Spirit Racing Systems

Not only do I excel in the classroom, but I also have tons of hands-on experience. This comes mostly through an activity called “buggy”, for which I was my organization’s head mechanic, data and analytics chairman, vice chairman, and build lead.

What is “buggy”?

Buggy is a race that happens every year at Carnegie Mellon between many student-led campus organizations. For buggy, we design, build, and maintain composite-based free-rolling racing vehicles (called “buggies”), and compete with other teams.

Through buggy, I taught myself how to use ANSYS Fluent and applied MATLAB and SolidWorks beyond the classroom. Beyond mechanical maintenance, I have learned many fabrication techniques.

I have gone through a design process for creating wheel fairings, beginning with the ideation of different profiles, giving a preliminary design review, and finally fabricating fairings for use by the team (the first ones on our buggies in over 20 years!). This was an iterative process, where I conducted research to come up with a design that marries aerodynamics with ease of manufacturing and minimizing weight, while at the same time minimizing heat transfer. I am also currently the build lead in many of our ongoing projects, including building a new buggy (which will be our first one in 6 years!).

From buggy I learned many technical skills, as well as how to be a better leader

As head mechanic, I was more than just another mechanic

I trained my mechanics in everything that I knew at the time - from changing wheels, to loading and carrying drivers, to fabricating more parts. They are the future of the team, and as a leader I had to make sure that they were ready for the next steps within the team, as well as the next steps in their lives.

In addition to teaching them about buggy, it was also my responsibility to help them develop professionally. Many are mechanical engineers, and I was able to relate what they were doing back to coursework, and they got an appreciation for how their classes are used in real world engineering. For the non-mechanical engineers, it gave them an opportunity to get hands on experience, as well as the opportunity to work in an interdisciplinary team.

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A buggy rolling around the course

Buggies are made of carbon fiber with a LEXAN windshield, three polyurethane wheels, and come fully equipped with a braking and steering system. The stick coming out of the top is the pushbar, and it is how a pusher interacts with the buggy to give us our propulsion.

A mold in progress

This is a quarter of the mold for a new buggy, before it has been attached and epoxied together.

A mold one step further

This is that same mold, having been lined up, epoxied together, spackled, and sanded to create the smooth shape that our designs require. This is a different quadrant than above. Each team has developed their own process for building buggies, and because of the competitive nature of the sport, the exact steps are closely guarded secrets.

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GPS data of a buggy rolling around the course

This is an example MATLAB output of a driver rolling around the buggy course. It gives speed, latitude, and longitude, as well as plotting it on top of a Google Map. The distances put on the wheels during each roll around the course are added to a separate wheel database that is updated every time the code is executed.

This was a project that I started at Spirit, and it allows us to compare driver lines, different wheel types, and inform our choice of pushers.

Satellite view of course and driver trajectory

This is the MATLAB output of the GPS data plotted on a satellite map. This is the same as the plot in the video, only with a satellite background. It uses a Google Maps Static API call to plot the map behind the GPS data, which is reformatted to WGS84 coordinates.

Gradient of driver speed and basic analytics

Along with the MATLAB output above, the program outputs a gradient of the driver’s speed throughout the course. It also gives max speed and hill 2 pushoff speed, and various times of interest (such as the freeroll times, hill times, etc.). The freeroll times are used to test the properties of different wheels and heating techniques, while the chute loss is used for testing out and comparing different driver lines. The hill times are used for pusher selection.

Speed-time plot

This outputs the same information as the gradient plot. In addition to the other information, the plot contains the location in the roll where certain markers occur (such as the hill transitions), allowing for easy viewing of where speed gains and losses occur.

A pusher database is automatically updated that assigns the hill times from each roll to the pushers. This is used in selecting pushers for raceday.

Gradient-Line Plot

Combining the best of both worlds, the gradient-line plot shows the overhead view of the driver’s roll on a Google Maps satellite map. The path is colored based on the smoothed speed data from the roll. The points of interest are drawn as lines along the course.

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Wheel fairing

The SolidWorks assembly of the final fairing design. It utilizes a low hatch angle to allow for lower coefficients of drag, as well as a rear upswept section to create a diffuser.

Side view of fairing

Here is a render of the new fairing attached to the CAD for a buggy. This was done to confirm clearances and geometry.

CFD on final fairing model

Here is a 3D computational fluid dynamics simulation on the model of the fairing. This was used to confirm higher conversion of dyanmic pressure into downforce.

Fairing on the buggy

Here is an initial prototype fairing on a buggy. It was fabricated with simple wet-layup techniques using Fibre Glast System 1000 resin and 3k twill weave. After attaching the two halves at the seam with strips of the same carbon fiber, it is filled with 8-lb pourfoam.

Note that this is using an older iteration of the fairings, and not the ones seen above. The above fairing was redesigned to reduce weight and improve aerodynamic efficiency.