German tanks adopt rear drive pre-WW2

Discussion in 'Alternate History Discussion: After 1900' started by wiking, May 18, 2017.

  1. wiking The One and Only

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    https://en.wikipedia.org/wiki/Tiger_I#Engine_and_drive
    http://forum.worldoftanks.com/index.php?/topic/30445-forward-vs-rear-wheel-drive/
    [​IMG]

    One of the major flaws of German tank designs in WW2 was that ALL production models used a front drive system, which everyone abandoned either before or during WW2. The US made the last use of it in the M4 Sherman, while the Brits and Soviets did not use it at all during the war. While there were some advantages like the system helping clean the track and it providing the best possible motive power due to pulling rather than pushing the tank, it had a massive flaw, illustrated above, that it required a lot of extra weight due to the drive train running under the crew compartment to the front due to the engine and final drive being on opposite ends of the tank. Compared above is the T-44, which had the final drive in a discrete combined unit at the rear of the tank, which enabled it to be substantially shorter, require less materials and automative complexity, and lighter due to having less moving parts and no need for a drive train compartment underneath the crew. The Panther in contrast was probably 10 tons heavier unnecessarily due to being substantially taller to make room for the drive train. The competitor to the OTL Panther, the VK3002DB, copied the T-34 in having a rear drive, which meant it stuck to the 35 ton weight limit placed on it, while the MAN design that became the Panther was then 10 tons heavier, much more technologically complex, and less reliable.

    Here is a comparison in layout:
    [​IMG]


    So what if the Germans recognized in the early 1930s that the rear drive just made more sense, leaving their tanks much less heavier, shorter, cheaper, less complex, and potentially with greater room for weight increases? The results for the Panzer III and IV would probably look somewhat similar to the British style tank layout before the adoption of sloped armor:
    [​IMG]

    Later designs with sloped armor would probably resemble the VK3002DB than the OTL Panther and weigh no more than 35 tons thanks to being a smaller tank overall, but with similar armor protection and gun.

    What sort of difference would making smaller, cheaper, less complex, more reliable, potentially more upgradable, but less capable of climbing tanks have made to German AFV production and combat potential?
     
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  2. Nik Speaker To Cats

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    Oh, but rear-engine, front wheel drive tanks were *superior* mechanically. Could the Germans even consider anything else ??

    I'm reminded of those old Mercs with the rear independent suspension. Nice cars, *very* nice cars, but if you piled just too much into the huge boot/trunk, the suspension could not cope, the half-axles became 'knock kneed' and the inner tyre-rims wore very, very quickly.
     
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  3. Coiler Well-Known Member

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    Unless this leads to bizarre mega-butterflies due to someone getting run over or blown up by one of them, about as much difference as Blondi being a dachshund instead of a German Shepherd.
     
  4. Catspoke Member

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    I am thinking its all about the MARK III and to a lesser extent the IV, in terms of 40-42 when winning is at least remotely possible.

    Smaller and Lighter means less fuel used (the Germans always seem logistically constrained) which means more a few tanks at German spearheads going further, even more if greater reliability is achieved. Can you change something at Dunkirk, close a Smolensk pocket, take the highest ground above Leningrad, push a little closer to Moscow??????

    The Stug III even smaller with the same armament would be a nasty little thing.
     
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  5. Peabody-Martini Well-Known Member

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    The Hetzer?
     
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  6. wiking The One and Only

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    Jan 19, 2006
    Pretty much, but more like the E-10 or E-25, both designs with rear drives.
    [​IMG]
    [​IMG]

    Pretty much agree with your statements, in terms of your questions I'm not sure if these would make any difference necessary to those operations in terms of fuel economy or reliability enough to matter. But studies during the war and post-war by the Soviets indicated that the greatest risk of being hit came from the height of the AFV and they found they had a very hard time spotting a Hetzer or even StuG when on the defensive because of their relatively lower height. Both the E-10 and E-25 were substantially shorter than their earlier war equivalents, so would have been even harder to hit.
    I'm actually partial to a 88mm equipped StuG that resembles the post-war Kanonenjadgpanzer, which also had rear drive:
    [​IMG]

    That is the trick, especially for second generation tank designs, as the Germans were producing in the 1930s, but not unimaginable.

