Russian ChTz T-800 1/16th scale Bulldozer model

[dozerbuilder]

I've completed the dozer. Here are the field test videos. #1 is a walk-around and #2 is 17 minutes filmed at a coal mine. Quite fitting since this machine was designed ripping and mass-dozing work.

[liftmys10]

No link to video?

[dozerbuilder]

No link to video?

Yeah well I just spent half-an hour setting up all the pics and text and links only to have the board bomb me out for exceeding 20 minutes on save. Grrrrate.

[dozerbuilder]

Anyway I can't be bothered doing all that work all over again if it's gonna bomb me out for exceeding 20 mins.

Here's the vids.
https://youtu.be/McxEmBQQzOM

https://youtu.be/2u0fJL94y5Q

[Rakthi]

Nice dozer even with only able to see 2 minutes of your videos (slow internet).

Looks like a substantial machine. How much does it weigh? Materials made of ... you know the usual details for us nosey parkers :)

[dozerbuilder]

This is a 1-16th scale model of the Russian ChTZ T-800 (T.75.01) bulldozer with tilt-blade and ripper. First, a little history. The 1:1 machine sits in between the D11N and D11T or just under the D475-5 for a size comparison, weighs 106 tons with blade and ripper and has an 820hp engine. It was made in the early 1980’s and at the time, was the largest crawler tractor in the world. At present, it still remains the largest crawler tractor to be manufactured on the European continent. It’s not a widely known machine outside Europe since only eight or nine were built and was not sold outside Russia. They were built specifically for ripping frozen ground and rock in the diamond mines in Russia. Blasting was not used there because it caused fractures in the diamonds so big crawler tractors with rippers were used.

The model is designed in a Russian CAD program by my friend Sergey in Russia with help and consultation and photos from my other friend in Russia, Vitaly. So I want to make it clear I did not design the model, it was designed from the original machine by Sergey in the Russian KOMPAS 3D CAD. From those drawings I made DXF files myself and had the parts laser cut in metal and some parts made in 3D SLA printing. That was quite a job in itself. The plans and drawings took about 400 hours then the build took at least 2000 hours from start to present day. Quite a lot of small engineering work such as the draft arm trunnions and trunnion balls were made by small engineering job shops. A fabrication shop rolled the blade and TIG-welded the sub-assemblies, blade, ripper and frame tub. Their journeyman sheet metal worker Chris did a brilliant job of rolling the blade curves from my drawings, on rollers and a bender. He also did a nice job on all the intricate TIG welding. The blade curve radius drawings took me a month and countless cardboard models to get right. There are three radii in that blade with a tri-planar curve on each side.

The model is 830mm long, 393 mm wide at the corner tips and weighs 27.3kg. It has RC control using a Turnigy 9XR Pro 8 channel radio, power is by 2 x 25Amp 12volt dc motors of 190 rpm with a final drive reduction of 4:1 at the sprockets. Battery is a 12v 12Ah SLA. Motor controllers are one DE 2x32 for the drive and two DE 2x5’s for the blade and ripper respectively. The speed is controlled by RC to the correct scale, 0-1.25km forward and 0-14 kph in reverse. Final drive is simplex chain drive to 8mm drive shafts. The frame is all welded 3mm steel sheet. The 8 per-side twin bottom rollers have pre-loaded suspension rated 15kg each. The blade and ripper are operated by screw actuators. The blade tilts though that cannot be seen in the videos since I changed the RC mixing because the actuators can’t handle opposing forces. I am working on some heavy duty screw-type actuators to replace the lot once and for all. The model can push or pull 15.7kg at traction break tested with a digital bag scale.

The videos were made by me at a closed down coal mine in Australia. It’s had four field tests, each time something broke so we simply made it stronger. The video’s are of the 4th field test. If there’s enough interest, I’ll make some more from the footage I have.

