Driven to Extremes : He Built a Plane You Could Pedal Into the Air. He Designed a Flying Dinosaur. Now Paul MacCready Has Taken On : the Sun.

PAUL MACCREADY doesn’t like what he’s hearing. Lying on his back in a howling wind tunnel, MacCready is running a stethoscope across the underbelly of an odd-looking vehicle. As the wind rips past the tear-shaped craft at 50 miles per hour, he pokes the scope first here, then there, listening closely. The gale tears at his clothes, lifts his thinning, gray hair straight off his forehead, and in the pale light MacCready looks like a physician gone mad.

“We’re getting some awful noises here!” he shouts, straining to be heard over the wind. Behind the glass window of the observation room, a team of technicians looks on anxiously, scribbling notations and murmuring softly about “drag coefficients,” and “laminar flow.”

The scene is the multimillion-dollar test tunnel at General Motors’ Technical Center in Warren, Mich., and the creature causing MacCready all the worry is his latest, whimsical attempt to change the way man travels. For the past 10 years, the 62-year-old engineer from Pasadena has specialized in designing energy-efficient Dream Machines that accomplish seemingly impossible feats.

In 1977, he conjured up his first revolutionary aircraft, a spindly-looking vehicle called the “Gossamer Condor” that made history as the world’s first human-powered aircraft. Last year, he designed the Quetzalcoatlus Northropi , a motorized replica of a flying pterosaur that sailed over North America 65 million years ago.

Now, MacCready has embarked upon a new technological adventure. With funding from General Motors Corp., he is attempting to design a sun-powered car that will win a road race covering the length of Australia. Named the GM Sunraycer, the car has reached speeds of 65 m.p.h. on its 1 1/2-horsepower engine and solar cells. The showdown comes next week, when the car will glide across the starting line in the northwest town of Darwin and head for the southern port of Adelaide 1,950 miles away.

It’s called the “World Solar Challenge,” brainchild of a Danish adventurer named Hans Tholstrup, and it is being billed as the longest, and certainly the roughest, race in the brief history of solar-powered-car competitions: a seven-day journey fraught with 110-degree heat, tornadoes and the sheer monotony of the Australian interior. General Motors, which has pumped an estimated $1.5 to $3 million into the project so far, handpicked MacCready as the one man capable of driving the team to victory.

Or so the company hopes. Right now, how the Sunraycer will fare is anyone’s guess. Twenty-five other competitors from Japan, Denmark, Australia, Switzerland, Germany and the United States are busily perfecting their own vehicles, and during a recent test run at the Arizona Proving Ground, the MacCready car barely made it past 40--25 miles per hour less than its hoped-for top speed. The uncertainties of the weather and motor performance mean that the car’s aerodynamics will have to be made as flawless as possible. So tonight, at a reported cost of $1,550 an hour, General Motors has turned its wind tunnel over to MacCready and his team, who have arrived from Los Angeles to search for glitches in the car’s design.

The machine, it turns out, is riddled with them.

“It sounds horrible here, Bart,” MacCready says to his colleague, Bart Hibbs. Hibbs is a bearded, rabbinical-looking engineer who, like MacCready, is a Caltech alum. Both men are experts in aerodynamic drag -- or the resistance exerted by the air upon a vehicle as it moves through the atmosphere. “Odd noises” are a bad sign. They mean that the car still has some undetected protuberances, which are causing the air masses to swirl around it, slowing it down. The more jarring the noise, the worse the implications for the car’s performance.

Bathed in floodlights, the Sunraycer sits impassively: a half comical, half lyrical machine that looks like a cross between a beached flounder and a Darth Vader helmet. The entire apparatus is balanced precariously on four wheels that could have been ripped off a baby buggy. Three feet tall, 360 pounds, the thing barely seems capable of making it through a soap-box derby in one piece. Its rear three-quarters are covered by dark blue, reptilian scales: 7,200 tiny panels that make up the “solar array.” The cockpit is protected by a bubblelike, reflective canopy, currently mirroring the distorted images of the two goggle-wearing aerodynamicists.

