Saturday, October 14, 2017

WSC 2017 Wrap-up

Hey solar car fans! Sorry the blog has been so quiet for the past two weeks - I've been incredibly busy, and it's been really hard to write this post from behind the Great Firewall of China.

Another WSC is wrapped up, so let's look at how things went down:

Challenger Class

The Challenger Class was really cool this year. Like I've written in other posts, I was extremely pleased when WSC shrank the array while increasing the allowed car size. The combination of those two changes opened up the design space considerably, and resulted in a much more varied field of cars.

I was really surprised that at the top of the field neither monohulls nor catamarans were dominant; the two monohulls from Michigan and Tokai were tightly intermingled with their three main catamaran competitors. It's clear that the teams haven't discovered a single dominant formula under the new regs, and as a result, I think we can expect an even wider variety of cars in 2019. Personally, I expect that monohulls may have an advantage in the future - teams have had 3 generations now to refine catamaran designs, while they have only made a first pass at designing monohulls.

On the array front, I was similarly impressed at how close the performance of silicon and multi-junction cars were. Yes, the three multi-junction arrays finished 1-2-3, but 2nd place was in question up until Glendambo, and 3rd place was a 3-way fight all the way to the finish line. I don't think multi-junction arrays had a clear advantage - the top three cars were from the 1st, 4th, and 5th place teams in 2015. I think it came down more to quality/experience of the teams than array chemistry - if you took a random team and gave them multi-junction cells but no other extra resources, I bet they'd finish in roughly the same position.

Alright, so how did the race itself go?

Well... not great, especially farther back in the pack. Weather played a major roll this year. You can see in the above chart from Scientific Gems that the weather between the Tennant Creek and Kulgera control stops just pounded the teams that were further back along the route. Principia, Goko, NWU, Aachen, ITU, and Kookmin all dropped out of the Challenger class along that portion of the route. Unfortunately, only 12 cars were able to complete the course this year.

Similar to last time, I've tried to compare each team's performance relative to 2015 by using Nuon's time in 2015 as a baseline to normalize their 2017 time against, and then scaling all of the 2017 finishing times accordingly. This is an attempt to account for regulation changes and weather differences - given how the weather disproportionately affected the back of the field this year, perhaps it's not as useful a metric, but there are still some interesting details.

Most teams had a lower performance this year relative to Nuon. WSU and JU were the only two finishing teams that managed to improve, by 1.8% and 1.1%, respectively - so for the second WSC in a row, WSU is the most improved team using this metric! Most of the rest of the finishers had single-digit decreases in performance. NIT was down 1.2%, Michigan and Punch were down 2.1%, Tokai was down 3.8%, Twente was down 6.2% (anything less than a nail-bitingly-close finish would have been a decrease for them), and Blue Sky was down 6.8%. The outlier is Stanford, who were a full 21.1% slower relative to Nuon than in 2015 - they seemed to be disproportionately affected by the weather between the Barrow Creek and Kulgera control stops.

I think I did pretty dang well with my Challenger predictions - I correctly called Nuon, Punch, and Michigan as the top 3, and Tokai and Twente in 4th and 5th! I did miss one Michigan prediction though - they finished in 2nd, which is exactly where I thought they would not be. I have to emphasize again how shocked I am that the monohulls were tightly intermingled with the catamarans; I absolutely did not expect that.

Monohulls in Coober Pedy on Oct 11: Michigan in 2nd, Tokai in 5th.
Only 16 minutes and 30 seconds separated them at this control stop.
Photo: MostDece

As of the Daly Waters control stop, the top 9 teams consisted of my "top five" + all three "challenging teams" + one of two "wild card teams", which I thought was pretty spectacular. The weather after that control stop shifted things around a bit - Stanford and NIT in particular seemed to have a rougher time with the weather. But in the end, out of the 13 teams I mentioned in my prediction post, NWU and ITU were the only two that weren't part of the 12 teams that finished. Antakari (the 10th place finisher) was the only finishing team that I didn't consider in my predictions as a likely top 10 team.

Some specific notes on individual teams:

Nuon: Great car, great strategy, great team. I heard that on the 2nd day of the race, their strategy team commandeered the media crew's satellite link, and their ability to acquire realtime or near-realtime weather data and ingest it into their strategy model was a huge advantage over the other teams at this edition of WSC. Nuna9 was also clearly a full step above the competition in terms of quality. The panel gaps were exemplary; the seam around where the array opens blew my mind every time I looked at the car in their finish line tent. The team really nailed every detail. There's a reason they've won 7 times now - which is half the WSCs ever at this point!

Aauugh so good!
Photo: MostDece

Michigan: The UMich team was finally able to break the 27-year-old 3rd place curse, finishing 2nd this year (or in other words, the top of the "Not Nuon" class)! Novum was a good looking little car and I think there were a lot of great ideas in it, but compared to their other close competitors, it was on the heavier side and there were some parts of the car that looked a little more roughly finished. I think the high performance of the car in spite of the higher weight and finish issues speaks to the aerodynamic advantages of their monohull shape over the catamarans. It also may reflect on the training and discipline of the team - Michigan did a ton of testing on public roads back in the USA and on the Stuart Highway prior to the race; the team seemed to be extremely well prepared and ran a very clean race.

Novum at Port Augusta on Oct 12.
Photo: MostDece

Punch: The team significantly improved their race operations for 2017. They did a much better job of keeping the car running smoothly on the road than in 2015, and this was a large contributor to their strong 3rd place finish this year. There were a lot of clever details in the car (including their steering system, which won the CSIRO Technical Innovation Award), but they were all solidly, functionally clever - nothing that was too clever for it's own good. A great car and a clean race overall.

Punch Two entering the Coober Pedy control stop on Oct 11.
Photo: MostDece

Tokai: Tokai appeared to be the most credible competitor to Nuon over the first half of the race. The two teams were neck-and-neck through Barrow Creek, and I'm not sure what happened to Tokai afterwards - they steadily slipped back over the next two control stops before recovering their previous average speed around Kulgera. I'm not sure if they outran their battery while pacing Nuon, or if they weren't as skillful/lucky as Nuon with the weather. Their inability to point the array as far to the side at control stops certainly cost them some energy... 4 of the 9 control stops occurred significantly far away from solar noon, and Tokai limited themselves to tipping the whole car a little bit rather than lifting and pointing the whole array as the rest of the top teams did. Regardless, they still managed to finish strongly.

