IN 1900, old experienced engine builders were saying “impossible” to an 18 to 22 lb per hp ratio for an engine which was being designed for use in the man-carrying flying machine under development by Dr. S. P. Langley, Secretary of the Smithsonian Institution. By December, 1901, working as Dr. Langley's chief assistant - and having taken personal responsibility for the engine development - Charles Matthews Manly had completed an engine which weighed, net 125 lb, developed 52.4 hp at 950 rpm and had demonstrated its durability in three separate 10-hr full-power endurance runs. This 2.4 lb per hp ratio was not surpassed until the advent of the Liberty engine 16 years later.
Dramatic details of this most frequently recorded achievement of the distinguished engineer who was SAE president in 1919 are recorded in this paper as part of an interpretive study of Mr. Manly's broad achievements. Mr. Manly's important development work on other phases of the Langley airplane, his pioneering designs in the field of hydraulic power transmission, his vital contributions to military aviation throughout the World War period and his broad service to society through SAE activities are summarized.
The theme of Mr. Manly's life, the author says, was engineering. “His criterion of an objective was: ‘Will it serve?’ of a method, ‘Will it work?’ The past informed, but did not form him. Novelty, in itself, he neither feared nor favored. His application of engineering principles was courageous and clear-sighted; it led him to many conclusions which, new in his time, have been approved by the irrefutable logic of experience.”