PS: I decided to put the build thread here at RC&T since this is where I learned most about what I needed to know for a build and the site and other builds here helped me tremendously. I had all this set up nicely earlier today with pics and links but got a speeding ticket from the board admin for exceeding 20 minutes editing and it all evaporated into the ethos when I hit the “save” button. Now I can’t seem to put up pics. That’s just too bad. I’ve got 1100 pics of every aspect of the build so I might have another go at a build thread tomorrow if I get time. Anyway, I think the vids say it all.

[sparkycuda]

Nice model! History of this dozer is interesting since I was not aware of its existence. Very cool. Hope you will be able to post the pictures because we always like to see how the insides work.

Ken

[Rakthi]

Hi, thanks for that detailed information! My hat off to you and the people involved in building this "monster".

If you want to write a build thread, be aware that there is also a limit to the amount of pictures per post - 5 if you have them as attachments and 15 photos if you use a Photobucket of similar account. So better to break it up in small postings. That way you don't run into the time limit.

Or you could also write it first in a simple wordprocessor including the links etc. and then just copy - paste from there into the reply window.

Again, thanks for the information, and hope to see some "how we did it" pictures :)

[JAMMER]

I can't see the attachment. Ed

[TRUCKMAKER]

Thanks for posting dozerbuilder, very nice model and interesting background. As previously stated a photo account will be your best bet and easiest way of posting the photos we would all like to see.:D

[liftmys10]

Nice job!!

[Lil Giants]

Never seen, nor never heard of such a model before. :confused:

For such a monster of a model, did hyds cross your mind at all? Looks like the speed of your actuators is about right, hope they last long time for you.

Sometimes when I make a long post, before I click "post", I highlight entire post & right click & copy... just b/c I've had it happen before with some computer glitch & loose it all ...I know your pain.

There is a 5000 character limit too to consider, so don't try to post an entire book in one post. ;) Take your time, lets have a look at this unique creation you have mastered. :cool:

[dozerbuilder]

Never seen, nor never heard of such a model before. :confused:

For such a monster of a model, did hyds cross your mind at all? Looks like the speed of your actuators is about right, hope they last long time for you.

Sometimes when I make a long post, before I click "post", I highlight entire post & right click & copy... just b/c I've had it happen before with some computer glitch & loose it all ...I know your pain.

There is a 5000 character limit too to consider, so don't try to post an entire book in one post. ;) Take your time, lets have a look at this unique creation you have mastered. :cool:


I looked into hyd's vs actuators and earned myself a migraine that lasted a week. I never really got to the bottom of it, I couldn't nail the hyd people down with precise specs about their products so I decided on screw actuators and ESC's. I'm working on new heavy duty ones to replace the ones fitted, all have failed miserably. I already have some parts and motors from China. They will be tubular resembling a hyd ram, but 12V electric. The speed of those 60's is about right as you say, and they have sufficient power.

I personally are not too happy about the possibility of oil leaks and also having high pressure oil in the mix. I like the controllability of the RC actuators - plenty of adjustment available in the RC mixing and the ESC's.

Cheers

[dozerbuilder]

Thanks for the interest guys.

I made another vid. This was the 3rd field test so some differences are noticeable in relation to the 4th field test and walk-around.

https://youtu.be/IdOlsBB4zQA

[dozerbuilder]

Nice model! History of this dozer is interesting since I was not aware of its existence. Very cool. Hope you will be able to post the pictures because we always like to see how the insides work.

Ken

Sure, I'm happy to share all about it. Soon.

Cheers

[dozerbuilder]

Thanks for posting dozerbuilder, very nice model and interesting background. As previously stated a photo account will be your best bet and easiest way of posting the photos we would all like to see.:D

Thanks truckmaker. Agreed. soon.
Cheers

[Panther F]

I watched a few of the videos (very envious btw) as this looks and sounds so real you now need a figure to top it off.

The walk around video looked as if you were actually walking around the full-scale vehicle the way you handled the camera... so kudos to you for that.

I really like it as I build 1/16 military/armor vehicles so it has my interest! :D





Jeff

[dozerbuilder]

I watched a few of the videos (very envious btw) as this looks and sounds so real you now need a figure to top it off.

