Monday, 13 May 2019

The Myth of the Disposable T-34

This is a claim that I'm sure many of my readers have seen. It's usually worded something like "the lifespan of a T-34 tank on the battlefield was X hours, so the Soviets saw no reason to produce a tank that lasted X+1 hours". The number varies, but the sentiment is generally the same slight rewording of the "human waves" myth, pushing a narrative of disposable soldiers with disposable weapons sent to die in incredible numbers. However, one would consider it strange that an army whose main breakthrough exploitation tank was so short-lived would not only survive in a war characterized by long and deep armoured thrusts measuring hundreds of kilometers, but excel in it. Even a brief glance at contemporary documents demonstrates that reliability was always an important component of Soviet tank manufacturing.

Let us begin at the beginning, before there was even such a thing as a T-34. When it was discovered that the A-32 chassis was capable of carrying additional weight, the first trials were performed were reliability trials. The A-32 with the additional weight was subjected to a 1230 km march in addition to off-road mobility trials specifically to determine how the extra armour that was planned would impact the function of the tank's mechanisms. 1230 km already sounds like a lot for a "disposable" tank, but this was much less than 3000 km covered by the first A-32 in prior trials. The A-20 was also no slouch, having travelled 4200 km.

As the T-34 evolved into the tank we know today through 1940, reliability of new components was constantly being tested. The V-2 engine, its warranty period set at 150 hours, was tested in a BT-7M tank over a 2050 km march in May. Meanwhile, the T-34 was breaking in its new Hadfield steel tracks links on a variety of surfaces, including the toughest challenge a tank's tracks can face: cobblestones highways. After the 417 km mark was reached, the track links were examined carefully, wear was measured and found that the track lifespan could be improved. Findings were sent to scientists, and the trials continued, since the tracks were still in usable condition. If the tank was simply expected to drive a short into battle and die, there would be no point in putting in any of this work.

When trials of three production T-34 tanks were held at the end of 1940, the engines had finally met their warranty period requirement, but this was no longer enough for the army. A new 250 hour warranty period was now required. Increasing the tank's reliability to new heights was one of the dominant themes of the entire report.

Work continued throughout 1940. Towards the end of the year, the Committee of Defense gave their requirements for reliability in the new generation of tanks: 7000 km of driving or 600 engine-hours in between major repairs. Considering that this kind of reliability was not reached until long after the war, the technical know-how of the committee members may have been lacking, but it was quite clear that the government wanted a reliable tank, not a disposable one.

Unfortunately, as the tanks were prioritized for the army, it was harder and harder to get one's hands on a tank that could be driven to death so that a post-mortem may reveal why it broke down. A plea from factory #75 director Kochetkov shortly before the outbreak of hostilities is rather illuminating about two things: the factory's desire to increase reliability and the expected lifespan for the V-2 engine (150-200 hours) by the summer of 1941.

With the start of the war, the situation naturally worsened. As production was affected by the departure of skilled workers and evacuation of factories, the lifespan of components, specifically the engine, decreased to 100 hours. 100 hours is not that bad of a warranty period, especially considering that's how much Americans were getting out of their R-975 engines in training conditions, but what is made even more clear from the document is that the tanks are clearly lasting longer than their engines. 

As the war went on, the amount of service expected out of every vehicle was not reduced, but increased. For instance, a new gearbox developed in 1942 was put through 3700 km trials, tires made in 1943 were put through 2000+ km trials. When reliability issues cropped up, such as with experimental tracks, these issues were quickly addressed. By 1945 the requirement for the lifespan of track links, an expendable and rather easily replaceable component of the tank, was increased to 1500 km. Similarly, the warranty period of the engine was increased to 250 hours. Recall that this is the warranty period, not the maximum or even average lifespan. The average lifespan by this point in the war was 250-300 engine hours with individual tanks lasting for even longer. Starshina Kharitonov's tank, for instance, surpassed his warranty period by at least 400 km. Senior Sergeant Russkih's tank fought for over 305 hours. Guards Senior Lieutenant Skvortsov's tank gave out at 308 hours. Guards Starshina Perederiy drove one tank for an impressive 370 hours and then 310 hours with no breakdowns in a different tank. These are just a handful of stories.

