“The Bridgestone Solar Car Challenge is a ‘challenge’, not a holiday!” So says lead driver for the Australian Technology Network (ATN) of Universities Team, Matthew Millar, who was also lead designer, build team leader and project manager, undertaking his Masters of Design at RMIT.
ATL Composites contributed to the construction of ATN’s solar car, working closely with the designers and providing the build team with the full range of WEST SYSTEM epoxy resins, the Kinetix resin system, ATL Composites fillers, resin infusion consumables and Divinycell foam as the core material.
Traversing 3,020km from Darwin to Adelaide, the event, 13 to 20 October 2019, involved students from over 30 countries.
Based on the original notion that a 1000W car would complete the journey in 50 hours, solar cars are allowed a nominal 5kW hours of stored energy, which is 10 percent of that theoretical figure. All other energy must come from the sun or be recovered from the kinetic energy of the vehicle.
The ATN vehicle was the product of a collaboration among five Universities, including RMIT.
Named “Priscilla” – an homage to the considerably more flamboyant and frill-laden Queen of the Desert of the silver screen – the ATN car was among the entrants in the hotly contested Cruiser Class, distinguished by its 2-seater configuration, which attracted around 50 vehicles.
Battling temperatures of around 50C, the roar of road noise, wind and bone-jolting bumpy roads, Matt and his alternate driver endured gruelling conditions, with their only creature comfort cup holders for their water bottles.
“Especially in the NT, there was strong sun and a lot of glare,” he explains. “It was very hot inside, I was sweating wearing just shorts, helmet and the team shirt. There are two vents on the front of the wheel spats, which meant there’s adequate air flow when moving – that took the edge off. Once we reached 50 to 60 kms, there was more air flow and some relief, even though the ambient air was quite warm.
“It was very challenging, maintaining the same speed, not swerving, controlling vehicle. I had to constantly adjust the wheels to counter the bumps and wind. It was very fatiguing, especially with the loud road noise – I’d estimate it was around five times what a normal car makes. Honestly, it was like a plane rumbling and the vibrations go through the chassis and into your body.”
The reality of the endurance event was pitstops on the side of the road. “We drove 8am til 5pm, with a pit stop of half an hour and camping on the side of the road overnight. Needless to say, we didn’t get much sleep.”
But the brief never mentioned comfort. The objective was to design, build and race the lightest, strongest, most efficient vehicle possible.
For Matt, a mechanic by trade, the allure of the Challenge was the culmination of all his skills and interests.
“I’ve always been passionate about cars and I’m very competitive as well. When I heard about it my interest was sparked. Our goal was to win the race, but as a designer I wanted to create a car that steals the attention from everybody else.
“There were so many factors to consider; to make something highly efficient that appeals to everybody, which has to be the dual focus otherwise solar cars will not take off.”
RMIT Lecturer in Industrial Design, Simon Curlis was Matt’s supervisor, assisting with design pointers and systems integration in the car.
“The design was based on the original concept of a bird of prey,” continues Matt. “The rear is thin and spread out like bird, with wheels hung off the back of the body. The front was reminiscent of an ultra-light sports car, or high-performance car, such as a Ferrari or Koenigsegg.”
“Design-wise we aimed to keep the down force low, to achieve a neutral downforce, negative lift, we were aiming for zero, which is all well and good straight line. When you get a huge gust of wind, it’s not so great. If you put a couple of kilos on the car, then get up to speed, downforce starts to take effect on the car. If you have too much lift, you lose handling.
“In the middle of 2017, the design was more like a ute, then we changed the aerodynamics and changed the design to a 2-seater sports car. There were 35 iterations to get it to the right efficiency for drag. It took a year and a half to finalise the vehicle to the current design.”
Priscilla sports a full carbon monocoque chassis with Divinycell foam core running through it, which adds strength to the carbon fibre. “Using titanium suspension was too costly, so we went with aluminium and light aluminium wheels.
“There were a few comforts onboard, but only the essentials, such as the cup holders, adjustable back rest and touch-screen iPad on the dashboard.”
Crucial to the entire process, ATL Composites worked closely with the design team ahead of supplying product to bring Priscilla to fruition.
Mac Dalton from ATL Composites and Andrew Morrison from Marine Sports were consulted and provided their expertise on resins, infusion consumables and structural foams.
“We provided the technical and product support, answered questions about issues and assisted them to improve manufacturing procedures, trouble shooting and general discussions on the advantages of using composites,” says Mac.
The whole idea was to create a vehicle that would be stiff and light, which is the whole idea of composites.
It needed to be easily driven and strong enough to carry the solar cells, battery and driver, while meeting their design criteria.”
ATL products included the Kinetix resin system, the entire range of WEST SYSTEM products, ATL fillers, Divinycell Foam which was perforated and supplied at various densities, and R118 infusion epoxy, instead of using pre-preg.
“There was a lot of the carbon laying into the moulds – three or four layers, to help the resin flow through and stick to the carbon,” says Matt.
“It wasn’t a simple process. We needed to make sure the fabric was stretched and laid out on top. Then we placed a plastic bag over the whole thing, vacuumed it, forced it into the mould, to inject the resin.
“This process was more cost-effective, but more complicated. There was only one other car that did the same and it was not in our Cruiser Class. In qualifying and scrutineering, I did the driving and we ran the second fastest time on the figure eight, then fastest around the track and top 10 overall.”
Matt, who has been a diagnostic test driver for a living, shared the driving with one other driver.
Despite being fit from a life-time of competitive sports, Matt said he was startled by the physical demands of the experience, which was cut short by mechanical failure and unfortunately, led to Priscilla being trucked to the finish line.
“On the second day, the other driver drove for around 30 minutes, then I was ready for a seven hour stint. We were around 700km to 800km in when the failure happened. Unfortunately, our race was cut short. The car was still going on battery, but we had a mechanical failure. We decided not to risk it. We were worried something else could go wrong, and because we were behind schedule. We didn’t have enough testing time.
Unable to finish, the ATN team was disappointed but not disheartened.
“When we first started, of course we wanted to win. It was our first time, so we were realistic about it, but at the same time, we were going there to try to win! But looking back now, the biggest success was the design. Compared to all the rest, ours was the best-looking car there. Design was compromised by engineering in that we couldn’t make it from start to finish.
“I don’t look at it as a failure. We couldn’t have given any more of ourselves, but it’s still disappointing.
“Structurally, she was excellent and the lightest in our class. Everything was led by aerodynamics. If we were to do it again, we would refine the details – the simple things such as doors opening and closing, clean finishes of the recesses of the doors, door handles flush with body, cleaner neater cuts. But we ran out of time.
“Some teams worked full-time on their projects, which is hard to compete with. The winner of the Cruiser Class, Solar Team Eindhoven from Eindhoven University of Technology, The Netherlands was winner for the fourth time in a row. Their car was perfection inside and out.”
As for the name “Priscilla”, Matt says he was slightly miffed at first, given he’d devoted close to two years of his life designing and building the vehicle, only to be overshadowed by the legend of larger than life drag queens.
“The detailing was meant to be silver with a pink outline, but it ended up being all pink! In the end, we realised the name ‘Priscilla’ embodies that larrikin Aussie spirit that united us and gave us a competitive edge.”
As for whether or not Matt and co will have another shot at the prestigious biennial event, he is confident they will get a team and a car that are up to the Challenge.
“It’s too early to say for the 2021 event, but we hope so. We learnt a lot from this experience for next time. We’re in talks. It’s highly likely.”