The walk around video looked as if you were actually walking around the full-scale vehicle the way you handled the camera... so kudos to you for that.

I really like it as I build 1/16 military/armor vehicles so it has my interest! :D





Jeff

Jeff,

The Russian Company (CHTZ-Uraltrac, also known as 4T3 )http://chtz-uraltrac.ru/ has manufactured in excess of 1.2 million crawler tractors. They began building Cat 60's under licence. The same Architect who designed the Ford auto factories of Detroit with moving assembly lines, Albert Khan, also designed the 4T3 factory in Russia. As a military enthusiast, you may be interested to know 4T3 is the same company that manufactures all their military tanks, from the T-34 to present day T-90.

The T-800 as a crawler tractor is essentially is a hybrid and has a tank-type hull, main frame and torsion bar /swing arm suspension like a T-34 though much more heavily built. That's why this heavy dozer can run at 14kph, the front idlers and rear sprockets carry no weight, the whole thing at 106 tons is riding only on the bottom rollers carried by a massive suspension arrangement comprising few moving parts, drop arms and torsion bars.

[dozerbuilder]

Jeff, here's a pic of the 1:1 showing the rolling gear and drop arms.

[TRUCKMAKER]

What a monster!

[Lil Giants]

I've seen it on several youtube vids of professional operators who say "use 3rd gear & you're fired!!! Higher speeds on tracked equip equals more friction & higher temps wearing out under carriage at an accelerated rate." ...not sure how fast 3rd gear is, but could be 14kph (9.3mph).

Not a concern for this Russian dozer to travel so quick?

[Lil Giants]

I personally are not too happy about the possibility of oil leaks and also having high pressure oil in the mix. I like the controllability of the RC actuators - plenty of adjustment available in the RC mixing and the ESC's.

Cheers

My Stahl 742 dozer was more than 13yrs old when I took it apart last fall, never ever had an issue with an oil leak & never needed the pressure to be that high either, just enough to lift the nose off the ground so the blade would dig in. I took it apart b/c some parts of the u/c need rebuilding.

[dozerbuilder]

I've seen it on several youtube vids of professional operators who say "use 3rd gear & you're fired!!! Higher speeds on tracked equip equals more friction & higher temps wearing out under carriage at an accelerated rate." ...not sure how fast 3rd gear is, but could be 14kph (9.3mph).

Not a concern for this Russian dozer to travel so quick?


Well the specs say:
Transmission: Hydro-mechanical, consisting of a single-stage three-wheel torque converter driveline and module consisting of a three-shaft planetary gearbox and rotation stopping brakes, bevel gear, two-stage final drive with a pair of spur gears and planetary row and hydraulic transmission.

Transmission provides four forward and two reverse gears.
Forward, 4 transmission ranges; 0-3, 0-5.1, 0-6.7, 0-10.6 (kph).
Reverse, 2 transmission ranges; 0-6.6, 0-14.0 (kph)

I guess it would be like any big tractor in ripped rock, slow is the go.

[dozerbuilder]

My Stahl 742 dozer was more than 13yrs old when I took it apart last fall, never ever had an issue with an oil leak & never needed the pressure to be that high either, just enough to lift the nose off the ground so the blade would dig in. I took it apart b/c some parts of the u/c need rebuilding.

Glad to read of your success. I like the smooth action of electric actuators all the same. Like Scranton, PA and R.G. Letourneau, I'm going all-electric.

[dozerbuilder]

Here's a couple of build pics.

One shows the frame detail. The other shows the completed sub-assemblies ready for final assembly. Of course it's been pre-assembled a hundred times prior, it was not a first-time perfect assemble so to speak. But in this pic, all is ready for final assembly. I built it in a series of sub-assemblies, it only takes 15 minutes and it's up and running. With the exception of the welded sub-assemblies, all moving parts of the model can be disassembled for repair. For example, the entire final drive can be unbolted and disassembled. I had to do that on the first field test when it sheared a 2mm dia final drive shaft roll pin.

