So over here, I posted asking for advice about building an RC car. I suppose I should share my progress (particularly since there aren’t many threads about this on the Dope).
I’ve been building and modifying a 1/10 scale electric RC model since January, the Tamiya Plasma Edge II. It’s a novice-level hobby grade buggy based around an on-road chassis (the Tamiya TT-02) with off-road suspension. It has a shaft-driven 4WD system and comes with a brushed motor, but the included speed control is brushless-compatible.
Originally, I built it using exclusively stock parts, other than a Futaba servo and Tower Hobbies-branded transmitter and receiver (since these are not included with the kit). Here’s all the boxes as they arrived from Tower. Here’s the unboxed buggy kit (section 1 of the instruction manual shown). Note: I recommend not working directly on the beloved Ethan Allen dining table your wife inherited from her grandparents, if you have a choice.
I was relatively far along before I remembered to start taking pictures of the build. Here’s the tub chassis with the front and rear differentials installed, as well as the front and rear lower suspension arms, front driveshafts, and the motor. Here, I’ve installed the upper suspension arms and propshaft. As you can see, pretty much everything in the kit is plastic, including the “dogbones” that serve as the hinged portion of the driveshafts (metal pints are molded into them).
Here and here are close-up views of the front suspension assembly with shock absorbers now attached. The shock absorbers are also plastic, but the dampers are oil-filled. Putting together the chassis, suspension and drivetrain was relatively simple. Tamiya’s instructions are excellent, though they could do a better job of keeping similarly sized fasteners separated in the parts bags.
Now, the first scary bit: hooking up the electronics. Here you can see the kit-included speed control (center), non-included radio receiver (center right), non-included steering servo (bottom right), optional receiver-mounted on/off switch (right), and a non-included NiMH battery (left), all connected while I tested the servo.
Unfortunately, I lost the pictures I took after this point, at least up until the chassis/electronic assembly portion of the build was completed, which you can see here. Note the neatly bundled speed control and motor wires (the orange, yellow and blue stuff). The servo is underneath the speed control (the thing with the metal vanes sticking out).
The kit comes with a receiver box that shields the RC receiver from dust and dirt. I didn’t use it because it is enormous and sat right up against the motor, in the space where the wires are in the image above. You can just about see where I mounted the receiver sans box under the wires. If you use the receiver box, it mounts to the chassis with double sided tape, and if you don’t use it the receiver is mounted to the chassis the same way (the speed control is also mounted to the top of the servo casing that way).
Next up was the body. I should have taken a piece of the single Lexan mold that incorporates the body and wing, but didn’t. You have to cut out the body and wing, which can be really hard due to some of the angles. Then you have to paint it. The body is supposed to be painted blue, but I wanted a black and yellow look to complement some of the decals and the yellow wheels. Here, I painted the body in metallic black and left it to dry. I masked off the windows and used Tamiya translucent yellow for them. You paint the inside of the body so that it functions as its own clear coat and gives a glossy finish, even if you did a bad job spray painting (as I did). I also made a major mistake in the paint process by using a generic black metallic enamel spray instead of polycarbonate-specific enamel. Non-poly-specific paints don’t flex well, so they tend to chip and flake when the body flexes with impacts, jumps, rolls, etc. So now areas of the black bodywork have small flakes of paint missing. The kit comes with decals that go on the outside; I thought they were too fussy and used only about half (and cut off parts of those). Here, I finished painting the wing and applying decals, and mounted it to the body.
Speaking of which, here is the finished product! If you look at the body near the top of the front shock absorbers, you can see where I made a bit of a botch of the body cutting process. However, other than that it was cut rather well. I was particularly pleased with the way the translucent yellow windows came out.
The car runs fine in stock form, and if I was building this for a kid I would have left it at that. However, one trip to the local track revealed that it would need upgrades to be a competitive racer (even at the club “novice” level).
