astronomy

Sunraycer

Sunraycer is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sunraycer rather than just read about it. In short: The Sunraycer is a solar-powered racing car built in 1987 through a joint collaboration between General Motors, AeroVironment, and Hughes Aircraft to compete in the inaugural 1987 World Solar Challenge, the first transcontinental race featuring solar-powered vehicles. Driven primarily by Australian racing driver John Harvey, the Sunraycer won the 1,950-mile (3,140 km) 1987 inaugural race from Darwin to Adelaide by m…

Key takeaways

Sunraycer belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sunraycer to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sunraycer from memory before moving on to harder problems.

Reference excerpt

The Sunraycer is a solar-powered racing car built in 1987 through a joint collaboration between General Motors, AeroVironment, and Hughes Aircraft to compete in the inaugural 1987 World Solar Challenge, the first transcontinental race featuring solar-powered vehicles. Driven primarily by Australian racing driver John Harvey, the Sunraycer won the 1,950-mile (3,140 km) 1987 inaugural race from Darwin to Adelaide by more than two days over the second-place entrant. The car is now part of the collection of the Smithsonian Institution's National Museum of American History. According to AeroVironment engineer and Caltech alumnus Dr. Alec Brooks, Harvey was involved with the testing and development of the Sunraycer at the General Motors Proving Ground in Arizona, by request of General Motors Holden's Australian arm.

Background The World Solar Challenge originated with Australian adventurer Hans Tholstrup, who with engineer Larry Perkins drove a solar-powered vehicle across Australia from Perth to Sydney in 1983, and who subsequently organized the first transcontinental race for solar cars. In late 1986, GM executive Roger Smith received a copy of the race rules and forwarded them to Hughes Aircraft, recently acquired by GM. Hughes vice president Howard Wilson proposed entering the race and, through Hughes technology director Ed Ellion, connected with Paul MacCready, founder of AeroVironment. With less than 10 months remaining before the race's November 1, 1987 start, AeroVironment took on the project, and GM funded the effort through Hughes which eventually became known as SunRaycer.

Design and development AeroVironment, led by MacCready with engineer Dr. Alec Brooks heading the design effort, prioritized low weight and low aerodynamic drag (an ultra-low wind resistance vehicle). The finished vehicle weighed approximately 390 lb (177 kg) and achieved a drag coefficient of 0.125-0.13, with a top speed of 68 mph (109 km/h). 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 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 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 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 36 mph (58 km/h) 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 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, driven by John Harvey, won the pole position with the fastest speed of all the 24 contestants (109 km/h), remaining in first place for the entire race. 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 broke 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.

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 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.

Illustrations

Worked examples

Example 1 — a first encounter with Sunraycer

Start with the simplest possible case. Write down what Sunraycer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sunraycer before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sunraycer ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sunraycer

In research: Sunraycer appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sunraycer in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sunraycer is common in secondary-school and first-year university syllabi. It links to neighbouring topics Racing cars, Solar car racing, so understanding it makes those chapters shorter.
In everyday life: Look for Sunraycer outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sunraycer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sunraycer means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sunraycer out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sunraycer in simple terms?

Why does Sunraycer matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sunraycer?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sunraycer.