Tokai clearly unable to point the array as far as far as Twente and Punch.
Taken at the Glendambo control stop on the morning of Oct 11.
Photo: MostDece

Tokai Challenger after departing Glendambo.
Photo: MostDece

Twente: Twente outperformed my expectations. I half expected them to be bumped out of the top five this time, but instead, the team was on track for a 3rd place finish throughout most of the race. They probably could have pulled it off... but they tried to play cute with a reflective ground sheet and ignored warnings on multiple occasions from officials before being slapped with a 30 minute penalty. You can usually get away with a lot at WSC, but ground sheets have been contentious in the past and WSC had very specifically called them out in the regs this year (reg 3.18.3). C'mon, Twente - you didn't even try to be sneaky (lol at this now-ironic caption), and whining about being caught and punished is poor form. Still, a 5th place finish is a major achievement, especially in a race as rough as this year's.

Red Shift under clouds north of Coober Pedy on the morning of Oct 11.
Photo: MostDece
Red Shift making tracks for the finish line after departing Port Augusta on Oct 12.
Photo: MostDece

WSU: I know I predicted they would do well, but I was still impressed at how well WSU stuck right with the top group for the first third of the race (which apparently caused some consternation among the teams behind them). However, the team made some miss-steps with weather strategy in the middle of the race. I don't think they outran their battery - if they had, they would have ended up with a dead pack under the clouds and would have suffered much more than they did. I suspect they thought the weather was going to be worse/unavoidable and began slowing down to conserve energy - and then were surprised when the weather wasn't quite as bad as they expected and the teams ahead of them were able to dash out ahead of the worst of it. One strategy mistake with a large weather system is all it takes... once they were back under the clouds; there was no way to drive fast enough to get out from under them and the team was forced to slow. The team has very few races under their belt when compared to the teams ahead of them; now they have some hard-earned experience with weather to apply to future races.

Unlimited 2.0 south of Port Augusta on Oct 13.
(image source)

Some other thoughts:

I've heard there was some drama centered around the close time of the Alice Springs control stop as a result of weather; apparently the control stop cutoff was extended, but this wasn't able to be communicated to all of the teams out along the route. I've also heard that there are two teams who definitely trailered forward along the route that are still currently listed as being in the Challenger Class with 3021 solar km credited on the website, and that some teams have filed formal protests over this. We'll have to wait and see how that shakes out; I haven't seen any official results PDF published yet and as far as I know the results are still provisional.

The control stops that I saw seemed to run much more smoothly this year***; the new "no touching the cars while in the control stop" regulation seemed to be a huge success. There were much fewer opportunities for shenanigans, and the stops appeared much less frenetic in general.

The only thing I didn't like was the extra stress put on the drivers... The "driver dash" to the timing tent in socks or bare feet across hot gravel parking lots looked particularly painful. I remember being a solar car driver; I was in no condition to run after climbing out. At least the clouds meant temperatures were low this year; so there weren't any heatstroked drivers passing out and going head first into the dirt/gravel/pavement on their sprint to the timing tent. What little drama I heard about mostly involved the control stop crews not being on-the-ball checking the teams into the stops, sooo... why not just eliminate that and the driver sprint altogether? They allowed the driver to stand next to the car at the end of the control stop rather than sprinting to the car from the timing tent, so perhaps have the team's observer simply note what time the the driver jumps out and sticks their hands in the air? Food for thought.

Punch's driver grimaces as he hops across the sharp gravel in the Alice Springs control stop. The blue shirt control stop crew inexplicably directed him to a parking spot as far away from the timing tent as he could possibly be, despite being the only car at the control stop.
Photo: MostDece

One aspect of the rules that I hadn't thought about prior to the event was that since only the driver is allowed to reconfigure the car upon control stop arrival and departure, the drivers had to load/unload their own ballast and water, connect up their own radios, strap themselves in, etc. I saw a lot of control stop departures delayed due to drivers having issues prepping to leave. I think the "No touching the solar car for the duration of the control stop" regulations contributed much more to the smooth control stop operation than the "only the driver can reconfigure car" regulations; even allowing a single person to help the driver strap in before departure might be an improvement. 5/6-point harnesses are pretty hard to put on by yourself and I'm pretty sure I saw at least one driver take off without bothering to belt in. Nuon had a major advantage here as they used a standard 3-point automotive seat belt, which was much faster to fasten. I'm not sure how I feel about that; automotive seatbelts are designed to work in concert with crumple zones and airbags, and I'm doubtful of how well one would restrain a solar car driver in a rollover. But if WSC keeps these rules for 2019, expect to see a lot more 3-point harnesses in the Challenger cars.

Anyway, like I said above, the control stop regs and operations this year were a huge improvement, so good job WSC. I'm nitpicking because that's just what I do.

***Caveat: I only personally witnessed the race from Alice Springs onward, where there were many fewer cars in a control stop at one time. I heard earlier stops (particularly Katherine) were complete zoos.

Cruiser Class

I was pleased with consistent updates on WSC's website. Official realtime coverage of the race has been lacking in past years, but this year's daily Cruiser summaries were nicely done.

The scoring formula seemed a lot more interesting this year, but I'm still scratching my head at the competition overall. WSC has been encouraging the teams to build ever larger and heavier cars while simultaneously reducing the allowed size of the solar array; the regs (written and unwritten) incentivize teams to build 4+ seat cars that can fit large amounts of cargo inside. Even without the weather, it seemed like this year was going to end up as a battery-electric car competition - most of the cars this year were going to end up with less than a third of their energy coming from the solar array. If WSC keeps following the trajectory that they've been on with the Cruiser class, I'm not sure what the point of the solar array will be. There was that interesting tidbit about having to interact with smart microgrids that was mentioned offhand at the awards... hmmmm.

Alright, time to talk about how the Cruiser competition actually went. Let's start off with some tables - we'll be referring to these below.

Pink background indicates invalidated efficiency scores due to finishing after the cutoff window

Briefly, the point I made in my Cruiser post before the race was right - the teams with more seats had many more strategy options, which was important for the success of both Eindhoven and Bochum.

The teams may have planned to charge off the grid at only a few select locations, but the weather threw a wrench in everyone's plans. In the Cruiser class, every team ended up charging off the grid every single night. Eindhoven was able to use the number of people in the car to modulate their performance - you can see in the efficiency table how they had the car packed with 5 people consistently up through Alice Springs, and then reduced to a single person in the car through Port Augusta in order to keep up the pace through the clouds. Similarly, when Bochum had motor issues, they were able to limp along with fewer people rather than be dead in the water entirely. Meanwhile, the 2-seat cars like Minnesota and IVE didn't have as many options in the cloudy weather and were unable to drop enough weight to keep up.

