Landships II

Yes, I've seen that pic before, but have you seen this one:

Its of a French Trench digger A bit small and difficult to discern, but I have a larger view of the same image in one of my osprey books... quite a bit smaller than its German counterpart, but do you think the machinations would be the same?
http://www.britishpathe.com/media/ThumbStills/00000000/00075000/00075820/00000005.jpg

Greetings, Josh




-- Edited by FR73 on Thursday 10th of February 2011 05:42:07 AM

many thanks for the big picture.

now that we can see better,
what do you gentlemen think of it? the same as on a A7V variant or no?

Regards, Josh

The IWM doesn't appear to have this image anymore, as it was listed as such in Fortifications of the Western Front 1914-18 by Paddy Griffith. But this is a WAY more clearer image of the machinery of these vehicles. its the best insight I can offer into coming up with the conveyors and digger on the A7V variant.

Here it is in google books:
http://books.google.com/books?id=qxsPYn0dUUMC&pg=PA49&lpg=PA49&dq=French+trenching+machine+Q+75984&source=bl&ots=RFTUtXWH5i&sig=OtyC2HO8s2YzZYGJSZD3F8Xb9RM&hl=en&ei=JmtVTYS7MpG-sAPM-KHCBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCIQ6AEwAA#v=onepage&q&f=false

Greetings, Josh

I'd say so, A trenching machine would either make for a high priority target for a Junkers JI or prize "Beute" for stormtroops if it was that close to the line apparently that it needs camo, as I doubt by the time these machines were prevalent, German observation planes probably couldn't get too far behind enemy lines for fear of being shot down "On Their Side" as the pilot jargon goes...

But this all helps. so, based on the info being gathered we can infer that on the A7V variant, it was very much the same layout but on a larger scale, unlike the these smaller profile machines we have just seen, my inference is that the excavator is most likely belt driven guessing from that large pulley up on that gantry on the back which would work the buckets. As I can't see any chains, a belt would be a cheaper and less heavy choice, probably be made from a tough ersatz material, (at this late stage in the war) and that the cab would undoubtedly carry a spare. I would imagine that for it to be set up in the operational position, it would simply be set down manually, as a bulky recoil mechanism would certainly slow the beast further. I suspect the Germans had high mobiltyof operations in mind when they built her, so being able to get to flak cover was a must. The gantry which often puzzles me why they would put such a high point on it, which may have turned it into a
1900s SUV- high center of gravity like today's Mercedes/Dodge sprinter vans if you can imagine... but I suppose where it was employed the ground was not as churned up as what its armored brother was used to, therefore it wouldn't topple over like I thought. The gantry seems to serve the purpose of being a drop off for the dirt onto the conveyors. a bit like a hay elevator on a farm. My guess is there is alot of machinery housed inside, as you have the pulley for the excavator and the motors for the conveyors. unless that is the Germans wired it all into the engine in front of the cab, which the space seems too small to accommodate the horsepower needed to run everything .

What do you guys think of all this hypothesizing?

Greetings, Josh

kieffer wrote:

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...You always wonder how the belt stays on the rimless wheel but it works and works. ...

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Alignment has to be be fairly-well perfect or those belts are always going to be thrown off. Then a little bit of treacle helps with the grip on the smaller pulley/wheel (if the load is a little variable as it is in many applications) without needing excessive tension and strain on the bearings/bushes.

-- Edited by Rectalgia on Saturday 12th of February 2011 04:11:47 PM

Any thoughts on engine power? would the engine drive everything, or would the excavator rely on its own power source?

also I notice the scale of the trenches being dug
-In the first images of the french diggers, you will notice its able to fit into a trench that as you can see from the image in the googlebook, is big enough for at most 3 men abreast of one another as you see the two sappers following behind it in the trench.
-On the A7V that Hugh posted, it appears to be digging perpendicular to the edge of the trench. Such excavation would take much more time then digging a slit trench like the other, but the key is that German trenches by that time were more concerned with width and depth not speed. I figure these pictures of it were taken probably in the process of building the Hindenburg line, where trenches needed to be dug more faster then men with spades could do. Also most important; they needed to be able ditch a Mk.IV

Greetings, Josh

-- Edited by FR73 on Saturday 12th of February 2011 09:14:57 PM

Rectalgia wrote:

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Here is a front view of some kind of excavator - http://www.firstworldwar.com/features/graphics/trenchexcavation.jpg - 

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I am getting a bit of confused here: isn't that the excavateur automobile, pictures are on this forum to be found under French Trenching Machine? Very interesting info on behalf of an Austrian digger as well can be found, that one probably inspired the Germans.

-- Edited by kieffer on Monday 14th of February 2011 10:27:32 AM

I think so, the automobile here unvisible.
Some more belting (wasn't that common use in some 'education'?).
Drawings are showing the gearing shift, reverse and on/off and an Italian war plant with lots of belting. Yummie!