Being able to drive for thousands of kilometers and hundreds of hours is certainly not the sign of an expendable tank. The government's demand for reliable tanks, the industry's ability to provide them, and the army's ability to put them to good use is evident in contemporary documents.

18 comments:

  1. It's still not a myth, T-34 were being destroyed in incredible numbers.
    You bring 200 motohours for an engine and give test of 4200 km as an example of reliability.
    Checking - average speed of 31.7 kph gives 132,5 motohours to reach that distance - 65% of the expected engine life span.
    With a prototype that takes extra care from factory crew (otherwise there may be gulag for sabotage, for example).

    Also there are no data, how many breakdowns happened during these trials.

    417 km of track trials, assuming 20 kph give 21 hours - a fraction of engine lifespan.
    Dymitryi Loza memories show even bigger numbers for Sherman' tracks: https://iremember.ru/en/memoirs/tankers/dmitriy-loza/ with the exception of overheating rubber covered tracks.

    ReplyDelete
    Replies
    1. Compare, if you will, the Panther which usually ate its final drive after circa 100 km on-road - as a direct result of the design cutting corners for the sake of faster manufacturing no less - yet to my knowledge never earns the "expendable" label for that...

      Delete
    2. You seem to be thoroughly confused about what this data means. 31.7 kph was the average speed during movement on a highway. Trials include far more than just driving on a highway in a straight line. Off-road driving or even idling adds to engine runtime without contributing to the distance as much.

      417 km is also not the entire span of the trials. Hadfield steel tracks had a total lifespan of 1000 km. Yes, this is less than the lifespan of the rest of the tank, but the tracks are a readily replaceable component.

      The "extra care from factory crew" excuse falls flat as well, since the trials performed in late 1940 were done with randomly selected production tanks.

      Delete
    3. What's meant by "incredible numbers", say, compared to other tanks?

      Krivosheev's Soviet aggregate loss data, for instance, does not differentiate between tanks lost to combat and tanks that were scrapped because they wore out or were deemed obsolete.

      I say this because of the frequent fallacy of using Krivosheev's Soviet loss estimates against other (read German) estimates that have been *demonstrated not to have included even all combat losses*, let alone losses due to wear and tear and obsolescence, and then saying this comparison "proves" the Germans were killing Soviet tanks at a 4:1 ratio or more.

      I have no problem with using Krivosheev's Soviet figures, just use his *German* figures as well of 42,700 which I think is more an apples-to-apples comparison. Zaloga is an offender here and he should know better!

      Delete
  2. To be fair in WW 2 the media in all countries was controlled by the governments. As such after the war, myths are bound to fill in the gaps. One aspect of the T-34 that might merit investigation is it's Christie suspension. Did one access the pull the tracks and the outer lawyer of hull armor just to the T-34s large suspension columns. Or could they change them from the inside? Don't get me wrong, the myth of any tanks being reliable back in those days defied the basic fact that smart armies moved their tanks on trains to the front.

    ReplyDelete
    Replies
    1. Plans to replace Christie suspension started before the war. But it was deemed unnecessary. What happens if suspension on your car brakes down? Its bouncy but the car is still drivable. Essentially same kind of suspension is Christie suspension. If one or more wheels have suspension issues tank is not immobilized. It's not so critical to replace. I have seen tanks completely missing one wheel and still functional. On the other hand bogey suspension as on American tanks are easier to replace but much more prone to detrack. Especially M3 stuart was famous for that since it only needed small rock to get in to detrack it. In case of torsion bars they are most beneficial, both in terms of easy maintenance and space saving. But in case of failure Christie holds advantage. Since both shock and spring have to fail and even if they fail they will still hold the wheel down to a greater degree then torsion. If torsion bar brakes, wheel arm has no resistance that is one of the reasons why torsion bar suspension has wheel arm blockers to limit vertical travel.

      Delete
    2. Everything is relative, and once away from the railheads and in action it became rather important indeed how far the tank can go on its own tracks before something gives (and how easy it is to fix). All the more so for the medium/cavalry/cruiser class whose job description covers the breakthrough exploitation role where even wheeled transporters were often impractical.