I tried to hammer this point in 2015, and still was true in 2017: under the Cruiser regs, aero efficiency is still king! Most teams built vaguely "car like" looking vehicles with relatively poor aerodynamic performance; they couldn't compete AT ALL with Eindhoven. The Dutch team's efficiency score was so embarrassingly higher than the rest of the field that Eindhoven could have scored a flat zero on practicality and still won the overall competition by a huge margin. I don't understand why teams keep fielding cars that are so woefully unsuitable for placing well in the competition; it's like teams are designing their cars as if the completion is scored 80/20 practicality/efficiency, rather than the other way around. I simply don't get it. In 2013 no one knew quite what to expect from the Cruiser class, but by 2017 I think it's pretty inexcusable. Eindhoven's victories result in great press releases for the Netherlands and WSC, but it makes for a boring and frustrating competition to spectate when you know exactly who is going to win and why for at least a month in advance.

So, how did I do with my Cruiser predictions? Well, not that great. I correctly called Eindhoven as the winner (but that was frankly a no-brainer) and Bochum as the second place team. After that, however, I didn't do so well - PrISUm, UNSW, and Lodz all were forced onto the trailer fairly early in the competition. PrISUm had battery issues on the first two days that left them running on empty when the clouds and rain hit on the third day, forcing them to trailer the car before Barrow Creek. UNSW withdrew somewhere around Tennant Creek or Barrow Creek due to safety concerns over their suspension issues. I'm unsure about what happened to Lodz, but given the small size of their battery (second smallest in the Cruiser class), I expect that they were unable to collect enough energy to keep up under the clouds. My consolation prize is that the three 2-seat cars I mentioned further down in my predictions ended up being the three remaining contenders. Arrow was the least efficient of the three cars, but their larger battery allowed them to pull more energy from the grid and keep their speed up through the clouds and rain. Minnesota had the smallest battery in the Cruiser class and IVE had a small battery as well; neither were able to maintain the minimum Cruiser pace despite charging every night and driving with a single person in the car. The past couple of WSC events have been pretty dry overall, so I guess some of the Cruiser teams forgot that sometimes WSC is cloudy and rainy...

My notes about the "cheater" Cruiser being the winning strategy were probably right. A team with performance comparable to WSU could have slapped a second canopy and an extra 1sqm of array on their car; with their standard-size Challenger battery and a single grid recharge, they would have posted an efficiency score so high that they could receive a flat zero on Practicality and still beat Eindhoven. Sure, Einghoven was so far ahead of everyone else that they probably ran a pretty conservative strategy over the later half of course, and could have posted a higher efficiency score if they were feeling pressure... But I still remain convinced that minimizing energy usage with a no-holds-barred aerodynamic vehicle could have yielded an extremely competitive entry.

Eindhoven: As in previous years, Eindhoven focused on packing a large number of people into the most aerodynamic shape possible, rather than building a vehicle that resembles a normal car. The efficiency of Stella Vie in terms of person-km/energy used was almost embarrassingly better than the other teams - more than double the efficiency of the next two cars, and more than triple the efficiency of the two cars after that. Not only did they tie for the 3rd smallest battery in the Cruiser class, but they were able to use it to haul an average of 3.38 people in the car across 3021 km. The three other cars with sub-10kWh batteries weren't able to keep up, even with only a single person in the car.

Eindhoven will simply remain untouchable unless other teams start focusing on aerodynamic performance. No matter how the Cruiser regs evolve, I find it hard to imagine a credible event that doesn't place a majority of the score on vehicle efficiency in some way - and as far as cars are concerned, efficiency = aerodynamics. Period.

But that's not to say that Eindhoven neglected the practicality portion of the competition, far from it: they also scored the highest on practicality. They received the highest score from the judges, and were the only team other than Bochum to ace the exercises. WSC 2017 was Eindhoven's most impressive performance to date.

Photo: Bart van Overbeeke, CC BY-NC-ND 2.0
(image source)

Bochum: The Germans were the most credible competitors for Eindhoven this year, but they were plagued by motor controller issues. They went through a total of five WaveSculptor22 motor controllers over the course of the event. They were only able to carry a single occupant over the first leg of the race due to motor controller issues, and were the last Cruiser car to make it to Katherine. Bochum were able to carry a full four people over the Daly Waters to Tennant Creek leg, but the car refused to drive out of Tennant Creek until they removed half the people from the car. It was a similar story in Alice Springs - they tried to depart with two people, but the car just didn't want to go until they removed some weight. The car seemed to run better over the second half of the race, but they still burned out another motor controller when they arrived at the parade grounds in Adelaide.

Bochum's post-race WaveSculptor graveyard
Photo: MostDece

Bochum's car also had some surprisingly crude aerodynamic modifications on the rear end. I'd seen these in photos after their wind tunnel trip, but I assumed that they'd have a more refined version installed for the race...

Crude rear wheel strakes on Blue.Cruiser
Photo: MostDece

Duckbill spoiler
Photo: MostDece

Bochum's interior was extremely nice, containing a lot of sustainable and recyclable materials - sadly I didn't manage to get any good photos. The team scored very well in the Practicality portion of the event, getting the 2nd highest Judge's score overall (including the highest score in the "Desireability" section) and acing the exercises.

Arrow: Arrow's car was a little rough around the edges, but it had it where it counted: the ability to actually drive. The team made steady progress through the outback, which was aided by the second largest battery in the Cruiser class this year. I doubt the team was ever short on energy, but their large battery also resulted in the lowest efficiency score of the five teams that drove the entire distance. As it turned out, that didn't matter much this year - so few cars finished that simply completing the course was good enough to get them onto the podium. They also scored very well (4th) in the Judge's portion of Practicality, but did abysmally badly in the Exercise portion. They only received 3 out of a possible 9 points there, resulting in the worse exercise score. Apparently they had difficulties with the 3-point turn? Not sure what went down there.

There were a lot of neat features - particularly, their gorilla glass encapsulated array, which they delighted in doing things to that you would never, ever do to a normal solar car array.

Arrow STF heading south out of Alice Springs on Oct 10
Photo: MostDece

Some gripes:

I didn't like the sharp time cutoff in the Cruiser regs this year - it basically meant that if teams had a single issue and fell off pace, they were out of the race. There were effectively zero ways to mitigate risk without drastically reducing the efficiency score. Yes, there's a sharp cutoff at the end for Challenger class as well, but Challenger cars are incentivized to be as fast as possible - as far away from the cutoff as possible. Because slower speeds are more energy efficient, the Cruisers are incentivized to be as slow and as close to the cutoff as possible, which basically encourages bad outcomes. It's a recipe for last-minute problems completely sinking a team. For example, if Eindhoven had experienced their midconsole structural failure at the start of the 6th day instead of the end of the 5th day, they might have simply been dead in the water.

