Racing Along on Sunshine

By Philip Elmer-DeWitt

One contestant looked like a horseshoe. Another resembled a giant pizza box with a bubble on the top. Others were shaped like teardrops, pea pods, torpedoes or pyramids. All were festooned with dark glassy cells that shimmered like fish scales in the sun as the vehicles purred, rather than roared, down the back roads of America. Along the way, people gawked and pointed, squinted and saluted, did double takes, took snapshots and lifted small children to give them a better look at what their future might hold. "Oh, here comes another one!" cried Susie Black, one of hundreds of people who lined the streets of Donalsonville, Ga., (pop. 3,500) last week to watch the strange procession roll along U.S. 84. "This is the most excitement we've had here since those murders a few years back."

The weird-looking machines are the solar-powered cars competing in GM Sunrayce USA, the nation's largest ever race for vehicles propelled solely by power from the sun's rays. Built by science and engineering students from 32 American and Canadian colleges and universities, the innovative cars, capable of reaching speeds of up to 113 k.p.h. (70 m.p.h.), are following an 11-day, 2,639-km (1,640-mile) course that began in Lake Buena Vista, Fla., and will pass through eight states. The high-tech Soap Box Derby is scheduled to finish this week at the General Motors Technical Center in Warren, Mich., outside Detroit. (In case of extended rain, the race may be delayed.) According to the < contest's sponsors -- GM, the Department of Energy and the Society of Automotive Engineers -- the race is more than a vivid demonstration of what today's solar technology can do. They hope that it will also stir the creative juices of a generation of science-shy students that seems inclined to leave the engineering challenges of tomorrow to the Japanese.

There was no shortage of Yankee ingenuity among the Sunrayce entrants. Each team had to devise its own solution to the basic technological problem of converting fickle sunlight into sufficient electrical power to drive a vehicle across the country. Many came up with bizarre gimmicks that surprised even veteran engineers. The Florida Institute of Technology's secret weapon was a thin surfboard of a car with solar panels not just on its top, but also on its underside, to gather light reflected off the asphalt. Western Washington University built a car with two drivers seated back to back and a solar panel tipped rakishly, and permanently, to one side. In the morning students drove with the panel tilted toward the east. After lunch they simply turned the car around, so its panel caught the afternoon sun, and drove backward the rest of the day.

The University of Michigan's chief innovation was to enlist students in the business school to raise funds and manage the team's financial affairs. Every school got $7,000 in seed money from the race's sponsors, and most raised many thousands more. But Michigan's team gathered nearly $800,000. Not only is its Sunrunner computer-designed and wind-tunnel-tested, but it is also assisted by a scout vehicle carrying weather-forecasting equipment and by a rolling metal shop (complete with lathes and drill press) to help make any needed repairs. The Michigan racers have a computerized map of every traffic light and speed zone along the course, a film crew and a public relations manager.

When will all-solar cars be rolling out of local showrooms? Probably never, says Paul MacCready, the guru of low-powered transportation and one of the designers of the GM Sunraycer, winner of the 1987 World Solar Challenge across Australia. To run dependably on cloudy days, a solar car would have to carry sufficient power to make the trip on batteries alone. Better to charge the car from a wall socket and use the solar cells elsewhere -- perhaps at power stations to ease the load of generators running on nuclear or nonrenewable fossil fuels. The real value of Sunraycer, says MacCready, was that its improvements in aerodynamics, lightweight materials and motor technology made possible GM's Impact, a non-solar electric car now being readied for mass production.

The first three finishers in the current race will be sent to Australia in November, at GM's expense, to compete in the 1990 World Solar Challenge, a repeat of the 1987 Darwin-to-Adelaide contest. But for hundreds of youthful participants, racing by day and swapping notes -- and solar cells -- by night, Sunrayce is one of those competitions in which just getting to the starting line may be as important as finishing first.

With reporting by S.C. Gwynne/Detroit and Don Winbush/Donalsonville