Paul B. MacCready Jr. (September 25, 1925 – August 28, 2007) was an American aeronautical engineer. He was the founder of AeroVironment and the designer of the human-powered aircraft that won the first Kremer prize. He devoted his life to developing more efficient transportation vehicles that could "do more with less". Early life and education Born in New Haven, Connecticut, to a medical family, MacCready was an inventor from an early age and won a national contest building a model flying machine at the age of 15. "I was always the smallest kid in the class ... by a good bit, and was not especially coordinated, and certainly not the athlete type, who enjoyed running around outside, and was socially kind of immature, not the comfortable leader, teenager type. And so, when I began getting into model airplanes, and getting into contests and creating new things, I probably got more psychological benefit from that than I would have from some of the other typical school things." MacCready graduated from Hopkins School in 1943 and then trained as a US Navy pilot before the end of World War II. He received a BS in physics from Yale University in 1947, an MS in physics from Caltech in 1948, and a PhD in aeronautics from Caltech in 1952. His doctoral dissertation Investigation of Atmospheric Turbulence was supervised by Homer Joseph Stewart. In 1951, MacCready founded his first company, Meteorology Research Inc, to do atmospheric research. Some of MacCready's work as a graduate student involved cloud seeding, and he was an early pioneer of the use of aircraft to study meteorological phenomena. Career and achievements He started gliding after World War II and was a three-time winner (1948, 1949, 1953) of the Richard C. du Pont Memorial Trophy, awarded annually to the U.S. National Open Class Soaring Champion. In 1956, he became the first American pilot to become the World Soaring Champion. He invented a device that told pilots the best speed to fly a glider, depending on conditions and based on the glider's rate of sink at different air-speeds. Sailplane pilots still use the "MacCready speed ring", and still adjust the "MacCready Number" (abbreviated MC) within their flight instruments, to optimize their flying speed. In the 1970s, he guaranteed a business loan for a friend, which subsequently failed, leaving him with a $100,000 debt. This was the motivation he needed to compete