This year, only 3 of the 13 cars managed to finish the course before the cutoff. IVE was just barely on-pace to finish, but got stuck in unexpected (to them) Adelaide traffic and was a bare 18 minutes late to the marshaling point. Minnesota was just a bit too slow over the entire route and arrived 54 minutes late. If those two teams had arrived on time, Minnesota and IVE would have been the 3rd and 4th place Cruiser teams overall. But because they missed they arrival cutoff, WSC has given them a score of zero for efficiency - in other words, they aren't credited at all for any distance driven. Strictly speaking, this follows the letter of the regulations... But by not recognizing Minnesota's and IVE's performance on the road in any way, WSC has bumped those two teams back to 8th and 11th place, respectively - far behind teams that completed less than a third of the route (and in some cases, none of the route). I would have understood if WSC had penalized the teams such that they placed behind Arrow - the last team to complete the course on time - but the current results seem extremely harsh for IVE and Minnesota. Perhaps for 2019 WSC should implement a target time rather than a cutoff time, with a sliding scale of penalties for missing the target.

Practicality scoring seemed much more haphazard than last year, which was surprising to me given the increased emphasis on practicality in this year's scoring equation. Instead of a big show in the center of the square, it was crammed off in a back corner. I was talking to a Challenger team and keeping my eye on the middle of the square while waiting for it to start, and completely missed the start of the judging as a result. This may have been due to the large volume of Challenger cars slowed by the weather and crossing the finish later, but parts of the judging still seemed like it was organized at the last minute and being figured out on the fly, rather than planned out ahead of time.

The teams were allowed a spotter to direct the driver through the parallel parking test, so I'm not quite sure what was the point of that test. Didn't WSC already test the turning radius of the cars up in Darwin? If they're not testing the car's rear and side vision by allowing a spotter, isn't this basically a test of the driver (and the spotter), and not of the car itself? And these two driver skill exercises accounted for a full 1/3rd of the practicality score!

"Storage" wasn't a varied set of items in a range of sizes like in 2015 - it was a stroller, a baby car seat, and an entire city bicycle that appeared to have been grabbed right off the street that afternoon. The baby car seat seemed to be picked to specifically penalize teams that used racing bucket seats, for some reason that eludes me. The bicycle had nutted axles instead of a QR, so the front wheel could not be removed, and WSC forbade teams from dropping the seat or rotating the handlebars... I haven't owned a single car in my life that I could have fit that bike inside! I've always needed to be able to remove the front wheel to fit a bike inside anything smaller than a minivan or SUV. Is WSC accusing my trusty old Camry of being an impractical car? It had a positively cavernous trunk, but without fold down rear seats I'm pretty sure that I couldn't have fit a bicycle inside even with both wheels removed...

Teams also didn't appear to be scored on how much time it took to pack the items inside. Iowa simply opened the rear hatch and chucked the bike inside the large cargo area, while some teams used several team members and many tens of minutes to carefully ease the bike through the roof into the passenger compartment - including requiring the driver to contort around parts of the bicycle intruding into their seating area. I could have taken Iowa's car and driven all the way from my house to my favorite mountain bike trailhead before Bochum finished packing the bicycle in their car, but WSC gave both teams the exact same score for this exercise. Madness.

Bochum laboriously, carefully filling their passenger compartment with a bicycle.
(image source)

A WSC official explained to me that they were trying to pick items for the storage judging that would differentiate the cars rather than award participation points to everyone, but the limited selection of large items really dismayed the teams that had attempted to design efficient commuter and around-the-town cars with lots of easy and convenient storage for daily items like groceries, but no bulk storage.

WSC seems really enamored with "family cars" like Eindhoven's entries over the past 3 years (perhaps not without reason, given the team's performance), and I'm not sure why they even bother to allow 2-seat cars in the Cruiser class anymore. Not only did this year's Efficiency scoring equation favor cars with more seats, but the Practicality scoring seemed to heavily favor the cars with more seats as well - the 4- and 5-seat cars uniformly placed ahead of the 2-seat cars in Practicality judging. A team relayed to me over beers that they were explicitly told at Practicality judging that points were being taken off for their lack of a rear row of seats. The regs state that teams will be judged on "suitability for the declared purpose" (4.4.13), but instead, every team was judged on how well they had built a family minivan. If WSC wants to see 4-seat cars, just get it over with - require 4 seats!

Personally, this sort of scope creep is really frustrating to me in the real automotive world as well - no one sells any genuinely compact trucks in the USA anymore, for example. I neither want nor need a giant Family Truckster, but it's becoming increasingly hard to buy simple and small cars that aren't painfully decontented and boring econoboxes. My daily-driver for the past 7 years has been a 2-seat car; it doesn't matter because the vast majority of the time I am the sole occupant. It's super easy to park and it gets great fuel mileage. I have a hitch rack for two bikes, so I can easily load it up for a weekend adventure with a friend. It's been to both the Atlantic and Pacific Oceans. But since I can't fit a stroller in the trunk or an entire bicycle inside the car, WSC would tell me it's "not practical"...

Ultimately, all of the practicality shenanigans and gripes didn't matter - the few cars that finished had such wildly disparate energy efficiency scores that practicality judging was a sideshow rather than anything that affected the finishing order.

Sorry for ending this post on an extended gripe - there was a lot of cool stuff in the Cruiser class this year, but there are just a lot of frustrating aspects as well.

Thanks for all of the fun memories, and I'll see you all in Darwin in 2019!

Thursday, October 5, 2017

WSC 2017: Oct 5th

Scheduled static scrutineering should be wrapping up soon in Darwin. WSC has a scrutineering tracker page set up now, and as of this blog post, only 15 of the 41 teams had fully passed static scrutineering. ScientificGems is also tracking scrutineering here. I believe the 6th is a free day in the schedule, so I expect that almost all of the teams will get through before the start of dynamic scrutineering on the 7th.

Through various sources, I've been piecing together the weights of the Challenger cars. Interestingly, it was surprisingly easy to find out the weights of the top cars - Nuon actually announced theirs on Twitter, and Punch published theirs on an Instagram story. The top teams from last year are all incredibly close in weight - Nuon is 141 kg, Punch is 143.1 kg, Twente is 143.4 kg and Tokai is 146 kg.  These are also the four lightest cars at the event (of the cars I have data for). The lone outlier among the top cars is Michigan at 193 kg. That seems very heavy for such a teensy car... One of my old solar cars was lighter than that, and it had more than double the array area!

EDIT  OCT 6: Tokai's car actually weighs 172.4kg. The initial weight was erroneously reported without the battery pack.

I have weight data on 17 of the 25 Challenger cars, but unfortunately I don't have information for some of the other cars that I'm very interested in - WSU, NIT, or Kogakuin. Stanford's Sundae is 218kg, which seems exceedingly heavy for a small car. NWU's Naledi weighs 225 kg, which is perhaps unsurprising given that it's the largest car at the event.

