The Bridgestone World Solar Challenge: Race Overview

The Bridgestone World Solar Challenge: Race Overview


Lees hier de Nederlandstalige versie

In the summer of 2014 the newly recruited team of 16 students started designing the ‘Punch One’, the sixth Belgian solar car. The 2013 team had demonstrated a very reliable solar car which was a decent baseline to start from. After the sixth place at the WSC 2013 and a third place at the Abu Dhabi Solar Challenge in January 2015, the new team was aiming even higher for the upcoming WSC 2015. After a year of hard work, we proudly presented ‘Punch One’ in July 2015 and were confident we had an amazing solar car.

The main goal of our team was to optimize the performance on every aspect of a solar car, which included a more efficient solar array, new motor, much improved aerodynamics and many more details to gain every watt possible.

With this goal of “Perfecting Performance” in mind we left for Australia in September 2015 to do some last preparations and tests before we could start the challenge. We completed about 2000 kilometers of testing on the Cox Peninsula Road without encountering any major electronic or mechanical issues. The car showed very promising figures in terms of energy efficiency and seemed ready to compete with the best.

 

Qualifications - 17 October 2015

The qualifications were held on the Hidden Valley Circuit in Darwin, one day before the actual challenge started. Our pilot Bert Longin drove a sharp time of 2:02 which qualified  for 4th place in the Challenger class. There were some very fast laps in the Challenger class this year, with Team Arrow taking the pole position again in an impressive lap of 1:54. They clearly know how to get the best out of their motor. We were happy with a 4th place on the starting grid which meant we would make the drive out of Darwin easier as we would not have to overtake many other solar cars .

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Day 1 – 18 October 2015

Around 8h30 the solar cars started rolling into their journey from Darwin to Adelaide. Everything went  smoothly and after leaving the city center we could start increasing our speed up to 95kph. We had overtaken Western Sydney University  as well as the two Cruiser class cars in front of us from Eindhoven and Bochum. A while out of Darwin we caught up on Team Arrow and greeted them while we moved further up front. By 11am we only had Michigan driving in front of us and we seemed to slowly gain on them. It looked perfect, too perfect perhaps. At 11h45 the pilot felt a flat tire and requested a stop. All tires were checked but they seemed all pressurized. We didn’t know what else to look for, so 2 minutes later we were back on the road. Everything somehow seemed fine again and we drove further, while brainstorming what could have been the issue. 20 minutes later we monitored abnormal values in power usage, and decided to look for a good spot to stop. While doing so, we noticed an object dropping out of our right rear wheel fairing. One the side of the road, we opened the rear fairing and noticed the wheel enclosure was badly damaged. We decided to remove the enclosure and perform a preventive tire change because the tire had been rubbing the carbon covers.

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The entire operation was performed within 7 minutes, but that was sufficient for Tokai and Twente to overtake us while we were stopped, setting us back to 4th position. From there it was only a short end to the first control stop of Katherine. We stood there next to Michigan, Tokai, Twente and Nuon. Shortly after leaving the control stop we noticed a problem with the motor, it dropped power intermittently. We expected that the wheel enclosure had resulted in strain on the cables between motor and controller, resulting in a faulty contact. We therefore did another technical stop, which took another 7 minutes. However, when we got back on the road the issue still wasn’t solved. Nevertheless we judged that we could keep driving, and decided to keep going to the rest of the day and fix it in the evening.

We reached the second control stop at Dunmarra at 16:29h, which meant we could drive out at 16:59h. However, we decided to keep the car in tilted position for evening charging as this saved us the setup time so we could charge a bit more. Moreover, it was an ideal position in an open space to keep charging until sunset, and also get a proper charge in the morning. We camped there along with Stanford and Megalux.

After day 1 we could conclude that we lost 16 minutes in 3 stops and we stood in at 5th position at about 15 minutes behind Michigan who ended the first day in the lead.

In the evening we had a lot of work to do, and the team worked late to repair the wheel enclosure and diagnose the motor problems. By 2am the car seemed ready to go again.

 

Day 2 – 19 October 2015

The second day we took off at 8h00 for a long stretch to the control stop of  Tennant Creek.

