2009/07/27

Lessons from German military vehicle history

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I looked a lot into the history of historical German military vehicles and found that it's full of lessons.

The primary lesson of WWI were probably that internal combustion engines can indeed replace horse power for operational supply purposes. Horse-drawn carts were limited in their radius of action because horse fodder had to be transported as well - and was both quite voluminous and heavy in comparison to the performance. It was impossible to supply corps adequately far away from the closest railway station. This was a huge logistical problem of the Schlieffen plan.
Trucks also raised the transport capacity of roads (ton-kilometers/day), that proved invaluable for the French at Verdun. Finally, motorized tractors enabled road mobility (not just rail mobility) for heavy guns.

There was another lesson as well; the importance of raw material supply. Natural rubber supply was quickly cut off by the British naval blockade and trucks had to switch to spring-cushioned metal wheels halfway in the war.


The 20's were a period of much basic development (like 8x8 systems), but also of strange ideas.
One such strange idea was that off-road vehicles had to be very agile in terms of turning radius. All axles were steerable in some models, and the turning radius was reduced by several metres. The utility of this extra complexity, cost and weight was near zero.
Another idea was that relatively simple, jeep-like cars would need three axles (apparently to reduce nominal ground pressure).
Both requirements led to the idea that off-road vehicles would be complex, large and heavy.

The 30's were a time of greater realism, but most military vehicles were still way heavier than normal. The Czechs produced some complex, no-compromise off-road trucks (Tatra) - that failed spectacularly to match the off-road utility of even commercial models in WW2.

The German officials attempted to develop some "standard" ("Einheits-") models of cars and trucks and anticipated that at least field units would need dedicated military designs. The only successful result of their program was a 2.5 ton truck (6x6) "Einheits-Diesel". Its ability to drive on muddy Russian roads was excellent, but its production got cancelled in mid-war because its payload was considered to be inadequate (apparently "inadequate" only in relation to its costs).


Wartime soft vehicle production was falling very short of the forces' needs, barely matching the peacetime recapitalization needs. Much of the automotive sector was producing non-automotive equipment during the war.
Ten thousands of foreign trucks had to be captured and produced in foreign countries (especially France) - almost exclusively commercial designs.

The problem of a good jeep-like vehicle got eventually solved by accident: The original VW Beetle was modified with more ground clearance and a new shape and was introduced as a very light and cheap 4x2 vehicle, the famous "Kübelwagen" (which was in fact a more general term). Its soft surface performance was astonishing even without 4x4 (few 4x4 and a couple thousand amphibious 4x4 versions were produced as well).


It introduced the off-road concept that became later known as "buggy". It was able to negotiate soft soil by moderate ground pressure (low weight) instead of complex 4x4 drive for maximum traction.

The best light trucks were also available by accident; the 3 ton Opel "Blitz" was a commercial 4x2 vehicle, but proved to be superior to most other light trucks on the poor "roads" of Eastern Europe.


The heavy trucks were apparently all satisfactory, but not very important.

Finally motorcycles; the German army failed to appraise their limited durability in pre-war tests and extended the use of motorcycle into troop transport. The reason was apparently that the motorcycle was the natural successor of the horse. A single motorcycle was less efficient than a motorcycle with sidecar - and that was their choice. Sadly, a good motorcycle is still less efficient in troop transport than a car and a car is less efficient than a light truck.
They somehow failed to do proper operational research on this.

The choice of the motorcycle models was problematic as well. Military motorcycle competitions on difficult tracks were held until 1939, but relatively light (as 350ccm) motorcycles dominated these competitions. The reason was that the competitions were short and placed an emphasis on handling characteristics - the strength of light models.

The later actual war (WW2) placed a much greater emphasis on durability during many weeks of uninterrupted campaigning on unpaved roads without thorough maintenance and repair.


Almost all motorcycles lighter than 500ccm (cylinder volume) were failures.
Some heavy (500-750ccm) motorcycles proved to be great, but were more expensive than a car with four seats.

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We could draw the lesson that dedicated military vehicles are probably not that good as they seem to be. Another possible conclusion is that requirements-driven development may be inferior to the diversity of the commercial vehicle portfolio.

It seems to be much more complex than that, though.

The Wehrmacht's experiences during WW2 were compressed in a period of just a few years The problem of muddy, unpaved roads and very difficult circumstances for maintenance were dominant factors. Their relevance is in question.

The Bundeswehr chose light motorcycles during the Cold War. It didn't expect to fight in Eastern Europe, and the light models were affordable and good enough on paved roads.

The great success of air-cooled vehicles as the Kübelwagen Typ 82 was in part based on extreme climates (Sahara, Russian winter) that played no role for the Bundeswehr till the 90's.


Several NATO armies bought more commercial off-the-shelf (COTS) trucks during the 70's and 80's for their low price (and to help the national automotive sector in times of crisis). These vehicles usually showed a central problem: Civilian cars and trucks are designed for high mileage in a period of 10-20 years. Modern military vehicles get a relatively modest mileage over a period of 20-40 years unless they're used in a major war.
This means that the higher initial cost of dedicated designs is in great part justified by their long life. Corrosion and other material failures (seals, rubber components, rust) are very different durability problems than the wear by movement. Firefighting trucks have the same challenge.

The idea of designs based on requirements, standardization and even vehicle families proved to be feasible with less politicized bureaucracies as well.



We could still expect the same for a major war as the 1930's planners: The most suitable military vehicles would likely need to be limited to field units, with commandeered vehicles being used in "rear" areas, in less demanding (on-road) tasks. Even the huge modern automotive sector would need several months to converse its production to military designs - and would probably need to make changes to those designs.

A certainly valid lesson is that vehicles need to be tested thoroughly, in all seasons and on different soils. Short competitions are inadequate compromises that weed out the greatest duds at best - long troop testing is simply necessary to unveil weaknesses.

Another (obvious) wisdom and conclusion is that simplicity is a strength in itself. We should remember this well. Today's automotive designers have a greater choice of gadgets and technical solutions than ever before - and they're enticing.


We should also check rationally whether our idea of off-road capability is a good one. The German planners of the 20's had a huge emphasis on the turning radius for no good reason. Modern Bundeswehr trucks can do impressive stunts with movable axles on uneven terrain.


Maybe we should place a stronger emphasis on soft soil performance (mean maximum pressure) and simplicity again?


There's one more thing that we should remember as lesson: The extreme importance of the ability to improvise, mobile repair shops and the standardization of spare parts.

S O
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2 comments:

  1. This post has been linked for the HOT5 Daily 7/29/2009, at The Unreligious Right

    ReplyDelete
  2. Urgs. You quoted a typo.
    I fixed that.

    ReplyDelete