[dozerbuilder]

Here's a link to the final field test for the big dozer. I think we were pretty well pushing it to its limits here. We wound the track speed back up a bit but it was a little too aggressive in rock so we set it back after this test finally to where it was in field test #3. Pushing leaves or sawdust or sand or dirt it wouldn't matter, in rock where we had it, it proved too aggressive. Perhaps a scientist can work this out but I think we are still getting the full 25amps from each drive motor regardless, the pulses from the pwm are just farther apart as I understand it. Certainly reducing the pwm does not reduce the torque it seems. It's been quite a brute in the overburden and rock as the vids show.



https://www.youtube.com/watch?v=nLGbWYp6u-U


Enjoy

[dozerbuilder]

The big T-800 dozer finally succumbs to field testing ripping loose rock. Appears a stone became entangled in between the bottom rock-guard rails and the RH rear sprocket while screwing the tractor. With the front idler tensioner pulled right back and the rock in between the bush and the sprocket gullet, something more had to give to accommodate the stone and it was the track links. We pressed the pins and bushes out and replaced two complete grouser and link sets. Took about 1 hour and back into service. I guess it’s far easier to replace two track link/grouser sets than twist up the final drive which can be got at through belly pan covers but is quiet time-consuming and requires roll-pins to be driven out.

The final drive seems to be immensely strong even though I’ve wound the mixing back on the Turnigy to 40%. I’m very happy with it. For those who are interested, the drive comprises 2x 25Amp (stall) car seat motors (made by Hyundai) running @3000rpm motor output speed (no load) with 16:1 worm drive reduction at the right-angle output shafts then another 4:1 reduction in the final drive which is done with 04B simplex chain and sprockets roll-pinned to 8mm dia output shafts. The drive can run at 47.5rpm full speed down to 0rpm at full motor torque using PWM. So my sprocket speed at 40% is running 19rpm which as can be seen in the other vids is about right. I also plumbed up the umbilical cord to my PC linking the 2x35amp DE dual motor ESC’s on the dozer and DE’s Describe software and used ramping to take the jerkiness out of the drive system, that’s why it runs so smooth between forward and reverse and turns.

Here’s the vid that shows the carnage.


https://www.youtube.com/watch?v=2rw9BWBx-34

[dozerbuilder]

Here's a view of the drive motors and how they are mounted. The grub screws were used just for holding the sprockets in the correct position while the roll-pins were drilled and driven in. You can see the roll pins in the larger sprockets. The motor sprockets are roll-pinned to the motor output shafts. All shafts are short and supported in bearings at each end. The third pic shows the outer final drive shaft bearing. The frame / hull is all-welded 3mm thick steel plate. Building the frame so strong in the beginning paid off handsomely later, no twisting in such a long frame and it provide a good strong base to weld or bolt the sub-assemblies to it. The entire final drive including the motors, sprockets, shafts and bearings can be removed piece by piece if necessary.

[dozerbuilder]

Here's a pic of the dozer.

[dozerbuilder]

blade sub-assemblies, ripper sub-assemblies, cab interior.

[modelman]

Very nice work!!

[dozerbuilder]

(Got a bit of time on the PC today getting ready to go to Lakeside and Brownsville and few others.)

Here's a pic of my Turnigy set-up.

The RIGHT stick operates Forward and Reverse (Up and Down) and turns, (Left and Right). Both drive motors are controlled by the one stick, mixed. For example, to affect a Right turn, moving stick to the right keeps full power on the left track while mixing reduces it on the right track incrementally from a nearly full power turn at just off-right centre to the right track fully braked #no power# at far right. I've not set it up for tracks running in opposite directions since the real machine is clutch and brakes, not hydro-static.

The blade and ripper are on the LEFT stick. You can see the blade /ripper flick switch at the top left. They are on separate DE 2x5 ESC's. So for the blade, the switch is down; this gives blade up or down, and tilt is left or right, all on the one stick #mixed).

The ripper is the same set up but on another DE 2x5 ESC.; flick the switch and the same stick raises or lowers the ripper and left or right on the same stick alters the angle of the tooth. Flick it back and you are back to blade control.