Race Day One

Electrical System, Featured, General, Solar, Texas / Sunday, July 17th, 2022

As we arrived at the track at 6:15 AM, the team was filled with excitement. With more than two years of work put into the car, everyone sprang into action… for about 2 minutes: we were quickly notified that we were only allowed to interact with our vehicle after 6:30 AM.

The day began like most race days do. The first thing was to tape the undercarriage of the car. A huge part of making the car as efficient as possible is the team’s ability to reduce the amount of seams and cracks on the exterior of the car. The smooth seams result in a reduction in aerodynamic drag and an overall performance boost for the car. A single piece of flapping tape or a small inlet for air to infiltrate the interior of the car could result in a loss of efficiency by nearly 5%. For this reason, the team took incredible care when sealing the bottom of the solar car.

Abigail Jawili (10) and Opal Heltzel (11) set up the pit for race day one

Race organizers gathered the teams for a brief all-team meeting. Then, as the clock struck 7:45, the team began rolling the car up to the start line filled with excitement. Now only 15 minutes away from the first lap of the race, all the cars began lining up one by one. As the Raisbeck Aviation Green Energy Team arrived at the start line, Maya Pena [12] set up to take the car on the first lap of the race. When the checkered flag waved, Maya pushed down on the accelerator; to our immediate surprise, the car did not move. Shocked, the team pulled the car off the start line and immediately began diagnosing the problem. It was found that the heavy charging that the team did in the evening before as well as in the morning was too much. The amount of energy stored in the battery due to charging was pushing the limits of the Battery Monitoring System (BMS). The braking that we did to stop the car at the start line provided enough regeneration energy to push the BMS past its limit. The safety protocol in our battery voltage regulator restricted the power leaving the BMS, the shutting down of the motor.

The solution to the issue was relatively simple. The car battery needed to be drained to a safe level so that the action of regenerative braking would not balloon the battery voltage to a “cut-off” level. After waiting for the rest of the cars to finish their starts, the RAHS Green Energy Team rolled the car back up to the start, now 10 minutes behind schedule. Maya once again put her foot down on the throttle and … it did not start. Luckily this time around, within 10 seconds, the car battery came back to life and the car lurched off the start line. As everyone clapped, “Jimmy” began the 2022 Solar Car Challenge.

Hai Lin Truman (11), Hagen Rankin (10), and Lucien Freemesser (11) watch our car as it speeds through the track

As the sun began to peek out more and more, the speed of the car increased. The increased input of power on part of the solar panels allowed for the car to output more power and thus move faster. The morning was flawless. A driver swap was made at 10:00 AM where Alexis Lee [11] took to the driver seat. As the day neared noon, the sun began to reach the highest point in the sky. The power input only got higher, allowing the team to reach staggering speeds. When the driver swap was made for Lucien Freemesser [11] to drive, the car was moving at maximum speed. Now averaging almost 90 kph, the team’s lap lead began to slowly increase. 

Just as things began settling into place, Lucien Freemesser [11] was coming around turn 4 and ran across some gravel and glass causing a puncture. He radioed in the emergency and the car dived into the pit lane. The second the car reached the start line again, team members gathered around to wheel it back to the garage for repair. The practice for fast and efficient tire changes really proved itself when the car was under repair for only a total of 11 minute. Team members raced to find correct tools for a quick removal of the damaged wheel, while others jacked the car up for better access. The car’s damaged tire was changed, and “Jimmy” was back on the track racing again.

After another smooth 2 hours of racing at maximum speed, Lucien Freemesser [11] encountered another puncture on turn 4. This time, the reason was slightly different. Due to the climate at the Texas Motor Speedway, temperatures on track were much more than the regular temperatures in Seattle. With the track surface reaching a blistering temperature of 145 degrees F, tire compounds for all teams began to run soft. Unfortunately, for the faster-moving teams, the increased exposure meant higher loads applied to those now-soft tires. At 1:45, the rear-left tire delaminated from the bead on the rim and the tire exploded.

Similar to the last time, the car came down pit lane rolling on a bare rim. After being received by the pit crew, it was wheeled back to the charging area where a quick and speedy tire change took place. Around ten minutes after coming off the track, the RAHS solar car was back on the track. 

After an eventful morning and early afternoon, the car was sent on to complete the rest of the race day. Rotating through drivers Hai Lin Truman [11] and back to Maya Pena [12] to finish the day, “Jimmy” was brought home safe and sound, finishing the day with an astonishing 220 laps and crushing the previous daily lap record; the team left the race feeling ecstatic. We are grateful for the help of our pit judge, Jon, who helped keep us safe and who informed and entertained us with some of his stories.

With only three days left in the race, the team is hopeful. Time will tell how this race will end!

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