Belgian solar team Innoptus is 214km away from winning back-to-back Bridgestone World Solar Challenges and will give thanks to wind for its lead, as much as the sun’s rays.
Barring incident, its bullet-shaped solar car ‘Infinite’ is expected to arrive at the finish line in Adelaide just before noon on Thursday.
Despite shaving 2 minutes off Innoptus’ 16-minute lead at Coober Pedy, Dutch rivals Solar Team Twente lost touch in the final leg between Glendambo and Port Augusta in South Australia’s arid zone.
It was a challenging day all round. All entrants in the Cruiser class – a regulatory category contested between passenger-vehicles inspired cars – were ‘trailered’ in the outback. None will reach the finish line unaided.
Innoptus now has a 35-minute lead over Twente. It wasn’t just solar energy powering its car on Wednesday, however, with powerful winds caught by its car’s unique retractable ‘fin’ boosting it to a dominant position.
The Belgian team is camping overnight just south of the lead smelter town of Port Pirie, about 165km north of a final control point on the outskirts of Adelaide. Competitors are prevented from overtaking one another after this location, owing to the suburban traffic along main roads into the CBD, but must still reach the finish line under their own power to certify their result.
Twente will restart near Port Germain, about 230km north of the finish.
Solar (and wind) energy the winning formula
In a battle between three aerodynamic designs at this event, the Belgians have proved superior.
Brunel – the most successful operation in solar car racing – was alone among the leading teams to stick with the ‘catamaran’ design it had driven to multiple successes over the past decade. It simply hasn’t held pace with its rivals in the second half of this year’s challenge.
On the other hand, Innoptus and Twente switched from catamarans to ‘bullet’ aeroshells. The decision paid off on Wednesday.
But it was Innoptus’ novel fin – deployed for most of the day – that gave it an added edge. The rudder-like extension acts as a dynamic sail that maximises significant crosswinds experienced across the far north of SA.
Near 60km/h wind gusts were recorded just outside Port Augusta late Wednesday afternoon. With the fin angled to catch those gusts, Innoptus got a 5-10km/h boost over Twente’s top speed.
“We’re really happy with the result,” says Innoptus team leader Cedric Verlinden.
“We still have we still have some energy within the battery pack, which we can use tomorrow to drive at a good speed.
“Priority No.1 now is mitigating all the risks to see that we can still hold together – tomorrow, the strategy will not be to extend the gap even more, just to hold it.”
Wednesday was still a day of achievement for Solar Team Twente. It passed the location of its 2019 crash in Mount Willoughby, and had reduced Innoptus’ lead by the time they reached Coober Pedy.
But Twente couldn’t keep the pace. It will have to settle for second place unless its rival strikes trouble on Thursday morning, with roadworks, reduced speed limits and traffic into Adelaide likely to dash hopes of an upset.
“They are further in front than we wanted,” says Twente’s technical manager Tim Woertman.
“We managed to get closer this morning and were pretty confident. Right now they have managed to get a bigger gap again. But the day went pretty well for us, we kept driving to our own strategy.
“It’s still three or four hours to go, so we have an exciting day tomorrow.”
Brunel – also from the Netherlands – sits in 3rd place after struggling to match the lead pace and suffering a puncture on the road to Port Augusta. The car was partly disassembled to replace the tyre, which effectively ended the 7-time champions’ hopes of returning to the top step of the podium.
Further back, the University of Michigan Solar Car Team (USA) sits 4th with Team Sonnenwagen Aachen (Germany) in 5th heading towards Port Augusta on Thursday morning. Tokai University (Japan) and Top Dutch Solar Racing (Netherlands) are further back but should reach Adelaide later in the day.
The JU Solar team (Sweden) has jumped into 8th place after overtaking Kogakuin University (Japan) on Wednesday, but both are likely to arrive on Friday afternoon. Durham University (UK) is poised to finish inside the top 10 with a Friday arrival as well.
Hard day for Cruiser entrants
While the light and fast Challenger class cars approach the finish line on Thursday, the larger, multi-passenger Cruiser cars experienced a difficult day.
None of these vehicles will finish the race, after being ‘trailered’ near Marla in far north South Australia late today.
Remaining entrants, which included the class-leading Sunswift 7 from the University of New South Wales, were overcome by the strong southerly headwinds draining their batteries throughout the day.
The Cruiser class is a regulatory competition, requiring competitors to reach set checkpoints within a given time window.
And the winner is not solely determined by arrival at a finish line. Instead, total kilometres per vehicle passenger, energy efficiency and showroom appeal are scored and contribute to a final ranking at a judging day in Adelaide this weekend.
The Sunswift team’s close rivals from the University of Minnesota (USA), Solaride (Estonia) and Geelong-based Deakin University were also towed to Coober Pedy.
Only one Australian team – Western Sydney University – is still competing in the event. It is currently camped just outside Marla and will battle for 11th place with the Eclipse team from École de technologie supérieure from Canada.
The Innoptus and Twente teams are due to arrive in Adelaide before 12:00pm local time on Thursday.
Cosmos is the Scientific Media Partner of the 2023 Bridgestone World Solar Challenge Follow our coverage.