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UK’s Solar Car Team at the annual Formula Sun Grand Prix: Scrutineering, Brake Testing and Heat

In July, the UK Solar Car Team competed in the annual Formula Sun Grand Prix (FSGP) at the Circuit of the Americas (COTA) in Austin, Texas. Eighteen teams from the contiguous U.S., Canada and Puerto Rico made the trek to Austin to compete in FSGP. Junior Monon Rahman, who serves as the team’s media and communications specialist, provided the recap below.

The first three days at the track were dedicated to scrutineering, which is the technical inspection process that teams must go through in order to race. This includes inspection on the various subsystems that make up the car. For example, the mechanical items such as the frame and suspension, the battery pack, battery protection system and so forth are checked during the inspection process. Scrutineering also includes dynamic tests such as slalom testing and brake testing.

The order that teams pass through scrutineering determines the starting grid order on the first day of racing, so being able to get through inspection fast definitely has its perks. Our team was able to swiftly work through the first two days, resulting in us finishing fifth in scrutineering. We also completed brake testing the fastest, which awarded us the “Fastest Braking Award.” Normally the wet pavement and difficulty of the test can cause issues for teams, but it was not a problem for us at all this year.

Finishing scrutineering early gave the team to catch a small break before the race. We made our final preparations, and on the first day of racing, the team took our car, Gato del Sol V, into its starting grid position. Gato V was ready for its final FSGP.

Just as everything seemed to be in order, our team began to face adversity that would last throughout the three days of racing. Just minutes before the green flag, the team found out that one of the connections for the horn—required for safety—had come loose. It was an easy fix, though, and in just a few minutes, Gato V rolled out onto the track. However, 13 laps later, we had to pit for a loose wheel; the center wheel nut on the front left wheel had come completely off the axle. This was such an unusual problem to have. In the four years Gato V has been running, the team has never had a wheel nut come off. Luckily, the team quickly found a spare, and Gato V was sent back out.

The heat was the main problem for us from then on. Racing in Texas in July meant that temperatures were hovering around 100 degrees for the majority of the entire week. This did not bode well for our batteries. During the afternoon of the first racing day, we had to pit once again and wait a bit to cool down the batteries. During the race, teams are only allowed to charge with the solar array on the car. The batteries were heating up to the point where it would be unsafe to charge them through the solar array, which meant that we would not be running on the track at a sustainable pace. After waiting for a bit, we got back out on track. We collected a total of 30 laps by the end of Day 1.

Before we started racing again on Day 2, we formulated a method to try to keep our batteries cooler. We added a larger fan to the battery box as well as a grid of fans to use when we needed to cool the batteries down faster. The fan in the box worked quite well; however, it was so hot that Gato V still had to pit to cool down. This time, the grid of fans cooled the batteries down quite well, and Gato V made it back out on track shortly before the racing day ended. Gato V made 28 laps around COTA on Day 2, bringing our total to 58 laps.

During the race, teams have a few hours to charge their battery pack using their solar in a designated charging area. At the end of Day 1, our team rolled Gato V to the area and was about to start charging when a huge storm forced all the teams to take cover, stop charging, and impound their batteries early for the day.

Later, when evening charging was about to begin, another storm popped up around COTA. Strong winds and heavy rainfall quickly approached the charging site, endangering the safety of the car and our team members. Luckily, our team worked together and acted swiftly to prevent any damage to the car. However, for two nights in a row, we were not able to charge at night.

Just as we were about to get back out on track, we ran into major battery pack issues. The main relay in the battery pack started malfunctioning, and the car was not able to run with the relay not working. With just a handful of hours left in the race, we needed a quick solution to a major problem. Since the day was ending soon, we figured out that we could bypass the main relay, use the relay for the solar array as the main relay, and just run without using the solar array. With some teamwork, some of the internals of the battery pack were rearranged, and Gato V was running once again.

This altered our strategy for the final day of racing. Instead of starting right when the track opened, we decided to continue charging until we had an acceptable amount of charge in our battery pack to race. This way, if the batteries started overheating and were not able to charge using the array, we would at least have enough charge stored to use for the day. Once our battery pack was sufficiently charged, Gato V was out on the track running laps. Unfortunately, excessive heat led to another pit stop to cool down.

At this point, only 20 minutes remained. At that moment, CalSol (Univ. of California - Berkeley) had the fastest time of 4 minutes and 35.848 seconds. With little time left, we decided to challenge and race for the fastest lap time. Gato V rolled back out on the track, and we clocked a lap of 4 minutes and 34.297 seconds—over a second faster than CalSol. Unfortunately, on the very last lap of the race, Polytechnique Montreal ran a lap of 4 minutes and 32.542 seconds, ultimately edging us out for the fastest lap.

Overall, the team came in 7th place with a total of 80 laps on track. For Gato V, this is the highest finish it has achieved in its four-year lifespan. In a race with so many brutal and varying conditions, the team was pleased to be able to come home with a top 10 finish. Our performance is motivating us as we begin constructing the next vehicle, Gato del Sol VI.

We cannot thank all of our supporters enough for helping us achieve our goals; without you, we would not be able to build, race, and most importantly, learn.