Written by Bill Bowman
In November, 1987, the solar powered vehicle GM Sunraycer, designed and built by Detroit-based GM Hughes Electronics, AeroVironment, Inc. and more than a dozen other GM divisions and suppliers, sped to victory in an inaugural 1,950 mile race across the middle of Australia. Nicknamed the Flying Cockroach by Australian journalists (due it its buglike physiognomy), the car covered the distance in 44 hours and 54 minutes, traveling at an average speed of 41 miles per hour. Including overnight stopovers, the entire trip from Darwin to Adelaide, along a desolate two-lane highway, took five and a half days.
The GM Sunraycer was powered by an array of 7,200 solar cells, covering a total of 90 square feet. On a sunny day, the car could move as fast as 45 miles per hour using solar power alone. On the road, the car normally used a battery to provide extra power for acceleration or climbing hills. Under those conditions, it could reach 60 miles per hour.
The car itself was 19.7 feet long, 6.6 feet wide and 3.3 feet high. Its aerodynamically shaped body was constructed from a lightweight, honeycombed composite material over a welded, aluminum tube frame. The car, including its electric motor, battery, electronic components and solar panel, weighed merely 360 pounds. Because temperatures can go as high as 120IF in the Australian sun, the GM Sunraycer’s canopy was plated with a thin film of gold to protect the driver. The film blocked 90 percent of visible light and 98 percent of the infrared radiation. Because the car was driven only in daylight, enough light gets through to enable the driver to see the road. The GM Sunraycer led the entire race and finished more than two days ahead of its nearest competitor, an entry from the Ford Motor Company, of Australia. A Swiss car, Spirit of Biel, came in third. Billed as the world’s first international transcontinental road race for solar powered vehicles, the competition attracted 25 entries from seven countries. Even two weeks after the race’s start on November 1, a few of the vehicles were still on the road gamely trying to reach Adelaide.
The Sunraycer’s success depended on several new technologies. Its specially designed, streamlined body had an extremely low air resistance, or drag coefficient, allowing the car to slip smoothly through troublesome crosswinds. The vehicle carried an array of particularly efficient solar cells similar to those used to power communications satellites and a superior, lightweight electric motor that weighed only 8.1 pounds, but could deliver 2 horsepower. A battery of rechargeable silver-zinc cells provided additional power for accelerating and climbing hills.
"We had no mechanical or electronic failures of any kind," said Bruce McCristal of GM Hughes Electronics. "Our only trouble was three flat tires." While some observers estimated that GM spent several million dollars on Sunraycer, the company, saying that the project was part of its general research and development effort, declined to name a figure. "We learned a lot about low speed aerodynamics, lightweight structures and materials, and other factors," said McCristal. "this could have practical applications in all electric vehicles somewhere down the road."
In June, 1988 at GM’s Desert Proving Grounds in Mesa, Arizona, GM Sunraycer established a new world solar speed record and seven international and national electric car speed records. Sunraycer set a new world speed record of 48.712 MPH for a land vehicle powered solely by energy from the sun.
After Sunraycer won the race and set the records, GM sent it on the road to events to garner publicity for the company, GM also created teaching materials for schools that focused on the Sunraycer.
The goal of the Sunraycer, in addition to winning the race, was to advance transportation technology that makes fewer demands on the earth's resources and environment, and to inspire students to become engineers.
The largest U.S. competition for solar-powered vehicles, Sunrayce, takes its name from the GM Sunraycer, the General Motors prototype, which won the first World Solar Challenge in Australia. This event, renamed the American Solar Challenge (ASC), in 2000, is scheduled biannually because of the rigorous planning and preparation period.
Today, the Sunraycer vehicle is permanently displayed at the Smithsonian Institution's Museum of American History in Washington, D.C.