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!


  1. Totally agree with your Cruiser criticisms. Maybe they should just start calling it the "World Electric SUV Challenge"

  2. I've been a huge fan of the Cruiser class since it began in 2013 but the further we get the more obvious it becomes that WSC do not know quite what to do with it.

    It is plain that the panel that fixes the rules see 4+ seat cars as the most practical. I have always found this strange since, if you look at any survey of traffic journeys, it is clear that the average occupancy of a car is nearer to 1 person than 2.

    Then again there is the juxtaposition that teams are asked to design cars to suit real life, and then tested in a way that is about as far removed from everyday life as is possible.

    Even when we come to energy efficiency there is the awkward problem that the winning team(brilliant as they were), in real life, would have dumped all of its passengers halfway through the journey in order to reach the destination on time. Hardly practical!
    If a competition element(a BIG if, I believe) is to be maintained in the future I think that performance against capacity should be measured.

    I fully agree with your comments regarding the practicality marking and indeed it seems that one aspect of a car, its size, is rewarded time and again throughout the competition.

    That said, I was astounded to see that the Tafe car managed to score less than maximum points for its storage capacity, how the hell did that happen?

    I am thankful that teams seem mostly to disregard the rulebook, in terms of winning I mean, and just make the car they want to make. After all, as we've hinted before, a good Challenger type car with a dummy second seat and a 5kwh battery could have recharged in Alice and still won the competition by a distance.

    I really hope that the class continues in the future but I'm starting to feel that it's time to stop trying to compare such disparate entries.


    1. I believe TAFE used seats that were unable to fit the child car seat, which is how they got a point off for storage.

    2. That makes sense, IF you usually take a baby to work with you.

      On that point, I was surprised that Tafe did not use a bench seat in their Yute.

    3. Thank you for your wrap up.
      I agree that challenger class was exciting this year. However, I'm not sure whether the use of GaAs-Cells is really no advantage. With more heat there could have been even more dominance of the multijunction cells. I think there should always be a slight disadvantage to use them, because only the best teams can afford these cells.

      For the cruiser class there is indeed a great chance to improve regulations. Nevertheless this years competition also had some good ideas: The objective to organize a race for efficiency has been a clue to be able to compare different solar cruisers. Although it is sad, that the cruiser class didn't use a lot solar energy. In my opinion the regs for the cruiser should not allow loading from the grid at all (or at least it should be treated like trailering). Instead the solar cruiser could be allowed to carry up to 2(?)m² extra array in the car for loading during stops. Practicality should be fun or be predictable (storage space/passenger or predefined set of boxes where the basis is always 2 Passenger). Of course 18 Minutes should not drop the efficience score to zero in 2019 but there could just an efficiency factor that makes it less attractive to drive slower than Friday 2 p.m.
      I'm looking forward to cruiser class in 2019!

    4. Dietrich: Perhaps if the race had been hotter and faster, the GaAs cells would have had a larger advantage. I'm not sure if WSC should reduce the area of the GaAs cells at all - if there's clearly a disadvantage, no one will use them (see 2011-2015), so why even bother allowing them in the first place?

      Agreed that the low proportion of solar energy on the Cruisers is lamentable - it would be nice if they were allowed big 8sqm solar arrays (like the single-seat cars were back in 2005 and earlier). Eindhoven could have done the entire course on solar with an 8-10sqm array.

      Everyone's been complaining about how practicality judging is a mystery since the first Cruiser regs were issued in 2012, but WSC seems to delight in keeping it a secret. I hear teams complaining every year, but they keep coming back...

    5. I think GaAs has too much advantage in 2017. Car can be smaller (low drug). efficiency never drops during hot weather in north (higher generation than Si). (even WSC banned sprinkle water on solar cells which affected only Silicone teams) Harvesting from wide range of spectrum works far better than Si under cloudy weather.

      I totally don't understand why WSC increased the ratio for GaAs cells because they reduced it to make the chance for lower budget teams before. I doubt the just compared the catalogue spec (at 25 degrees) of both cells.

      If it applied to 2019, there is no change to win without paying more than $300,000 only for cells. It is the philosophy of WSC?

  3. I guess the video from Kogakuin puts their performance into perspective.

    Nice ending though.


    1. Wow, amazing work by the (extended) Kogakuin team. I know we expressed both our admiration for the beautiful and unique design and our concerns for the behavior in windy conditions. Sad still when it actually happens. Good the driver wasn't (physically) hurt. Next time with a smaller MJ-based Wing they may be doing much better on speed and safety.


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