The motor issues seemed to be solved, and the pilot confirmed everything sounded and handled perfectly. Our battery was pretty full due to the consecutive control stop and evening/morning charge. So when recalculating our optimal speeds, we set a speed of 105kph as we encountered a tailwind and anticipated the upcoming weather conditions. By 11h00 we were only 11 minutes behind the leader Michigan. Then our solar car passed a cattle grid, not the first in the day but this one seemed to be more harsh and the impact caused the left rear wheel enclosure to get loose. We knew it right away and stopped immediately, removed the enclosure, inspected the tire and decided to leave the tire in place. The entire stop only lasted for 3 minutes this time, and we could drive the rest of the day without any problems. We reached Tennant Creek, then continued to Barrow Creek, then drove on and ended the day right next to Tokai, camping along with them.

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However, the day ended with some terrible news. We had to sit out a time penalty of 60 minutes for an incorrect overtake of our media vehicle during the day 1. We could hardly believe it, and still hoped it was a mistake.

 

Day 3 – 20 October 2015

At 9h00 we arrived at Alice Springs, the first control stop of the day. Nuon, Twente, Tokai and Michigan were still there and reacted very surprised when they read our penalty of 60 minutes on the leaderboard. We believed this was not justified and submitted an appeal.  The clerk of the course decided we could delay the penalty time until the next media stop of Kulgera, leaving us time make the written appeal. We continued to Kulgera and then received the verdict that we had to do our one hour time penalty there. A hard moment for the team to sit there doing nothing while the other teams took off.

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Nevertheless we all wanted to keep our focus and go on. We had a serious delay, but we also had a well charged battery after standing tilted for an extra hour. From Kulgera onwards we could spend this extra energy, and there was a headwind but it appeared to come at a favorable angle. While we drove on we saw the average power use decreasing under influence of this sidewind, and we increased the speed to match it. We were effectively sailing, and the faster we drove the more we took advantage of it. This led us to drive the rest of the day with speeds of 105 to 110 km/h, while still consuming less than anticipated. At the end of the day we were curious to find where the others were. We did some scouting and found Tokai surprisingly only 12 kilometers ahead of us, Michigan at 25 kilometers away and Twente and Nuon about 80 kilometers from us. While we had given up any hope when we sat for an hour of penalty around noon, a podium position now somehow seemed  within reach again.

 

Day 4 – 21 October 2015

We started the fourth day only one hour away from Cooper Pedy, the first control stop that day. The drive up to Cooper Pedy went excellent, although we had to stay concentrated for abrupt winds. The control stop was an open space without traffic, but the last right corner was noticed a bit late and the solar car had to make an abrupt turn. The driver felt something went wrong with the rear wheel, but still could drive the car into the control stop. When we took a look, we noticed a snapped rod end at the rear suspension. During the control stop everything was analyzed and prepared. The rules state that any reparations to the solar vehicle can only be started after the control stop, so we waited and meanwhile had the time to bring all our tools in place and distribute the tasks. The repair wasn’t simple as it involved cutting and grinding of metal, but we managed to fix the problem and get back on the road in 16 minutes.

Here is a timelapse video of the reparation and departure at Cooper Pedy:

 

Een video die is geplaatst door Punch Powertrain Solar Team (@ppsolarteam) op 20 Okt 2015 om 8:40 PDT

 

And if that wasn’t enough, shortly after we were back on the road the motor problem of our first race day seemed to have returned. But this time it was even more problematic and we had to pull over again. We replaced some motor connectors until the signal came back and we continued our way. The problem stuck with us however and we had to do yet another technical stop. We suspected the MPPT box and decided to reroute the CAN circuit to bring the MPPT box at the end of the circuit and insure the stability of the CAN communication from steering wheel to motor controller.  This one eventually did the trick and we managed to drive the rest of the day and eventually the rest of the race with this configuration without any further issues.

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We were eager to reach Port Agusta before closure in order to combine the control stop and overnight again, allowing us to eliminate a setup and breakdown of the tilting system. We rolled into Port Agusta at 16:54h.