There's not too much I can talk about with scrutineering - not being on the floor myself, I can't get a sense of what's going on, and the photos that are being posted are of the "here is a pretty car" variety rather than detail shots of unique features. That said, a few things that are worth pointing out:

Punch's steering mechanism
(image source)
It's always gratifying when something you called early on based on a few pixels turns out to be completely correct. In this case, I noticed some oddities with Punch's steering mechanism way back in mid August, and my silly theory was right! Punch posted a closeup of their steering mechanism with the cover off to Facebook today, and it's really cool. They're doing a 4 wheel steering setup: the front wheels are directly driven from the steering wheel, but the rear wheels are driven by a Geneva drive. So the rear wheels are locked straight ahead most of the time, but kick out when the steering is near full lock. 

If you're still not sure what you're looking at, see the lovingly MSPaint annotated image below:

The systm is pictured in the straight-ahead orientation. As the driver turns the steering wheel, the face highlighted in red slides along the face highlighted in light blue. So the front wheels steer continuously, while the rear wheels remain locked straight ahead until the pin circled in orange interfaces with the slot outlined in green. At this point, the countershaft turns and the rear wheels begin to steer. This is not a continuous drive, as in the gif on Wikipedia - there should be steering stops set to limit the rotation of the main shaft such that the pin can't exit the slot on the other side. For steering in the other direction, presumably there's a matching slot on the bottom of the plate on the countershaft, as I can see another pin peeking out at the bottom of the plate on the main shaft.

This is extremely clever! It's much more lightweight than electrically or hydraulically driven rear steering, and has none of the control system lag that's a possibility with electrical steering (Michigan famously failed to qualify for ASC 2003 because there was too much lag in the control system for the electrically steered rear wheels). That said, there may be some interesting jerkiness to the steering feel - the highest rear steer rate is the point at which the rear steer kicks in; it won't be a gradual ramp. But I'm sure Punch has designed the system so they only need that much steering at very low speeds.

I'd also like to point out a few photos of Nuna 9:

(image source)
(image source)
Nothing too mindblowing here, but I wanted to point out extremely clean seams and the gasket sealing around top shell and driver hatch. The separation of the driver hatch opening from the array opening in the top photo is particularly clean. The seams on Nuon's car are incredibly good this year; you can barely see the edges of the wheel cover panels in photos of the car.

The second Nuon photo is a great example of the integral array stands we've been seeing on a lot of cars this year. I think the revisions to the regs this year did a much better job forcing teams to build clean, integral array standing mechanisms than the 2015 regs did. Hopefully the updated regs will result in less control stop shenanigans as well. While on that topic, I've yet to see any array normalization mechanism on Tokai's car. There are some asymmetric features on the back of the driver compartment that are presumably for an array tilting mechanism, but the team has been simply lifting the top off at all of the inspection stations.

As far as I am aware, both the Tehran and Mississippi Choktaw teams are still missing their cars. Choktaw's car has competed in the USA previously and is only entered in the adventure class, so hopefully they can blaze through inspection if they get their car tomorrow. But as far as I'm aware the Iranian car still needs a lot of work in order to be ready to compete, so unfortunately I think that at this point their withdrawl from the Cruiser class is pretty much guaranteed.

That's all I have for today. Good luck to all of the teams!

Monday, October 2, 2017

Quick Links: October 3rd

We've been forwarded a schedule for WSC 2017 scrutineering:

October 2
1200 77: Blue Sky 5: SunSPEC
October 3
0730 88: Kogakuin 15: WSU
0800 14: Flinders 45: Lodz
0830 75: UNSW 18: UiTM
0900 20: DUEM 25: NIT
1200 28: Neul-Hae-Rang 32: Principia
1230 35: IVE 82: KUSTC
1300 71: ITU 37: Goko
October 4
0730 3: Nuon 21: Twente
0800 10: Tokai 8: Punch
0830 16: Stanford 2: Michigan
0900 70: Sonnenwagen Aachen 7: AUSRT
1200 4: Antakari 43: ANU
1230 52: Illini 34: RVCE
1300 38: NWU 46: JU
October 5
0730 9: PrISUmn 11: Bochum
0800 22: MDH 23: Tehran
0830 42: TAFE SA 40: Eindhoven
0900 30: Team Arrow 49: Siam Tech
1200 53: Mississippi Choctaw 94: Minnesota
1230 95: KUAS/Apollo 12: CUER

It's currently 10:30am on the 3rd in Darwin, so several teams have been through scrutineering already, although we don't know how many (if any) have passed yet. The World Solar Challenge has actually been updating their TwitterInstagram, and Facebook accounts, so go and check them out.

Note that Kogakuin's Wing has no signs of damage, so the rumors that they had a wreck testing in the outback in SA seem to have been erroneous.

The rest of the teams have arrived at Hidden Valley: Michigan, Stanford, Iowa, Bochum, TAFE SA, and Apollo are all there now. I still haven't see photos of Siam Tech's Nikola or Tehran's Persian Gazelle IV, however...

Feast your eyes on NWU's Naledi: The array tilts! I've been waiting a while for a picture of this.

This year, MDH is the unlucky team with last-minute battery shipping issues. They're pressing onward and building a brand-new battery in the pits at Hidden Valley; hopefully they'll get it running well enough to compete. MIT was in a very similar position in 2011 and managed to perform acceptably.

In more unfortunate news, CUER has wrecked their car while testing somewhere around Alice Springs (presumably at the Alice Springs Inland Dragway). The team states "The CUER vehicle Mirage has been involved in an incident during testing at a facility in Alice Springs over the weekend. The driver was taken to hospital where she was treated for minor abrasions and fractures, and has since been discharged. Mirage has sustained major damage and regrettably will be unable to compete in the Challenger Class for the Bridgestone World Solar Challenge."

I'm glad everyone is still alive. With a simple rear roll hoop, there's not a lot protecting the driver from frontal impacts if the car ends up on its side at speed. Broken bones are no joke; I think this might be the worst solar car driver injury in over a decade. I'm pretty sure the drivers walked away from the car when MIT flipped in 2005, when Stanford wrecked in 2007, when Umicore, Nuon and Twente wrecked in 2009, and CUER's own incidents in 2013...

(For those playing along at home, CUER is now two-for-three on wrecking their "Resolution Concept" vehicles during testing in AU prior to the start of WSC...)

Saturday, September 30, 2017

Quick Links: September 29th

I've been super busy with work and next week looks just as bad, so rather than the usual long-form team by team update, here's a brief post with some quick links.

Scientific Gems has been keeping his map up to date. The vast majority of the teams are in Darwin at this point, and the rest are all enroute from points south (with two exceptions: I don't know where Siam Tech's or Tehran's cars are). Here's a really, really brief location update for the teams:

In Darwin

Nuon, PunchTwenteJUSonnenwagenBlue Sky, and Eindhoven have all been testing on the Cox Peninsula. 

