Charles Matthews Manly was born at Staunton, Virginia, and was the son of Charles and Mary Esther Hellen (Matthews) Manly. His father, a Baptist minister, was the son of Basil Manly, 1798-1869, and the brother of Basil, 1825-1892. Mechanical aptitude was a common heritage in the Manly family, but rose to genius in Charles.
Graduating at Furman University, Greenville, S. C. , in 1896, he pursued graduate work at Cornell University, from which he received the degree of M. E. in 1898.
On the recommendation of Prof. R. H. Thurston, he was engaged by Secretary Samuel P. Langley to have charge of the construction of a large aeroplane, then building at the Smithsonian Institution for the United States War Department. Langley had already flown (1896) 13-foot models with light steam engines in flights up to three-quarters of a mile, catapulting the models from a houseboat. The same launching method was to be followed with a large machine, though Manly suggested flying from wheels on land. In the final trials October 7 and December 8, 1903, disaster from the launching device occurred in both instances, and Manly, acting as pilot, narrowly escaped being drowned in the wreckage.
Charles L. Lawrance, president of the Wright Aeronautical Corporation, speaking before the International Civil Aeronautics Conference at Washington, December 1928, said of 5-cylinder water-cooled radial gasoline engine designed by Manly: "When we consider that the most popular type of airplane engine of today is almost identical in its general detail and arrangement with the one evolved by Charles Manly in 1902, we are lost in admiration for a man who, with no data at his disposal, no examples of similar art on which to roughly base his design nevertheless, through the processes of a logical mind, the intelligent application of the science of mathematics, and the use of his surprising mechanical skill, succeeded in constructing this engine which may in fact be characterized as the first 'modern' aircraft engine in the world". While yet in Langley's employ, Manly invented and patented, October 7, 1902, the Manly drive, a hydraulic device for transmitting power at variable speeds from a constant-speed motor. In essentials it comprised a radial multicylinder pump of constant speed delivering oil to a radial multicylinder motor. The throw of the pistons was continuously variable from zero to a maximum, thereby enabling a wide-ranged continuous change of speed of the driven element to be made at the pleasure of the operator. The firm of Manly & Veal, consulting engineers, and the Manly Drive Company developed this device in New York, applying it to heavy trucks and to battleship turrets. Manly was the owner of some fifty patents on automotive transportation and power generation and transmission. He completed and edited the Langley Memoir on Mechanical Flight, published by the Smithsonian Institution in 1911, which was begun by Langley and gives in detail his experiments in aviation. He served as consulting aviation engineer to the British War Office, 1915; to the Curtiss Aeroplane & Motor Corporation, 1915-19, of which from 1919 to 1920 he was assistant general manager; as a member of the United States commission to the International Aircraft Conference, London, 1918; and as consulting engineer to various corporations. He was a member and president (1919) of the Society of Automotive Engineers.
Manly's great contribution to Langley's work, and his permanent contribution to aviation, was his design and construction of a 5-cylinder water-cooled radial gasoline engine of fifty-two horsepower, weighing but 125 pounds. This engine performed in an exemplary manner, making continuous runs of ten hours in tests. In 1930 the Smithsonian Institution, in recognition of the permanent value of his pioneer work on the light radial internal combustion engine, awarded to him posthumously the Langley Gold Medal for Aerodromics.
On June 9, 1904, he married Grace Agnes Wishart, who died May 15, 1921, leaving two sons.
