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Paul MacCready

Flying Higher and Quieter

In 1977, much of the world watched as television news reports showed a wiry bicyclist pedaling like mad to propel a human-powered airplane across the English Channel, barely staying above water. With a see-through skin revealing its framework, it looked like it was flying backwards, like an early Wright Brothers craft. After the heroic feat, the man who developed the plane, Paul MacCready, became known as the father of human-powered flight, as he was the first to do it successfully.

Most people would consider this the pinnacle of their career and could live happy even if this was the only significant thing they accomplished. Others may play the role of barnstormer and relish the publicity of such an event that brings a brief flurry of fame. MacCready took neither path. Rather, this was just one in a series of accomplishments for the 77-year-old head of AeroVironment in Monrovia, California. He had made a name as a pilot and innovator in highly-efficient flight long before the epic channel crossing, and he has done many things since, in aviation and beyond.

Born in New Haven, Connecticut, MacCready developed a passion for flying at an early age. "When I was ten or 11 years old, I lived at the shore at Branford, Connecticut in the summers and got very turned on to butterflies and moths," he recalls. In collecting them, he marveled at their ability to fly with such delicate wings. At the age of 12, he got into flying model airplanes and designing his own gasoline- and rubber-band-powered models, everything from gliders and helicopters to ornithopters and autogyros. "I remember thinking this was so wonderful and natural." Then at 16, he graduated to real planes and soloed in a Piper Cub.

MacCready entered Yale in 1943 and soon after joined the U.S. Navy flight training program. But the war ended before he completed his training, so he resumed his studies fulltime at Yale and received a B.S. in physics. He would later earn a master's in physics and a Ph.D. in aeronautics from the California Institute of Technology.

Something else happened during this time that would set the stage for MacCready: he developed a passion for gliders. As he tells it, "I was interested in them when I went in the Navy. It seemed like such an elegant form of aviation." His father-in-law-to-be and president of the Soaring Society of America took him to Elmira, New York, a hot bed for gliding, for his first glider flight. He was hooked.

Between 1946 and 1956, MacCready enjoyed a stellar career in soaring. He won the U.S. National Soaring Championships three times, and he became International Champion in France, the first American to do so. He credits soaring and the people he encountered doing it for influencing his thinking and creativity, calling the craft a mixture of nature, art, and technology. But in 1956, MacCready got away from the field, as other activities beckoned, and he felt contests were getting too serious with competitors taking dangerous chances.

As one of those other activities, in 1950-51, MacCready had started Meteorology Research, a firm involved in weather modification and atmospheric science research. He says of weather modification, which involves cloud seeding to induce rain, "It was a new field, and not many people were related to it, but I found it was really fascinating, and my thesis at Cal Tech was on atmospheric turbulence, so it fit right in." He pioneered the use of small instrumented aircraft to study storm interiors, often handling pilot duties. He did this until 1962. "By then, I found the field wasn't as interesting economically as I hoped because every time somebody seeded an area making rain, other people in the area who didn't want rain and would sue you." He left the firm in 1970 after another company bought it.

Then in 1971, MacCready founded AeroVironment. "I had a couple key employees who, like me, had Ph.D.s in aeronautics from Cal Tech but didn't want to just work in an aerospace program on airplane design," he states. They did various projects -- "whatever we could get business in" -- including building radars and sonars and researching vortex wakes of airplanes. "Projects slowly grew as time went on."

Came By Chance
MacCready would stumble into human-powered flight almost by happenstance. As he told it in a lecture he gave, "The venture began because I had acquired a $100,000 debt by co-signing loans to a friend, whose new business didn't succeed. I had three young children and a fledgling engineering company. In 1976, I had no interest in human-powered flight but was aware of the 50,000-pound Henry Kremer Prize established in 1959. I also knew that talented teams in England had devoted huge resources to competing and had created elegant but unsuccessful airplanes. The light bulb of creativity flashed on while I was daydreaming on a vacation trip. I noticed in a newspaper that one pound now exactly equaled two dollars. The prize equaled the debt! Suddenly, human-powered flight was exciting."

British industrialist Henry Kremer offered his prize to anyone who could fly a human-powered airplane over a one-mile-long, figure-eight circuit. MacCready's preliminary calculations showed that a conventional design wouldn't work. On a cross-country trip with his family in 1976, he and his sons marveled at the flight of hawks, vultures, and frigate birds overhead, remaining aloft for hours without flapping their wings. After touring Kitty Hawk, North Carolina, he realized he could win the prize with a different approach. The plane would have to be larger and lighter. The only unknown was that the wings would be so large they'd need exterior wire bracing, and he didn't know if that would induce too much drag. Dubbed the Gossamer Condor, his concoction had a wingspan of 96 feet and was covered in Mylar sixteen thousandths of an inch thick. The pilot pedaled a bicycle-like mechanism to power the propeller.

In developing his theory for the Gossamer Condor, MacCready realized that a hang glider requiring 1.2 horsepower would need only a third as much power if its dimensions were tripled without a weight increase. A good cyclist could generate .4 horsepower indefinitely. After working out hundreds of details, including maneuverability, he had the concept. The 84-pound Condor went on to stay aloft for 7.5 minutes in a flight that won the prize.

Soon after that, Kremer upped the ante and offered another prize, this time for crossing the 22-mile-wide English Channel under human power. MacCready still needed money, as he had sunk so much into building the Condor, he had wiped out only a third of his original debt. "We realized if we just made a variation of the Gossamer Condor, with carbon spars and more ribs and so on, we could make the Gossamer Albatross and get it across the channel," he explains. "The prize money, equivalent to $214,000, was enough to pay all the expenses on the project and pay off the loan." Two years later, his team created the Gossamer Albatross with DuPont sponsorship. In 1979, a cyclist powered the Albatross precariously across the channel to win the new Kremer prize, the largest cash prize in aviation history.

