W. DUNCAN RANNIE 1914-1988

BY WILLIAM R. SEARS

Duncan Rannie was born in Canada, the son of the beloved physician of a small Ontario town. He was educated in the fine British-Canadian tradition and graduated from the University of Toronto in 1937 with an M.S. in applied mathematics. He was attracted to the California Institute of Technology by the fame of Theodore von Kármán and the institute's other bright stars, and continued graduate studies in mathematics there in 1938. When he observed that the kind of mathematical applications that interested him most was found in the applied science departments at Cal Tech, he became a candidate in aeronautics.

He was a brilliant student. Von Kármán became involved with the Tacoma Narrows Bridge disaster and the aerodynamics of suspension bridges in general; he made Rannie his trusted assistant in theoretical and experimental (wind tunnel) studies in this area, and Rannie produced definitive studies and reports on bridge dynamics and flutter.

He was also a key player when von Kármán and several of us, his students, became interested in power generation by wind power—the project that led to the Smith-Putnam Wind Turbine, which was constructed on Grandpa's Knob in Vermont. Unfortunately, Rannie's analytical findings regarding the stability of the giant windmill were not incor porated in the prototype that was built and tested on the mountain.

The relationship between von Kármán and Rannie was warm. In 1942, following von Kármán's suggestion, Rannie joined the staff of Northrop Aircraft, where a major project was under way to produce an aircraft gas turbine—the ''Turbodyne'' project—sponsored by the U.S. Navy. There, during the war years, Rannie developed theories and design procedures for axial compressors. This was pioneering work, based on sound theoretical principles, that became the basis for much of the progress of gas turbine technology that followed.

In 1945 Rannie returned to Cal Tech, specifically to the Jet Propulsion Laboratory (JPL), where he continued his studies of flow in axial compressors and turbines. He was encouraged to write up his definitive work on suspension bridges to complete the Ph.D. program that had been interrupted by wartime work, but he preferred to write on heat transfer in turbulent flow; this dissertation was accepted and published; his Cal Tech doctorate is dated 1951. He became chief of Ramjet and Combustion Research at JPL in 1945. In 1951 he moved from JPL to the main campus as an associate professor and a major member of the Daniel and Florence Guggenheim Jet Propulsion Center. He continued both theoretical research and publishing in gas turbine technology, and served his adopted nation on the Air Force Scientific Board, the first and second Air Force Long-Range Planning Groups, the U.S. Air Force's Aircraft Propulsion Laboratory Advisory Panel, and industrial advisory committees. His students became leaders of the aircraft engine industry throughout the western world.

Duncan Rannie was elected fellow of both the American Rocket Society and the American Institute of Aeronautics and Astronautics, and in 1979 was elected to the National Academy of Engineering. He became Goddard Professor of Jet Propulsion at Cal Tech, and in 1956, director of the Daniel and Florence Guggenheim Center.

He was a devoted family man and, throughout his life, a lover of nature. His personality was one of great modesty—he considered his own research and publications to be quite unexceptional. He was deeply devoted to his students and to the profession of teaching. His dour sense of humor was worthy of his Scottish-Canadian forbears—and the delight of his host of friends and admirers.