CUER team manager Keno Mario-Ghae shows the new design alongside the 2011 challenger
Students in the Cambridge University Eco Racing (CUER) team have come up with a completely new design for a solar car in their attempt to win the 2013 World Solar Challenge, a gruelling 3,000km marathon across the heart of Australia from Darwin to Adelaide.
Not only is their vehicle, codenamed Daphne, lighter than any previous competitor but it also features a more aerodynamic shape and, most importantly, a “gamechanging” array of solar panels that track the position of the sun.
To secure the trophy, team members believe they will need to maintain an average speed of over 80km/h during daylight hours for four days, in a vehicle that has the power of a hairdryer but is robust enough to survive hazards ranging from encounters with road trains to bush fires that block out the sun.
The students created their car in record time after late changes to the rules forced them to tear up their previous design.
In 2011 the team had decided that to move away from the established ‘table-top’ design and build the lightest, most aerodynamic vehicle they could achieve, with the biggest possible ‘engine’ (i.e. solar capacity).
“We came up with a two-wheel concept,” explained CUER vice-manager Oliver Armitage.
“We thought we were going to build a recumbent bike.”
Then in June 2012 the Challenge organisers announced major changes to make the event more relevant to the automotive industry.
In particular, vehicles must have four wheels, positioned conventionally.
Undeterred, the team applied what they had learned over the year to come back with a highly innovative vehicle meeting the 2013 race parameters.
Using modelling code written by one of the members, they were able to iterate designs very rapidly to come up with the final concept.
Daphne’s design draws on the team’s knowledge not just of automotive engineering and aerodynamics but also of sophisticated modelling, space-grade composites and optimising solar cells - all skills they acquired through taking part in the project.
CUER team manager Keno Mario-Ghae predicts that Daphne will weigh at least 25kg less than any previous competitor.
“This means we can design innovative, energy saving features that wouldn’t be practical in a heavier car,” he explained.
A major breakthrough has been to embed the photovoltaic panels in an aft-facing solar tracking plate that follows the trajectory of the sun as the car travels south, enabling a 20 per cent gain in power.
This arrangement has never been seen before in a solar car.
A state-of-the-art canopy allows maximum light to pass through while maintaining the car’s aerodynamic shape.
“The reason the design works so well is by using a canopy which houses the solar cells, the aerodynamic and solar performances are decoupled,” Mario-Ghae continued.
“This means we can improve the aerodynamics, without having an adverse effect on solar performance, making our design highly efficient. Efficiency is where our real strength lies.”
Daphne will have a monocoque chassis made of aerospace grade carbon fibre, as well as a composite suspension system that is “orders of magnitude lighter” than standard metal suspensions, while hub motors save further weight.
CUER is working with an impressive list of commercial sponsors, but much of this support is in kind, through advice and access to facilities.
The team still needs hard cash to buy components and to cover their air fares and living costs during the Challenge.
They argue that backing the project and the intellectual property it generates is an investment in the regional economy and in sustainable technology, while through their participation the students are developing skills that are very attractive to employers.
