The Sunraycer was a solar-powered race car designed to compete in the World Solar Challenge, the world's first race featuring solar-powered cars. The Sunraycer was a joint collaboration between

General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...

, AeroVironment, and

Hughes Aircraft The Hughes Aircraft Company was a major American aerospace company, aerospace and defense contractor founded on February 14, 1934 by Howard Hughes in Glendale, California, as a division of the Hughes Tool Company. The company produced the Hughes ...

. The Sunraycer won the first World Solar Challenge in 1987. The team's lead driver was John Harvey, an Australian driver with (at the time) nearly 40 years of racing experience. Harvey was involved with the testing and development of the Sunraycer at the General Motors Proving Ground in

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

Development

The Sunraycer project started with a request from GM's Australian division to GM Headquarters to participate in the upcoming World Solar Challenge. This race, to be held in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

in late 1987, would feature purely solar-powered cars. Roger Smith, the CEO of GM, was interested in the idea and agreed to fund a study to see if a solar powered car could be built within 10 months. Smith hired AeroVironment to do the study. A month later, AeroVironment engineers concluded that a highly competitive car could be built within the time available. AeroVironment, led by Paul MacCready, was given the contract to build what would be called the Sunraycer. During the conceptual process, the goal was to create a very low-weight and ultra-low wind resistance vehicle. With this in mind, AeroVironment produced a design that proved to be very lightweight (only ) and created a very low drag coefficient (c_d: 0.125). The Sunraycer was designed to be fast and was capable of a top speed of . A total of 8800 solar cells were manufactured and installed by a team from Hughes Aircraft. At high noon, the car would generate about 1500

watt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s of power. The engine was created for the Sunraycer by GM using a brand new

electric motor An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a electromagnetic coil, wire winding to gene ...

based on Magnequench

permanent magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, c ...

s. This kind of rare-earth magnet was invented in 1983 independently by the GM physics department and Sumitomo Special Metals. Both companies discovered and eventually commercialized two significantly different manufacturing processes for this material class; the GM concept was commercialized under the Magnequench brand. The new motor was lightweight and efficient; GM stated its motor efficiency was around 92%. In 2011 its constructor won the IEEE Nikola Tesla Award. Aside from the driver, the single heaviest element in the car was the Hughes battery pack that utilized silver-oxide batteries. These batteries were included to provide extra power when passing trucks, to smooth out the performance of the vehicle, and because the race rules mandated driving only between the hours of 8 AM to 5 PM, but the cars were allowed to charge their batteries from sunlight even when they were not on the road, allowing driving during allowed hours even when the weather was overcast. The frame of the car weighed 14 pounds. AeroVironment engineers made use of

Kevlar Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as ...

for the shell of the car. The Sunraycer was tested through the spring and summer of 1987. During the testing period, the team had the time to set a new world speed record with the Sunraycer, achieving a speed of from solar power alone, breaking the old record by 10 mph. The Sunraycer reportedly cost slightly less than $2 million to build.

Race

The race, in November 1987, was from Darwin in the north of Australia, to

Adelaide Adelaide ( , ; ) is the list of Australian capital cities, capital and most populous city of South Australia, as well as the list of cities in Australia by population, fifth-most populous city in Australia. The name "Adelaide" may refer to ei ...

in the south. The race course followed the

Stuart Highway Stuart Highway is a major Australian highway. It runs from Darwin, Northern Territory, Darwin, in the Northern Territory, via Tennant Creek and Alice Springs, to Port Augusta in South Australia; it has a distance of . Its northern and souther ...

for nearly the entire trip, going past

Alice Springs Alice Springs () is a town in the Northern Territory, Australia; it is the third-largest settlement after Darwin, Northern Territory, Darwin and Palmerston, Northern Territory, Palmerston. The name Alice Springs was given by surveyor William ...

in the middle of the continent. The Sunraycer, driven by John Harvey, won the

pole position In a motorsports race, the pole position is usually the best and "statistically the most advantageous" starting position on the track. The pole position is usually earned by the driver with the best qualifying times in the trials before the ra ...

with the fastest speed of all the 24 contestants (109 km/h), remaining in first place for the entire race. It raced the with an average speed of , finishing the race in just 5.2 days. This was 50% faster than the second place vehicle (which arrived in Adelaide two days after the Sunraycer). Roger Smith, the GM CEO, went to Adelaide to congratulate his winning team. In June, 1988, at

Mesa, Arizona Mesa ( ) is a city in Maricopa County, Arizona, United States. The population was 504,258 at the 2020 census. It is the List of municipalities in Arizona, third-most populous city in Arizona, after Phoenix, Arizona, Phoenix and Tucson, Arizona, T ...

, the Sunraycer broke the solar powered speed record with a top speed of . By comparison, the winning car in the 2005 World Solar Challenge was the Nuna 3, which had a top speed of 140 km/h (87 mph) and cruised with speeds of 110 to 120 km/h (av. speed 103 km/h for entire 3000 km). This record held until it was broken by UNSW Sunswift in January 2011.

Post-race and legacy

GM put the Sunraycer on tour, where it was displayed at several events across the United States. GM also produced a promotional 30-minute film about the Sunraycer aimed at middle-school and high-school students, narrated by one of the drivers of the Sunraycer. GM then donated the Sunraycer to the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...

. The Sunraycer led directly to the creation of the GM Impact, an electric powered car also designed by AeroVironment with help from both GM and Hughes; though the Sunraycer used solar power and not electrical power, it was not considered feasible at the time to create a solar-powered car for the American car market. The GM Impact led to the GM EV-1, an experimental electric car which was leased to customers for a few years in the late 1990s before being controversially retired and scrapped.

References

Bibliography

Racing with the sun

Popular Science Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is more broad ranging. It may be written ...

November 1987 PP.84 * Marshall, Jeff. "Racing with the sun." The Science Teacher 71.1 (2004): 40.

External links