Success with human-powered flight led MacCready to pursue the next logical step: solar-powered flight. Again with DuPont sponsorship, the AeroVironment team developed two aircraft powered by the sun to draw attention to photovoltaic cells as a renewable and non-polluting energy source and demonstrate the use of DuPont's advanced materials for lightweight structures. They scaled down the Gossamer Albatross to three-quarters of its size to get the Gossamer Penguin and mounted 3920 solar cells on it to produce 541 watts of power. In 1980, with MacCready's 13-year-old son Marshall piloting -- he weighed just 80 pounds -- the Gossamer Penguin became the first plane to carry a pilot aloft solely on the power of sunlight. A year later, the team unveiled the second plane, the Solar Challenger, and piloted it 163 miles from Paris, France to England at an altitude of 11,000 feet.

Time to Reflect
By now, MacCready had become obsessed with squeezing every bit of efficiency from aircraft, embracing a credo of doing more with less. But he rarely paused in his work long enough to consider why. Then, as he tells it, "In 1982, I won the Lindbergh Award and gave a talk to that society, which forced me to really think through all the different subjects I had been involved with over the years and what I should be doing, what motivated me, what was important. And that talk made the big difference in my life because I realized the importance of being on the earth, not using too much energy. Now, we've modified the company. Much of what we do is related to energy and efficiency for airplanes, for ground vehicles, and things on the ground that don't move." Taking on a worldly view of sustainability, he adds, "Oil is a real problem. We're very close to the oil peak internationally, after which there will be less oil each year. Oil, coal, and gas cause pollution. That's a reason I've been involved in electric cars."

AeroVironment's first foray into electric vehicles came in the form of the GM Sunraycer, a joint venture with General Motors and Hughes Aircraft. In 1987, the solar-powered car won the World Solar Challenge, a 1867-mile race across Australia, proving that photovoltaic cells can produce significant power and leading to electric vehicles with acceleration comparable to fossil-fuel-powered vehicles.

Actually, AeroVironment had suggested conventional electric vehicles to GM in 1985, but the company showed no interest. Then in 1987, after GM became acquainted with AeroVironment through the World Solar Challenge, they began working with them further. AeroVironment developed the concept for the GM Impact electric vehicle, introduced in 1990, and this later became the production vehicle EV-1. MacCready formed the Electric & Hybrid Vehicle Systems division to design and build electric and hybrid concept vehicles.

To date, critics have maintained that battery capacity renders electric vehicles impractical. But MacCready says otherwise. "Now, batteries have recently gotten so super good. If you take the lithium cells used in cell phones an microcomputers and use that technology in battery-powered cars, you have cars that go 350 miles on the batteries and have great acceleration. It looks like as prices on these batteries come down in the future, this will be the preferred way to make cars environmentally sensitive."

Setting Altitude Records
Meanwhile, MacCready has also ventured into unmanned aerial vehicles, focusing on high-efficiency, high-altitude solar-powered aircraft jointly sponsored by NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The first unmanned solar plane, the Pathfinder, flew to 71,500 feet in 1997, and a modified Pathfinder, known as Pathfinder-Plus, flew to 82,000 feet, higher than any other propeller-driven aircraft. Building on Pathfinder's success, AeroVironment built a next-generation aircraft, the Centurion, with a 206-foot wingspan.

The Centurion wingspan was then further extended to 247 feet and the aircraft renamed the Helios Prototype. Powered by 14 electric motors that turn propellers, Helios flew to 96,863 feet in 2001 in Hawaii at the U.S. Navy Pacific Missile Range Facility in Kauai, shattering the world altitude record for both prop- and jet-powered aircraft (the SR-71 spy plane previously held the record, having flown to 85,068 feet). It spent about seven hours above 50,000 feet in its record flight. AeroVironment is developing a regenerative fuel cell system to power night flight using excess energy stored during daylight. Within two years, they hope to have solar-electric airplanes capable of continuous flight for up to six months at altitudes over 60,000 feet.

Why have something fly this high and long? NASA sees Helios as an eye in the sky with uses for science and also as a way to watch enemies and assist in fire fighting, emergency services, and disaster analysis. They envision thousands of them circling the skies. It could help in crop management; keep tabs on environmental changes; monitor fisheries, coral reefs, and forests; collect air samples; conduct meteorology research; and assist with mapping. It could fly over a hurricane to determine its direction. Applications also include telecommunications and remote sensing.

Seeing the potential for Helios in the telecommunications arena, MacCready created the SkyTower division of AeroVironment to build and operate solar-electric airplane-based telecommunications networks. Early potential applications include fixed broadband and third-generation mobile service for high-speed Internet, voice, video, and data connectivity. Later, direct broadcasts and wireless telephony may come.

In carrying out his vision of doing more with less, MacCready has also formed two other divisions within AeroVironment. A joint venture with Delco Remy International, iPower Technologies has developed natural-gas-powered microturbines to use in distributed generation systems for residential electric power, industrial co-generation, standby power and for use in hybrid electric vehicles. PosiCharge brings to market a rapid-charging battery system for industrial electric lift trucks and other electric vehicles, including chargers that allow an EV to regain 50 percent of its range in under 10 minutes.

With all this going on, it comes as no surprise that MacCready takes only a week's vacation every year. He serves as chairman of the board of AeroVironment and stays active in all its technology areas. But last year, he announced he was going to get his glider license and get back into the sport that spawned much of his success. With all he has accomplished, he has earned a little time off for fun. There's more to it than that, though. He wants to get back to silent flight so he can preserve what inspired him as a child.

Progressive Engineer
Editor: Tom Gibson
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©2004 Progressive Engineer