    The problem the Germans had was putting too much weight on the front with the front drive and overloaded that side of things. They found putting the rear drive on actually helped balance out the armor and gun on the front.
     
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  7. James Ricker Own your mistakes

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    Hetzer gonna Hey,big time
     
  8. James Ricker Own your mistakes

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    Cheaper, lighter and easier to build means more panzers.Germany's tank shortage might be delayed a few months.Heaver Russian armored vehicle losses,slower Russian advance,longer war.
    The longer the war lasts the more screwed Germany is at the end.
     
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  9. NoMommsen Donor

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    First : I would like to point out that the VK 300.01 of Daimler-Benz was also about 5 t "overweight" to the goal of 35 t.
    Also I would say, that there might have been several other issues as well, contributing to the different weight of the two prototyps (lenght of tracks, mechanic/design of the turret, etc). I would render a weight difference only for the drive train from back-to-front of 1o t rather excessiv. It would be more in the region of 2-3 t.

    However, what were the reasons for the germans to prefer front drive ?
    Besdie track cleaning and better motive power you already mentioned : experience.
    In the late 20s, early 30s they did a lot of testing in the SU, mainly with the "Leichttraktor", that continued with several modifications to the drive train, tracks and drive positioning. even after Hitler took over and the Kazan site was abandoned. In these tests it was "testified", that rear drive tracks throw (much) more often than front drive tracks. Hence the demand on following designs for front drive.

    A "demand" taht stayed in force, even after the more obviuos reasons for throwing (too small/narrow tracks for a given weight to be moved) ceased.
    And you might know, how difficult it is, esp. for militaries, to change a once set regulation, even if its necessity has ceased or even if its reasons have been proved to be without further effect.

    About the "unreliability" of the early (and to some extent also the later) Panther : it was not the drive train but the gear-box itself.
    Former "experience" kick in here also. In the early Panzers having the gear box easily available for the crew from inside to "work" or intervene in case of malfunction was an "asset" often used and therefore rendered as such. Ofc, a gear box of 1941 was a completly different beast from what was used in PzKw. I and II, but again: old habits don't die easily.


    However, IMO the switch from front to rear drive in german tanks in 1941 wouldn't have made much of a difference on the performance of the german tank forces as well as for the number of available tanks. The perhaps "spared" material might have been used up in producing or "exchange" gear boxes for easier replacement, for building a couple of more subs or ... some more of Hitler architectural wet dreams.

    Nevertheless it could have been one piece of mosaic with a number of others to enhance german performance ... feelable.
     
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  10. Riain Well-Known Member

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    IIUC there are a bunch of valid reasons for front drive, for example the length and width of a tank must be within certain ratios of one another. So a tank of a certain width, perhaps dictated by railway loading gague, can be only be within a certain minimum and maximum length. These lengths then drive the placement of the turret ring; British tanks with flush deck turret rings were limited to what size could fit between the tracks whereas the Sherman had a high hull so the turret ring wasn't limited by the width of the tracks.

    Does anyone know the key design limits of the panther : length, width and turret ring? One or a combination of these may have been the driver of the front drive design.
     
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  11. tomo pauk Well-Known Member

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    You've mentioned most, if not all of the benefits. The climbing ability has next to nothing to do with tank having the rear- or front-drive (yes, I've watched the Swedish video).
    Basically - a 'Panther-esque' tank that weights 35-40 instead of 45-47 tons immediately brings better reliability of final drive, engine, consumes less fuel, can be produced in more examples, better accelration and speed (= harder target to hit)...
    In similar vein - Tiger-esque tank, 45 tons, with similar benefits. Plus there is easier thing to tow a damaged tank, more bridges tank can use etc.

    Granted, the thread is about pre-ww2 mostly, so perhaps a Pz-III or -IV with proper armor from day one?
     