“We just tested a quarter-sized scale model in the Caltech wind tunnel and got the lowest drag ever recorded,” says Hibbs. Behind him, a milky stream of propane cyclate gas is being shot over the car’s canopy, every chink in the flow indicating a spot that needs to be smoothed over.

“But everything changes when you get into a real-life situation. Even a decal put in the wrong place can make a difference. You have to smoke out each individual problem as you go along.” The Corvette Stingray, one of the fastest commercially produced cars ever built, had a “drag coefficient” of .25. MacCready’s team hopes that, by the end of two nights of testing, they’ll have the Sunraycer figure down to less than half that.

SINCE CHILDHOOD, Paul MacCready has been captivated by the notion of movement that defies the limits of low energy: the effortless soaring of birds and butterflies, the gliding grace of balsa-wood model airplanes, the uncanny ability of sailplanes to ride gusts of air for a thousand miles without an engine. The Gossamer Condor, he says, was an extension of that fascination: 90 pounds of aluminum tubing, piano wire and plastic that took off and flew on pedal power alone for a mile. For being the first to achieve human-powered flight, MacCready was awarded the $100,000 Kremer Prize, part of a British competition established to encourage breakthroughs in aviation.

To many in aeronautics, the accomplishment was as significant as the first supersonic flight by Chuck Yeager in 1947 or the round-the-world odyssey of the Voyager in 1986--a project very close to MacCready’s own spirit. “Dr. MacCready was the only person we figured could compete with us when we built the Voyager,” says Dick Rutan, the plane’s pilot and designer. “We kept a wary eye out for him.”

MacCready’s creativity didn’t dissipate with the Gossamer Condor. In the decade that followed, the inventor continued to turn his technological fantasies into improbable successes. He followed the Condor with an improved variation called the Gossamer Albatross, which was pedaled over the English Channel from the British coast to Cap Gris-Nez, France--a distance of 22.25 miles. Next came the the Solar Challenger, a sun-powered plane that flew 163 miles from Paris to Manston RAF base in Ramsgate, England, in 1981. Last year, at the behest of the Smithsonian Institution, he and a team of aerodynamics experts crafted their wing-flapping pterosaur, using as a model fossils discovered in Texas in the early 1970s. As a member of the International Human Powered Vehicles Assn., he has designed high-speed mutants of bicycles, tricycles, skateboards and hydrofoils. Now, all of the principles of flight, lift and drag he developed during those projects are finding new expression in the Sunraycer.

“Most engineers would approach this design by conceiving of a car, and then asking, ‘OK, so what do I have to take away from this car to make it run on solar power?’ ” says Bart Hibbs. “Not MacCready. He starts with the human being, and asks himself, ‘What do I have to put around this person to make it go?’ He takes a minimalist approach in all his designs.”

Some scientists and engineers, naturally, have sneered at MacCready’s projects, calling them “fun and games”--which is perfectly all right with MacCready. He delights in the apparent inconsequence of it all, the daydream elements, the whimsicality. But there is a serious side to MacCready’s work: He sees the Gossamers and the Sunraycer as meaningful syntheses of biology and technology, bringing man toward an accommodation with dwindling resources.

The engineer’s heroes have never been supersonic speed devils like Yeager, booming through the atmosphere with a roar of jet-engine-propelled force. MacCready finds his true idols in early aeronautic pioneers such as the Wright Brothers and Charles Lindbergh, who entered the field when it was raw and booming with new advances. Similarly, when MacCready began tinkering with pedal-powered airplanes, there simply wasn’t anyone else doing it. And he remains one of a handful of people working in the field of human-powered vehicles. “I was soaring in sailplanes at a period when it moved from being a general hobby to a much more scientific subject. I got involved in the weather-modification business before anybody knew what ‘cloud seeding’ was,” he says. “In any field, the most exciting time to enter it is during the first five or 10 years, when new discoveries are being made every day. There’s a real joy to that--and a sense of fun.”

