This post was originally published on the PTC blog as “Formula SAE Takes Engineering Beyond Theory.”
When my friends and family hear that I’m going to a student racecar competition, they often assume it’s a competition for building the best model cars, or that it involves driving remote-controlled cars around a parking lot. In reality, the FSAE competitions are huge events that involve over a hundred teams, each bringing a self-designed and self-built Formula-style race car.
My team, Knickerbocker Motorsports, attended the FSAE competition at the Lincoln Airpark, a quiet airport whose traffic is mostly small, regional planes and military aircraft. Our journey from New York City started on June 16, and we arrived in Lincoln, Nebraska just in time for the first day of competition on the 18th.
Day One: The first day was spent waiting in line for a technical inspection. During technical inspection, the car gets scrutinized for safety by professional engineers (“scrutineers” in competition lingo). Inspection ended for the day before our team made it to the front of the line, so we were forced to come back the next.
Day Two: In contrast to the first day, the schedule was jam-packed with static events. We arrived at the competition site early and headed straight to the tech inspection line, where the scrutineers found some minor issues with how our safety harness was attached to the frame. During inspection, two team members split off to answer questions about the car’s bill of materials and to pitch the car to a panel of mock investors. We regrouped after lunch for a three hour sprint to make the scrutineers’ modifications, a deadline we barely met for our 3 PM design event.
We set up posters demonstrating the various steps we followed in the engineering process, and a second round of tech inspection showed that our car weighed 483 pounds, which was over 40 pounds lighter than last year and made this car the lightest in our team’s history. The only downside was that more adjustments had to be made before we could pass tech inspection and start other events. From dinnertime to 6 AM, the team painstakingly drilled tiny holes into a few dozen nuts on the car to minimize the risk of the nylon in the locknuts from melting, and after a brief breakfast we were back in action.
Day Three: Our car passed tech inspection early in the morning and completed the acceleration and brake tests shortly thereafter. But we fixed one issue and discovered another: Our battery had died. While a scouting team was out finding a replacement at a local store, we achieved a 59.4-second autocross lap time despite a malfunctioning differential that hampered the car’s ability to corner properly. We managed to replace the fluid in the differential that evening before a thunderstorm forced all the teams to pack up for the day.
Day Four: The final day went by smoothly compared to the others. We spent the morning preparing the car for a grueling endurance event, where teams drive their homebrew creations for 22 km without making any repairs. It’s so intense that nearly half the cars that start don’t make it to the finish line. We had run into some mishaps during prior years (including one year where we ran out of gas), but this year completed the event without a hitch.
Out of 80 teams with internal combustion cars, we placed 8th in cost efficiency and 35th overall, a huge improvement from last year’s 77th overall. Many of these improvements were made possible by our use of PTC software when designing our race car.
Thanks to finite element analysis, the hubs on this year’s car are half the weight of last year’s. And the FEA last year made those half the weight as the year before! PTC Creo software also allowed us to to analyze our chassis design, and we found that by moving certain tubes we could increase the rigidity by 65 percent without increasing its weight.
Another area our team improved this year was the design of the of the wheel assembly. The ability to import a wide variety of computer-aided design (CAD) formats created by manufacturers reduced the time needed to model various suspension parts. After creating an entire kinematic suspension assembly, we found it much easier to reduce wasted space while ensuring that everything would assemble properly. Combined with weight reductions, modeling the entire wheel stack-up enabled us to create a car whose overall speed is competitive with the top 20 teams.
And the competition this year may be over, but we are already working to make improvements to next year’s car.