Tamiya’s latest radio control car takes the form of the US Army’s Jeep replacement, the Hummer, and we think it’s one Tamiya’s “classics”.
Marcus Nicholls builds and runs the new kit,
and adds a Desert Storm bodyshell …
When the US Army introduced the AM General Hummer (sometimes known as Humvee) at 1984 Farnborough Air Show, the vehicle rapidly became the accepted as a capable replacement for the ubiquitious Jeep.
Wherever you see US Armed Forces these days, chances are you will also see a Hummer, in on of its many manifestations. The basic vehivle is designated M988 (M1038 when equipped with a winch on the front fender), and is by far the most numerous variant around.
The chassis of a real Hummer is steel, with aluminium body to save weight. Suspension is all round independent, featuring coil springs and double action shock absorbers. The powerplant for all variants is a General Motors 6.2 litre (379 cubic inch) V8 Diesel the develops 150hp – not much for such a vehivle you might think, but that huge diesel engine generates a vast amount of torque, which is more important than quick 0-60 mph times.
The power is delivered to the wheels via a three speed automatic transmission, also built by GM. Full time four wheel drive offers excellent traction, and a “central tyre inflation system” (CTIS) has been developed, allowing the crew to inflate or deflate the Goodyear Wrangler RTII tyres from inside the Hummer to cope with extreme terrain conditions
Takes off over
rough ground
Enter Tamiya
Tamiya already offer two Hummer kits: the 1:35 scale M242 with Bushmaster cannon, and the more recent 1:20 scale M1025 in the Collectors Club Series, which is supplied in a pre-painted and semi-assembled form. It is the latter variant that company’s latest kit is based on, and the thrill is that it’s a fully blown radio control model!
Anyone who has built a Tamiya 1:20 scale RC touring car kit will instantly recogniese the Hummers’ TA01 4WD chassis, as this forms the backbone for the new kit. By cleverly tweaking a very well proven and easy to maintain unit, Tamiya have given more life to this design, and it even looks and functions like the chassis of the real Hummer!
The front diff works hard to keep all
tyres moving
Altered spec
Some changes have been made, but they are not immediately obvious. For a start, the whole chassis is longer, as are new wishbones. A set of four superbly detailed wheels are supplied, fitted with chunky Wrangler tyres. A host of other smaller changes can be seen such as new body posts, but you still have the solid TA01 Four Wheel Drive chassis in the centre.
The bodyshell is a stunning item, supplied as a huge one piece moulding in ABS plastic which is tougher than regular styrene. It’s coloured olive drab, but some work with airbrush will be needed for realism. Lifting lugs, front indicators, wing mirrors, weapons turret and glazing are all moulded separately and attached using small screws and dabs of cyano glue.
Tamiya have slightly altered the way assembly progresses with this kit. Stages 1 through 9 use parts from “Metal Parts Bag A”, then changes to “Metal Parts Bag B” from stages 10 to 17 and so on. Before, you had to jump between parts bag throughout construction – this new system is far more logical and easier to follow.
The first assembly encountered in the 21 page instruction book is the rear differential. This is a ball diff, and careful studying of the assembly sequence will be needed to make sure the various washers and ball races are stacked in the correct order.
The result is a neat drum unit which drops into a larger rear gearbox housing. The rear gearbox ~ also carries the 540 motor, which is Ithe standard item and more than capable of shifting the model at 11: distinctly non scale speeds…
The front differential is next, and this is a less sophisticated hut tougher geared unit. Add plenty of grease and it will last forever. Again, this drops into the front gearbox moulding, followed by a set of gears that take power offthe longitudinal steel propeller shaft from the rear gearbox. This system is not as efficient as a belt drive hut it has proved to be bullet proof in operation, and once built, needs virtually no maintenance.
The new wishbones are added to the gearboxes, trapping the steel drive shafts in the process. The instructions say to add grease to these, hut we fan OUTS dry to prevent dust from sticking to the exposed lubricant.
The Dampers
Dampers
Like the real vehicle, the kit comes with oil filled shock absorbers, and these require patient assembly to prevent air bubbles flom collecting in the oil. Once screwed tightly together, the dampers worked beautifully in conjunction with the chrome coil springs. We were going to spray these black, but soon realised that the paint would crack offmessily when the springs flexed, so they were left chrome!
We chiselled the TMMI office radio control gear flom the Calsonic Primera and fitted to the Hummer chassis tub -this must be the tenth RC car that this outfit has been in!
