|Brooks cools off his solar panels. Click to enlarge.|
Sunlight-propelled dragsters competed down a quarter-kilometer raceway in the second annual Solar Drag Race held in Wenatchee, Washington on June 24th.
Unlike other solar race events, solar drag racers do not use batteries or other pre-energized devices. The racers’ only fuel source is sunshine captured by the vehicle over the quarter-kilometer distance.
|The CHS dragster.|
Removing batteries from the vehicle and limiting the race to a short distance creates unique engineering challenges. While solar dragsters and cross-country solar racers both benefit from lightweight construction and high efficiency solar cells, solar drag racers do not use motor controllers, battery management systems, or expensive batteries.
Three racers participated this year; one in each of three categories: unlimited, college, and high school divisions. Randy Brooks with Brooks Solar won the unlimited division with a time of 57 seconds.
|Central Washington University’s entry.|
Chehalis High School in Western Washington came in second and Central Washington University came in third. Since Chehalis and Central Washington University were the only ones competing in their divisions (college and high school), they each won a $1,000 scholarship.
The college scholarships were provided by Renewable Energy Corporation (REC), the world’s largest dedicated producer of solar grade polysilicon for the photovoltaic industry.
Theoretically, a solar drag racer should be able to exceed 50 mph, according to Jim White, one of the two entrants in 2005. In order to achieve that kind of speed, the dragster will need a variable speed transmission, lightweight/high efficient solar cells, and sleek aerodynamics.
Randy Brooks used a variable speed transmission suggested by White.
I called it a cassette drive. The motor spins a small diameter shaft that unwinds a strap wrapped around the drive wheel. As the dragster progresses down the track the motor shaft diameter increases while the drive wheel shaft diameter decreases. At the end of the race the strap fully unwinds from the motor wheel, but by that time the race is over.—Jim White
Although there were relatively few participants, the 2006 event grew by 50% from the 2005 event, in which there were but two. The organizers anticipate that the event will grow each year as awareness grows.
(A hat-tip and kudos to Jim White!)
Solar-Powered Drag Race website