During an exemplary engineering career Charles Matthews Manly (1876-1927), former president of the SAE and one of America's foremost aircraft engine pioneers, contributed greatly to the design and development of the radial piston engine, which came to dominate aircraft propulsion until the 1950s. He is best known for development and refinement of a world-class 52-hp, five-cylinder, water-cooled radial aircraft engine at the Smithsonian Institution. His early academic achievements led to his appointment as chief assistant to Professor S. P. Langley, secretary of the Smithsonian Institution, who was engaged in early aeronautic experiments and, in 1903, racing with the Wright brothers to demonstrate the first manned aeroplane. Easily the most advanced aeronautical engine in the world at the turn of the century, the so-called Manly-Balzer radial powerplant used in Langley's Aerodrome was almost 20 years ahead of its time in terms of specific-weight excellence. Manly risked his life twice in 1903 in unsuccessful attempts to fly the Aerodrome (launched from a houseboat on the Potomac River), although the engine itself performed flawlessly during these tests.After this aeronautical work, Manly diverted his talents into the design and production of variable-speed hydraulic drives, a field in which he ultimately earned about 40 U.S. patents. Maintaining his interest in aeronautics during World War I, he first served as a consultant to the British War Office and then worked in various engineering and management positions at the Curtiss aircraft concern from late 1915 to early 1920. During this time, Manly became involved with the SAE, first in 1917 and 1918 developing aircraft standards, and ultimately serving with distinction as president in 1919. Consulting automotive engineering activities (in partnership with C. B. Veal-later to become SAE's research manager) consumed the balance of his career until his premature death in 1927. In 1929 Manly was posthumously awarded the Smithsonian's prestigious Langley medal for outstanding aeronautical achievements (previously awarded to the Wright brothers, Glenn Curtiss, and Charles Lindbergh). In 1928, the SAE board of directors also honored him by originating the Manly Memorial medal for best annual SAE paper on aeronautic powerplants, which is still awarded today.