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December 13th, 2012, 03:13 PM
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#1 | | Archivist
Joined: Jun 2012 Posts: 152 | half-tracks used to be very popular
why did we change that?
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December 13th, 2012, 03:30 PM
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#2 | | Historian
Joined: Jan 2011 From: South of the barcodes Posts: 3,249 |
They weren't very good.
Half tracks are a way of improving the mobility of civilian trucks in the case of the Maultier series, the various Kegresse and the American M3. The up side is that the track spreads ground pressure and improves cross country mobility, the downside is that the track is more complex than wheels and more prone to maintenance problems.
The second problem is steering. In a tank you can brake one of the tracks and the vehicle will pivot around the stopped track. If you do that in a half trackthe front wheels will rip off, steering comes from the front wheels as in a normal vehicle.
Now here is where things get complicated. The steering action in a truck is only having to act against the few square inches of ground pressure and friction of the rear tyres, on a halftrack its fighting to turn several feet of track in contact with the ground.
The Americans got round it by reducing the length of the track to 30% of the body, reducing the effectiveness of the track and especially its traction. Its a simple system helped by one piece rubber band tracks so maintenance is lowered.
The German method was to make the tracks 60% of the bodies length giving phenomenal traction and cross country ability and great performance as artillery tractors but the front wheels become largely ineffective, the only way to turn them is by linking the front wheel steering to partial braking of the tracks which is a brilliant engineering answer to a problem but easily broken and no fun to fix when your in the middle of a Russian forest and all you've got is a hammer.
That over engineered system means they can pull a house but they steer like an ocean liner while the US version steers easily but tends to get bogged down in heavy mud. win some lose some.
The German extra length individually linked track is also a swine to maintain and unlike the commercial origin of the US equipment spares are going to be difficult in mass production.
Simply put the half-track was an attempt to marry the cheapness and utility of a truck to the performance of a tanks and in all honesty it didnt do either. Most militaries reckoned the effort wasnt worth it, they'd buy trcks to do the rear line work cheaper and with loss hassle than a half-track and they'd buy a dedicated full track APC for the dangerous front line work which was more expensive but had better performance and could carry more armour and weapons.
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December 13th, 2012, 03:50 PM
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#3 | | Pain in the butt
Joined: Dec 2011 From: Bury St Edmunds, Suffolk. Posts: 3,588 |
Ashide from what Nemowork said, which is pretty spot on, they were only popular for a short period, namely WW2. This was the early days of armoured warfare and especially Armoured Infantry. I guess adapting trucks to serve the role was easier than trying to develope fully tracked APC's for the role. And the lessons learnt from that war is what lead to the post war fully tracked APC's.
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December 13th, 2012, 06:39 PM
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#4 | | Historian
Joined: Jan 2011 From: South of the barcodes Posts: 3,249 |
They had some useful service pre-war, the French were early leaders in the field using adapted cars and trucks (Citroen Kegresse) as half-tracks for desert exploration in the early 20's, i guess thats where the development came from since the track wont sink into sand the way a tyre will and gives greater traction over greater area.
The Russians got there even earlier using them for civilian cars and military vehicles from WW1 and earlier like the Austin-Kegresse. https://www.google.co.uk/search?q=ke...w=1375&bih=879
Kegresse is Adolphe Kégresse - Wikipedia, the free encyclopedia
As another piece of trivia Kegresse spent his last few years developing a tracked mine for attacking fortifications. The Wehrmacht pinched his research about the time they pinched the north of France and turned it into | | |
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December 13th, 2012, 08:29 PM
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#5 | | Historian
Joined: Jan 2012 From: City 17 Posts: 2,912 | Quote:
Originally Posted by Nemowork | my my! it's actually quite hard to believe that germans lost the war 
they had the best technology no doubt.
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December 13th, 2012, 08:49 PM
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#6 | | Revisionist
Joined: Nov 2011 From: Closer to Calais than to Birmingham Posts: 3,463 | Quote:
Originally Posted by infestør my my! it's actually quite hard to believe that germans lost the war 
they had the best technology no doubt. | Read this! Short Story - Superiority - by Arthur C. Clarke | | |
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December 13th, 2012, 09:58 PM
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#7 | | Lecturer
Joined: Oct 2011 Posts: 339 |
Tires have evolved greatly in the last 50-60 years.
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December 15th, 2012, 01:07 AM
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#8 | | Historian
Joined: Feb 2012 Posts: 1,325 | Quote:
Originally Posted by Bish Ashide from what Nemowork said, which is pretty spot on, they were only popular for a short period, namely WW2. | There was at least one half tracked vehicle in WW1. Again the idea was to improve traction in muddy conditions though I understand the vehicle was not widely used.
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December 15th, 2012, 07:23 AM
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#9 | | Varlet
Joined: Dec 2010 From: Pillium Posts: 2,869 |
I have a question that I hope is pertinent to this thread.
If half tracks were such a pig to steer properly then how was this problem solved with the Kettenkrad?
If two steerable wheels are hard work then one wheel must be impossible.
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December 15th, 2012, 03:43 PM
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#10 | | Historian
Joined: Jan 2011 From: South of the barcodes Posts: 3,249 |
The same way they did it with the larger Hanomag half tracks, a combined steering/braking system.
The front wheel has a limited degree of free traverse for minor steering correction. Anything turning the handlebars over a few degrees and it activates the track braking sytem causing the track on the inside of the turning curve to brake casuing the vehicle to pivot. Its the complex engineered linkage for that turning system thats prone to failures. Its not technically a bad system but it is high maintenance.
As the front wheel is pinched off the NSU motorbike it has all the drawbacks of motorbikes in russia, snow or mud would get caught between the tyre and mudgaurd and freeze it solid turning it into a ski.
The kettenkrad didnt actually need the front wheel, it could be taken off and it would still run and turn perfectly adequately and in fact it was recommended to do so in rough terrain.
The complexity aside it was a very decent little utility vehicle, it had been designed initially for the German lumber industry so it was already proof tested as a light tractor in rough and snowy conditions, once the armies utility bikes and sidecar combinations became unsuitable it was ready to go off the shelf.
Its a nifty bit of design by NSU, the front wheel and steering comes from an NSU motorcycle, the engine is pinched from an Opel Olympia commercial car, the tracks are basically Hanomag clones scaled down a bit so apart from the body shell theres very little redesign or unusual parts which is rare in a German vehicle, they had a love of over-engineering any problem.
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Last edited by Nemowork; December 15th, 2012 at 03:48 PM.
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