Tamiya Bigwig Project

Page 1: Assembly

The Bigwig is based on the Hotshot and shares many parts of the build in common, so I'm only including details on the differences here. Please see my Hotshot build page for full details.

Th Bigwig comes in a big, beautiful box with classic looking art on the front. Inside you won't find any fancy blister packs, but the parts are still nicely arranged with the hardware in a smaller inner box in the lower corner.

This is not a particularly complex build but it does come with a lot of brightly colored plastic parts trees. Many of the suspension parts are bright blue and many of the body details are yellow. There are also 5 tightly stuffed hardware bags.

The rear gearbox (shown on the left) looks just like the one in the Hotshot with the substitution of some bright colors. It uses the same differential, internal gearing, and housing. The same is true of the front gearbox (shown on the right). So far, this model is just a Hotshot.

The Bigwig re-release comes with a custom labelled motor just for this kit. It is a rebadged GT-Tuned motor with 25 turns. The original kit used a Technigold motor capable of running on 8.4V which was the key selling point of this model. The old Technigold was 21 turns, but this modern 25 turn motor is probably just as fast.

Here's where we get the first major change from the classic Hotshot chassis, and indeed from any other Tamiya chassis that I know of. This model uses rack and pinion steering. The pinion gear connects directly to the steering servo through a servo saver spring as shown. There is no linkage.

Here the steering servo and drive pinion have been installed into the bathtub chassis. The pinion teeth protrude from the bottom of the chassis. I chose a metal gear servo for this model because it seemed to me that the direct load path from the steering back to the servo had a greater potential to impart impacts to the servo than usual. It probably wasn't necessary. The wide chassis bathtub size for a 7-cell Ni-Cd battery pack is very different from the narrow channel we saw on the Hotshot.

The rack gear sits inside the yellow housing. The rubber boots which enshroud the steering rods on either side keep dust and contaminants from reaching the gears.

The suspension arms and hubs look very similar to the Hotshot apart from being blue instead of red. The rear upper arms have been changed and a shock tower added. Front upper and lower arms have also been changed to make room for shocks but still use the same unusual method to capture the pivot balls. The suspension assemblies are modular and simply bolt to the chassis tub. Note the yellow exhaust pipes and faux engine valve covers in the back of the chassis.

The yellow CVA oil shocks are pretty conventional, although the rear shocks are particularly long. The shock configuration differs almost completely from the original Hotshot by using 4 independent vertical dampers. Note that the front shocks use separate upper supports instead of a shock tower which allows the nose of the body to pass through this area.

The front bumper is huge and effectively prevents any forward impacts to the front wheels. The wheel attachment method is unusual. Instead of using 12mm hexes, it uses triangular adapters as shown which means your wheels choices are very limit. The tires use an oval block pattern which I really like for traction and durability.

With the wheels and tires installed, the chassis is almost done. An upper cover encloses the electronics and is also used as a battery hatch. It is held with a cotter pin in the back and pivots in the front.

Time to prepare the body. I was happy to see that the slot behind the driver and ahead of the rear wing is already trimmed. This internal area would be very hard to trim accurately by hand. The rest of the body still needs to be cut out though. Before and after are shown above.

The next step is to mask off the areas to be painted white so the blue can be painted first. Even though the lines appear mostly straight, this takes a lot longer than you would think. I started by taping the striped sticker to the body and using it to draw a demarcation line on the outside. I then followed this line with the masking on the inside. The results are on the right.

The body detailing is now complete. The paint has been finished, the overspray film removed, and the stickers applied. The roll cage and intake make up a separately molded part and the sheet metal roof is secured with cable ties.

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