This is Mammoet, a six wheel drive, six wheel steering monster mutant truck.

It was built from a Tamiya Juggernaut 2 and TXT-1 truck kits, both of which were originally 4WD vehicles.

So without further ado, some answers to frequently asked questions…

How big is this thing?
The truck is about three feet long, 20″ wide, and closes in at 24lbs.

How fast does it go?
It is meant to be a scale truck, and has a top speed limited to 21MPH.

What powers this thing?
This is an electric powered truck. The ’standard’ for electric are 6-cell rechargable battery packs that usually come in a stick form factor.
The average car model takes one stick pack. This truck consumes three at a time.
Two stick packs drive the motor, and one stick pack is dedicated just to run the electronics and radio gear.

The current trend of new trucks is to go with nitromethane and alcohol powered ‘glow fuel’ engines.
However they are much louder, definitely get messier, and require more maintenance to get running.
Don’t get me wrong, i love nitro power too, but it does not fit well on a scale-type rig like this.

How long do the batteries last?
It depends. On a standard 2400mAH ’sport’ pack, the truck gets about 10-12 minutes of full driving per set of packs. The electronics battery lasts about 30 minutes.
Yes, i do own bowling ball bags, filled with batteries

What is this rig based on/inspired by?
Well… honestly Mammoet is not entirely to scale, as the body is 1/14th from the Tamiya Ford Aeromax kit, while the rest of the drivetrain comes from the 1/10th Tamiya TXT-1 and Juggernaut 2 kits. It’s sort of a fantasy mishmash of things.

In terms of inspiration, the long discontinued (and now highly valuable) Tamiya Toyota 4×4 Pickup Bruiser kit is what got me going. The Bruiser featured a variety of goodies such as:

• Three speed manual shifting transmission with 2WD and 4WD modes.
• Steel chassis, and many metal parts for scale realism.
• A hard plastic body, with further scale realism amenities.
• Authentic leaf spring suspension.
• Large RS-750SH motor (most kits that time had the smaller RS-540 sized motors).

Although the Bruiser and its predecessors were legendary, they had a number of shortcomings too.

• Despite being largely metal, the bulk of the metals were diecast pot alloys. They were somewhat delicate!
  • The trucks of this design did not have rear differentials.
  • Front differentials were just a ’slip’ design using a failure-prone one-way bearing.
• The transmissions shifted with gears in motion, as opposed to gears always in contact shifting via nubs or synchromeshes.
  • This meant the opportunity to grind gears during misfired shifts was a dangerous thing.
  • The stock transmission did not come outfitted with ball bearings.
• The steering linkages were less than desirable on most models.

But all of that having been said, Bruisers were really fun trucks to drive around.

Their leaf sprung suspensions gave them a really scale ride which simply has to be witnessed. Their shortcomings are among the things that made them interesting.

I tried to address some of these with this project. The name Mammoet sort of stuck, after i thought about a good name for the truck, and couldn’t come up with anything that sounded cheesy. Mammoet features the following:

• Three-speed manual shifting, with Tamiya’s more modern transmission from the Tamiya Big Rig series of trucks.
• Leaf sprung suspension, in the form of long travel, dual-ellipitical leaves facing one another. This design was inspired by Amish horse-drawn buggies of all things!
• A brushless electric motor. Just one would be needed to move this truck around with authority.
• An adjustable slipper clutch, to keep the driveline from melting.
• Six wheel crab-type steering, for ‘agility’, since this thing is going to need any help it can in that department!

Are you insane?
Well, i really hope so.

How long did it take to build this?
I started this in late summer of 2003. It was structurally complete about four weeks later.
The truck then sat around for a while and i had resumed work in summer of 2005.

Why not build the real thing?
Because i don’t have the estimated $200,000 in cash lying around, nor the storage space or garage to house this thing. Forget about the support equipment like one hell of a flatbed to transport it on, and the space to actually drive it.
Yup, this version of the hobby is much cheaper.

What’s the turning radius?
Surprisingly… about three and a half feet. For a truck of this size, and without using high-torque servos on the axles, it steers rather well.

You spelled ‘Mammoth’ wrong.
Well, the name comes from Dutch for ‘Mammoth’. Too many things are named ‘Mammoth’ so i figured it would mix it up to do something different yet recognizable.
Mammoet is also the name of a Dutch-owned heavy lifting and transport company.

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

• ESC – Jeti Master Car Sport, 12 cells. These days, i would go for Schulze or Castle Creations instead.
• Motor – Hacker C50L, 11 turn. A nice beast of a brushless motor.
• Wheelbases
  • Front to mid axle – 16″
  • 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 – dual-facing elliptical leaf springs, stayed with 4-links, dampened with coilless HPI Savage oil units, 80 weight oil.
• Steering – Claw type, 6WS. Front axle moves opposing the rear and middle axles.
• Balance – Almost 50/50, CoG about 1″ above the tires.

Links and Resources

• http://www.scale4×4rc.us/ – An excellent bulletin board catering to scale 4×4 radio control enthusiasts.
• http://www.tamiyatrucks.com/ – Tamiya’s official bulletin R/C truck bulletin board.
• http://www.tamiyaclub.com/ – A commercial site, but an excellent resource where builders can display their older (and newer) Tamiya models.
• http://www.sherline.com/ – Sherline, a maker of excellent tabletop machining tools.

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.

• Tiamat’s Picture Gallery

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.