The first thing I did was swap the kit-included plastic bushings for Acer ball bearings (shown in the picture is the front of the main propshaft; at the top, you can see the steering servo). In fact, I recommend that anyone building a Tamiya kit do this during the original build process because the bushings can wear down metal parts that turn inside them, no matter how well greased they are.
After that, I went a bit nuts, but didn’t take pictures as I went, so the following pictures were all taken in the last week even though I’ve been fitting new bits gradually for months. Here you can see the front carbon fiber shock tower and turnbuckle upper suspension arms that I replaced the kit plastic bits with. You can also see silver aluminum lower arms from GPM, although they look almost black in this lighting. What you can’t see is a replacement steel hinge pin assembly (that holds the lower arms on the chassis) after the stock “u-pin” bent in a particularly heavy accident and tore the plastic lower arm.
Here you can see the aluminum propshaft (long blue thingy) and steering assembly (C-shaped blue thingy on the right). You can also see the receiver box - it’s the large black box ahead of the motor that says Tamiya. I started using it after I realized the receiver was filling with dust. Here’s a better view of the steering assembly. The propshaft and carbon shock towers are Tamiya parts, while the steering assembly is from a third-party manufacturer named Eagle Racing. The battery holder has been replaced with a silver aluminum item from GPM. You can also see the alloy front lower arms more clearly here; note the stock black plastic ones at the back.
Here you can see aluminum shock absorbers from GPM fitted at the rear. The rear shock tower is now carbon fiber, but it’s hard to see the weave because it’s dusty. The rear upper suspension arms have been replaced with turnbuckles, like at the front. Perhaps most significantly, you can see a Trinity Monster Max 17.5 turn brushless motor that I replaced the standard 25T brushed motor with. I hadn’t soldered the speed control connectors on yet, so you can see the positive (blue) wire hanging just above it with the end stripped. I bought the motor “slightly used” from a guy at my local track, unlike everything else which was new.
I re-learned how to solder over the weekend and connected the new motor. My soldering skills are not great since I haven’t soldered anything since about 1993, but I was able to connect the motor without shorting anything. I’ll post pictures of the connected motor later in the week. My non-scientific observation suggests the car is now at least twice as fast at the top end as it was in stock form before all the upgrades (around 50 mph versus 20). I’m going to try testing the top speed with a cellphone app, or maybe pick up a GPS speed tester.
Stuff you can’t see that’s been replaced: nearly all the running gear. I switched the plastic motor mount for an alloy one from Tamiya. I also replaced the spur gear with a smaller one that comes with a removable holder, to allow a broader range of spurs to be fitted. I’ve replaced the spur gear and pinion gear twice each while I experiment with gear ratios; currently I am using a 22T pinion and 68T spur, but I will probably switch the pinion to a smaller one (18-19T) since the new motor doesn’t need a big one. Not incidentally, I stripped some of the spur gears until I learned about proper gear mesh.
I also bought a 5000 mAH 2-cell lithium polymer (LiPo) battery; it lasts several times longer than any NiMH battery and gives constant current regardless of how much charge it has, whereas NiMH or NiCad batteries give less current as they run down (even at, say, 80% charge).
In case anyone was wondering, I didn’t choose that rather lovely blue color that most of the alloy upgrade parts came in. Anodizing them in light blue just seems to be The Way that RC manufacturers denote alloy upgrade parts; any aluminum Tamiya “hop-up” will come in that color, and most of the third-party manufacturers follow suit. Keen observers will note that the Tamiya propshaft is a slightly darker shade than the Eagle Racing steering arms. GPM’s stuff is all available in a range of colors, which is why the replacement dampers and front lower arms are silver.
I have replacements for the remaining suspension components from Eagle Racing on their way, as well as ER steel driveshafts to replace the dogbone assemblies. I’ve also ordered a set of alloy dampers for the front from GPM, since the rear replacements worked well. At that point, every single moving part will have been replaced except for the differentials.