A russian scientist wanted to develop a new superweapon : Time travel.

So he arranged for a experiment to be made. A tank and its crew was transported back in time to 1941. But there was a problem : They are unable to return to 2000. Locked in 1941 they are now enlisted in the soviet army to defend the motherland versus the hordes of the nazi-fascism.

The T-90 tank is used in the Battle for Moscow where it showed its mighty against german tanks. Superior mobility, armour, firepower and sighting, and help from KV-1's and KV-2's in protecting its flanks, allowed it to hunt down a whole battallion of Panzers and help hasten the fate of the german offensive in moscow. (Dont care if this is feasible or not, thats not the question).

Now that matters are less dire for the Soviet army, the tank was taken back from front line and sent to test grounds where it is being examined by engineers from all soviet tank factories.

What can the Soviet period engineers develop based on technology taken from said T-90 ?

  1. Can the engines be reproduced with the period tech ? (Even if you have to remove the eletronic engine controls and revert back to mechanical governors etc)
  2. Can the gun be reproduced ?
  3. Can the armour be reproduced ? Is there anything on composite armours that is too complex for the period or simply having the armour cut in half to look inside is enough to determine the materials it was made from ?
  4. Can the ammunition be reproduced ? (Even if the 9M119 guided rounds are ignored as too complex)

You may discount all the eletronic devices that are based on integrated circuits as this is hard to reproduce. But the mechanics of the machine are more advanced than WW2 tech but still within reach ?

Sorry for the total rewrite of the question.

  • $\begingroup$ Not dupes, but useful (partial) answers: worldbuilding.stackexchange.com/questions/12219/… and worldbuilding.stackexchange.com/questions/14960/… $\endgroup$ – Ghanima Apr 22 '15 at 18:30
  • $\begingroup$ Its not about how long this tank might survive (even a broken T-90 might be usefull), its not about the effects of this tank in WW2, its plainly simple about what can be done with reverse engineering this tank in WW2. $\endgroup$ – Jorge Aldo Apr 22 '15 at 19:13
  • $\begingroup$ Russians success in WWII was due to mass production and sheer numbers that they were able to produce...1 tank in a battle of hundreds of thousands of tanks isn't going to be the biggest impact. I get the feeling the Russian scientists would be better off disassembling the t-90 and learning what they can $\endgroup$ – Twelfth Apr 22 '15 at 19:16
  • $\begingroup$ The topic is SQUARELY about reverse engineering the T-90. It would probably be pressed in service at the height of german invasion in 1941 during the desperate times of the battle for moscow, but would later be returned to test units. $\endgroup$ – Jorge Aldo Apr 22 '15 at 19:22
  • $\begingroup$ While you have specified some more details here, there is not sufficient change for this not to count as a dupe... $\endgroup$ – ArtOfCode Apr 22 '15 at 19:39


The Soviet engineers will be able to get some tricks out of it, such as the anti-spall lining to protect the crew from non-penetrating rounds. They already know about spaced armor, either from captured German tanks or from French efforts in World War I. They'll be able to figure out the principles behind the explosive reactive armor and the ceramic layers, but they probably won't be able to reproduce either.


The mechanical elements of the main gun can be reproduced easily enough, though apart from caliber, it's not appreciably superior to what they're already using.


The engine can be duplicated using period technology. The duplicates will be heavier (greater reliance on mass of metal rather than strength of metal) and probably less reliable (inferior alloys and less-precise machining). You'll also lose some power from not having an engine-control computer, but it shouldn't be too much.

However, they won't be able to adapt or improve on the design. The computers and engineering knowledge used in designing it were left up-time, and many of the techniques, such as combustion-front simulation, can't be deduced simply by examining the end result.


Reproducing the ammunition won't be a problem from an engineering perspective. High-explosive shells haven't changed in decades, while the principles behind APFSDS and HEAT ammunition would be obvious to any engineer looking at them -- the trick to both isn't in designing it, but in realizing you can design it.

The problem with the ammunition is logistical. Tungsten for long-rod penetrators was too expensive for any WWII army to have a reliable supply of it, and without a nuclear-weapons program to provide depleted uranium as a waste product, DU penetrators are even more expensive.

The big one: the gunsight

The things that gives modern tanks their huge advantage over WWII tanks is the gunsight and gun-stabilization system. During WWII, tanks would fire from the "short halt" because when you're bouncing across the ground, you can't aim. The gunsight and stabilizer work together to let a modern tank fire on the move, hitting a target several kilometers away.

Unfortunately for your Soviet engineers, the key elements of both are purely microelectronics. They can incorporate all the mechanical elements of the T-90 into their tanks, but without the gunsight and stabilizer, all they've got is a faster T-34 with a heavier punch.

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    $\begingroup$ I just have to make an add. you dont really need to use DU to make uranium rounds, you might very well use natural uraniun and deal with the radiation later... $\endgroup$ – Jorge Aldo Apr 23 '15 at 14:29

Although previous questions on the topic (e.g. 1 and 2) come to different conclusions whether just one super-tank would prevail against a whole Panzer Battalion or massive artillery or air strikes or what not.

I will assume that any singular super-weapon can and will be brought down despite the necessary effort and a high toll resulting. And even if it would not be destroyed by the enemy it would still wear down and fail eventually - how many shots could the main gun take before being worn out? And just one more thing, even if it were indestructible it could still not cover long front lines. I think that just one tank is simply not powerful enough to be a deal maker here. (If on the contrary you'd send back just one ICBM with MIRV nukes I'd go for the use-before-study approach. Nuking Berlin and a few other targets will certainly put an early end to that war.)