IN PERSON, PAUL MACCREADY is a less-than-awe-inspiring figure. He’s a slight man, with a pale, birdlike visage and oversized horn-rimmed spectacles perched on a sunburned nose--a classic Walter Mitty character. His voice comes out in a reedy monotone, devoid of the tiniest change in pitch or emotion. He moves awkwardly, carrying traces of the ungainly adolescent who was always picked dead last in schoolyard choose-’em-ups.

Unlike Thurber’s Mitty, however, MacCready dreams up adventures that take place as much in the real world as in his head. He is a sailplane and hang glider expert, a hiker and a globe trotter who’s leaving next month for a four-day ascent of Mt. Kilimanjaro. And MacCready has always taken the riskier career route, rejecting the security of jobs with Boeing and Lockheed in favor of precarious start-ups: He founded Meteorology Research, which pioneered cloud seeding in the 1950s, and in 1970 started AeroVironment, whose 129 employees manufacture windmills and anti-pollution devices.

Spend a few hours with MacCready and you get a quick sense of his eclecticism and unorthodox creativity. On a Northwest DC-10 flight from Detroit to Los Angeles, MacCready thumbs through a pile of singular correspondence: New York bicyclists want him to address a rally protesting the closing of two Manhattan arteries to human-powered traffic. The California Skeptics--dedicated to the debunking of telekineticists, paranormalists, and New Age prophets invite him to a picnic in Pasadena. After reading his letters, he turns to his inseparable companion: a heavy, blue leather notebook, filled with sketches, diagrams and notes on yet more dream machines. On one page is an inflatable boat whose design, according to MacCready, allows it to be paddled 50% faster than a canoe.

A few pages later come studies for a windmill tower, an auxiliary-powered glider and a skateboard-sized “microbike.” At the moment, he’s sketching the plans for plastic foam caps that fit over the wheel wells of the Sunraycer.

When it comes to money--the obstacle that stops most dreamers--MacCready has been particularly shrewd. Long ago he sensed that the right corporation would pay a lot to share in the glory of his inventions. That was why the Du Pont Corp. underwrote MacCready’s $215,000 Gossamer Albatross and his $800,000 Solar Challenger. And why Johnson Wax chipped in roughly $600,000 for the pterosaur. In these unlikely alliances, MacCready knows, the corporations can cast themselves as instigators of American creativity--and he gets the financing. General Motors was doubtless driven by the same motive.

MacCready was tailor-made for the project, which originated last winter when GM’s chairman Roger Smith received a brochure touting the transcontinental odyssey. MacCready, brought in by a friend at Hughes Aircraft, had already fiddled with low-energy land vehicles, developing three-wheeled, high-velocity bicycle substitutes. (“Just something that your aunt would use to go to the grocery store with speed and comfort,” he says.) And he was stimulated by the primitive state of solar-car technology.

In the past, a few factors have prevented solar cars from achieving speeds beyond a leisurely 15 m.p.h.: heavy materials, poor electronics and the rigid shape of the photovoltaic cells, which are wafer-like rectangles made of the same kind of silicon used in the microchip. Because of those rigid cells, the cars have tended to be flat-topped, drag-ridden vehicles--”a table-top on wheels with a hole stuck in it for the driver’s head,” says Ervin Adler, Hughes Aircraft’s project manager for the Sunraycer’s power sources. But recently, Adler says, “we came up with more flexible cells that could bend around curves and allow for some aerodynamic innovations.”

So, in a matter of weeks, MacCready and his aerodynamicists--including Alec Brooks, who had helped design the Gossamer Albatross--crafted a streamlined design guaranteed to slice through the wind: A flat-bottomed teardrop. The body, though seemingly delicate, is fashioned from Kevlar, a lightweight, strong-as-steel material manufactured by Du Pont. Electronics experts from GM designed an 11-pound motor and a “power tracker” to channel electrical current from the solar cells to the motor. MacCready added rigid, finlike “strakes” atop the cockpit to cut down on crosswinds and planted rudders beneath the tail for stability. And for the past several months, a team from Hughes, GM and AeroVironment has been shuttling between California, the wind tunnel in Michigan, and the auto proving ground outside Mesa, Ariz., putting the vehicle through a series of durability and drag tests.

