As part of the continued evolution work for the Traxxas 1/16 chassis, I have been looking into ways to stretch the wheelbase for stability and center-of-gravity purposes as well as to give me a platform to improve on the odd proportions defining my body-shell designs.

Working on an idea for long 'tusks' on the nose of the rXA, I realized I might be able do away with the entire standard Traxxas front bumper and mounting assembly and replace it with a bracket and beam setup (similar to the latest LMP wing mount).

To take full advantage of aerodynamic downforce, the chassis needs to provide a rigid foundation for the wing to act on. Previous iterations of my wing mount were prone to flexing. Throw in a crash or two and they would eventually fail entirely.

Prototyp is celebrating its fifteenth birthday with what is effectively a re-launch: a completely new website, new model designs, and new project cars. All of which deserve a new graphic theme and a new logomark.

The 1/16 Traxxas VXL is one of very few rocker-arm-suspension R/C chassis available, but even this compact layout still brings a major challenge to creating low-drag, low-frontal-area body designs. The lowest and narrowest possible roofline is defined by three critical components: set high and wide across the middle of the chassis are the receiver box on the left, the Velineon 380 motor, and the speed controller and its chunky motor wires on the right.

The cardboard stock I use is perfect for prototyping parts. It's very stiff and nearly the same thickness as 2mm Stratocore, and it's cheap (well, free with purchase of Bisquick from Costco).

Toward the end of the GTP and Group C era, the quest for downforce lead some teams to a double-wing setup. Jaguar, Toyota, Joest, Peugeot and many others ran short tails and double wings, usually with massive endplates. The large lower wing was just off the trailing edge of the deck and effectively functioned as an extension of the underbody diffuser tunnel system, while the upper wings tended to be more compact and run at shallower, less-drag-inducing angles.

The most recent build of the LMP revealed more dimensional problems between the source CAD model and the physical chassis. Since several parts were going to need to be revised, I made the update an opportunity for further refinement of the design concept.

Most successful livery designs place at least a few colors together to form borders of larger color areas. This makes for more dynamic color transitions and keeps the design from looking like just a bunch of multi-colored panels.

The focus on these Decim8 cycles was to generate more layered and flowing treatments on the TRX LMP.

It make take a little squinting, but some of the Decim8 outputs conjure reinterpretations of classic prototype liveries: Tulius' Group 44, Leyton House, Silk Cut, even Joest's pink Italya-sponsored car.

Running more LMP renders through Decim8 . These revisited and refined the intricate color-blocking from the early experiments. Takes a little squinting and imagination to filter out the noise, but some really interesting patterns and textures emerge.

Rapid-prototype work for the Traxxas project is done with paper-modeling techniques. Paper is a relatively low-cost way to validate the LMP body design as well as the underlying chassis model and all its various hard-points and clearances. Getting the chassis model right is important as it will serve as the basis for additional design projects.

It's taken a few rounds, but I think I've now resolved the last few trouble spots on the overall bodywork design. So let's call the design work for the TRX LMP done. (unless, as it turns out, a test build reveals there are still a few things to address)

The Traxxas LMP model got to see some simulated wind tunnel time. Autodesk Labs has a lightweight CFD simulator available for a limited time. It'll take a 3DS or STL model and run computations in a fixed-ground tunnel environment. The results are perhaps not absolutely precise but for my purposes insightful enough.

Runs of the r2 red paper test build enabled me to experiment with airflow through the bodywork. Hacking and covering various inlets and outlets, the optimal combination seemed to be an open nose intake over a splitter, running air under a modified wing-profiled bumper then leading up and out through multiple vents along the forward cowl (essentially the trailing edge of a big forward wing). More overlap down the side of the car between the front fender trailing openings and the leading surfaces of the side pods kept the airflow smooth and controlled past the rear fenders on the way to the wing.

All the cardboard experimentation I do is leading up to a set of design templates to be used for constructing the final Stratocore components.

