Published: May 28, 2009 08:40 pm      

Roadster with a little solar flair

Students prepare $100,000 vehicle for its run in the sun

San Marcos —

It’s the ultimate in efficiency, aerodynamics and it’s pretty shiny, too. But it’s not exactly roomy for the price.

University of Texas engineering students tested their solar powered vehicle at Harris Hill Road race track in San Marcos on Wednesday while preparing to pit it against similar cars at next week’s Formula Sun Grand Prix.

’This is the first time this car has been on this track, so it’s a shake down,’ professor Gary Hallock said. ’It’s time to get a little experience and see how the car is handling and just to kind of look at the reliability and any issues we have, electrical and mechanical.’

The $100,000 vehicle was designed and built completely from scratch by engineering students, has zero emissions and is powered by lithium ion batteries and energy collected from just under 400 solar cells.

’They produce, ideally, manufacturers calculations about 1,200 watts, that basically translates to less than two horsepower and so it’s equivalent to maybe a bathroom hair dryer,’ Hallock said. ’All power has to be budgeted very carefully.’

During an official race, a driver controls the car from inside and the rest of the team monitors the car’s functions from a computer. The idea is to complete as many ’official laps’ as possible.

’There’s a lot of strategy involved with the race and looking at what the weather is and what the weather’s likely to be,’ Hallock said. ’In poor conditions, clouds, rain, that sort of thing, one would drive very slowly to build up distance, which is what the challenge is about, and be as aerodynamic as possible.’

The teams are allowed one good electric charge of the batteries before the three-day race begins, but after that, they have to rely on the weather.

’Once the race starts, until it finishes, we’re not allowed to pull any power off the grid. All of our power for three days has to come from the sun, so if we deplete our batteries and it’s cloudy, you just don’t race,’ Hallock said.

The project is two years in the making. Students built large molds to create the carbon fiber shell, designed all of the mechanics for the car and built complex electrical and computer systems.

’The students design it right down to the level of resisters and capacitors for interfacing with these systems, for reading voltages and generating telemetry,’ Hallock said. They went through more than a dozen electrical circuit boards and hundreds of feet of wire.

The vehicle’s perks include a rear-view camera, LCD monitor and touch screen controls, along with a communication system to connect with the pit crew if things go awry. Though it can race at more than 65 mph, the vehicle is not street legal because it lacks essentials like headlights, turn signals, safety features and mirrors.

’There’s not air conditioning in the solar car,’ said Hallock, because air conditioning draws a lot of power. Also, ’because of aerodynamics, we don’t want to have actual rear-view mirrors sticking out of the car.’

Wednesday was the team’s chance to put on the finishing touches and really see what the car could do.

’It drove really smoothly. There are a few things that we have to work out like the motor bearings clicking,’ engineering senior Erica Thorson said. ’It’s got a really good turn radius, we can even turn quickly, like 30 mph turns, at least around this track. I’m surprised.’

The team will compete against 10 other schools next week at the Samsung Solorean near Fort Worth.