Solar car sets world record
By Kristin Slanina
The MIT Solar Car Club returned victorious from the Solar and Electric 500 at the Phoenix International Raceway in Phoenix, AZ, where MIT placed second behind a Swiss team.
The MIT team set several world records at the event, including a solar track lap speed in excess of 62 miles per hour (99 kmh), and straight-away speeds in excess of 70 mph (112 kmh).
The Engineers finished 11 laps behind the Biel School of Engineering, a Swiss team, after two days of racing. The Biel team had completed 300 kmh of racing. California State at Los Angeles finished third, 27 laps down.
The race brought solar racing to new levels of excitement on Saturday, when driver and team captain Peter Rexer '91 passed the lead car, had a rear tire blow-out, and went into the first solar car spin on a race track.
"It was pretty exciting," Rexer said after the first day of the two-day race. "I didn't even see the Biel car go by, because my back was to them as they went around me."
The Engineers lost five laps as the pit crew ran to the scene of the blow-out and changed the rear tire. Even with the five lost laps, MIT was solidly in second place at the end of the first day.
The race was sponsored by Swatch, Inc. and the Arizona Energy Office. The other teams competing were Virginia Tech, University of California at San Luis Obispo, Western Michigan State, Arizona State, the Rose-Hulman Institute of Technology, and the Mauros brothers, a private team.
Most of the team members who went to Phoenix were participating in a solar race for the first time. Rookies included Amy Smith '84, Kristin Slanina '91, Kathy Nelson '93, Therisa Chiueh '94, and Abraham Farag '94. Veterans included Rexer, co-captain Lee Weinstein '80, Olaf Bleck '89 and Thomas Massie '93.
MIT's entry into the race represented a technical and financial gamble. After reading the race rules carefully, Rexer, Weinstein and team member Mark Henault G concluded that the majority of the power consumed in the high-speed race would come from the reserve batteries of the car, and not from the solar array itself.
A decision was made early on to run with a "solar torpedo," where the solar panels were actually stowed inside the car during the race to reduce aerodynamic drag. The car used in the race was a redesign of MIT's famous winning solar vehicle, Solectria 5.
The design of Solectria 5 was modified by removing the solar wing, adding a narrow, precision-fitted top, and incorporating a number of aerodynamic and mechanical tweaks to achieve maximum efficiency.
The original Solectria 5 vehicle was conceived by James Worden '89, the "father of solar cars," and designed and built by Worden, Gill Pratt '83, Erik Vaaler '84 and Catherine Anderson '90.
The team was badly in need of the extra help after the first day of racing, when one of the car's custom magnesium wheels was damaged. Weinstein and Rexer took the wheel to a nearby airport, where the foreman helped weld new metal onto the wheel. The three worked until 3 am to recreate the lip of the wheel for the next day's racing.
Pratt developed the motor control and power electronics which have been used in all MIT solar cars to date. Pratt, now a staff scientist at the Laboratory for Computer Science, serves as faculty advisor to the club. Vaaler and Anderson also remained at the Institute and offer assistance to the club.
Worden heads Solectria Corporation, a company that manufactures solar-electric vehicles. Two of Worden's electric cars took second and fourth place in the electric part of the Solar and Electric 500 in Phoenix.
The team also received a great deal of support from the MIT community. Mark Drela '82, assistant professor of aeronautics and astronautics, helped improve the aerodynamics of the car. William Saddler '66 housed the team while it was in Pheonix, and worked with the team to develop strategy programs that were run on a laptop computer during the race.
The financial challenges the club has faced this year have been as difficult as the technical ones. Money has been very scarce in the declining economy, and even though the club has increased its fund-raising efforts tenfold, there has barely been enough money to buy necessary items that could not be procured as donations.
The batteries for the Phoenix race cost nearly $9000 and solar cells for the new Aztec commuter car will cost several thousand dollars. Though the club went to the race several thousand dollars in debt, the prize money has given new hope of being able to finish Aztec in time for Earth Day and the American Tour de Sol.
The MIT solar cars will be the centerpiece of Cambridge Earth Day this year, and will be featured at University of Massachusetts Boston Earth Day, the City of Boston Earth Day, Wakefield Earth Day and the Earth Day concert at Foxboro Stadium. In addition, the club will race several solar vehicles this summer in the US Tour de Sol, the Swiss Tour de Sol, and possibly in the Clean Air Challenge in California.
(Kristin Slanina '91 is a member of the MIT Solar Car Club.)