# Building A World Solar Challenge Solar Car: By The Numbers

It’s a new week and our solar sailors have hit the books this week to find a solution to the new requirements. Does it all add up?

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 Four

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Compliance with the new regulations continue to dominate the work done by our intrepid students.

Safety of the drivers on the cross-country voyage is paramount, and even the slightest miscalculation could see the lives of the our two female drivers put in jeopardy.

Rule 2.14 in this year’s rulebook states that drivers must be enclosed in a safety cage that is built to withstand an impact force of 5Gs in any direction. Last year, the regulations stated that the cage had to withstand 4Gs of force, meaning that a redesign and recalculation of the cars roll cage needs to be considered, and that means playing around with the weight of the car, a risky gambit in these endurance races.

Our team has it under control, though:

[5G tolerances] were not required in the regulations [in 2011]. Because of the new regulations, we must base our calculations on the weight of the car (180 kg) and the person inside (80kg) to take a calculated load:

(180+80)×9.81×5 = 12.753 kN

This equals an approximate force of 1300kg in any direction. To keep the weight low and design simple, it was decided to bulk up the chassis rather than developing a separate aluminium cage that would bolt onto the chassis.

The team is also working on a new seating position for the driver. A regulation change now requires the driver to be seated in a more traditional orientation you might find in a normal car, rather than a flat bed for a pilot to slid onto.

These two regulations mean that more meetings with suppliers are required so that the team can get the materials they need:

This will include more finite calculations to ensure the safety of the driver and the body of the vehicle. It will most likely be 50mm square tubing with a special weave and layup (in carbon fibre) to give the necessary strength. Further to this, we need to ensure that the joins of the drivers cockpit well to the main body are laminated properly to maintain strength throughout the race. Jay [team leader] will be working on this throughout the week.

Modifications to the undercarriage of the vehicle to reduce the drag caused by the heavier roll cage are also being researched.

Our team still needs sponsors, so if you’re keen to help the underdog get a leg up in this amazing contest, contact Greg at UWS Solar Car.