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A first-hand account of the World Solar Challenge

Building and racing a solar car is a true team effort. Matt Cumming

The World Solar Challenge (WSC) is a race held every two years in which roughly 40 teams race solar-powered cars from Darwin to Adelaide.

I’m a member of the UNSW Solar Racing Team (called Sunswift). The team originally built their fourth car, IVy, for the 2009 WSC. For this year’s event – which concluded a few weeks ago – IVy was improved with a new in-wheel brushless DC motor, a brand new solar array, a new battery and a host of other new features including improved electronics and mechanical brakes.

This time, the team placed 6th out of 37 teams and the race was truly perilous and testing in the extreme. Nature presented us with all manner of tests, including bushfires, strong winds and heavy rain.

These poor weather conditions meant the race took considerably longer than was planned, with our car taking approximately seven days to make the 3,000 kilometre trip from Darwin to Adelaide.

Cockpit temperatures can get beyond 40 degrees. Matt Cumming

In addition to some horrendous weather conditions, this year’s race required us to adhere to a number of new race regulations. The most considerable change meant teams had a maximum power limit on the solar arrays they could use.

No longer were the teams with huge budgets at an advantage by being able to afford high efficiency Gallium Arsenide solar arrays. This put almost every team on a relatively even playing field from a power-production perspective.

As a result, we had always expected this year’s race to be very competitive. Unfortunately, mechanical reliability issues hit hard, and we lost a frustrating amount of time to repairs. A lack of consistent sunshine didn’t help either.

Regardless of the hindrances, we were very happy with the outcome overall. Indeed we were happy just to complete the entire race without putting our car in its trailer as many other teams were forced to do.

From drafts to driving

Of course, there is a considerable amount of preparation required to get a car ready for the World Solar Challenge. For Sunswift IVy, it took roughly a year to go from conception to racing (in the 2009 event).

The Sunswift team at Tennant Creek. Matt Cumming

The process started off with the drafting of an aerodynamic design. Then we constructed a mould, laid sheets of carbon fibre over the mould and cooked the whole thing in a huge oven. With the moulds and layups completed, we were able to produce the top and bottom shell of the car. The rest of the car was then glued, bolted, cable-tied and taped on to the bottom and top shells.

Our team was made up of people from a range of backgrounds, including undergraduate students, postgraduate students and past team members who acted as mentors. The students come from a number of different specialist backgrounds, including electrical, mechanical and computer engineering, business and finance.

All in all, around 30 people were part of the Sunswift team for this year’s WSC. Unlike some other teams, the students working on our car were also studying, meaning they had to divide their time. Some of the other teams had the luxury of many people working on their cars full time.

Of course, building a high quality solar car isn’t cheap and the money needs to come from somewhere. Sunswift’s funding comes from a range of sources within the University of New South Wales and from industry. But most of the support for the project comes from in-kind sponsorships that provide products or services.

Matt Cumming

In the hot seat

We often get asked how hot it gets inside the solar car. The answer is “very”. The ambient temperature in the outback is usually between 30 and 40 degrees. While the car is moving at highway speed, the temperature inside the cockpit is similar to the outside temperature.

However, when the car is stationery at one of the control stops throughout the race route, the temperature in the cockpit can rise considerably. To allow air to circulate and cool the driver, team members lift the canopy or the entire solar array off the car.

This year, the team had three rotating drivers: Robby Hutchinson, Kristen Casalenuovo and Barton Mawer. The drivers took turns in the cockpit, usually swapping at control stops or at the beginning of the day.

What now for IVy?

After the race, and depending on the new regulations, the cars are stripped of useful parts and then stored. In special cases, the cars are put in museums or other prominent locations.

Our team’s second car, Sunswift II, is on display at the National Motor Racing Museum in Bathurst. Sunswift IVy is earmarked to be displayed in the foyer of the new Tyree Energy Technologies building at UNSW.

Given the WSC is a biannual event, the team tries to find other interesting things to do in the off-years. Earlier this year we broke the world record for the fastest solar car.

We might find ourselves in a position now where we need to design and build a new car, which will take most of our time and effort. Nevertheless, other teams are going to be challenging our world record so we may have to try and defend it.

For the next WSC, in 2013, we will be focusing more on reliability to ensure we don’t waste time on the side of the road, when we should be racing.

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