Tamiya Fighting Buggy Project

Page 1: Assembly

I have previously built the Sand Scorcher which uses the very similar SRB chassis. Please see that page for a more detailed explanation of the build process. Here I will focus primarily on the differences and unique features of the Fighting Buggy.

You can tell that this is a premium Tamiya product by the packaging. Inside the large box with the beautiful cover are a pair of blister packs book-ending a blue hard shell body. Among the metal parts displayed are the gearbox housing, the shocks, and the suspension arms.

The gearbox uses a sintered (or possibly cast) metal housing with 3 internal gears. The fastest moving gear is brass and the others are nylon. Note that there is no differential gear here; the lower gear shaft drives the wheels directly. Once the gears are greased and the housing halves joined, the universal joints can be added. Since this model has swing arm suspension, these u-joints connect directly to the outdrive axles. Another point of note, unlike most Tamiya models this kit comes with full ball bearings and hex hardware.

Now we'll flip the gearbox around and install the suspension arms. There are only lowers here so the camber changes with suspension travel. While the SRB uses torsion bars attached to the arm rotation axis and running forward, this chassis uses rods facing aft to connect to the mono shock. In the right hand image the motor has been installed along with the protective clear cover. The rear axles have also been inserted.

This rear view shows how the suspension arms are connected to the cranks which will support the shock. You can also see the rear bumper and the "FS" shield. Since "FS" doesn't stand for either "Fighting Buggy" or "Super Champ", I am going to guess that it is supposed to mean "Floating Suspension".

The kit comes with two sets of pinion/spur gears: 65:20 (3.25:1) for speed and 70:15 (4.67:1) for torque. The gear mesh is not adjustable which is why only fixed combinations of gearing will fit. I chose the higher speed gearing, shown installed here with the clear protective cover. This old buggy is pleasantly fast with this arrangement, even with the stock motor.

The included aluminum mono shock is not like anything I've seen before, and seems to have evolved from the somewhat leaky version of the original. This version has double rod seals and a delrin guide ring. It is actually built much like a TRF shock and performs very well indeed.

The shock is mounted between the rear crank arms and then an inverted oil bottle is installed above with a silicone tube between. This allows the fluid to expand into the reservoir as the shock is compressed. You can also see the progressive coils on the springs. The coils are much closer together (lower pitch) at the ends than in the middle.

The metal roll cage is nearly the same as that on the SRB. It protects not only the driver but also the shock bottle and motor from impacts.

Now the rear gearbox and suspension module can be attached to the lower chassis plate. On the SRB you would see torsion bars here, but on this model there are only some vertical standoffs for attaching the upper plate.

The aluminum front oil shocks are the same as those on the SRB, but the servo saver is different. The SRB uses a wire for a saver spring, but this model uses the more familiar tapered wedges held together with a compression spring. The forward body mount is integral.

The front suspension is taken directly from the SRB with no changes. It uses trailing arms and torsional springs connected by lateral tubes. All metal. The ball joints snap into white plastic sockets which I assume are a wear item.

Now the front suspension module has been attached along with the front bumper. The servo saves goes in next followed by the steering servo which is bolted to the lower chassis plate.

The use of an additional upper chassis plate has the potential to greatly increase the bending stiffness of the chassis, but in practice this one doesn't do much because the rear mounts are slotted. This is to allow easy removal of the upper plate for battery access. There is no room for a full size battery here, instead the model was designed for an unobtainable Li-Fe battery. I am using a small Li-Po.

The body is a beautiful one piece hard shell which I painted in metallic blue. The portion of the roll cage integral to the body is red. The decorative stripes are the same as the original, but all of the sponsored decals are gone and replaced with generic. For example, what was "Budweiser" is now "Major Pro". The set includes a half driver figure and netting for the side windows. The body attaches with 3 body clips and also snaps to the roll bar. It must be removed for battery access.

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