Re: Axle suggestions?
 

That's really cool, i don't remember ever seeing a Structo Dozer with a Bellydump! A dozer would probably be easier to work with than upfitting a wheeled tractor power unit.

Hmm, a flat OD green with some black or white stencil could work for like an Army Corps Engineers or Navy Seabee vibe.

I was just kicking around Blast, prime, shoot in white, then keep mixing paint shades to try to do the entire thing in grayscale like a black&white picture. Maybe lettered up as an easter-egg for something obscure like "Shandor Mining Company" or "Kelland Mining Company"...
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Looks like in the time period these were made, the "Articulated Dump Truck" was just in infantcy, with Dump trailers hooked to the heavy, slow, torquey, and overbuilt power unit machines that were made to pull a Scraper.
So the Heil or Wooldridge power unit could apply to running both the Belly-dump or a Scraper, but not seeing many pics of a Heil with a belly-dump.

The official Wooldridge bottom-dump attachments i'm commonly seeing has a pretty cool ''box slides off trailer floor'' thing instead of bomb-bay doors of the model. They also had a tip up rear dump available.

Heil - Heiliner 2T55, 2T75
Wooldridge - TerraClipper, TerraCobra TC-Y scraper. CobraWagon, CobraHaul dump

Scraper training video
https://youtu.be/hld5ydgeWlU

Some Heiliner company info
https://contractormag.co.nz/classic-...l-earthmoving/
Doepke possibly inspired by the 2H700 / 2H800 models

Some Wooldridge company info
https://www.constructionequipmentgui...-history/16566

Re: Axle suggestions?
 

I hadn't seen that combination before either....it would really help with the traction issue
Black and white...faded paint....letter it in a kind of 50s style.... lots of options if you go that route...

Re: Axle suggestions?
 

Looks like the Wooldridge tractor is going to work easier than Heil tractor, fair amount more room inside. It should have room for the bigger black-can 12v 90 degree gearmotors.

I need to look into possible motor swaps for the Silver-can gearmotors i ordered to start with. If i can find some, nice 6v rock-crawler cans could probably turn 'meh' power into a beast
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Looks like the smaller silver-can "jsx-370 series" boxes are maybe 370 motors?

The larger black-can "jsx-31yz series"

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Also I found another TournaPull build, starts with a Nylint Tourna-rocker then finding drawings for real one and 3D printing. Also has some narrow gearmotor info and motor swaps

https://www-modelltruck-net.translat...tr_pto=ajax,nv

Re: Axle suggestions?
 

Nice find.... but he had problems finding motors small enough and strong enough to move the truck.... and his had more room then ours will.

Re: Axle suggestions?
 

I remembered the Redcat Everest-16 rock crawler that was a donor for my Structo Dump originally had a 280 / 370 motor. So ordered pair of Redcat 'RC370' 28026N motors.

https://imgur.com/996o5iMh.jpg

Redcat motors are a direct swap into those jsx-370 series gearboxes.
Screws were originally installed with very much red locktite, assume the need for heatgun or soldering iron to break hardware loose.
Brass worm gears are a press fit on rotors, but you can lever them off the original motors with Diagonal cutters.

Uh, gear ratio is probably WAY off. But i'm learning. Maybe?

Re: Axle suggestions?
 

I use those redcat motors on my WPL motor/transfer case combos they work really well they add just enough speed....You can put a drop of solder on those press on gears to help hold them in place....

Re: Axle suggestions?
 

Glad to hear you've had good luck with these motors.

Now that i know some 'high torque' RC motors do fit, i probably should go back through my first truck build to see if i kept any notes on gear ratios, final drives, gear inches. Ya know, boring stuff.
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Luckily i didn't save any of that!

https://www.amazon.com/gp/product/B0...0?ie=UTF8&th=1

Jungle website sells those 370 gearboxes in several flavors: 3, 6, 10, 18, 23, 30, 40, 66, 90,160, 210 RPM

Then there's a questionable review for those with chart they posted as stolen from ebay, claims gear ratios: 40, 65, 160, 200, 260, 340, 600,1000 (xx to 1)
Sketchy chart 90rpm = 65:1
Then i'm thinking something 200:1 (30), 260:1 (23), or 340:1 (18) sound much more likely numbers for dragging 10+ lbs of truck, some dirt, maybe another truck

So far all i do know for sure is that 90 rpm + Redcat motor = Too fast.
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Got some 12v at 23 RPM (260:1) units on the way. Less than 1/3 speed of the first try, and the reduction ratio seems more like a crawler. Hopefully it can get a machine out of its own way in a realistic manner.

