Chasing The Sun Week 2: New Rules, New Design, New Ideas

Chasing The Sun Week 2: New Rules, New Design, New Ideas

Gizmodo Australia is along for the ride with the University of Western Sydney’s Solar Challenge team, and every week we’ll be checking in with our solar sailers to keep track of the build. This week, rumours of new rules forced a backup redesign of the car and a visit from an aerodynamics engineer.

Support the UWS Solar Challenge Team! If you have marketing/sponsor dollars (hello car makers, telcos and electronics multinationals) or engineering support to donate, please contact Greg at UWS Solar Car.

The Challenge

25 engineering and industrial design students from UWS are working together to build a car powered entirely by the sun, ready for a race across the spine of Australia. In October next year the team will race the car from Darwin to Adelaide as the underdog, pitted against better funded rivals.

Team Diary: Week Two

This week the team had a visit from an industrial engineer who had a few things to say about the design of the car itself.

Aerodynamics testing on the front taper

Team leader Jay Manley told us last week that the main aim in the race isn’t speed, it’s efficiency. While the solar car will be capable of running at a maximum speed of 130kph, the team is aiming to average around 100kph over the 3000km race. That means that aerodynamic performance is key to overall performance — the less drag the better.

“We had our 1:10 scale model car analysed by an aerodynamics engineer. He liked the overall design but said [that] having a tapered front also has the disadvantage of increasing the frontal wetted area. Each side has to push the air out and around the side of the car. If it was basically straight then this area would be reduced and drag would be reduced,” Greg Hatten said this week.

Could that be right? Albert and Greg did a bunch of computational flow simulations on the team’s original aerofoil shape running at 100kmh and found that the engineer did in fact know his knitting.

Greg said this week that by removing the tapered design from the front of the car it would reduce drag by 60% at a conservative estimate. It’s a weight increase, he told us, but it’s worth it for the drag reduction.


Meanwhile, the solar car community is being rocked by an upcoming a rule change. The change, expected to be announced officially tomorrow, will force teams to make a four-wheeled car for use in this year’s race, which throws our three-wheeled team for a loop, forcing a major redesign of the car. Says Greg:

UNSW contacted us with rumours that there would be major design changes coming in with the new regulations. This was proved correct on Sunday when the new regulations where released including the requirements for 4 wheels and a more upright driver position. This will mean major design changes to the car.

The team scrambled to action stations this week, working on designs for a four-wheeled version of the car.

Further design remediation involved removing the front roll bar as we are allowed to use the body work as part of the overall roll cage. However we will need to ensure that all of this is still valid and designing concepts for new read wheel suspension.

Because of the rule change, it means it’s been a week of design, rather than build, Greg added.

We’ll check in next week to see what the rule change really means for our team in the long run.

Gizmodo Australia is excited to be on board: each week we’ll be posting build reports leading up to the rolling chassis tests this August, powered trials in September, and the race itself in October 2013.