26.11.2012 Cambridge team takes on Solar Challenge

Cambridge University is to construct and race a solar powered car across Australia as part of the 2013 World Solar Challenge.

In October next year, teams from across the globe will set off from Darwin in the north of the country on a gruelling marathon to Adelaide, some 3,000km to the south.

The students from the Cambridge University Eco Racing (CUER) team are required to design and build a car capable of harnessing the power of the sun to propel them across one of the harshest environments on the planet at an average speed of 80 km/h (50 mph).

Earlier this year the Challenge, which has been running since 1987, was modified with new rules stating that all vehicles must have four wheels, with each wheel at the corner of a rectangle. A change which would have seen all but one of the 37 teams competing in the 2011 race disqualified.

The Cambridge contingent have designed a car known as Daphne, a vehicle they say will be 98% efficient, allowing them to reach speeds in excess of 82 km/h (51 mph) using a motor with the equivalent power of a hair dryer.

Commenting on the design process, second year engineering student, Keno Mario-Ghae said: "We predict that at the very least, Daphne will weigh 25kg less than the lightest car ever to enter the World Solar Challenge. This means we can design innovative, energy saving features that wouldn't be practical in a heavier car.

Usually suspension in a car involves a spring and a dash pot, but Daphne will have an in-built carbon based suspension system, ensuring even less energy is wasted. Locating the motor in the hub of the wheel means there is no need for gears, chains or differentials which each account for a 5% loss in efficiency. As in previous years, many of the innovations developed for the Challenge have found their way into the design thinking for conventional vehicles.

Mario-Ghae continued: "The reason the design works so well is by using a canopy which houses the solar cells, the aerodynamic and solar performances are decoupled. 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 and this is how we plan to compete with the bigger teams."

"The race crosses 22 degrees of latitude so we have created a modelling programme that will adjust the solar cells to maintain the optimum position at all times.

According to Mario-Ghae, provided the team can attain their financial goals they are confident that they stand a good chance of success: "We’ve come a long way in a short time but there is still a way to go. We are confident that with a bit more support we can use the next few months to complete the prototype before work stops for exams."

World Solar Challenge