First off, apologies for the delayed writing of this blog post. As will soon become clear, the entire race crew has been very worn out and short of sleep.
The past week has been very hectic for the team, to say the least. After assembling the majority of the car in the Autobay on campus, we set off for Monticello Motor Club on July 5th to compete in Formula Sun Grand Prix.
Right when we arrived at the racetrack on the 6th, we began finishing the car and getting it ready to race. Despite high tensions caused by the huge amount of work that needed to be completed together with the low amount of time it needed to be completed in, the team pulled through and accomplished many major tasks, such as installing and testing our electrical system and solar array, as well as making important modifications that the race officials requested, including designing and adding a support bar for driver protection to supplement the rollcage.
We had been going at it all day and night when finally, at 4:00AM in the Hampton Inn parking lot on Wednesday morning, our motor ran for the first time and our car was practically complete.
The next day, after tying up some loose ends, we started going through our scrutineering checks, which are sessions where the race officials inspect all aspects of our car. The scrutineering went well, other than that they noticed a large amount of flex in our composite rib structure between the front suspension mounts. When the car was rocked back and forth with the wheels in place, the composite rib structure caved in several millimeters. After talking to race officials and getting help from other teams, we decided on an appropriate way to reinforce the ribs so they would not bend, and added the reinforcement that night.
The last step before we would have been allowed to race was dynamic testing, which is when the car is driven through various situations, including a figure-8, u-turn, slalom, and emergency braking. On Thursday morning, with a brand-new car, we were going through these tests before the race day started. SC6 successfully passed all the other tests, but during our final test, the emergency brake test, it’s front suspension experienced a major failure.
In the braking test, the solar car must come to a complete stop from over 31mph with an average deceleration of greater than 4.72 m/s2. The moment when our driver, Jess, slammed on the brakes, the car dove to the front and the front wheels tilted off from center.
We ran to the car and found that the right composite rib had been torn apart by the force of the emergency brake maneuver. Such a composite failure is repairable, but the repairs are time-intensive and demand resources we couldn’t take on the road, so we knew this ended our race :(.
We determined two key factors that led to this. The first is that our suspension could have been designed to generate lesser forces to the body. Our suspension’s geometry made the wheels roll very efficiently and placed them where they needed to be located in the front fairings, but also made strong forces act on the frame it was attached to. The second is that our carbon fiber and Nomex structure was improperly supported. Our mounting system did not transfer force to our monocoque carbon frame correctly and although we took the properties of carbon fiber into account when designing it, more research needs to be done into creating a mounting system that takes full advantage of carbon fiber.
Although this incident was unfortunate and disappointing, it has given the team new focus. As we were walking back to the paddocks just moments after the car stopped, I overheard members calmly and earnestly discussing what the team needs to get done next school year and proposing plans for how to do it. The instant after an accident occurred, and improvement was being thought of right away! That took me completely by surprise, and is one of the things I will remember most about this week. Realizing I was part of an organization so resilient and so persistent that giving up wasn’t even considered for a moment was very eye-opening and incredibly motivating. Then again, that’s been the story of this whole week—through 3 or 4 hours of sleep a night, through an early power generator failure, through toolboxes falling on and destroying a section of solar array, through needing to make major structural changes on short notice and many other challenges, the team always kept it’s eye on the goal. Only once there was literally zero chance of success did the team pack up the trailer. I’m incredibly proud to be a part of this organization, broken car and all.
The team resolves to spend the rest of the summer learning about suspension design and composites, so we can better understand what went wrong. Then, once school starts in September, we will hit the ground running with a recruiting drive to gain new freshman brainpower, and get to work repairing and improving SC6 for our next race. SC6 was our first time using a carbon fiber monocoque frame, which is a technology that only the most advanced sportscars and racecars use. In fact, Lamborghini just unveiled their first ever production car with a partial carbon-fiber monocoque frame, the Aventador, last year. We could have stuck with familiar materials but chose to be on the cutting edge instead, and learned a lesson the hard way as a result. But, we will continue learning how to use today’s advanced materials—after all, they will be tomorrow’s everyday materials. And as always, we will keep our supporters and fans updated as we go.