World Solar Challenge: statistics and recent news

 
 
Top left: Onda Solare revealed their modified Cruiser Emilia 4 LT on 31 July (credit); Top right: Western Sydney revealed their new monohull Challenger Unlimited 3.0 on 7 August (photo: Anthony Dekker); Bottom left: STC revealed their unusual passenger-behind-driver Cruiser on 8 August (credit); Bottom right: Durham revealed their asymmetric Challenger Ortus on 12 August (credit)

We have had a few new solar car reveals recently (see above – click to zoom). The pie chart below shows current statistics (excluding #67 Golden State and #86 Dyuti, which do not seem to be active teams). Among the Challengers, the designs for #4 Antakari, #10 Tokai, and #18 EcoPhoton are still unknown.

Monohulls remain a minority among the Challengers (though a minority that has doubled in size since 2017). I am using the term “outrigger” for cars with monohull bodies but wheels sticking well out to the sides (the two new Swedish teams, #23 HUST and #51 Chalmers). There are also two quite different wide symmetric cars (#22 MDH and #63 Alfaisal). Among the Cruisers, 4-seaters remain a minority, in spite of the substantial points benefit for carrying multiple passengers. As always, see my regularly updated illustrated teams list for details.


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Australia’s fastest solar car team is now even faster!


The Western Sydney University team reveals their new car (photo: Anthony Dekker)

Australia’s champion Challenger-class solar car team (not to detract from the two excellent Cruiser-class teams, Arrow and Sunswift) is Western Sydney University, who have just revealed their exciting new solar car (above and below).


Another view of the WSU car, which is a monohull design with a gallium arsenide array (photo: Anthony Dekker)

After being forced to trailer in the 2013 World Solar Challenge, Western Sydney University came 10th in 2015 and 6th in 2017 (see graph below). And that 2017 result did not do their car justice, because in 2018 they went on to defeat the second-place team, Michigan. Their superb new car (above) is engineered to be even faster. Could they win this year? Or does the Dutch team from Delft have a stranglehold on the top position? I guess we’ll just have to wait and see…


American Solar Challenge 2018: The run to Burns

I recently got my hands on the GPS tracker data for the American Solar Challenge last July. Above (for the 6 Challengers completing the stage) and below (for the Cruisers) are distance/speed charts for the run from Craters of the Moon to Burns, which seems the stage of the route with the best data (at this time of year I haven’t the time for a more detailed analysis). Click on the charts to zoom. Small coloured circles show end-of-day stops.

Stage times were 15:Western Sydney 8:05:16, 101:ETS Quebec 8:20:13, 2:Michigan 8:25:08, 55:Poly Montréal 8:42:52, 4:MIT 9:07:58, and 6:CalSol 9:30:12 for Challengers, and 828:App State 10:22:37, 559:Bologna 12:13:57, and 24:Waterloo 15:29:12 for Cruisers (note that Bologna was running fully loaded on solar power only, while the other Cruisers recharged from the grid).

The data has been processed by IOSiX. I’m not sure what that involved, but I’ve taken the data as gospel, eliminating any datapoints out of hours, off the route, or with PDOP more than 10. Notice that there are a few tracker “black spots,” and that trackers in some cars work better than in others. The small elevation charts are taken from the GPS tracker data, so they will not be reliable in the “black spots” (in particular, the big hill before Burns has been truncated – compare my timing chart).


A Belgian solar car climbs the mountains of Chile


Punch at CSA 2018 (picture credit)

Well, Punch Powertrain Solar Team, from Belgium (above) is currently racing against just one other Challenger car in the Carrera Solar Atacama in Chile (see: and the live tracker). I thought it would be interesting to compare Punch’s performance against that other mountain race, the 2018 American Solar Challenge, won by Western Sydney University.

The two races can’t be compared directly, however. The Carrera Solar Atacama has a greater elevation range (sea level to 3415 m, compared to 296 m to 2585 m for this year’s ASC). The CSA is south–north, rather than east–west, and takes place around 20° closer to the equator, on average. More dramatically, however, this year’s ASC allowed 2 m2 supplementary solar panels during static charging (see image below). This made the ASC a faster race.


WSU using supplementary solar panels at ASC 2018 (picture credit)

What I have done instead is compare the average speed for each segment against the approximate average climb rate, using the information provided in Punch’s wonderful infographics (see their social media: ). The corresponding datapoints for WSU were calculated in exactly the same way, and linear regression was applied for each team (see lines on the chart at the bottom of this post). The flatter line for Punch shows that they were less affected by the steep climbs. This is presumably due to their fancy new motor, which has a half-speed/double-torque mode. This Mitsuba motor was built by Nomura Co to Punch’s requirements.


Punch’s motor, built by Nomura Co (picture credit)

Update: the chart below has been updated with new data.


ASC 39: Road Race Last Day

Well, the American Solar Challenge is over. The “Faster than Lightning Gem” goes to Western Sydney University (team 15), who won by 16 minutes after a very hard-fought contest with defending champions Michigan. Western Sydney have shown themselves (again) to be one of the best teams in the world. Congratulations!

The “Multi-Occupant Vehicle Gem” goes to Onda Solare from the University of Bologna (team 559), who were the only Cruiser (MOV) to complete the entire course. They did this with 3 passengers (except for the “big climb”), zero external recharging, and zero penalties. Felicitazioni!

Here are the Cruiser (MOV) practicality scores.

Here is my final race chart, with penalty minutes added in on the right. Cars with partial distance credit are shown at the top left:

And my final average speed chart, in the colours of an Idaho sunset:


ASC 38: Road Race Day 8


Start, drive, cross the line, recharge (picture credits: 1, 2, 3, 4)

Day 8 of the American Solar Challenge was another sunny day. The road to Burns included several steep hills, climbing out of the Snake River Plain, and teams that did not negotiate them yesterday had to do so today. Appalachian State were the first Cruiser to arrive in Burns. Onda Solare are the only untrailered Cruiser, however (and still with 4 people and no external recharging). The chart below summarises the race so far (penalty minutes are added at the right of the chart).

I am awarding my “Cruiser Pioneer” gem to the University of Minnesota Solar Vehicle Project, who are America’s Cruiser (MOV) class pioneers. They were the only Cruiser at ASC 2016. They came 4th in the WSC 2013 Cruiser class, and 5th in the WSC 2015 Cruiser class. They won the FSGP MOV class this year by a convincing margin, and were clear leaders for the ASC road race until they ran into trouble 40 miles into stage 4 (with an electrical fault). Thank you, UMNSVP, for showing everybody else the way!


ASC 37: Road Race Day 7


ASC, Day 7 (picture credits: 1, 2, 3, 4)

Day 7 of the American Solar Challenge was full of drama. An incredible race between Western Sydney and Michigan saw average speeds to the checkpoint in Mountain Home of 90.8 km/h (56.4 mph). In the Cruiser class, there was a tragic breakdown by Minnesota, which I think will leave Onda Solare the winners by default.

I am, however, giving my “Most Desirable Car Gem” award to PrISUm. Their car did not qualify for the road race, but I still think that their “solar SUV” is a fantastic concept.

And here are the night-time car positions (unreliable in the case of Michigan). I have overlaid them on my elevation map to emphasise the 850 metre downhill run into Mountain Home, and then the climb back up into Burns.