These sleek, silvery racers are in the midst of the 2001 Formula Sun American Solar Challenge, a Chicago-to-LA race for solar-powered vehicles. The 40-or-so entrants mostly hail from American universities, including Principia College of Elsah, Ill., and the University of Missouri-Rolla.
The Rolla entry, dubbed the Solar Miner III, is considered one of the favorites; the car won the last installment of this biannual race. In the two years since, the race team has worked diligently to improve every facet of the car.
"We use composites of Kevlar, carbon fiber, fiberglass, aircraft aluminum and foam to make the lightest possible body," reports Tim Alfermann, vice president of operations for the Rolla solar-race team and a recent Rolla grad. "This car has a better aerodynamic shape, a modified airfoil shape with a shortened canopy and a lot lighter weight than last year's. Before, we had around 320 pounds of lead-acid batteries, and we replaced them with 70 pounds of lithium-ion batteries. Solar Miner II weighed around 820 pounds; our target weight for this one is 530, 540 pounds. Each design team had a goal to make their component lighter by a certain percentage."
This year, the race will last 10 days and cover 2,300 miles along the former Route 66, making it the longest-ever race for solar-powered vehicles. Every evening, each solar car team will recharge its car's batteries, which provide enough power on their own to get the car to the finish. (In fact, during the '99 race, it rained on the racers for nine of 10 days.) The added power from the solar cells, however, allows the cars to go faster and farther.
How fast can these energy-efficient little cars go? During the race, the rules limit them to 55 mph, and of course they have to obey various local speed limits as well. According to the Rolla solar team's Web site, they usually maintain a speed between 30 and 40 mph to conserve energy. Alfermann reports that during practice runs in the Rolla area, the car was humming along at about 70 mph, though.
The drivers also have to get used to being stared at, Alfermann notes. "On our practice run," he says, "it was strange to pull up at a stoplight and you'd see little kids and parents just turning their heads and watching it go."