      Delete
    3. Thanks for not mocking some of my jumbled wording. I woke up last night low on blood sugar.

      Delete
    4. Well, typos and whatnots happen to the best of us. That did remind me I don't actually know how exactly the Christie suspension system in general *was* accessed for repairs, maintenance etc. though. I'd assume the parts along the fighting compartement walls were easily enough reached from the inside but I'm curious about the ones by the rather less readily accessible engine compartement; layman's blind guess would be the roof was opened or removed to get at those, as when working on the engine etc.?

      Delete
  3. I'm so glad you wrote this article, few days ago I had a discussion with a person who claim exactly this. Tanks were bad because they didnt need to be any better because crew will die anyway. And when I asked him why he thinks this way he said experts from the field say so. When I've asked who the experts are. He said curatour from Bovington tank museum. And no matter how much evidence I gave him he dismissed it because some bloke said it's so.

    ReplyDelete
  4. I'm not arguing with the corectness of your article. But what about the "myth" of T-34 crews taking along a spare transmission in the early productins version ?

    A related question: how much did the Soviet army rely on rail transport for strategic movement of tanks ?

    ReplyDelete
    Replies
    1. Taking a transmission along is not a proof that the tank is made for short amount of use. Taking a transmission is a smart way of preparing for possible breakdown, even if failure of transmission is enevetable, that act is yet another proof of prolonging tank operation. This article is made to prove that people behind the machine did everything possible to make a lasting tank. And as early as December of 1942 we have definitive prof of improvements and operational success of t-34s. Making a deep penetration behind enemy lines, 24th tank core pushed 240km and took tatskaya airfield. In doing so they sealed the fate for German 6th army in Stalingrad. If t-34 was so unreliable as people claim this would be an impossible task. Yet reality is much different.

      Delete
    2. I do not doubt that the tank was made to last. I was just curious about the transmissions carried along

      Delete
    3. Everyone's tanks also routinely carried extra track links and presumably also whatever other spare parts they could cram in. That was simply a sensible precaution in light of the limitations of period automotive technology and the inevitable damage from combat, harsh terrain etc.

      Various elements of the transmission were subject to particularly hard wear and tear, simply given what they do (ie. transmit considerable mechanical forces to move tens of tons of steel around at some speed), so it's not surprising those would have been among the first picks for spares to take along. Outta curiosity, what *part* of the transmission? I'm tentatively assuming the gearbox which was fairly compact and easily accessible - the actual final drive gearings etc. would seem a bit too massive and requiring heavy equipement to swap out for this kind of thing.

      Delete
    4. As far as I can tell, the "carried transmissions on their back" claim is made based on a single photograph. Reports do not mention that this was done regularly.

      The transmission was indeed a weak link in the drive train, namely the clutch was. Work to prevent clutch slipping due to deformation of the friction disks started in 1940. It appears that it was eventually successful, there is a report of an experimental clutch tested in an A-34 over a distance of 3000 km in heavy conditions that appears satisfactory. I don't know when it was implemented in production, but presumably this was eventually done. The American report on a T-34-85 captured in Korea states that there was no indication of clutch slipping.

      Delete
  5. About that 'carrying spare transmissions' comment. I believe that was only seen once and was a T-34 caught between the railway station and the depot while bringing a replacement for another vehicle. Why waste a road test?

    The huge losses in 1941-2 are, as often as not, due to units being ordered to stand and fight rather than conduct a tactical retreat. Add in the numbers bogged by inexperienced drivers and such and the numbers climb quickly. Although some Russian designs were crippled by the inadequate technical base (KV gearbox?) the T-34 was a very good tank indeed.

    As final support for Peter's position look at what they did against the Chinese. Russian border to central Korea in about a week(?). Doesn't sound like a disposable tank to me.

    ReplyDelete
    Replies
    1. I'd say a lot of the 1941-42 losses (though you touch on this) were due to mechanical failures, plus the lack of spare parts. Even with well-designed and reasonably reliable hardware, if you don't have spare parts, you'll suffer losses, and on a retreat, these become permanent losses.

      Delete
  6. Whoops should read in China/Korea against the Japanese.

    ReplyDelete