2022/01/08

Low silhouette vehicles

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The most iconic German post-WW2 wheeled military vehicle is the "Unimog", a 2-ton (2.200 kg) extremely offroad-capable 4x4 vehicle. You can see the basic version here and see other versions listed under "LKW 2t tmil gl" here.

As far as I can tell the vehicle is extremely popular, but I never liked it, and the dislike was almost instant: The vehicle just seemed to be way too big (especially way too high) for its very modest payload. The wheels alone are huge, and the high performance suspension with huge ground clearance all-but guaranteed that the vehicle stands very tall.

The rough French equivalent ACMAT VLRA has also big wheels, but some versions feature a collapsible  cabin/folding windscreen for a much lower profile (which earlier Unimog generations also had).

ACMAT VLRA, 4x4 version for approx. 1.5 tons

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I found long ago (and recently rediscovered) a book; "U.S. military wheeled vehicles" by Fred W. Crismon, 1983. It features an entire chapter on a program for low profile wheeled motor vehicles.

It turned out that the U.S. Army discovered around 1940 that the then-modern motor vehicles were difficult to conceal on a battlefield, and tried to get less tall vehicles. Folding windscreens were a must-have, but the seating of the driver was also often exotic. Some prototype vehicles were modifications of existing vehicles, and the whole program basically went nowhere because the Department of War/U.S.Army had already settled on wheeled motor vehicle standard types in 1941/1942, and this low profile vehicle program only began in 1942.

The logistics vehicles in this program were able to be configured for a very low silhouette, but most payload onboard would have prevented this.

The French tried and succeeded at developing some 8-wheeled (not 8x8) armoured vehicles with remarkably low silhouette going back to a late 1930's development and the Dutch improvised a remarkably compact 8x6 (not a typo) APC in the 1950's.

It appears that keeping the silhouette low was considered desirable, but hardly ever won out when design compromises needed to be made.

I'm not really in a position to complain; my favoured wheeled army vehicle is a 8x8 15 ton to 20 ton vehicle because this is the most efficient choice regarding driver personnel and convoy size / passthrough duration*.

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We should nevertheless pay attention to the topic of concealability of motor vehicles. It makes sense to me to think about two very different types of units (or convoys):

There are on the one hand the vehicles that can normally be associated with an army combat brigade. This is where the convoy efficiency argument strikes in favour of fewer bigger payload vehicles.

And then there are scouting / observation / reconnaissance style vehicles. Not all of the latter need to be armoured. Four or five men teams for observation (Fernspäher/LRRP/LRS) could infiltrate and exfiltrate together with armoured recce (small) units, and 'peel off' when close to their mission area. Then they'd need to hide their vehicle and move by foot for some distance. Later on, they'd have to recover their vehicle (maybe first check some unattended sensors to see if somebody had discovered them), and join an exfiltrating armoured recce convoy. This could very well be done with a compact 4x4 car that fits into the garage of an abandoned civilian home, even with a civilian-looking 4x4 car (for hiding in plain sight). Alternatively, a very compact and very low silhouette design could be hidden among or even be disguised as something else without anyone suspecting a car.


related:

/2013/11/non-comat-vehicles-musings.html

/2012/12/parasitic-land-vehicles-for-army.html

S O

defence_and_freedom@gmx.de

*: This is definitely not the correct term, but I don't know the correct one. Motor vehicles move so quickly that in addition to the convoy length in metres it's also interesting to think about the time it takes the convoy to pass a point.

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9 comments:

  1. A vehicle with off-road capability and able to hide among civilian cars would be a SUV. These are widespread all over the country. Which one of these would you consider best suited for the task?

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  2. Whatever fits the region and team size. A team size of five with backpacks would be an issue with many vehicles.

    Some "SUV"s are 4x2 or huge, so I avoided that acronym.

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  3. SO:

    What do you think about the GRF 5.12 PLATFORM

    https://www.defenture.com/grf-5-12-platform-2/

    Would this be a plattform for your low silhouette approach?

