The dust has settled on our trip to Australia, everyone’s back home, and it’s time to take a look at how things went! This was CalSol’s first appearance at the World Solar Challenge since 2011, and Tachyon’s first-ever road race, so there were lots of chances for exciting new things to happen.
Expectations
While we made a lot of progress on Tachyon in Texas (and after getting home), we only had about a month between the Formula Sun Grand Prix (FSGP) and our ship-out date for the Bridgestone World Solar Challenge (BWSC), and we had to use a lot of that time switching Tachyon to comply with Australian regulations. Tachyon was still ultimately a new car. Its recent completion also meant it didn’t have license plates yet, so we couldn’t road test! Although we knew we had built a fundamentally sound vehicle, there will always be inherent uncertainty in competing in a road race with a vehicle only tested on the track.
Trailer Trip
Due to Darwin’s relatively small size, we found it was only feasible to ship our car to the south coast of Australia. This meant we needed to rent a trailer and a pickup truck , and trailer Tachyon across the race route in reverse to get to Darwin. (We ended up renting a “ute,” which I consider to just be an Aussie term for a pickup truck. I’ve been assured that there are differences, but I assume I’m just too American to understand.) We sent an “early crew” consisting of myself, Annie Wang, Avinash Jois, Eric Lu, and Lekha Duvvoori (Team Manager, Solar Driver/Operations, Electrical, Chef, Solar Driver/Mechanical, respectively) to Melbourne ahead of the race to get our shipping container cleared through Australian customs and then drive to Darwin. In addition, we were fortunate to be joined by Des Riessen, an Adelaide resident, firefighter, truck enthusiast, and all-around incredible person.
Due to our timeline, budget, and the large size of our car, the most reasonable choice of trailer seemed to be a flatbed. Many teams favor these; you simply roll the solar car on, ratchet-strap it down, and secure a tarp over it, and then you can drive off! Although an enclosed trailer does provide more protection, the walls would also restrict the car significantly, and we would likely have difficulty getting Tachyon in and out. Enclosed trailers of the width we would need are also much harder to find.
Unfortunately, the decision to use an open, flatbed trailer also comes with risks. We experienced this firsthand when our windshield, which was at the time constructed of two separate sheets of polycarbonate, failed near the beginning of our trailer trip. We’re not sure exactly what caused the break, but part of the smaller section of the windshield broke completely off. At highway speeds on the back of the trailer, a large amount of air was able to flow into Tachyon through the hole in the windshield, which was not a parameter we designed for. This airflow caused serious problems when it blew the roof off while we were driving! Tachyon’s solar array and the composite roof it was attached to were forced off of the main body of the car and landed by the side of the road. Thankfully, no one was hurt.
Although the roof landed composite-side down, the fragile solar cells still took significant damage. In a more pressing concern, the structural part of the roof also split down the middle.
After this significant setback, we were very careful on the rest of the trailer trip. We got some canvas and a lot of foam to protect our remaining cells, and then used ratchet straps around the entire car to keep anything from moving. We also perfected our tarping technique so the tarps would not tear in the wind.
Scrutineering
Once we made it to Darwin, we were able to reunite Tachyon and the early crew with the other 11 members of CalSol’s race crew, which drastically increased our work capacity. We immediately got to work fixing the roof, replacing damaged cells, and replacing the windshield, as well as making a handful of other fixes that we knew about before ship-out. We even tried to install a second battery pack to triple our range (Thank you so much to Octillion Power Systems for providing us with the modules!), although we unfortunately did not have enough time to make that particular project ready for this race.
The actual scrutineering process went very smoothly. We passed most stations quite easily, and most of the requested changes were relatively easy fixes. Even the notorious mechanical inspectors required no changes to be happy with Tachyon!
Dynamic scrutineering was similarly smooth sailing; our brake test in particular drew congratulations from the officials standing near me at the time. Tachyon successfully braked in less than half of the available space.
On the Road
For whatever reason, the BWSC event officials no longer keep granular track of how far the solar cars drive. The only measure of distance is how many stages are completed. However, by our own reckoning, we think Tachyon drove about 700 km on its own power, including more than 400 km uninterrupted in a single day. While there is certainly room for improvement, we consider this a definite success. The start of the racing period was dogged by overheating concerns and motor damage from a rock getting where it shouldn’t have, but we successfully overcame those problems to finish strong.
Finish
The public showcase period after crossing the finish line afforded us a valuable chance to talk with other teams after most of the stress was over. All of the world’s best solar car teams compete at BWSC, so this gave us ample opportunity to learn from our role models.
Lessons Learned
We learned a lot from our Australian adventure. As our first race in eight years not affiliated with the American Solar Challenge, it taught us how to navigate an unfamiliar competition structure and regulation environment. We also relearned how risky it can be to race with a brand-new car. In the future, we plan to leave more time between finishing a car and racing it, so we can have a proper chance to test it out and iron out the kinks. We have also resolved to rent an enclosed trailer whenever we can’t use our own, no matter what.
Most importantly, we talked a lot with our friends, old and new, on other teams. Many teams we saw had never gone to the American Solar Challenge, and others only rarely. This outside perspective really helped us challenge our preconceived notions about how to run the best team we can, and we’ll be putting some of what we saw into practice.
Acknowledgements
I would like to thank everyone who contributed to CalSol’s effort at this year’s BWSC. Foremost in my mind are the 16 people who joined me on the journey. Many took the entire semester off of school to be able to attend. Des Riessen, mentioned earlier, joined us when we needed another authorized driver for our ute on the trailer trip to Darwin, but ended up contributing in countless ways throughout our entire journey.
I’d be remiss if I didn’t acknowledge the incredible assistance offered by other solar teams; everything from pasta given by Onda Solare (University of Bologna), to a critically important vacuum pump we borrowed from Western Sydney University when we needed to wet layup (i.e. glue) our roof back together. This trip underlined for us the generosity and camaraderie in the solar car community, and I know that it at least inspired me to be more generous myself.
Speaking of generosity, I would also to thank our generous sponsors, without whom none of this would be possible. Included in this are last year’s crowdfunding donors, who specifically contributed to our WSC effort.
All things considered, this year’s BWSC was a very rewarding experience, and I’m honored to have had the chance to lead CalSol’s effort. I’m sure that when we go back, we’ll be able to do even better.
Alexander Zerkle
BWSC Team Manager for CalSol