Antakari, AUSRT, WSU, UiTM, DUEMMDH, NIT, Neul-Hae-Rang, Principia, Goko, RVCE, ANU, ITU, Kookmin, Kogakuin, SunSPEC, Flinders, Arrow, IVE Sophie, Lodz, UNSW, Minnesota, and Illini all have their cars in Darwin and have settled into their pit bays at Hidden Valley. I'm not 100% on Mississippi Choctaw, but I think they have as well.

Minnesota may be heading out on the Cox Peninsula at some point to do some road testing; I'm not sure about any of the other teams at Hidden Valley.

Tokai has arrived in Darwin after traveling north from Adelaide. I'm not sure if they were test driving the car, or just hauled the car north in the trailer - they didn't post any photos of the car driving while en-route. I'm also not sure if they're going to test on the Cox Peninsula, or set up in a garage at Hidden Valley.

NWU has their car somewhere in Darwin, but not in Hidden Valley. Portions of the team appear to still be traveling north to Darwin.

In The Outback

Michigan has completed a second, shorter mock race in South Australia and is now heading north for Darwin. At this point I think they've spent 12 days doing mock race stuff in the outback - about two and a half WSC's worth of time.

CUER has been testing in the outback, and has finally received their canopy.

Stanford has packed the car up after completing testing in SA and is in transit to Darwin

Iowa State has finished testing in the Outback and is currently enroute to Darwin

Bochum has completed their repairs in Coober Pedy (aided by several other teams) and is on the way to Darwin. The rain in the outback looks really nasty...

(image source)

TAFE SA has departed for Darwin, and Apollo is on the way as well.

Location Unsure???

Siam Tech's team is definitely at Hidden Valley, but their car is conspicuously missing from their video, and I unfortunately don't speak Thai... I haven't seen their car in anyone else's photos from Hidden Valley either.

Tehran shipped the car a while back, and posted a video of it driving from before it shipped, but I don't know the current wherabouts of the team or car.

Other News

Nuon reports that they have an entire battery pack's worth of cells that are up for grabs if any teams have having last-minute trouble with battery pack shipping - and it sounds like that's a situation that at least a few teams are in, yikes!

Weather: Bochum and CUER aren't the only teams talking about the weather; I've heard similar news from Stanford and Michigan. Every solar car race is affected by the weather, but it could be a larger factor than usual at this year's WSC. A rainier race may negate some of the possible advantages of the multi-junction arrays and monohull cars...

Unfortunately, I won't be making it down to Australia before the race to cover inspections like I did in 2015. I'm going to be really busy with work next week as well, so I might not have too much time to scour the teams' social media, either. There's a lot of activity on the Facebook discussion group; definitely the place you should be reading for up-to-date information. This Twitter list that I put together is another good thing to bookmark, as is the #BWSC17 hashtag.

will make it into Adelaide a few days before the finish line, and hope to intercept the leaders somewhere around around Coober Pedy - so keep an eye out for some good finish line coverage from here and on Twitter.

Thursday, September 28, 2017

WSC 2017 Cruiser Summary

Solar car racing has never really been about practicality. Sure, teams have built and raced multi-seat solar cars in the past - Honda famously won WSC 1996 with their back-to-back two-seat Honda Dream, and 6m x 2m ISF6000 two-seat cars went head-to-head against 5m x 1.8m ISF5000 single-seat cars at ASC and WSC from 2001 to 2005. But none of those cars were designed to be practical; they were still race cars that were designed to be as light as fast as possible.

All of this changed in 2013 when WSC developed the Cruiser Class for their event. Cars in the Cruiser Class would be allowed to recharge their battery off the grid(!), and would be required to seat more than one person. In addition, for what I believe was the first time, the solar cars would be judged based on something other than which car crossed the finish line first. They would be judged on the sum total distance of people carried in the car (person-km), the amount of grid energy used, and the subjective practicality of the car.

In 2013, elapsed time was worth 56.60% of a teams final score, energy usage was worth 18.87%, person-km was worth 5.66%, and practicality was 18.87%. The formula was tweaked slightly for 2015 (elapsed time 70%, energy usage 15%, person-km 5%, practicality 15%), but the event was largely the same.

2017 Changes

There have been a lot of changes to the Cruiser class in 2017. For starters, I wouldn't call it a race anymore. Teams must arrive in Adelaide between 11:00 and 14:00 on the 6th day, and no credit will be given for arriving earlier. Without the "trying to go faster than the other teams" aspect, I'd simply call it a competition...

Scoring this year is 20% practicality and 80% "energy efficiency", where the "energy efficiency" score is calculated as person-km divided by energy usage - energy usage being the capacity of the battery pack, multiplied by the number of times a team charges off the grid + 1 (to account for the energy in the battery at the start line). While we're talking about charging off the grid, that has changed for 2017 as well - a team can charge off the grid anywhere, any number of times (in 2013, there were three locations, and in 2015 there was a single opportunity in Alice Springs). And battery size limits have been eliminated as well - a team can pick any size pack they want.

Speed and energy usage were such a big part of the old scoring formulas and person-km was such a small part; I really think that the old rules favored 2-seat cars*. 2017 is a completely different ballgame: instead of a dinky 5% of the score, person-km has a multiplicative effect on a factor that accounts for 80% of the score!

Looking at the energy efficiency score, I don't see any downsides to cramming as many people in the car as possible. Sure, a 4-seat car will have more aerodynamic drag than a comparable 2-seat car, but it won't have double the drag. It won't weigh twice as much either - many things will weigh the same regardless of how many people are in the car (the solar array, the lights, the steering wheel and pedals, etc). So by placing more people in the car, the drag-per-person and the mass-per-person both go down, which should reduce the energy-usage-per-person - exactly what the teams are being scored on. I'd also expect cars with more seats will place better on practicality, so more seats appears to be a win all around.

*Yes, Eindhoven won with 4-seat cars in both 2013 and 2015, but I'd argue this was due to the quality of the car and the team, rather than designs with more seats having an inherent advantage. In 2013, they carried more people, used the same amount of energy, and yet went FASTER than two of the three 2-seat cars that finished the course. 2015 was a similar story - the Eindhoven team was simply in a class of their own.

How many people can teams fit?

So how many people is it possible to fit in a solar car? Several things place an upper limit on the number of people that makes sense. Each person added increases a team's potential score by a smaller amount - the score increases towards a horizontal asymptote as people are added, rather than increasing linearly. But the score theoretically does keep rising as people are added... Practically speaking, however, an increasing number of people will at some point result in aerodynamic compromises to keep the car within the 5m x 2.2m planform, and at that point adding more people will rapidly stop making sense. Even earlier than that, a design will run into a weight problem - I think that's what ultimately puts an upper limit on the number of people that a team can reasonably fit.