General Motors refuses to say exactly how much money it has poured into the project so far, but some Sunraycer team members have put the figure as high as $3 million. In any case, the budget and the expertise involved have undoubtedly cast GM as the Goliath among the 25 entrants. The field includes colleges like MIT, independent entrepreneurs and a few other corporations. An American shampoo maker, John Mitchell Hair Care Systems, is funding a $200,000 car built by Hawaiian environmentalist Jonathan Tennyson.

WHAT GM CA afford to do, after all the hype and all the expense, is lose the race. The company is taking no chances when it comes to testing the Sunraycer’s durability in conditions similar to those in the Australian outback. On a stifling desert morning in early September, MacCready and company are set up at the GM Proving Ground 30 miles southeast of Phoenix, a scrub-covered wasteland framed by distant buttes. Their aim: to run the Sunraycer over a couple of hundred miles of rough Tarmac, seeing how the engine holds up, how the solar cells perform and how vulnerable the car is to crosswinds. It’s a brutal world Down Under: “Willy Willies,” or dust devils, can spring up out of nowhere, blowing a vehicle straight into the bush. “Truck trains,” carting supplies to outback settlements, barrel down the 1 1/2-lane Stewart Highway at 70 m.p.h., stirring up winds that can be fatal to a poorly stabilized car.

But this morning there’s an even more serious problem: a complete motor breakdown, which has left the team immobilized in the 115-degree heat. MacCready, his nose burned by the Arizona sun to the texture and color of a strawberry, has taken refuge in an air-conditioned recreational vehicle parked by the side of the highway. “If this happens in Australia, we’re finished,” he tells Adler. “We can’t afford to spend too much time on the side of the road fixing things,” agrees Adler. “Thirty minutes a day times five, that’s 2 1/2 hours. That could kill us.”

By midday the burnt-out motor has been replaced, and the driver, Molly Brennan, a 27-year-old Chevrolet engineer, is sealed inside the cockpit (where temperatures can rise to 120 degrees). With MacCready following in a chaser car, the Sunraycer lumbers around the track--less a vision of speed and sleekness than a soporific tortoise. Inside the RV, Adler anxiously reads solar-cell and battery voltage levels from a blinking computer screen, directing Brennan to shift from solar to battery power to solar-and-battery combinations. In Australia, the Sunraycer team will be forced to make snap judgments about how much power to draw from the precious battery--vital during overcast periods. But it can only be charged by the sun for four hours at dawn and dusk, and it has to be used sparingly.

Clearly, something is going very wrong. Brennan has cranked up both the battery and the solar cells, but the Sunraycer is creeping along like a windup toy.

“There’s no question,” says Adler. “This motor is a dog.”

Later, MacCready tries to hide his disappointment. “This is exactly what we wanted to happen,” he insists. “Better the motor should go kablooey here and give us a chance to correct it, rather than somewhere in the middle of Australia.”

Problems aplenty arise in the next few weeks--more cases of engine failure, faulty suspension, drag-causing holes in the fuselage, protrusions hanging from the underbelly--and MacCready and his AeroVironment team will pick each one apart, examine alternative solutions, conjure up a remedy.

Each part, from the Sunraycer’s 17-inch spoked wheels to its 7,200 solar cells, from its welded aluminum-tubing chassis to its silver-zinc-cell rechargeable battery, will be meticulously scrutinized for flaws. And when the car crosses the starting line a week from today, MacCready will be right behind it in an RV, monitoring shifting weather patterns and communicating with the car’s driver (five will alternate at the wheel) via radio. Whether it wins or loses, he says, the Sunraycer will take its place alongside his other inventions as a modest symbol of harmony with the environment, recognition of shrinking resources and the power of the mind to overcome the most formidable obstacles. It is an old MacCready theme, trying to make a statement with his small-scale designs.

“I tend to think about what the world is gonna look like a couple of hundred years from now,” he says. “Is there a more congenial way of reaching equilibrium with the rest of the planet? And do we get there comfortably or by extreme strife? I happen to think that comfortably is a lot nicer way for it to happen.”