devised to manufacture 100mm guns and its ammunition, when it was far easier to use the machines used to manufacture the A-19 gun that has been produced for quite a long time.

Not true. As you mention the 100mm gun was already in service on the Su-100... one of my favourite tank destroyers of the war... its nickname on both sides was "F@#$ end to everything"... which is a pretty cool nickname for a tank destroyer.
The real factor was HE power. The 122mm shell had a much better HE shell because it was designed as artillery, while the 100mm gun was developed for velocity and penetration. The 122mm shell had less penetration than the 100mm gun but even when it didn't penetrate the target it could knock the turret off its bearings even if it didn't penetrate the armour.

Very simply with just 8,000 odd German heavy tanks out there it made more sense to have a powerful HE shell than one that penetrated a lot of armour. That is not to say the 122mm was not a powerful long range tank killer...

popular myth that the Is-2s gun is some sort of a lazy inaccurate "derp" howitzer

Tanks don't spend all their time shooting at other tanks, and IS-2 tanks generally started firing on enemy tanks as soon as they saw them, which was as far away from them as they could.

The German tanks generally had better optics, but by the end of the war most Soviet tanks were being taken out by Panzerfausts and similar weapons in urban combat.

By that time German super tanks are better engaged with air power, or simply isolated and left to run out of fuel and ammo to be abandoned by their crews

Build a tank around an anti tank gun and you get a superior anti tank platform,the 57 mm gun wasnt great at anything else but punching nice holes.

Exactly.

And if you want to build thousands of T-34s with 57mm main guns you have to ask yourself how many Panthers and Tigers is it likely to meet in combat, because against most other armour the 76.2mm gun is actually more effective as the heavier shell, while penetrating less armour would actually do more damage after penetration.

Equally against soft targets its HE shell would not be that effective.

Having said that of course the Soviets had a 45mm towed anti tank gun that served throughout the war, though after about 1943 it was not effective against most enemy armour but had a useful HE shell and was retained for other targets.

Much like the anti tank rifles like PTRD-41 and PTRS-41, which both lacked the penetration later in the war but was still useful against a range of targets like trucks and light armoured vehicles... and even shooting through walls at people.

There was a better write up in one of Steven J Zaloga's books on Soviet Tanks.

The KV positioned itself in a fork in the road in an area of very soft ground. The Germans had no other choice but to go that way and the KV could see quite a distance so sneaking up was difficult. Their initial attacks were ineffectual... using 50mm guns barely scratched the surface of the tanks armour.

Over night they sent in sappers who placed explosives on the tracks and the tracks were blown off as were the side mud guards but the tank itself was uneffected. One of the sappers went back and placed a charge on the main gun but again it had little effect.

the second day they sent in lots of vehicles to distract the KV while they brought in some 105mm guns, but the KV crew saw the big guns and destroyed them and the trucks that brought them. Later they sent in light tanks to distract the KV while they brought up some 88mm guns, which opened fire and hit the KV a dozen times. As the German troops approached they were shocked to notice of the dozen direct hits by the powerful 88mm gun only two hits appeared to penetrate the armour and as they got to the vehicle the turret started to traverse and the machine guns started firing. One of the Germans quickly flipped open a hatch and threw in a grenade, whose detonation killed the remaining crew and ended the standoff.

Most people used to think that soviet technology lagged far behind nazis's war machine. But they are wrong, Especially regarding tanks, guns, aircrafts -we will discuss about this last topic later-.

Well yes and no.

In terms of lessons learned the Soviets learned a lot from the war in Spain and other conflicts, but their designs still had flaws...

For instance their T-34/76 had a four man crew but two in the turret and two in the hull... so the commander also had to load the gun...

They fixed that when they redesigned the turret for the T-34/85, but it was internal design that let them down along with some of their tactics.

And it wasn't just the Soviets... the other allies had to learn the same lessons too.

The sophisticated inter-weaved wheels on some German tanks was a good way of spreading the heavy weight of their vehicles without needing enormous tracks... but in the winter in the soviet union the smaller tracks were not an advantage and mud got between the wheels and froze so the vehicle was immobile in the morning...

The 75mm high velocity gun of the Panther was excellent for penetrating armour but the HE round was not so effective and the barrels didn't last very long either.

The Tiger was exquisitely designed... a total waste of energy and material and time for a weapon sent into a war zone... it could not fire while moving either.

Indeed... many German officers speculated that the interruption of production of the Panzer 4s to make Panthers and Tigers was a mistake... they basically stopped production of the Panzer 4s that were in desperate need to produce the Panthers and Tigers... but that production took a while to get underway so in the mean time they got nothing but promises of new tanks...

Late model Panzer 4s had a reasonable gun and OK armour but their layout was excellent, as was their optics and communications.

An amusing aspect largely ignored in the west.... look at the side profile of a Panther tank next to the side profile of a T-34... they are very similar except the angle of the rear deck on the T-34 slopes downwards, while the Panther has the opposite angle slope.

The Panther was a German T-34, but with a gun that was optimised for anti armour use over general usefulness against a variety of targets (ie good armour penetration, not so good HE round)... but for the Germans that made sense because they had 30 thousand T-34s and a similar number of Shermans to deal with... with more on the way.

HAhahahaha.... that old chestnut... only hear it from Americans though.

The Christie design suspension was used in the BT series of fast tanks... and was basically bought by the Soviets... the Americans at the time were not interested.

The Christie tank design was not bought... only the suspension design and it was applied to the early model BT tanks.

It was found the original design did not scale well and needed redesign for each model as the vehicles got heavier, so by the final BT-7M tank the idea was the same to the actual suspension was completely different from what the Soviets bought from Christie.

The T-34 was a medium tank that also adopted the Christie design of suspension, but it was nothing like what Christie sold to the Soviets again, because the weight increase meant it needed to be redesigned.

And this is the first I am hearing of the claim about the engine... the V12 engine used in the T-34 was a diesel engine first used in the BT-7M...

Would be very much interested in learning about this French aluminium V12 diesel engine that the Soviets copied... the main reason I ask is because French tanks tended to have Petrol engines...