My brother Alex and I had a Traxxas Nitro Rustler when we were kids, and after a few summers of fun, it was retired and sat in a box for many, many years untouched. At one point in the past I tore it apart and performed an engine port and polish grind following a tutorial online. It never got put back together however, and it went back to sitting in a box in our parent's attic.
During a trip back home, I brought the box of parts back out to Utah and was able to rebuild the car and get it running again. This was quite the task as there were no instructions or diagrams with it. It had not been run since making the engine mods, but it fired up and with a little tuning sounded quite mean.
I started driving it around for fun, inevitably breaking something each time out, and replacing the damaged components with higher strength parts. While these parts were more durable, they did little to actually improve the car's performance, and in many instances actually degraded it as the aluminum parts weighed more than the plastic parts they replaced. I also started filming with a GoPro mounted inside a clear polycarbonate body, which produced some promising results.
At that point I decided it would be fun to try and make the car faster and improve some of the known problems with the Nitro Rustler. While a bigger motor would have been the obvious choice, I decided to take Colin Chapman's approach and add performance by adding lightness.
To do this, I determined that most of the sub frame and structural components could be deleted and incorporated directly into the design of a carbon fiber tub chassis. I started thinking about how the tub would need to be shaped to mount the various components, and determined that it should be possible to build something that would achieve this.
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The first step was to reverse engineer the main components and build the car virtually in Solidworks. Luckily I was able to find a GrabCad model of my exact motor, which saved a great deal of time.
While I was importing all of the geometry for the car, I was also working on determining and aesthetic direction for the exterior. The Nitro Rustler is a 2WD chassis with an body modeled after stadium racing trucks. I wanted to keep that heritage and retain the look of stadium truck body.
The first complete sketch of the body was drawn over an overlay of the sub components. At this point I determined that I definitely wanted to design the truck to incorporate a GoPro mounted in the cab so that I could capture first person footage.
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My plan for the construction is to utilize 3D printed molds to create a single layer laminate that would define as many features as possible. This constraint requires features to be drafted and designed so they could be laid up in the mold.
From the initial drafts of the mold, the process kept moving along, building both exterior design features and structural elements concurrently. With each adjustment, something else inevitably would need tweaked.
Eventually the design started to come together as seen in the screen capture below.
The project gets worked on when I have idle time, and is slowly progressing forward. It has come along way since I started working on it, and the virtual design process is nearing completion. I would like to perform aerodynamic evaluations and develop downforce generating features to improve handling performance.