  12. wiking The One and Only

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    Jan 19, 2006
    35 tons is heavier than the stated weight of 30 tons (VK30.01 is a reference to the weight of the spec for those that don't know), which is 10 tons less than the 45 tons of the VK30.01MAN design.
    Otherwise I don't understand what you're saying, are you saying that the final weight of the production model Daimler design would have been only 2-3 tons lighter? The biggest part of the weight savings is having a lower tank height, whereas the length isn't nearly as much of an issue.
    Compare the Tiger I and IS-II, the former was taller, substantially shorter in length, and wider, while the IS was close to 2 meters longer, less wide, had thicker armor, with a bigger gun, but was 10 tons lighter:
    https://en.wikipedia.org/wiki/IS_tank_family
    https://en.wikipedia.org/wiki/Tiger_I
    .
    So the majority of reasons no longer mattered by the mid-1930s?


    The gear box was a problem in the Panther because it was designed for a 35 ton tank, not a 45 ton one. Keep the weight down and you have a less problematic gear box. So again, the design issues came from early experience. Why did the Soviets draw different conclusions from the Kazan experience despite working with the Germans there in the 1920s?

    If the spared metal, which was allocated to the army as a block grant, they decided how it was spent, went to extra spare parts, then they are actually quite a bit ahead of where they were IOTL, as one of the core problems of the tank force was the lack of spare parts and resulting inability to keep what they had in service operating in the field.

    What do you mean by Feelable?

    It applies to all wartime designs, so a 45 ton Tiger would be a subject of discussion too. Maybe it looks more like the Porsche design?
    [​IMG]

    What if 'proper armor' to you for the Pz III and IV? Certainly both would be lighter if they kept their same armor and armament, so faster and likely less fuel consuming.
    Ironically the Pz IV could end of looking like the Cromwell in 1941:
    https://en.wikipedia.org/wiki/Cromwell_tank

    And the Pz III like the Crusader:
    https://en.wikipedia.org/wiki/Crusader_tank
    Probably topping out around 20 tons.

    Perhaps with a turret ring upgrade it could have been able to mount the 75mm gun...
     
    Last edited: May 19, 2017
  13. tomo pauk Well-Known Member

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    Yes, looking a bit like that (but with 'all rear' powerpack).

    'Proper armor' - basically 20 ton tanks that can withstand 37,40, and 'short' 45 mm ATGs of 1939-41, and when up-armored (to 22-23 tons) resisting the 'long' 45mm and 6prd firing non-APDS ammo, also less susceptible to Soviet 76mm or US 75mm.
     
  14. wiking The One and Only

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    Was that possible for a 23 ton tank?
     
  15. tomo pauk Well-Known Member

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    See Valentine at 16 tons, and T-70/T-70M at 9.2/9.8 tons.
     
  16. Coiler Well-Known Member

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    So:

    -Is this rear-drive tank going to fix the monstrous structural problems of the German industry?
    -Is this rear-drive tank not going to outrace the production of spares, thus meaning any increase in production leads to more tanks sitting around until they're overrun?
    -Is this rear-drive tank going to boost German logistics to the point where more of them can actually be fielded?
    -Is this rear-drive tank going to make the Germans not chronically underestimate and misinterpret the Allies the way they did OTL?
    -Is this rear-drive tank going to change German war plans for the better?
    -Is this rear-drive tank not going to spur Allied countermeasures in design and tactics?
    -Is this rear-drive tank not going to have any other flaws or quirks, related to its drive or not, that the OTL tanks didn't have?
     
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  17. tomo pauk Well-Known Member

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    Amazing.
    A member posts a reasonably simple and straightforward topic, and all of the sudden the topic should answer both related and unrelated problems and issues.
     
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  18. wiking The One and Only

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    Jan 19, 2006
    What does any of that have to do with the scope of the question?

    Honestly, like what? They all adopted reardrive themselves either pre-war or during it. Perhaps the Allies counter by adopting front drive in spite! See that answers all your questions, the Allies counter by making more complicated tanks and ruining their own war effort :p

    Not AFAIK. Look that the T-34 and all rear drive tanks of WW2 and post-war, did they have any rear drive problems?
     
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  19. marathag Well-Known Member

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    Feb 2, 2013
    By reducing the interior space and dropping the hull gunner, there was less to armor.

    But by doing that, made a cramped tank, that hurt crew efficiency.

    It's all about trade offs. Soviets kept with that, so if you were over 5'4", you had trouble.
     
  20. marathag Well-Known Member

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    Even at 35 tons, it would still have had trouble, with the straight cut gears, vs the double-helical gear like on the US Tanks