View Full Version : Huge Tatra 813 (sort of) 6x6x4

Old Busted Hotness
01-14-11, 08:53 AM
This is what happens when I have time on my hands, but not much cash (which is typical these days). Got to looking at the RC collection with an eye toward making improvements, decided that two under-performing rigs, each quite cool in their own way, could be combined into one uber-cool rig. So I started dis-assembly, and re-assembled the bits into this chassis:


Using the chassis rails and homemade 2-speed transmission (with PTO winch) from the BBW 4x4, and the axles and transfer case from the old (2006) 6x6, I managed to create this beast. This wasn't just a rip-and-tear job, there was a bit of re-engineering, too. The front axles' link mounting points are different, and the links are twice as long as before, so the suspension cycles a lot more smoothly with less bump steer. I turned the transmission around and moved it forward, stuffed the front axles closer together, lowered the ride height and lots of other performance-oriented tweaks.

So let's put some clothes on the tubby girl:


I have a lot of styrene sheets, and the Tatra is pretty much a box on wheels so the cab didn't take long at all. I did take a little (okay, a lot) of liberty with the cab placement; the 1:1's front doors sit out in front of the first axle, but I wanted to keep a decent approach angle (and it ended up at 88 degrees; that'll do).

Now, with all that weight, what's going to happen when I roll this thing over (and I will, sooner or later)? Styrene hell, that's what. So I went to the local auto-parts store and picked up 40 feet of brake line to make an exo cage:


Got this far before I ran out of MAPP gas. Now she's starting to get real heavy.


Has to have a dashboard


Widened and shortened the flatbed from the old 6x6, and added a rear bumper.


Finished the cage the next day, and painted the body. Yeah, white is boring but I have a nearly-new can of it, so white it is.


Front of the cage. This thing is strong!


I wanted to use the air intake from the Mercedes cab, but the cage got in the way. So I did a little surgery.


Roll cage for the bed, too.


This is me being clever. The rear cage goes down thru the bed and is held to the crossmember by the same screw that holds the rear of the front cage. The front cage pivots up, and the bed is held on with two more screws. So by removing four screws on the chassis and 4 more on the body, I can strip it down to a bare chassis for whatever service/adjustments might be required.


Out on the rocks, it's pretty impressive for a 15-pound hog. And lots of fun to drive.

A short video:


Enjoy! gringrin

Old Busted Hotness
01-16-11, 02:56 PM
Some pics from today's run:





It did better than the other 1.9's, but all that second-gear action was too much for the styrene motor plate. The screw holes melted enough to loosen up the gear mesh. Quick fix with an old Associated motor plate, which will either act like a heat sink, or hold enough heat to really melt the tranny. Time's gonna tell on that one.

Oh, and the roll cage is definitely strong enough.

hot ford coupe
01-16-11, 05:33 PM
Now that's what I call a cool build.

Old Busted Hotness
02-25-11, 07:41 PM
Been tweaking here and there, changed the tires to a more modern compound (the old ones were 6 years old!) and added a Cummins QSX15 to cover up the (rebuilt) transmission and motor.


Old Busted Hotness
03-18-11, 09:22 PM
And last Sunday I rolled the pig down about 20 feet of rocky cliff.

End of the road? Not hardly. Broke a few suspension parts, but I drove it for another hour after that. Only called it a day when the rear driveshaft barfed (because of the broken suspension) and even then I got it back to the parking lot on the first two axles. This sucker's pretty tough.

03-18-11, 09:54 PM
Hey, where can I get a yellow dog with racing goggles? 1strange1

Seriously, how many cars do you have????

Dr Dave
03-19-11, 04:00 AM
Hey OBH, that's a tough lookin' truck you've built there, looks a bit like one of those Paris/Dakar race trucks, but this one can take a bigger flogging. You never cease to amaze me the way you can knock these things together.

Old Busted Hotness
03-19-11, 08:04 AM
Hey, where can I get a yellow dog with racing goggles? 1strange1

That's Pikachu, he's been my race pilot for many years. Little guy knows no fear. He's also about deaf from the racket that Cummins makes.

Seriously, how many cars do you have????

45 if you include trailers in the count, 36 if you don't. I might have a little problem 1bigmoney1

Don Garrett
03-19-11, 01:22 PM
Problem? What problem?
The only problem I see is finding enough affordale foam core to build an airplane hanger to park 'em in. Of course you'd probably need your own zip code too.

I'm still trying to figure out where I'm going to put my 1/6th scale monsters. Got no basements in Florida...and my shed etc, is packed with of full size stuff.
The digs started out as 3 BR 2 bath...it's already down to 1BR and 2 hobby rooms (kids grew up and moved away).
The old woman had a fit when I told her I wanted to convert one of the baths to a spray booth.....what to do, what to do?

03-20-11, 01:07 PM
Problem? What problem?
The old woman had a fit when I told her I wanted to convert one of the baths to a spray booth.....what to do, what to do?

Thats Nice!!!! I like the idea about the paint booth,, er, a, I mean bathroom LOL I'll have to think about that??,, maybe my landlord would? a?,, Na... Oh well,,, Good idea anyway.. I see dollar signs tho,, LOL,, I can see it in lights now!! The bathroom Fan For The Hobbyist!! Guaranteed to suck out yer?? aa.. never mind...

A 6x6x4 RC Truck is good LOL...