The Michelin Radial X and Schwalbe Energizer S both have a load rating of 150kg (and I suspect the Bridgestone Ecopia is similar), so a 4-wheeled car can weigh a maximum of 600kg. Each occupant weighs 80kg (if they're lighter, they're ballasted up to that amount - reg 3.12.8), so a 4-seat car has 320kg of occupants, and a 5-seat car has 400 kg of occupants. This does not leave a lot of weight budget left over for the car itself! Typical Challenger cars weigh 135-150kg; add in some extra weight for a larger battery, more seats, stronger chassis and suspension, etc... and you'll be over 600kg really quickly. A 6-seat car would need to weigh less than even the lightest Challenger cars to stay within the load rating of the tires, and that just ain't happening. A 6-seat car would have to move up to real car tires, which would increase weight, aerodynamic drag, and rolling resistance - and that would result in a huge downward step function in score.

Of course, this is all probably irrelevant at WSC - given the "roll cages" they still allow, do you think they'll care about something as trivial as load ratings on the tires??? Eindhoven claims Stella Vie weighs 375kg, so with 5 people inside, it weighs 775kg - 30% over the maximum allowed load on the tires (and that assumes a perfect 50/50 F/R weight bias). If WSC was being strict, they'd only allow Eindhoven to drive with two people inside a car that heavy!

But even if WSC won't prevent teams from blowing past the load ratings on the tires, I'm not sure how far I'd want to push the limits. Some of the worst crashes in WSC history have been due to tire blowouts, and with such heavier cars, the kinetic energy to deal with in a collision is much higher... Honestly, the 4/5 seat cars give me a little bit of the heebie-jeebies; we've already seen a suspension failure from UNSW and some sort of structural chassis failure from Bochum, and the event hasn't even started yet.

(EDIT 9/29: A comment below notes that the load rating on the Bridgestone Ecopia is higher than the 150kg load rating on the Michelin and Schwalbe tires. They don't say how much, but anything over 195 kg would allow Eindhoven to carry all five people without blowing the load rating.)

How small can the battery get?

So we've looked at how many people a team can practically fit. What if we move in the other direction? What if instead of adding people to maximize the person-km/energy-usage equation, we minimize the number of people and radically reduce our energy usage instead?

Given the arrival window, a team needs to have an average speed of at least 65kph. This speed would be good enough for about 9th or 10th place in the 2015 Challenger class. So, imagine if Nuon elongaged their driver canopy and stuck a "cheater" seat behind the driver's seat so it's technically a 2-seat car... how small do you think they could shrink their battery and still be able to place around 10th?

Back-of-the-envelope calculations tell me that the point a cheater-car beats a good 5-seat car is around a 2.5kWh pack. If you built a high-quality cheater-challenger car for the Cruiser class with a sub-2.5kWh pack and managed to finish the competition without recharging off the grid*, I think victory would be possible**. I heard that a few different teams strongly considered building this sort of car, but none of them ended up doing so. I think this sort of car is just too risky - because if you mess up your strategy, end up behind the minimum speed, and have to charge off the grid just once, your score gets cut in half. Which brings me to yet another way that more seats are better this year: strategy risk.

*Is 2.5kWh enough to finish the competition with? Once the pack gets small enough that you can't store all the energy from an evening and morning charge, performance of the car starts to drop off quickly, and I'm not sure if 2.5kWh is past that line...

**I don't speak Dutch, but it appears that Eindhoven thought about doing this in the past - lots of highly aero-optimized 2-seat concept sketches are shown in this video.

Cruiser Strategy

Strategy has really been turned on its head in the Cruiser class this year. In a race, it's easy to adjust your strategy. Have a little extra energy in the pack? Speed up a little bit to burn it off, and place higher. Looks like you're going to have an energy shortfall? Slow down a hair to save some energy. But in the 2017 Cruiser class, you can't adjust your speed. No extra credit is given for arriving early, so there is precisely zero advantage to driving faster than 65kph (other than to build up a buffer to account for unforeseen issues). And you can't drive slower, because otherwise you simply don't finish. The only knobs a team can turn is how many people are in the car, and how many times they charge off the grid - and both of those are BIG knobs to turn, resulting in LARGE step functions in a team's score.

In the absence of speed as a variable that can be tweaked on the fly, the Cruiser teams are left with weight - in other words, how many people are in the car at any one time. They can only change this so many times - a seat must be continuously occupied for an entire leg between control stops for the person-km to be counted, and there are a limited number of control stops, as ScientificGems illustrates here. Therefore, the Cruiser cars with more seats have an advantage when it comes ot adjusting strategy over the course of the race, as they have finer control over the weight of the car. It's probably smart to design the car and strategy such that at the optimal speed, one of the seats is empty some of the time - this allows the team to increase their scoring performance if they're using less energy than expected. If a team starts off the competition planning to have all seats occupied all the time, they don't have a good way of increasing their energy efficiency score if the conditions end up allowing for it.

On the battery front, I'm not sure whether it's better to use a large battery that you plan on never charging off the grid, or a smaller battery that you intend to charge nearly every night. 

A smaller battery is lighter, and allows for more strategy modulation - skipping a charge or adding an extra charge has a smaller effect on score*. However, every time a team charges their battery off the grid, it's assumed they charged it from completely empty to completely full; there's no net-metering credit for only partially charging the battery. So every time a team charges overnight, they effectively "throw away" the "free" solar energy from that evening and morning charge, as well as whatever residual energy was left in the pack when they started charging.

A team that never charges off the grid doesn't "lose" any energy to the scoring equation, but they have to lug around a heavier battery throughout the competition. The strategy is riskier as well - if they fall behind and have to recharge off the grid a single time, their score is cut in half**.

*But still far larger an effect than adding or removing a person for a single leg of the competition, even in a 2-seat car.

**For what it's worth, I think Eindhoven is going with the "big battery, no recharges" strategy this year. They did 2015 with a 15kWh battery and a single recharge. This year they have a 12kWh battery, but competition speeds will be about 10kph lower, which means less energy expenditure over the event (and I think their aerodynamics have improved significantly as well). The array is smaller, but due to the lower speed they'll have more time under the sun, and I think they'll collect about the same amount of solar energy overall. I wouldn't be surprised if Eindhoven does the whole competition without recharging, and I would be surprised if they charge more than once.


Due to how the competition is done this year, it will be impossible to tell how it's going just from the road position of the cars. I expect that all of the cars will be bunched very tightly together; all trying to drive no faster than necessary to finish before the deadline in Adelaide. Unless WSC publishes the battery capacity of each of the competitors prior to the event, and over the course of the event publishes when teams grid charge and how many people arrive in each car at each control stop, we will have literally no idea who is in the lead until WSC announces the winner at the awards ceremony. I implore WSC to publish this information as the competition progresses, so the public can follow along. If they don't, the Cruisers are going to drop off of everyone's radar the moment they cross the start line.

