The Sunraycer was a solar powered race car designed to compete in the world's first race featuring solar-powered cars. This race is now called the World Solar Challenge. The Sunraycer, a joint collaboration between General Motors, AeroVironment, and Hughes Aircraft, won the first race in 1987 by a huge margin. The team's lead driver was Australian John Harvey, a driver with (at the time) nearly 40 years experience racing speedcars (Speedway), open wheelers, sports cars and touring cars. Harvey was involved with the testing and development of the Sunraycer at the General Motors Proving Ground, Arizona.
The Sunraycer project started with a request from GM's Australian division to GM Headquarters to participate in the upcoming Solar Challenge. This race, to be held in Australia in late 1987 would feature purely solar powered cars. Roger Smith, the CEO of GM, was immediately interested in the idea and he 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 their famous owner/engineer Paul MacCready was given the contract to build what would be called the Sunraycer.
During the conceptual process, the constant 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 585 lb (265 kg)) and created a very low drag coefficient (cd: 0.125). Sunraycer was fast and capable of a top speed of 109 km/h (68 mph).
A total of 8800 solar cells were manufactured and installed by a team, from Hughes Aircraft, which had a great deal of experience with photovoltaic cells used in the many communications satellites that they designed and built. At high noon, the car would generate about 1500 watts of power.
The engine was created for the Sunraycer by GM using a brand new electric motor based on Magnequench permanent magnets. 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 were using/commercializing 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. (So, the battery allowed driving during allowed hours even when the weather was overcast.)
The frame of the car weighed just 14 pounds. AeroVironment engineers made use of Kevlar for the shell of the car. The Sunraycer was tested through the spring and summer of 1987, and it had no problems.[dubious ] During the testing period, the team had the time to set a new world speed record with the Sunraycer, achieving a speed of 36 mph (58 km/h) from solar power alone (breaking the old record by 10 mph).
The race, in November 1987, was from Darwin in the north of Australia, to Adelaide in the south. The race course followed the Stuart Highway for nearly the entire trip, going past Alice Springs in the middle of the continent.
The Sunraycer, with John Harvey driving won the pole position with the fastest speed of all the 24 contestants (109 km/h) and from the start of the race to the end, it was always in first place. It raced the 1,867 miles (3,005 km) with an average speed of 41.6 mph (66.9 km/h), 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, the Sunraycer smashed the solar powered speed record with a top speed of 75.276 mph (121.145 km/h). 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.
GM put the Sunraycer on tour and it was transported to many events across the U.S. GM also made a promotional film about the Sunraycer aimed at middle-school and high-school students. The film (about 30 minutes long) was narrated by one of the drivers of the Sunraycer. The Sunraycer was then donated to the Smithsonian museum by GM.
The Sunraycer was a very expensive car to build (slightly less than $2 million 1987 dollars all told) and at the time it was not considered feasible to create a car for the American car market based on solar power. Instead, the idea was to create an electric powered car.
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). In turn, the GM Impact led to the EV-1, which was leased to customers for a few years in the late 1990s before being retired and scrapped. GM now has a series hybrid electric car (with propulsion only by the electric motor) called the Chevy Volt which was introduced to the US market in late 2010. Within the framework of GM's vehicle electrification strategy, the 2014 Chevrolet Spark EV is the first all-electric passenger car marketed by General Motors in the U.S. since the EV1 was discontinued in 1999.
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- History of Rare-Earth Magnets: Patents and Intellectual Property
- Hitachi Metals history
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- Paul MacCready talks about the Sunraycer project
- Smithsonian article on the Sunraycer
- EV-1 Timeline
- Paul MacCready bio
- Short history of the Solar powered car race
- MacCready, Paul B. (Winter 1988). "Sunraycer Odyssey: Winning the Solar-Powered Car Race across Australia" (PDF). Engineering & Science. California Institute of Technology.