Re: Axle suggestions?
 

A couple minutes with these new "23 rpm" / 260:1 boxes got the motors swapped. Wired straight to a 6 nimh stick pack seems like it should have the torque up closer to where i need it.

I'm sorta basing this off a Redcat Everest 1/16 rock crawler, because a shaft drive solid-axle donor for my Structo dumptruck seems just like a dual-motored belly dump Wiggle-wagon. Nope.
Looks like those used a rebadged Hobbywing esc, that are possibly programmable with a card. "25-Amp continious Brushed ESC"
so i shouldn't need to get too crazy with holding crazy power or features here.

Re: Axle suggestions?
 

Based on your findings I wonder if a 23 or 30 rpm 6v would work... I've started ordering more 6v motors.
12v running on 7.2v cuts speed and torque almost in half... but a 6v running 7.2 give you almost 20% more of both... and a 6v motor should easily handle 7.2v
I wana see how well these fit on your wooldridge bottom dump and see if they hold up cause if they work I want to use them on my tournarocker and tournadozer

Re: Axle suggestions?
 

These '23 rpm' boxes use the same case as the '90 rpm', differences are just internal, gear sizes & layout.

As it fits in tractor before i made new hitch, did involve notch & flatten part of frame C-channel to get 4 frame mount bolts per gearbox. Motor cans point forward.
https://imgur.com/qjU8G9eh.jpg

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I had looked at some of their 6v versions of them, and wasn't very impressed with the specs provided using their supplied Silver-can motors!
https://nfpshop.com/product/6v-12v-2...el-nfp-dwg-370

With their 6v 260:1 ratio box coming in at 17 rpm. Then pushing 4" tires at 1 foot per rpm, i can't really see being satisfied with this equipment moving at 18 feet per minute empty, downhill, with a tailwind. The rc hobby can build better motors than that.

4" diameter tire has 2" radius = 5.08cm. Gearbox spec sheet lists Max rated Torque at 25 kg-cm. So i think that's like 5.08kg at tire tread.

I started with this form-factor because it would fit in the narrower Heiliner tractor that i had first. The Wooldridge tractor can take bigger, but i'd like to get a useable setup for something before i start buying another size and completely forget what i'm learning about this.

Today i welded up a swivel-wobble thing for the test tractor, now I think i'm on the right path!!!

A Wooldridge with 2 of these "12volt / 23 rpm / (260:1)" that are motor swapped to the Redcat motors listed above that say "370" on label, parallel wired straight to a stick pack. Gets a decent slow walking speed that looks pretty scale for heavy equipment. Added 10 pounds of steel in the box, still pulls it like it's her job. Might be about time for a build thread.

Re: Axle suggestions?
 

Looking at that link you posted the 6v and 12v motors have the same specs. Except the 6v motor pulls more current...
Plus like I said if you drive a 12v motor at 7.2v your 17rpm becomes about 10rpm and your torque drops almost in half. With a 6v motor 17 rpm becomes about what 18 or 19rpm and the torque comes up slightly also.
Either way I'm looking forward to seeing this build....

Re: Axle suggestions?
 

Yeah jerry, that's a big chunk of why i went to some RC hobby 6v motors as used in a rock crawler vs trying again with the 6v Industrial motors. Bearing, Windings, Brushes, Armatures, Magnets all aimed at making power, or just trying to squeeze more efficency and longevity into a gutless package.

Wow, i didn't know there were so many LeTournau toys that seem to use the same power-unit
http://www.tnttoytrucks.com/NYCONstruction.html
Should be fun to see what you'll come up with there

Travel speeds of similar vintage Euclids, bottom dumps start about middle of video.
https://youtu.be/YDfPw6DHTGw

Re: Axle suggestions?
 

I was looking for something else, but thought this info about the Tournalrockers might help motivate your Nylint model C

https://contractormag.co.nz/classic-...tournarockers/

Re: Axle suggestions?
 

I had seen that before but lost track of it thanks... I book marked it this time