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Tiamat 6WD/6WS

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This is Tiamat, a six wheel drive, six wheel steering monster mutant truck.
It is based on the Tamiya Clod Buster platform, and originally started out as two trucks.
I built this truck in the fall of 2001, and it has been periodically upgraded ever since.

Lineage

Based on the timeless Tamiya Clod Buster monster truck kit which was incredibly popular when first released in 1988 and is still sold today (albeit as the ‘Super’ Clod Buster)

Powerplant

The truck is powered by three Hacker C50L brushless electric motors. They are more powerful and efficient compared to their more commonly available brushed motor counterparts.

And now some answers to frequently asked questions:

How fast is this thing?
The truck tops out at about 26MPH. While it is not fast for racing truck standards, it’s definitely one heck of a handful for a large, scale-ish monster truck.

How many motors, and how many battery cells each?
The truck has three gearboxes (for each axle), and one 6-cell stick pack of batteries for each.
The motors are Hacker C50L, 10T units.

How many batteries does it need for a run?
On a typical bash day, this truck will consume 40 battery packs, which is about 10 runs or so, depending on how loud i leave the engine speaker volume.
The batteries are carried in a bowling ball bag.

How heavy is it?
The truck closes in at 24.5lbs fully loaded.

Why the name Tiamat?
The thought of a large, destructive, rumbling beast sort of came to mind naturally.
At the time i was thinking of the multiheaded dragon thing from Babylonian mythology.

How long did it take to build?
About four weeks initially, to chassis and rolling stock complete. The whole truck took about another two weeks to get to a running state.
The truck first drove on 20 November 2001.

Six wheel steering? What? Why?
I wanted a maneoverable truck. It has about a four foot turning radius.
The setup chosen worked extremely well. The servo savers are of the Kimbrough black version variety.
The quarter-scale servos (normally reserved for large scale airplanes) that were used are able to turn the truck’s tires standing still while on pavement!

What kind of chassis is it?
It’s a chassis that i made with hand tools, predating my purchasing of proper machine shop tools.
Its made of aluminum and is fairly beefy. Contrary to the beliefs of a barely literate backcountry Floridian hobo, it is not a Sassy brand chassis 🙂

How is the handling?
Actually very predictable, and plush when driving. The truck oversteers because of the torquey servo setup, but tends to drift nicely on dirt. It absorbs bumps reasonably well, with the long travel HPI Savage coil-over-oil dampers doing the dirty work. This vehicle will never have the jump handling of something like a stadium truck but it does have a fairly plush ride over the rough stuff.

How reliable is it with all that weight and power?
This is not my most reliable truck, but it’s rock solid in the right places. The driveline is pretty much bulletproof now. However it has issues mainly with the plastic parts breaking from wear over time, but as i run the vehicle i replace things with similarly designed parts made of more durable materials.
Therefore this truck is like an endless race to convert things that were once plastic to aluminum, what was once aluminum to steel, and so on.

Are any of these chassis for sale?
I don’t have plans to produce these, even in limited production runs. Besides, the total number of 6X6 enthusiasts is fairly small, and the design is fairly straightforward. I would be more than willing to help builders spec one out. Check out the wonderful forums at Scale 4X4 R/C.

Specifications

This section is just for the hardcore R/C crowd. Newcomers, please feel free to skip over, or just let your eyeballs glaze 🙂

  • ESC – Triple Jeti Master Car Sport, 6 cells. These days, i would go for Schulze or Castle Creations instead.
  • Motors – Triple Hacker C50L, 10 turn.
  • Servos – Triple quarter scale- two Futaba 9301s for middle and rear. Single Hitec servo up front.
  • Wheelbases
    • Front to mid axle – 15.5″
    • Mid to rear axle – 8″
  • Radio – Futaba T9CAP surface, with analog servos.
  • Lights – Tamiya Tractor Trailer (generation 1) kit.
  • Sounds – Tamiya Tractor Sound (generation 1) kit.
  • Suspension – 4-link, dampened with HPI Savage oil units, 40 weight oil.
  • Steering – Claw type, 6WS. Front axle moves opposing the rear and middle axles.
  • Balance – Almost 50/50, CoG about right above the tires.

Pictures

This photo gallery contains a bunch of pictures from when the truck was initially built, to its current state.

In addition i have made a few higher resolution pictures available.
They are Portable Network Graphic (PNG) files that most web browsers should be able to read.

Higher Quality Image 01 (1280 x 1024) 2,310KB
Higher Quality Image 02 (1280 x 1024) 2,321KB

Movies

These are some movies with Tiamat in action. More clips will be added over time.
Please note that since i am a cheap bastard, you will want to save these links to your machine before playing. Thanks!


Tiamat_bashing02.wmv (6.4MB) – Bashing around again in our favorite Central Park proving grounds. This was the first time i really felt comfortable with all that brushless power on the truck. Filmed in Summer of 2003.

nyc_cp_bashing01_small.wmv (11.1MB) – Tiamat and a bunch of other trucks and vehicles bashing around in the proving grounds.

I guess if you like watching radio controlled stuff it is fun, but the fact that what was being filmed was just bashing around, it might be boring to those outside the hobby.

Written by Tijger Tsou

September 29th, 2001 at 10:38 pm

3 Responses to 'Tiamat 6WD/6WS'

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  1. What a fantastic Machine! Seems like it’s quite stable since the Aeromax body is still in one piece. I run 14 turns on my clod and the hard body didn’t last…

    I’ve layed down some frame rails for a 6x6x6 of my own after giving up on finding a Sassy Chassis.I have a question about the motors. Did you have to come up with some sort of triple Y from the ESCs to the reciever?

    Nolan

    24 Nov 10 at 12:44 pm

  2. Thank you! The key to travel stability is the lack of torque roll from the motors. I definitely do run the truck somewhat conservatively though. Not much crazy jumping and such.

    In regards to the triple Y setup- that is exactly what I used. It is very straightforward with white to white, red to red, black to black straight pin cabling.

    Also assuming that you are using all three ESCs of identical make and model, you can also safely leave the battery eliminator power active across all three ESCs. This will allow for plenty of servo power for steering, and won’t bog down any single ESC. Or you can disable the BECs or just run dedicated power for the servos- whichever way is comfortable with you.

    Don’t worry about not finding a Sassy chassis. I think they are a bit on the short end, and you will most likely be able to build a superior chassis on your own. Please keep me posted, and good luck with your project!

    Tijger Tsou

    24 Nov 10 at 5:04 pm

  3. I am planning to run a triple brushless setup; I’ve always wanted to incorporate brushless into something and this seems like as good a time as any.

    I’m waffling somewhat on a suspension setup.I find multi-shock setups too stiff on my other clods so I was contemplating running cantilevers, but a 6x6x6 Clod is heavy so 2 shocks per wheel may be fine.

    I almost have the parts ready for the chassis to go together.I’m working on the round stock cross members and the 4 link stanchions.I hope you have no objections to the use of your design for them, but I find it brilliant. I’ll give credit when I decide to do a build thread. My frame rails are different, however.I found some sturdy aluminum channel for those. I’d also like to borrow from your upper shock mounts.

    Nolan

    25 Nov 10 at 2:52 pm

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