Wooldridge 1940s Bottom-Dump Truck

[frizzen]

Goal: I want a larger Dump truck that's going to be easier to hit with a Dragline bucket than my Structo 1960s pickup, and Nylint 1930s pickup.
Yeah, just for ease of loading, i'm not even worrying about production volume.

Doepke toys produced a Wooldridge articulated Belly-Dump truck from 1946-49. http://www.tnttoytrucks.com/DPKWooldridge.html
I'm all over Unique, Old, Rare, Mechanical equipment. I finally found some parts in bad enough shape the collectors weren't interested.

Go get your Tetanus boosters, some full grain gloves, and some good workboots. It's time for another Will It Run?


Wait, that's most of a Heiliner scraper, and only 1/2 of a Wooldridge dump? Plus the red machine is yellow, and the yellow machine is orange? And they still rusted through their repaints?



I hope the monkey in the machine might have a little better luck getting this bed loaded.



So i began searching for some possible powerplant options.
https://rctruckandconstruction.com/s...ad.php?t=13938

Then i found a Wooldridge power unit with both wheels, but the hitch was ripped off. Yup, load 'er up.

Atleast this yellow one is green?

I am abusive and like to ruin old metal machines with added awesomeness, but I'm not beating up on a NOS or even a Fair condition machines. Relax.

[jerry56]

LOL this should be good.!!!!!
Really want to see how you mount the motors and the rest of the electronics. Looks like the power unit might give you enough room...

[Blender]

The vintage machines have a cool aesthetic to them. Excited to see your choice of drive, steer and dump actuators

[frizzen]

Jerry, thanks for your help brainstorming on this one! I think the Wooldridge power unit should be good for 2 esc, 1 rx, some sub-C nimh, pilot light, driver. Then the attachment can carry servos and actuators as needed.

Blender, thank you! Planning to keep it all fairly simple. The vintage stuff usually speaks louder to me. I keep reading about people saying Wooldridge equipment was ugly, but i think it's distinctive.

The biggest challenge on this is finding axles/trans, I need seperate control on each side because drive & steer. These are an "Overslung" machine so think like a Tractor minus the front axle, and only steering using cutting brakes. A computer TX can mix the drive & steer channels tank-style with offsets -100% / +100%, and be all happy happy, but that's for later. I didn't like the idea of massive servo trying to wrestle it around corners since they didn't use hydro-steering yet.

I started this project assuming i'd use a Heiliner power unit, it has a narrower frame width than the Wooldridge.
I picked up a pair of "jsx-370" gearboxes in "90 rpm" to test out. Good form factor, bad setup. Reordered those around "23 rpm" and did motor swap below.

Shaft couplers to adapt D-shaft to Wheel
https://www.amazon.com/gp/product/B0..._title_o00_s00

Gearmotors
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 says 90rpm = 65:1
Started thinking something 200:1 (30), 260:1 (23), or 340:1 (18) sounded much more likely numbers for dragging 10+ lbs of truck, some dirt, maybe another truck

I also 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.



Redcat motors are a direct swap into those jsx-370 series gearboxes.
Mount screws in the first set 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 some Diagonal cutters.

I had looked at some of the 6v versions of these gearboxes, 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
Their 6v 260:1 ratio box coming in at 17 rpm. Then those 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. Yeah. The rc hobby can build WAY 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.

My RC motor swap in the 260:1 boxes got enough torque that a 4" wheel doesn't want to ponybrake by hand, and got a reasonable top speed of around a slow walk. Because large 1940s off highway equipment suspension was sidewall flex, and they aren't paying my driver to get beaten up or break stuff on the machine.

[pufferfish]

Hui. This project looks very fiddly

[frizzen]

Pufferfish, There are some small parts, but other than some gearbox screws and the setscrews for shaft couplers, it's not being too fiddly yet.

Mounting these gearboxes to the inside of a smaller C-channel could have been lots of 'fun' with making filler pieces, shaft extensions and all that. So instead i notched the lower rails, folded them flat with outer face to give enough mount surface. Since original axle holes needed to go lower to fit gearboxes into frame channel, i also moved the axle shafts aft to keep an even fender gap.



Shaft coupler mounts to the modified rim halves, and the stackup still pinches tire like a beadlock.

I'd mentioned this broken power unit had no hitch, so my mig fabricated something, but it's best to not look there too long. I'll clean that up more when we get up to sandblast & painting. Original hitch had like 4 spotwelds to frame.

Yes, there is hardware missing, wrong lengths, and not using locktite yet since this isn't final assembly.

[frizzen]

Anybody remember what's the big thing a DUMP truck really needs to be able to do?

Well then we better do something about that!



These bomb-bay doors have a 'wired' rolled edge, so i poked some brass rod stock into them. Brass rods have a groove to retain a splitring that attaches to chain. Notched out bottom of the forward C-channel for clearance to fully close. Attached some split-rings and chain to doors. Made a servo holder and stuck that in the 'bridge' going to hitch.another splitring holds chain to servo

I dunno, maybe that's enough servo to hold the doors?

