Paul MacCready

UXL Encyclopedia of World Biography, (2003)

Paul MacCready

Paul MacCready (born 1925), known as the "father of human-powered flight," first gained fame when he won the Kremer Prize for inventing an aircraft powered solely by human effort. He went on to develop a solar-powered plane and car and a radio-controlled replica of a giant pterodactyl. MacCready helped develop the Impact demonstrator electric vehicle, which, in 1991, inspired California's zero-emissions mandate.

Paul MacCready was born in New Haven, Connecticut, on September 29, 1925. His father was a doctor, and his mother was a nurse. MacCready had a learning disability, dyslexia, about which he later said in an interview with Discover magazine, "It keeps my mind jumping. It also gives me a short attention span, which forces me to really focus on things that are important." Small, shy, and a poor athlete as a child, MacCready collected moths and butterflies and built model airplanes. "I think kids do better if they have a hobby, a topic they know better than anybody else," he noted.

By the age of 13, MacCready was building flying machines, including autogiros, helicopters, and ornithopters. Three years later he had a pilot's license. "That really gave me confidence in myself," he recalled. At age 20, MacCready took up glider plane flying, called soaring. "Unlike with conventional aircraft, this was pure, quiet, birdlike flight. It was my first insight into how technology could be combined with the natural world," he explained to Discover.

At the end of World War II, MacCready trained as a Navy pilot. He completed his bachelor's degree in physics from Yale University in 1947. At the California Institute of Technology, he earned a master's degree in physics and a Ph.D. in aeronautics in 1952. While still in school, MacCready continued to practice soaring. He won the U.S. National Soaring Championship in 1948, 1949, and 1953. In 1956, he became the first American to win the World Soaring Championship. MacCready pioneered wave soaring, in which a sailplane uses strong lifting currents of air to reach extreme heights. He also invented the MacCready speed ring, an instrument still used by glider pilots to select the best flight speed between updrafts. MacCready stopped competing in 1956, after realizing the dangers of the sport.

Marriage and a Career

In 1957, MacCready married Judy Leonard, the daughter of one of his soaring friends. They later had three sons, Parker, Tyler, and Marshall. MacCready was ready to begin his career as an engineer but was not impressed by the way standard aerospace firms got things done. "Such places foster by-the-book thinking, a lockstep way of approaching a problem," he said in Discover. MacCready founded his own company, Meteorology Research Inc., a business specializing in flying small planes into clouds to try to affect the amount of rainfall they produce. He was the first to use small aircraft to study storm interiors. "We got pretty good at creating lightning, but there wasn't much of a market for it," he noted.

MacCready sold Meteorology Research Inc. in 1971. He soon founded AeroVironment in Monrovia, California, to develop renewable energy sources (like wind and solar power) because he was concerned with how quickly people were using up the planet's resources.

A Bad Loan Leads to Great Discoveries

In 1976, MacCready found himself $100,000 in debt after guaranteeing a loan in 1970 to his brother-in-law, who had developed a scheme for manufacturing fiber glass catamaran sailboats. Wanting to get out of debt, MacCready remembered an 18-year-old challenge conceived by British industrialist Henry Kremer. The first person to take off using only the muscle power of the pilot, clear a 10-foot hurdle, and complete a 1.15-mile-long figure-eight course using human-powered flight would win $100,000. When his family was driving across the country on vacation MacCready watched hawks and turkey vultures soaring in circles overhead, using updrafts. He calculated a bird's flight speed and its turning radius by estimating its banking angle and using a watch to time how long it took to make a 360-degree turn. He then realized that as long as the weight stayed the same, an airplane's wings could get bigger and bigger. The flight speed would decrease, but so would the power needed to make the plane fly. In this way a trained athlete could power the plane.

In 1977, MacCready and his colleagues at AeroVironment created the Gossamer Condor, with 96-foot wings of aluminum tubing, corrugated cardboard, and balsa wood, made rigid with piano wire, and covered with a thin layer of Mylar (polyester film). MacCready used his sons, then teenagers, as test pilots. Bryan Allen, a bicycle racer and hang-glider pilot, flew the Condor around the Kremer course, earning MacCready a place in history. The Condor won Kremer's prize and earned MacCready the nickname "the father of human-powered flight." The craft is now displayed in the National Air and Space Museum in Washington, D.C. "I think it was a milestone, leading toward what I still don't know. But Charles Lindbergh's flight didn't add anything to the knowledge of aviation. It made other things happen, but it was really just a symbol," noted MacCready in an interview with Science '86.