2016 - Tamiya TB-04R "Cobblestone Edition"
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I've built a bunch of 1:10-scale electric cars in the past few months, but I didn't have a proper mid-motor touring car. I decided to fix that.
I think this might be one of the prettiest bodies I've ever detailed -- and one of the most complex. The headlights alone were four decals per side, plus buckets that had to be painted chrome-silver and attached on the inside. There was also a hollow spoiler and an internal support, which had to be painted and then Shoe-Gooed in place, and two chrome bumpers and internal supports that I opted to leave off because I didn't think they looked good. The body was actually more work than the chassis, in this case. It sure came out well, I think. In case you're curious, it's a 1978 Mazda RX-3 Savanna GT, made by ABC Hobby.
The keen observer (which is to say, anyone with eyes) will notice there's rather a lot of ground clearance. I did that on purpose, because it means I can drive on crappy pavement without scraping the chassis every few feet, and it was that design decision that inspired the use of a vintage body -- so the equally "vintage" ride height would look scale-accurate instead of ridiculous.
HPI stock-car wheels were used to complement the vintage look as much as possible without having to use HPI's vintage wheels and tires, because HPI's vintage tires are just awful -- no traction at all. The tires are HPI's Super Radial tires, which will never be accused of having too much grip, but they're still better than the HPI Vintage tires and they give the car a realistic look and feel while driving.
Underneath the body, there's not much to talk about; it's pretty much a standard TB-04R chassis, with the only drivetrain modifications being a front gear diff instead of a spool, and both diffs have metal gears for durability since there's no slipper clutch. (call me paranoid.) The motor is my standard Tacon 3930KV motor, SkyRC Toro 120-amp ESC, Hitec HS-8775MG low-profile servo, and Spektrum receiver. Why mess with a formula that's worked for so many of my vehicles?
I have to take a moment to admire something about the chassis layout that is just quintessentially Tamiya, and that's the gratuitous use of right-angle gears where other companies would just change the orientation of the motor. This car has a pair of right-angle gears driven by the spur gear, which transfer power to the front and rear driveshafts (the front one being spring-loaded and removable for easier maintenance), at the other end of which are the differentials that also have right-angle gears. And yet, with low-friction nylon gears and a bit of grease, it works quite well -- and because of the motor's transverse mounting, it doesn't try to torque the chassis to one side every time you mash the throttle.
Aside from detailing the body, the only thing I did to this car that really took a lot of effort was modifying the suspension. There were two parts to that modification, the first being clearancing the chassis as shown above. Another view of just the bare chassis immediately after modification is shown below:
The same modification was, of course, made to the rear of the chassis, but there's nothing unique about what it looks like, just more of the same angled filing to allow the A-arms to droop more.
The second part of the suspension modification was actually something I stumbled across by accident by fiddling with parts while assembling the kit, and it made mounting the shocks with longer lower eyelets SO much easier: I discovered I could raise the shock tower mounts by inserting aluminum 5.5mm-diameter spacers where they interface with the upper halves of the diff cases, and using longer screws as necessary. This doesn't weaken the connection at all, because the shock tower mounts were already relying on the tensile strength of the screws to hold them in-place. The result is that almost all of the shocks' travel is used, whereas in the stock configuration the chassis would bottom-out before the shocks could compress more than about halfway. So I didn't even need longer shocks to get more travel, just creative mounting of the original shocks.
So that's my take on the TB-04R -- not really "R" anymore, since it's not raceworthy, but it works great on a bumpy parking lot or sidewalk.
I replaced the ESC on this car a few days ago. The previous ESC never quite lived up to my expectations, and since I was replacing the same type of ESC in other vehicles, I decided to do this one as well.
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