Richmond-built solar car ’Impulse’ gets ready for Formula Sun Grand Prix

A shiny bean-shaped rolling contraption, barely three feet high, struggled up a steep gradient on a recent Saturday morning as it entered the streets of Richmond from El Cerrito, turning heads and slowing down traffic as two escort cars flashed their blinkers and carefully stewarded it through crowded traffic intersections.

”We are taking a right on San Pablo, Roger, right on San Pablo,” a navigational assistant in the lead car said through the team’s chatty mission control system, giving a cue for all three cars to bear right in time to avoid the buzzing freeway.

Meet Impulse, a solar-powered car that is the product of nearly two years of work by CalSol, a group of engineering students at UC Berkeley’s Richmond Field Station, an engineering and research facility tucked in the lower eastern corner of Richmond.

Cruising under 40 miles an hour, the minimum speed on the interstate, Impulse was near break-neck speed for a car in its class, powered by solar energy from an array that makes up much of its frame and is supported by only three specially designed wheels.

The three-wheel design was part of an effort by engineers to center the car’s weight as well as to increase efficiency by reducing wind resistance, and this has paid off in races and rallies.

On this recent trip back to the car’s home at the Richmond Field Station, driver Jack He decided not to take Impulse onto I-80, where despite being able to keep up with traffic in the slow lane at a little over 50 miles an hour, the car is prone to losing its balance due to harsh tailwinds whipped up by bigger, faster cars.

Built from scratch by students majoring in engineering and computer science, Impulse is among the pride of Bay Area student engineering, yet it looks fragile among the fuel-guzzling, six-foot high monsters that zoom past it, and pale in the smog generated by their fumes.

This is the car of the future,” David Butler, one of the Berkeley residents that stopped to look at Impulse as the car left the Berkeley campus for Richmond said. ”It may be slow, but the first cars were slower than horses after all.”

Apart from specially designed low rolling resistance tires, imported from Germany, all components of the car were made at the RFS.

Powered by a rear wheel electric motor, Impulse has participated in rally races and track races in the United States and in Australia, winning fourth place at the 1,600-mile American Solar Challenge in Rochester, New York, and coming in 20th out of 36 at the World Solar Challenge 2011 in Australia.

CalSol is preparing Impulse for its last race, the Formula Sun Grand Prix in the Southern California desert in October 2013, where the car will compete against solar cars made by engineering students from schools around the world.

”We have learned from these experiences and we’ve had only very minor mechanical challenges,” said Tristan Lall, a graduate student in the UC Berkeley mechanical engineering department who is a member of CalSol. ”The ideal operating environment for this car would generally be a sunny day on a road without too many lights and stops.”

Out on the streets, Impulse had a difficult time negotiating steep gradients, potholes, and having to stop at lights just as it was beginning to gain momentum, giving passing motorists time to take pictures.

Behind the wheel, He, an undergraduate sophomore majoring in electrical engineering and computer science, was dressed in full racing gear, complete with a radio helmet and a racing shirt from one of CalSol’s rival teams, the University of Michigan, where the school’s solar car team UmSolar just completed building Quantum, their 11th solar-powered vehicle.

He, an international student from China, drove Impulse during his first summer as a freshman at Berkeley, just a few months after he had joined the club of nearly 70 students.

”It is like, the coolest thing you can do in the first summer of your freshman year,” He said. ”We have really good team dynamic and everyone is very competent.”