The Cars

There are 14 entries in the Cruiser Class this year:

# of Seats
40: Eindhoven 5
45: Lodz 5
9: PrISUm 4
11: Bochum 4
23: Tehran 4
75: UNSW 4
14: Flinders 3
5: SunSPEC 2
30: Arrow 2
35: IVE 2
42: TAFE SA 2
49: Siam Tech 2
94: Minnesota 2
95: Apollo 2

Unlike previous years in which 2-seat cars comprised most of the field, half the field is doing more than two seats this time around. Unlike the Challenger class, none of the teams have taken the multi-junction array option.

Not too much more to say, so let's get to our top picks:


Eindhoven is the undisputed champion of the Cruiser class, having won both previous events, and the car they've designed for WSC this year does not disappoint.

Photo: Bart van Overbeeke, CC BY-NC-ND 2.0
(image source)
Photo: Bart van Overbeeke, CC BY-NC-ND 2.0
(image source)
Photo: Bart van Overbeeke, CC BY-NC-ND 2.0
(image source)

Stella Vie takes advantage of 2017's larger bounding box and smaller 5sqm array to fit an extra person in a much more curvaceous car than 2015's Stella Lux. Yes, this is a 5-seat car, with 3-across in the second row! The quality appears just as high as on Eindhoven's previous cars, and as I detailed above, I think that designing for more people was definitely the smart strategy this year.

This is the team to beat. Full stop, end of story.


Bochum has been credited with inspiring the Cruiser class - the team fielded a side-by-side 2-seat car at WSC in 2011, before the class existed. This year, they've built their first 4-seat car, Blue.Cruiser.

Photo: Stephan Schwabe
(image source)
(image source)
(image source)

Bochum's previous two Cruiser cars were hampered by their solar arrays. Both 2013's SunCruiser and 2015's SunRiser were built with 3sqm multi-junction arrays, and they were competing against cars with up to 6sqm silicon arrays. They were cute cars (particularly SunRiser), but they simply didn't have the array performance necessary to be competitive. This year, Bochum is getting more serious about winning - they fit the full 5sqm of silicon cells allowed; Blue.Cruiser won't be at a power disadvantage. The car also appears more aggressively streamlined than in the past, and it packs 4 people into an impressively tight cockpit (There's enough room in the back to nap comfortably, however).

Bochum had some sort of incident while testing in the outback - I don't have many details, but I've heard through the grapevine that the rear array panel blew off, and perhaps some structural chassis damage occurred. The damage sounds minor enough, and the latest news from their Instagram is that they're back on the road. I expect that Bochum will do very well in the Cruiser class this year - maybe even challenging Eindhoven for the win.


Iowa State University has been in the solar car game for a long time - I remember seeing an "Iowa State University: Shading your array since 1989" t-shirt at an event some years back. They've attended Sunrayce and the American Solar Challenge every single time the event has been run, from the inaugural 1990 event onward.

Their Cruiser entry into WSC 2017 is the first time they have ever competed internationally; they're bringing a 4-seat car named Penumbra.

(image source)
(image source)

On the one hand, PrISUm is a quality team - they've done very well at ASC lately, finishing 2nd in 2012 and 3rd in 2014 (and 7th in 2016's "Rain Rayce", but dang that was a rough year for everyone). The car looks extremely well finished inside and out; it should place very highly on the practicality portion of the event. On the other hand, I really am not a fan of the rear end of Penumbra. I can't imagine that it will be able to come even close to matching the aerodynamic performance of Eindhoven or Bochum, and aero performance still matters a ton in the Cruiser class.

But I think the most important factor is how prepared this team appears to be: PrISUm was one of the first teams to unveiled their car, and they took the car on a 3-week driving tour of all 99 counties in Iowa way back in June. This is may be one of the best prepared cars and best trained teams in the Cruiser class this year, and that alone is probably enough to put them into the top five. I wouldn't be surprised if they managed a podium finish, especially if the next two cars I list have issues on the Stuart Highway.

(EDIT 9/29: See this comment chain for a discussion of their solar array; I hadn't realized that Iowa State fits significantly less than the allowed 5sqm of cells on the exterior of their car. I stand by my prediction that they'll likely finish in the top five, however)


Like Bochum and Eindhoven, Sunswift has competed in both of the previous editions of the Cruiser class. They finished 3rd with their 2-seat eVe in 2013, and brought it back to finish 4th in 2015. This year, they've built a 4-seat car named Violet

(image source)

Violet is very sleek, and it looks like UNSW has really engineered it to compete for the victory under this year's Cruiser scoring formula, but the team really let the construction schedule come down to the wire. They were one of the last teams to unveil, and actually had to delay unveiling due to a suspension failure while testing the car. I have concerns about the readiness of both the car and the team, but I still think they have a better shot than most of ending up in the top five.


This team from Poland was a rookie at WSC in 2015, and was unable to complete the entire route. However, they completed the most person-km of the Cruisers that didn't finish, and the construction of the car appeared to be high quality.

This year, Lodz is the only team other than Eindhoven to construct a 5-seat solar car.

(image source)

Eagle Two looks like a well constructed car, and I have suspicion that Lodz may do much better in their second attempt at WSC (similar to WSU's improvement from 2013 to 2015).

Other Cars

I waffled back and forth on this for a while when I was writing this blog, but I ended up only picking cars with more seats for my top five predictions. However, it's worth mentioning a few of the 2-seat cars:

Team Arrow did quite well in the Challenger class in 2013 and 2015, and has shifted to the Cruiser class this year. Their car Arrow STF looks hot; it probably would have done extremely well in the previous Cruiser class, but given how the regs changed for this year... I also have the same concerns that I have with UNSW: The car was unveiled extremely late, and I'm dubious of the amount of testing that has been done on both the car and team.

Minnesota is the fourth team that has competed in both previous editions of the Cruiser class, and they've struggled to finish the event both times. Their car Eos II is visually a massive step up in quality from Eos in 2015, but it's still a 2-seat car fielded under regulations that seem to heavily favor more seats. Also, while writing up this post I realized that despite being unveiled in early July, I couldn't find a single mention of test driving the car until their recent trek north from Melbourne to Darwin... so I have some doubts about how prepared the team and car are. They'll probably finish in the top half of the field, but given their competition this year, I won't be surprised if they end up bumped out of the top five.

Finally, I'm not quite sure what to expect from IVE. They struggled badly in 2015; only completing 896 person-km. The car this year appears to be a much better constructed car, but I don't know how much they've really improved. It's also only a 2-seat car...