Sad to report that the very fragile prototype LMP body has met its untimely demise. I pulled to the side of the road to make way for a passing car and drove into the couple-inch-deep fermenting algae gunk hiding against the curb around the corner. The primordial ooze dissolved the paper bodywork and cardboard prototype underfloor system; a total loss.

Test-build of the preliminary tunnel underfloor design. The Traxxas battery boxes angle up from a central low point on the underside of the chassis, so they leave some room for underfloor tunnels that the flat floor wasn't utilizing. The outlet end of the floor, and the rear diffuser, run at about the wheel/axle centerline. Aggressive, but effective...

Very rough build of the LMP evo body design using very crappy paper... Really just a fitment check and validation for the underlying model, but still can't help but zip it around on the street. This is the first time I've had a complete body, along with a useable wing and full tunneled underfloor running together.

The Traxxas runs really well with the light kit and an aero kit on. It's very fast and very stable and a good time, even in the dark.

I had intended for the aero bodywork project to be a simple "bolt on" approach which would require no (permanent) chassis modifications.

This approach imposed that many standard hard-points of the chassis be retained. The motor, the receiver radio box, antennae, the bumper... these all define the minimal boundaries of the bodywork. A place where this has probably the biggest impact on the effectiveness and appearance of the prototype style bodywork is the rear bulkhead.

After building a prototype of the twin-goose-neck rear wing and diffuser setup, it looked like it could develop even further. Also, the flat floor left quite a bit of unused room under the battery boxes which could be utilized for underfloor tunnels.

Running a very low, dynamically-loaded chassis requires precise spring and damping rates. However, the Traxxas chassis is optimized for off-road use with provisions for very long-travel suspension. Unfortunately this bias is exactly the opposite from what would be ideal for road use. In stock configuration, the front wheel rate to shock rate ratio is nearly 2:1, allowing a compact shock to take up a very long-travel load from the wheel.

LMP model needed another round of changes to accommodate some new aero ideas for the underfloor and wing-mount as well as correct some fitment and dimensional issues.

Decim8 is a brilliant iOS app designed to destroy photos through a expansive set of processors and filters. Aside from curating the selection and sequence of these filters, there is very little in actual user control. The variables built into each step ensures that no two outputs are the same.

I intended to avoid any permanent modifications to the Traxxas chassis to accommodate my new bodywork concepts. However, there are a couple relatively simple things which could be done to allow for much more optimal designs.

Took the back half out for a spin and it looks amazing in motion. Of course there are few places that can use some inner structue, and a few form things to change. Also have to build the new wing mount and rear diffuser. But still, this thing tearing down the street is pretty spectacular.

Quite happy with how this worked out. Fair bit of complex curved forms changing from the roof down the back, ridiculous to try in paper but totally worked. The character lines flow nicely from the windscreen screen down the sides.

Starting with the critical roof for fitment. Should fit like a glove over the motor, esc, radio box, and servo.

Decided to go with a clean, simple Prototyp // theme for the test build... will get to the crazy layered hexagonal themes in later renditions. Right now just need to focus on nailing down fitments and any other adjustments before moving forward with the design.

As the LMP body design continues to evolve, I needed to work out the most effective airflow management approach for the sidepod design.

I had a custom chassis-mount light kit built for me by Alpat Tugay via eBay. The whole rig is designed as a self-contained modular layer that fits onto the chassis without any tools or parts modifications. I wanted to be able to easily install the kit for occasional night runs, but leave it off and out of the way for daytime running.

As my skills improve and car speeds increase, the little Traxxas Rally's instability at speed is becoming an issue. The chassis handles so much better without the bodywork on that I believe it's probably more than just a weight consideration.

Amongst the R/C boards, there's a lot of desire for stability at speed. These little cars can be juiced upwards of 70mph or more, and their short wheelbase and high center of gravity pretty much guarantee they go cartwheeling at the slightest twitch of steering. More often than not, the advice turns to adding weight to achieve stability.

Complete tear-down and rebuild of a Traxxas 1/16 Rally with a little tribute to the old Tamiya catalog end pages.