Miniart Cat D7 & scratch built Hyster logging arch

The little details like that really stand out.

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Wow … had missed a few (lots) of the updates for one reason or another and just binge caught up with it all … This is really exceptional scratch building on that Hyster arch … its exquisite… real skill there :+1: :+1:

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You didn’t miss a single detail. Beautiful!

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You are doing a fantastic job on it. Keep it up.

Cheers,
Ralph

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Images found on line:


Interesting that this Athey trailer has its’ track set mounted further to the rear and utilizes a thin wheeled intermediate limber between the Trailer and the Dozer. I would think that such an arrangement would totally defeat the advantages of the low ground pressure tracked wheel set, especially in such soupy mud.

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Thanks gents for the kind words .
@165thspc
Hi Michael - it may be that the prime mover did not have a proper drawbar and so the dolly was needed for the trailer tongue.
What do you suppose the load is ? Looks like ammo in tubes to me .

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When the logging arch is loaded it will lift the drawbar so there will be no heavy lifting to get it connected to the tractor (heavy logs pulling down the top pulley behind the pivot axle → drawbar goes up).
The tracked trailer has a different load distribution, the majority of the load is in front of the pivot axle.
Load it and the drawbar will be dang heavy to lift and connect to the tractor (winches on the tractor would solve that issue). When the trailer is not hitched to the tractor it would behave like a see-saw
200w
when loading starts, possibly with bad results …
Moving the center of gravity forwards and adding a limber solves all of these problems.
The limber wouldn’t carry more than maybe 20% of the load and even if it did then any tractor who can haul the tracked portion through the mud would have no problems with the narrow limber wheels. Those wheels would slice through the mud without any problems.

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Robin EVERY Athey trailer I have seen until just now has the tracked wheels in the center of the trailer frame (fore and aft) and the weight of the hitch tongue rests of the towing vehicle (giving the towing vehicle even more downward weight for improved traction) Then too if there is some sort of hitch THAT WON’T couple to a standard bulldozer then that would make that trailer even more useless.

Sorry but any farmer could tell you that is a poor design choice if your goal is to navigate soft or muddy ground/beaches with a heavy load. Which is exactly what the Athey trailer was designed to do.

All depends on how/where the load is placed on the trailer. Push a heavy load to the front and you would easily have more than 20% of the weight carried on the spindly front limber/dolly.

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It looks to me to be an International tractor - TD 4 ?
If you look at the two men in the foreground what appears to be the tongue or shaft of the limber/dolly can be seen just above the wrist of the man on the left . Projecting this line forward it does not appear to end up where a drawbar on the tractor may be - the tractor is in a nose down attitude and so any rigid drawbar would seem to be higher than the dolly hitch . The tractor may be disconnected for any number of reasons. Or it may be pulling the trailer with a chain - hence the need for the dolly .
Agreed that any load not centered over the trunnions for the rocker beams would increase the tongue weight. The wheels of the dolly would assume part to all of the tongue load . I suppose if the design of the connection between the dolly and the trailer were somehow rigid other than allowing it to turn ( seems unlikely) it would put some of the load on the tractor IF the footprint of the dolly wheels were not sufficient to support the tongue weight for a given type of terrain and the drawbar on the tractor were rigid.
It is pretty obvious that the wheels of the dolly exhibit a higher ground pressure than the tracks as they are immersed nearly to the axle.
Although unrelated to this discussion, it is interesting to note that this image is reversed - see
“ USMC” on the side of the fuel tank and some characters on the front crossmember of the trailer.

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The track unit is “climbing” something hidden in the mud (solid terrain, a log, whatever) so the front wheel of the track unit is higher up than the rear wheel.
The pivot of the rocker beam seems to be located well aft of the center of the load bed (distance A < distance B)

Edit: The construction of the limber, if it is a limber, is mostly hidden. The section of the wheel that can be seen doesn’t look all that spindley to me.

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Here’s the original picture

Looks like a TD-9…

H.P.

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Spindly as compared to the rear tracks that have at least 10, 20, 30 times the ground contact area of the front limber wheels. With a fully loaded, heavy trailer those tiny front wheels will ALWAYS dig in unnecessarily.

Put away your calipers and your slide rule Robin - you just love to argue and I ain’t gonna play your game. That particular Athey trailer is an unwise design both then and now. That’s all I am saying.

However if your incessant arguing and bickering garners attention for the Athey line of tracked trailers and perhaps helps one day to bring about the creation of a model of the same then I guess it’s all good!

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The D7 is largely done - only the exhaust stack and hand crank for the pony motor remain . Due to their fragile nature they will be added after model is mounted on base.
I replaced the kit sediment bowl on the air cleaner with one made of clear sprue as this was a glass jar on the real thing and the kit supplied part was solid color. I’m surprised MiniArt missed this as there is a nice clear sprue provided for the headlamp lenses.
The Placo canopy is now permanently installed and bolt detail added where the sweeps mount over radiator.

Now working on ideas for the base and making up winch cable and rigging .
Thanks for looking - RT

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Wow Richard. Just wow. Outstanding in every way. I’ve run out of compliments over the course of this blog. Your skill and talent are remarkable. Incredible build!

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What he says ^^ :smiley:

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It’s been amazing watching this from start to finish … The logging arch was the show stealer though … That is some seriously cool skill there :+1:

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Thanks gents for the compliments and interest - still more to come as I begin to explore base ideas .
The base may need to be bigger than I had hoped .
If I have a log in the arch ( which I think is needed to show it’s purpose) it looks like the base will need to be 18 “ long or so . It would be nice to have it wide enough to show some terrain and a stump or two but as it is I don’t have much room to display it .
We’ll see…

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Looks great now it’s all connected and you see it as a whole … And I think a log is a must …that will be the icing on the cake :+1:

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Yep gotta have a log in that arch to show what it does!

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That is some pretty wild scratch work, outstanding!

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