    About the use of civilian vehicles for military use: despite that you can easily confiscate such vehicles in the case of war, most of them (especially most SUVs) are not very good for military use. So buying such vehicles in peace makes no sense at all.

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    Replies
    1. The cab seems to be fixed.

      Variable height suspension, folding windscreen, folding rollover bar and flexible weather protection and civilian-ish tire profiles (no treacherous tracks on soft soil or on road after entering it with dirty tires) is rather what I'm thinking of.

      The HMMWV-ish vehicles are a mistake IMO. Convoy-inefficient and driver-inefficient compared to 15 ton 8x8, but also too big for stealth and with those vertical windscrens too easily identified.

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    2. I agree with you about the cab and Humvee like vehicles, but as far as i know it this plattform could also be used with a different kind of construction on it. So all the things you mentioned here could be realised with this plattform. This would also give an additional advantage: as the basic plattform is for moving around a much heavier cab this would free enormous power and load capacity.

      That would be my idea behind that: to have an vehicle with the tire profile like an civilan vehicle and with all the qualities you mentioned like folding windscreen, folding rollover bar etc but on a much more powerful basic plattform with military specification instead of an civilan plattform for more total output.

      I studied for example many examples of the typical Toyota "hordes" and other such examples of the use of civilian vehicles for military use and nearly always was the performance of the vehicle unsufficient.

      So an lighter "upper" on a more powerful base / plattform is imo the solution here.

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    3. OK, here a takedown based on the image at the link you gave:

      All wheel steering long-understood to be nonsense:
      https://defense-and-freedom.blogspot.com/2009/07/lessons-from-german-military-vehicle.html

      Multifuel engines are suboptimal. The military only really uses diesel anyway, so drop the hassle of multifuel capability and use an ordinary diesel engine instead, preferably a civilian mass production model with an additional backup mode (if turbo and/or original electronics are busted).

      4x4 can very easily be had (and without such a huge volume spent for mechanical transfer of power) if you electrify one axle (preferably front axle for regenerative braking). Optimum for 4x4 is IMO diesel engine in the back with mechanically driven rear axle and front axle optionally driven by electric engine (front is best for regenerative braking).

      That huge volume for the driveshaft on the picture reminds me of why the Sherman tank got so awfully high. The whole chassis looks more like a mediumt ruck chassis than a car chassis

      The entire design looks like a mashup of bad 1930's ideas, bad 1960's ideas and bad 1980's ideas.

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    4. OK, I will be fair and say one good thin about the design because it's deserved: Designing for very low temperatures is what I advocate for. Diesel engines have issues at very low temperatures. They might not start, or take long procedures to start, or be started with methods that risk damage to the engine.
      Too much Western military hardware was designed for the Central European climate (and sometimes slightly modified for Arab export customers).
      https://defense-and-freedom.blogspot.com/2013/10/east-european-military-technology.html

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    5. If a diesel engine is too cold, the driver also suffers from the cold and both would likely profit from a built in heating unit. The downside would be that the vehicle is more visible in IR.
      But how important are operations at Arctic temperatures for the defence of a Central European country? Doesn't this communicate a willingness to be able to invade Russia again?

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    6. The coldest temperatures on record in the Baltics are cooler than -30°C. It's rare, but it can happen.
      To prepare for -20°C only is too optimistic for NATO Eastern security.

      Moreover, I am concerned about the snow cover. 60...100 days of snow per year in Lithuania creates huge challenges because tracks in the snow give away your position easily.
      https://helda.helsinki.fi/bitstream/handle/10138/228620/ber19-5-337.pdf?sequence=1&isAllowed=y

      The thickness of the snow cover may also be an issue for dismounted movement and wheeled vehicles on some days.

      Furthermore, water obstacles freeze and lose much of their obstacle nature and few of the Baltic ports don't suffer from ice issues.

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