Kieffer

The comparison between the workshop belting systems used in the photograph sent in by Kieffer, and that used on any conveyor system, including tracks is similar in only one aspect, and that is that they are both a form of belt.
On closer inspection of the photograph it will be noted that the belts are in fact twisted prior to clipping together ( a mobius band or strip after August Ferdinand Mobius the German Mathematician) this created a continuous one sided surface and so ensured that the belt wore in a uniform manner.
Belts on the other hand - conveyor or otherwise, and including those used in strip or open cut mining are "tracked" by means of a pulley with take up adjustment on either side, have a look at those threaded take ups on the first tanks, one each side ensured that the track was indeed tracking and would not run off the wheels, this could and does happen with tracked vehicles and conveyors when mud, coal etc builds up causing the tension that keeps the tracking true to vary on one side and the belt or track runs off.
Any track or belting system has a regime of adjustment and maintenance to ensure the continued operational efficiency of the machinery, the use of crowned drums does exist but is not always necessary, and even these need adjustment to maintain tracking.
The closest modern equivalent to the systems shown in some of the early trench diggers would be the grain elevator which has a belt fitted with metal buckets, one can imagine the wear on this mechanism, and the problem of the buckets tearing from the belting.
Modern dredgers such as those used in open cut mines have a rotating 'Bucket wheel', this is a solid metal structure which removes the coal or ore and as it rotates drops it through a chute onto the conveyor, the conveyor as the name implies does not dig the coal but conveys it away from the source.

Tom Nash

Well I would buy the idea of the grain elevator method, with pulleys and leather drive belts, but I guess the question I was asking is, do you think its power source is separate from the main engine? I would guess so. but now where would that second engine be; my analysis of the gantry is that with the excavator lowered into position by hand, the digging commences, dirt is lifted away in a diagonal direction to the top of the gantry, and then down a chute inside the gantry to the conveyors that dump the dirt to either side. pioneers with spades ready would move the dirt around to make the parpet, parados, and fill sandbags. the excavator and conveyors are operated by a separate motor, which in theory should be in the gantry, but on Closer examination of Hugh's photo, The belt on the main pulley for the digger seems to terminate in the cab, could it have operated like today's garden backhoe tractors with two sets of controls inside the cab? the size of the cab in the front view says no, but what do you gentlemen think?

Greetings, Josh

A different housing, but I think too there's a separate engine. Hughs attribution shows some kind of exhaust on the housing. Which itself looks quite similar to these railway gantries from that era. One gets the idea that some civil mining digger has been implantated on the panzer chassis.
I guess the Tankograd copy might give much of the answers on Josh's questions.
On www.panzermodell.de is a fine picture of a model, I think showed on a contest. Might be not the one you'r after but it reveals quiet some technical details.
The site itself is nice but a bit a bit 'difficult' if it comes to searching for digibets like me, so I think you better google 'grabenbagger' for pictures and you'll find it on page 6


-- Edited by kieffer on Wednesday 16th of February 2011 08:06:23 AM

-- Edited by kieffer on Wednesday 16th of February 2011 08:08:37 AM

Well, so far a search for 1/72 scale farm implements turned up nothing. it appears this will truly be scratchbuilt. I am in need of plans/photos of agricultural/civil mining trenching machines from that time period probably through the early twenties. Any input is crucially helpful.

Greetings, Josh

Well, that is certainly of use to me, especially Excavator 1908, thank you very much!

Greetings, Josh

Oh, I almost forgot. In my brief look for conveyors, I thought of the closest thing I knew that was similar to what I am looking for: the classic American Hay bale elevator. Here is its patent. It is the simplest design I know. Now how would a modeler come up with the belts for them? this patent also provides a very plausible idea of how it was driven if you look at the second drawing.

http://www.google.com/patents?id=OWpUAAAAEBAJ&printsec=abstract&zoom=4&source=gbs_overview_r&cad=0#v=onepage&q&f=false

Greetings, Josh


-- Edited by FR73 on Friday 25th of February 2011 08:42:09 AM

The following link should help http://www.plastruct.com/Pages/USDealers.html
I think something like masking tape may be of use for the belts.
Paul

To simplify the search for plasticcard:

http://cgi.ebay.com/high-impact-Styrene-Sheets-030-plasticard-Scratchbuild-/110621829899?pt=LH_DefaultDomain_0&hash=item19c1932b0b

http://cgi.ebay.com/high-impact-Styrene-Sheets-060-plasticard-Scratchbuild-/110645085701?pt=LH_DefaultDomain_0&hash=item19c2f60605

there's a bunch on ebay all appear to be differing weight. which weight is ideal for 1/72 scale part fabrication?.

Greetings, Josh



-- Edited by FR73 on Saturday 5th of March 2011 09:06:55 PM