Set up is carried out with the transmitter and receiver switched on so that the steering servo is in neutral je; exactly halfway through its arc. The servo saver (stage 23) can then be screwed on in the correct position, with small adjustments made by altering the length of the tie Tods, and final tweaks on the transmitter trim tabs after assembly is complete.
Following the instructions, the front and rear gearboxes are screwed onto the chassis, not forgetting to insert the prop shaft into the power take-offs.
The tyres are slipped onto the specially designed wheels and secured to both inner and outer rims with a drop of superglue. This might not seem to be necessary as the tyres are a tight fit, hut when power is applied during driving, centrifugal force makes the tyre expand and the wheel will slip, causing a loss oftraction and control. The new design body mounting posts were screwed onto the darnper frarnes, and the Hurnmer’s chassis was complete.
Painted bodyshells
Crisley detailed bodyshell
Bodyshell
There are two approaches to model car bodyshell production; blow moulded lexan items, and solid injection moulded shells. Lexan bodies are designed primarily for racing -they are lightweight, the paint won’t scratch off in a crash and they are virtually indestructible. The down side is that blow moulding can not incorporate the same level of detail that injection moulding can offer, and so RC models such as the Hummer tend to use conventionally moulded bodies.
This kit includes such a shell, and the surface detail is of the same quality as Tamiya’s 1:35 scale kits, in other words, awesome! Rivets, bolt heads and panellines are reproduced very crisply, making this as much of a scale model as an RC one.
Painting was carried out just like a smaller scale model, using Tamiya Acrylics colours; XF65 Field Grey, XF64 Red Brown and XFI Flat Black. The XF65 was modified slightly, adding more green, and the XF64 was toned down a little as it seemed a bit “fierce” straight from the bottle. We mixed our paints with cellulose thinner which helps the paint adhere to the plastic. The green was airbrushed first, followed by the brown and finally the black, using the illustrations in the instruction book as a guide. A little weathering was applied using XF52 Flat Earth, with a large drop ofX21 Flat Base to give a dry, dusty look. Markings, glazing and wing mirrors etc were added once the paint was dry, and the Hummer in European scheine was complete.
A second bodyshell was sprayed in a Desert Storrn scheme of overall XF59 Desert Yellow, with the distinctive “inverted V” Allied identification marks sprayed on the sides. The sand scheme changes the look of the Hummer, and makes a nice contrast to the dalkeT camouflaged machine.
Driving the Hummer…
With a fully charged Tamiya 1700 SCRC nicad pack inserted into the slot in the chassis, Tamiya’s new Ml025 Hummer was ready tor action. Full power was applied and the Hummer sped off in a cloud of dust across OUT improvised test area (a local unmade car park).
The weight of the injection moulded bodyshell makes the model a linie top heavy, as we found to OUT peril. We watched in horror as OUT speeding model fit a patch of clean tarrnac in a corner, suddenly gaining lateral traction and flipping up, rolling three limes before coming to a rest on its roof. We rushed over to the crash sight and inspected the car. Luckily, very linie damage was clone to the Hummer, hut cornering was taken a linie more carefully tor the rest of the test drive. A case of driver error we think…
The Hummer is definitely suited to off load motoring, especially on sandy or dusty surfaces where the hard and high Wrangler tyres allow the vehicle to drift in impressive power slides. It is at this point that the need to superglue the tyres to the rims becomes apparent, as the wheels can spin inside the tyre, or pop off the wheels completely.
Driving at full speed over an area of undulating dry mud bumps, the Hummer looks awesome, the dampers working hard hut fIawlessly to keep all tour tyres in contact with the ground. Four wheel drive is essential in a vehicle of this type -you will be going off road a lot, and traction at each corner is a must. A group of children had gathered after a few minutes of driving, captivated by the clouds of dust and the squealing of the motor as we blasted the model across out improvised sand dunes. A word of warning hefe -people of all ages love to watch RC cars whizzing about, hut keep the model weIl away from spectators at all times, if you lose control it can cause injury…
The drawback with all this dirt blasting is that the chassis tub quickly fills up with sand and dust. If dry, it can simply be tipped out, but the task becomes rather tedious if you have been driving in muddy conditions. It’s important to clean the car after each running session to prevent it working its way into the mechanical components. A large, soft decorating brush comes in handy für this task.
Summing up the Hummer
The sight of this model zipping around is very dramatic, made all the more so by the fact that it represents a modem military vehicle that’s in service all around the world, adding to the realism. The Hummer’s body is a süperb piece of injection moulding, and coupled to the highly successful tour wheel drive chassis from the touring car kits, this model is a winner. We are waiting to see who will be the first to convert this kir into one of the many distinctive Hummer variants…