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.