[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.