 

Day 5 – 22 October 2015

The final day we left Port Agusta at 8:24h after serving the last part of the control stop. There was a strong headwind, but we knew we had a good morning charge and weather conditions were improving with high likeliness of sun when we would reach Adelaide. So we still managed to drive 100-105kph, and when the headwind wind reduced we could even speed up to the speed limit of 110kph. At Angle Vale road our finishing time was clocked at 11h12, confirming our fifth position. Then it was time for the fountain on Victoria Square, followed by Belgian beers!

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Penalty

The justification for the time penalty of 60 minutes still seems vague for a lot of people, including ourselves. Nevertheless we will try to give an explanation of what happened, as we believe teams should know so they can learn from it.

A couple of days before the race a team member of our team was speeding while leaving the Hidden Valley circuit in Darwin, an unnecessary mistake. A couple of phone calls and emails between the organization and our team manager led to the action of withdrawing our team member’s driver license. The organization seemed satisfied with this decision and decided to not give us a time penalty but an official warning , which meant that any further violation would lead to exclusion from the event.

We formally agreed to this, we were obviously not expecting any traffic violation as this also never occurred in the past events were we participated.  Our team member gave his sincere apologies towards the team and we decided to leave this behind us.

As a convoy we paid particular attention to keeping the correct distances, following the correct safety procedures when pulling over, etc. However on the second day of the challenge during the stop at Barrow Creek we were informed about a penalty given for an overtaking maneuver by our media car which would have occurred on day 1. We contacted Mission Controls to find out what had been the issue.  We were told that our media car had gone wrong during the overtake of Stanford by placing itself between their solar car and their chase vehicle. This is something which can lead up to very dangerous situations and certainly is a no-go in solar car racing.

Our media crew however was very surprised by this news and believed it must have been a mistake. They had been in communication with Stanford over the radio to request permission to overtake, and did not recall any hazardous situation during this overtake. Fortunately they could show video footage of their maneuver which clearly showed that they passed the chase and solar car in one fluent movement without placing themselves between both cars, without staying parallel to the solar car and without cutting in front of the solar car. Just a smooth drive by.

We sent this footage to the organization hoping to get a positive feedback. However, we received the response that the actual incident was what happened afterwards. Apparently our media car would have endangered the oncoming traffic, which had to slow down or move to the left to avoid a collision. This was again something our media crew denied, only this time they couldn’t prove it with video footage since the video stopped when they passed the solar car.

We do believe that in the spirit of the event, it would be certainly more helpful towards the teams if the penalties would be obvious from the moment they are handed out to a certain team. We appealed for this penalty, but received the answer we already expected. Normally the penalty given to a team for this type of traffic situation would be 10 minutes, in our case it was raised to 60 minutes due to the earlier warning for the Hidden Valley incident.

We fully acknowledge the importance of safety in this event, and we do not take this lightly. However, we have difficulty to match the severity of this penalty with what we see happening in the whole event. We believe in both incidents that occurred from our side, we did not directly bring anyone into a dangerous position. Up until today we don’t know what exactly happened during the maneuver of our media car, but we did hear from a lot of other teams that our media car was always very respectful when they tried to pass.

Nevertheless, we will do our very best to learn from this and make sure to drive as correct as possible in any event. We hope to leave this behind and restart from a clean sheet in the future.

We also hope as many teams as possible do take notice and that it that sense this penalty will have had a positive effect on overall safety.

 

Conclusion

In terms of speed and energy efficiency, our car performed even better than we had hoped for. However we have to acknowledge the fact that in order to win in such a competitive event, there is simply no room for error. We had various technical issues which made us spend too much time on the side of the road.

We ended 1h23 behind Nuon Solar Team, the winner of WSC 2015. Comparing with 2013, where we ended 7 hours behind the winner, it is a huge step forward.

We know we lost about 1 hour with repairs and 1 hour at a media stop due to our time penalty. Moreover, we drove two days with partially removed wheel enclosures, which was not optimal for aerodynamics. On the other hand we also charged the battery during these two hours of standstill, and the fact that we ended up driving slightly behind others did place us in more favorable weather conditions on the last day. So as a conclusion, would it have been sufficient to compete for first place? We will probably never know for sure, but we think it would have been close.

This only makes us eager to improve and return for more races .

 

Thank you to everyone who supported us during the past 2 years!

 

 

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