[9W Monighan]

Check back a few years where I converted a Nylint Tournarocker
You have the basic idea I had driving both wheels independently
Mine had to because that's how it steers.

[frizzen]

Monighan, I thought i'd remembered a really nice Tournarocker build of yours. It was really trick, but i'm aiming a little lower since i don't have a Mill, Lathe, Layout blocks, Skill...

https://youtu.be/oDaM27S9hKs
https://rctruckandconstruction.com/s...t=Tournarocker

I think this one is modeled on a Wooldridge Terra-Clipper instead of the later Terra-Cobra. Unless it really needs more steering help than the seperate motors, i wasn't going to try making something that works like the Cobras ''dual hydro rams moving a chain around a gear steering."

[jerry56]

I wondered how you were going to do the dump gates.... great idea...

[frizzen]

Thanks jerry, i'd wanted to come up with something overly complex, probably having little pivots that would get dirty and jam. Then i noticed some 1/10 crawler accessory chain still on the bench. I thought this way might be more durable, and able to self-clean better.

I'm sure that somewhere there's info on determining chain lengths and angles to maximize leverage against the weight on doors, so i just didn't go looking for any of that.

[jerry56]

Now that you mention it.....looking at those chains, it looks like if the doors open any more they may over center then bind... Might be better if they open just a little less so they can't do that... maybe take one or two links out... just a thought...

[frizzen]

Good thoughts jerry. I really wasn't sure if i would be better off to let the doors have more room to do what they want, and remember to close when it's on the flats. Or if different amounts of restricting the doors could cause something like a high-center while dumping or jam when closing? I really don't know enough about operating different types of dump trucks yet.

I did learn that the original hitch for these uses a 1/2" OD bushing that the trailer rides on for yaw, over a smaller vertical pin attached to the roll axis of tractor. Also original setup has WAY MORE travel in roll articulation than i had expected.

[jerry56]

What the heck... give it a try it's easy to shorten them...
For whats it's worth I have the Euclid and the rock wagon.... if you have a question I can always dig them out and measure or check stuff... if that helps...

[frizzen]

I'd wondered how much roll articulation your Euclid has, and probably same for the Tourna-rock trucks? Either looking at it like axle angle, or tire lift height & wheelbase distance?

Looks like the Wooldridge gets almost 3" vertical tire travel, but i haven't started straightening everything on that yet.

So if a Terra-Cobra Wagon has the Walls slide off the Floor to dump, then what's a Belly Dump?

[frizzen]

Got a new 6ch rx, and 2 pack of dkky cheap 40a brushed esc (Fwd 40/160. Rev 20/80) i dunno, claims to be good for pushing 380 motors

A guy has a computer radio, doesn't want to get a big Tank track controller style esc like Sabertooth or something. Using 2 sticks seperately to drive is lame, so we're putting Full drive function mixed on Right stick. Works for stuff like Tank, Bulldozer, Bobcat, Wiggle-wagon, Scraper...

Basic tune before i even get it wired to motors looks something like

Mix 1: ch1 master, ch2 sl
Pos. -100
Neg. -100
Offset 0

Mix 2: ch2 master, ch1 sl
Pos. +100
Neg. +100
Offset 0

Splice the battery connectors together on both esc.
Pull a red lead out of 1 esc servo plug and cap, so the BECs can't fight if the stowed power switch gets turned on.

Figure out the high-amp (faster) output channel throw, wire that as Forward rotation for each motor
Probably tune in some center-stick deadband with Expo,
Play with Offsets or Sub-trims to get it steering straight
--
Is it enough ESC? Yo, I dunno.
Mr Bruder at the handle, gotta drive it like a vandal.

[jerry56]

That sounds like a good start.. only weak point might be the cheap ESCs... might have to consider a QR 1060... if they become a problem

[frizzen]

Thanks for the suggestion! I really wasn't sure what would be a good enough esc for this. That Hobbywing QR 1060 does sound like a nice step up. I was also aiming for something small enough to fit in the triangle 'fenders', and seems like nobody gives footprint specs.

Put a longer servo arm on Dump chain. Made some noise, rewired stuff a couple times, started getting deeper into radio programming. This thing is going to look really cool driving once it's dialed in!

Found a video about program Differential Thrust planes that suggested starting setup mix Offset at 50%. I believe on this, that should slow down the rate of steering.

Post #16 will get updated with my radio program stuff once i'm happy with it.

[ddmckee54]

Originally Posted by frizzen

Found a video about program Differential Thrust planes that suggested starting setup mix Offset at 50%. I believe on this, that should slow down the rate of steering.

Yeah, you probably don't have to worry as much about this thing rolling over when you give it a turn command if things are a little TOO touchy.

[frizzen]

Ddmckee, i'm not really worried about prop torque and left turn tendencies. More about over commanding a turn, slamming the tractor into the trailer, with the load weight shifting to the outside of corner.

In another build thread somewhere, somebody replied, but decided to start swearing at the build. I thought i was in polite company over there, but they used "that P-word". Well fine, this thing has bias plies.

Oh yeah, look at this thing we saved from the dump. She's f*****g Mint!


Mint!!!