U.S. Solar Car Slowly Gets Up to Speed : Energy: The vehicle is small and uncomfortable, but it is a national champion in its category.

Today’s state-of-the-art solar car resembles a waist-high, bright yellow tadpole that is 20 feet long. Getting in without breaking it is an adventure, and only one person will fit.

Taking such a vehicle home from the showroom isn’t likely to be possible soon. The price comes to about $650,000, without $350,000 worth of computers and other ancillary equipment.

But the University of Michigan’s Sunrunner has one thing going for it: It’s a national champion in solar speed, and it’s headed for an international test on the roadways of Australia next month.

In July, the Sunrunner and 31 other solar-powered cars built by student teams raced from Disney World in central Florida to General Motors Corp.’s Technical Center in the Detroit suburb of Warren. The Sunrunner, traveling by day only, won the 1,641-mile race in 72 hours, 50 minutes and 47 seconds. Its average speed was 22.5 m.p.h.

GM is entering the Sunrunner and other top finishers in the 1990 World Solar Challenge. In all, 43 cars from 10 countries will compete in the 1,863-mile race race from Darwin, on Australia’s northern coast, to Adelaide on the south coast.

For the race, which starts Nov. 11, the Sunrunner team hopes to attain an average speed of 32 m.p.h.

To take the car out for a test drive at the Michigan International Speedway recently, industrial engineer Paula Finnegan had to buckle on a safety harness and have a colleague boost her up into the open top of the car. Inside, she balanced on the aluminum-tubing skeleton and a hammock-like seat slung in the frame.

She then threaded her legs through the jungle-gym-like tubing to reach the accelerator and brake pedals, reclined in the seat, buckled on safety straps and donned a headset with microphone.

The Sunrunner still wasn’t ready. Three people then gingerly lifted its floppy plastic canopy from the ground, lowered it over Finnegan and sealed it in place with bright yellow tape.

During test laps on a mostly sunny day with thin, high clouds, the car reached 23 m.p.h. To go faster or to climb, the Sunrunner’s circuitry draws power from a battery. At slower speeds or going downhill, it stores excess power from the solar cells back into the batteries.

In bright sunlight, the solar cells produce about 1,200 watts, enough to power a toaster oven, hair dryer, or the 500-pound Sunrunner. Cloudy weather can cut the power to 300 to 400 watts, enough for a bright light bulb.

A 1.5-horsepower. electric motor the size of a coffee can powers the car via chain drive on one of the 26-inch mountain-bike wheels.

There’s a slot through which to view the road ahead and a rear-facing, fiber-optic viewer that allows the driver to get an idea of what’s behind.

Two ports in the front of the cockpit bring in fresh air. “The drivers said it wasn’t too bad as long as they kept moving,” said Mike McAlear, strategist for the team.

For now, electric cars will have to rely on batteries. Solar cells and motors must be made more efficient before energy straight from sunlight will be able to propel a car faster than 30 m.p.h.

Solar cars, therefore, aren’t on the verge of becoming a practical alternative for commuting, Finnegan said.

“Not any time in the near future--but with improved technology, it can happen.”