Spee-D-Print (3D Printed R/C Car)

This is an almost fully 3D printed r/c car that fits a lot into a small chassis. Designed in Tinkercad, this 322.08mm long, 100mm wide car has all the functionality of a hobby grade car. It took every cadding skill I had. At the time of writing this, parts are still arriving and printing. I had to make every second count, every print work, every part fit, just to enter into this challenge. I was faced with many challenges and setbacks. I wasn't able to finish, But I learned a lot. So without faster further ado, here is how I made this one-of-a-kind creation so far. Also HUGE shoutout to my parents who provided financial support for this project, it would not be possible without them.

The first iteration of the design

FDM 3D printer (Build plate at least 9.25 in wide)

PLA, PETG, And TPU filament

33mm R/C Oil Shock Absorbers

25T Aluminum 3 Hole Micro Servo Saver

25T Digital Micro Servo

2.4Ghz R/C Radio Controller

Adjustable Stainless Steel Steering Links

Sensorless Brushless Motor (Shaft Diameter 2.3mm)

Waterproof Brushless ESC/Receiver

Stainless Steel U-Joint Drive Shaft, Axles, And Wheel Hexes Set

Screws

The first step was to find inspiration (OK, maybe that's not the right word, but whatever...). I looked at pictures and diagrams of some really small R/C cars, like the Losi Micro T and B, which I ended up using parts from. I also searched the web for parts, only using ones with dimensions either listed, or included in a picture. I then designed the chassis around them. (More about that later)

This is one of the most important parts of the project, if a dimension was off by even a hundredth of a millimeter, it would mess up the entire project, (OK, yes, I could sand it, but I would like to avoid that if I can, and printing already takes long enough). I searched for the smallest servos, motors, receiver/ESCs, and suspension I could afford. I was having trouble with the suspension specifically until I stumbled across something on Thingiverse. It had all the suspension parts I needed, and helped this project a lot. I also made gears, but this section is getting too long.

With the chassis and suspension all designed, it was time for the aesthetic part (well, I guess wheels are both functional and aesthetic, but that's not really important in this context). First off, the body. The chassis was almost maxed out with only a few millimeters to spare lengthwise, so the body was split into two parts, front and rear (obviously). The big scoop on the front is not just for show, it provides the clearance needed to fit the servo horn. The NACA style duct on the side, however, is just for looks. the wing in the back is a real airfoil, flipped upside down to create downforce, not lift. For the rims, I found some rim designs from a fellow Tinkercad user and car enthusiast. The rim was all misaligned due to their limitations of using a tablet. I fixed it up and added some Mustangmania flair to it.

So with the design all, well, designed it was time to print.

It was time to print, and I started with the chassis, because that was where most of the parts would go on to, and, let's just say, it did not go well. First off, there was a layer shift that occurred early on in the print. Also, there was buildup of a "Blob", basically filament that somehow goes on the heatblock, and not the bed. This was my lowest point in my project, and I almost gave up on this whole thing.

But I didn't.

On the brink of giving up, I wanted to find solutions. luckily, I found a few VERY helpful YouTube tutorials, so I cleaned the hotend, adjusted the settings, and kept on going. About an hour later, I checked on the printer, and... nothing. I had sliced the file too quickly. More problems. But this had happened before. I just re-sliced the file, and restarted the print, occasionally pausing it to wipe away some filament from the nozzle, as it wasn't fully tightened (I tightened it after it printed). This gave me a successful print, and after that, the suspension too.

I started to print the parts, and this time, everything worked. Again, I printed the chassis first. After that, I printed and tweaked several parts, like the gears, rims, lower suspension arms, and rear hubs

The first batch of parts arrived, the shocks, servo (came with some decals, which was nice), servo horn, and controller. one day later, the motor, steering links, and ESC/receiver.

Now it was time to install the parts. first, the shocks went on, and easily, although the screw stripped, so I had to tighten it with pliers. I then took small sections of paperclips, and used those to install the suspension arms.

Now for the electronics, I had to cut a few things for these to fit. The servo went in fine, but I had to cut the top bar of the mount for it to be able to go in with the horn. Next, the brushless motor. I had to cut a significant portion of the chassis, since it was a few millimeters too long. Since the motor was longer, the ESC/receiver did not fit perfectly into the spot, but that wasn't really important. the remote was not working, so I returned it and got a new one. (it will be arriving on the 18th.) I used a battery I already had, for testing, and I used a remote from one of my other cars, since it paired with the receiver.

While I did not finish in time, I got pretty far, and learned a lot from it. I will soon be installing axles, the rest of the suspension, the body, decals, and lights.