Therefore I'd argue that this present from the future should not be put to the front lines unless a matter of last resort but instead should be disassembled to the last screw and reverse engineered in all details. Any feature or technique that could be re-made with reasonable effort and the tools and materials available at the time will then be used to make loads of better tanks.

Other than that:

Why hack existing 120 mm rounds for the 125 mm gun? Make new ones according to the bore. This is really not rocket science.

APDS was developped in the early 1940. Thus the techniques to make such rounds are available in that times. Using the samples that travelled back in time as templates for reverse engineering would advance the research on that topic within the Red Army.

Making the engines work on diesel of the era or duplicate most of the mechanical parts - I have no doubt in the proverbial makeshift skills of russian engineers!

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Provided that the tank has limited armour, limited spare parts and limited fuel, how could the russians hack something to keep the T-90 fighting, as it is now the most powerfull weapon in Soviet arsenal ?

Probably. Since the T-90 is a Russian tank built on top of the Soviet T-72, I have no doubt the Soviets of the day could find a way to construct replacement parts for the more modern version. As Ghanima points out, it may be better to reproduce this one tank than field it. The technology behind the T-90 (early 1990s) is considerably advanced for the era, so any reproductions are likely to be at least 18 months away.

Is it possible to hack a 120mm tank round from the artillery branches to fit the 125mm smooth bore of the T-90 ?

Yes. The device to do so is called a sabot.

Could the APDS rounds be developed earlier due to reverse engineering the T-90 rounds ? (First APDS round was made for the 17 pounder by the british not much later).

Yes. The APDS rounds were already in development at this time. The effort was led by the French Edgar Brandt company and later picked up by the British, who fielded it during WWII. See this for the development of the APDS round.

Could the T-90 engines run on the diesel of the era ?

Probably. Diesel hasn't changed significantly since its introduction in the 1890s. The problem here becomes one of logistics. Tanks of the time weren't designed with diesel engines, mostly for logistical reasons. Many of the American, British, and German engines were initially intended for aircraft and converted to tank use.

Could the russians reverse engineer at least the mechanical parts ?

Yes. As I mentioned before, the T-90 is based on a Soviet tank. The Soviets were always keen on mass production for instruments of war. While the technology is more advanced, I suspect the basic designs will be simple enough to be reverse engineered. The first reproduction might roll off the line in 18 months, if you have the logistics to support it.

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While it is theoretically feasible to reverse engineer a tank from the 1990's in 1941, the difficulty will be in reproducing anything you discover.

As you already alluded to, most of the electronics would be far beyond the ability of anyone on Earth at the time to reproduce (indeed a lot would be difficult to simply understand).

But the real issue is the ability to reproduce what you discover from stripping down the article. The various alloys used in even the unarmoured parts generally won't exist, and it will be difficult to reproduce the alloys using the sorts of understanding and technologies that existed at the time. Even the glass from the optical systems is probably of far better quality than anything possible in 1941.

The other part which will cause difficulties is the precision needed to make the parts. Most high quality machinery requires close tolerances to work properly, and Russian tooling has always been deficient and behind the West for the most part. 1990 Russian tooling and machining techniques are still far advanced on 1941 (the early T-34 turrets were initially cast by pouring molten metal into a turret shaped hole dug in the ground!). Try doing precision machining on totally unfamiliar metal alloys, or treating large plates of exotic alloys to make layers of composite armour and the problem increases 10X or more.

In order for the T-90 to really make a difference in the "Great Patriotic War", the Russians will actually have to invent entirely new tools and methods of production. Since they were extremely hard pressed to even keep up with the needs of the current battles, I suspect the T-90 would be a project on hold for a considerable period of time, at least until after the tide turned and the Russians could start devoting their attention to the project.

As a BTW, the T-90 carries 22 rounds in the carousel of the automatic loader, so the single tank would not even be able to destroy an entire Panzer battalion, since they could have as many as 103 tanks (battalions with later model tanks like the Panther or Tiger could have fewer, but we are still talking about 60 tanks per battalion in this period).

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  • $\begingroup$ The other 81 tanks in the battalion where killed by KV-1s and KV-2s :P $\endgroup$ – Jorge Aldo Apr 22 '15 at 22:31
  • $\begingroup$ What about the carousel loader, can it be reproduced ? I imagine a KV-2 with the ability to fire from a carousel... $\endgroup$ – Jorge Aldo Apr 22 '15 at 22:32
  • $\begingroup$ The autoloader is one of the more complex pieces of equipment on the T-90 (especially since the commander can select different ammunition from different "slots" in the autoloader as needed. The gun's breach and ejection system is also built to accommodate the autoloader, something which might not be possible with the KV cannon.) The other issue here is the tank is essentially built around the autoloader. A KV-1 would have to have one custom built and sized for it, and it is difficult to say how many rounds or what rate of fire would be possible with a 1941 era device. $\endgroup$ – Thucydides Apr 22 '15 at 22:36

A cheap new car today has more microprocessors than the 1969 lunar module. Any and all microprocessors in the Tank, even if feeble for today standards, are inimaginably powerful supercomputers for 1940's standards. Even if they cannot be reproduced, it's possible that some of them can be reused.

Cryptanalysis would probably be among the first applications, but engineering would take a big boost.

Post-war, if unshared, these supercomputers would remain a huge advantage until the last one failed. Perhaps Soviet central planning would not fail as hard with those.

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