Published in 1971 by the Smithsonian Institution Press as part of its Smithsonian Annals of Flight series.[
t poor fuel economy, were always evident; and, moreover, at that time the majority of operating engines were four-stroke-cycle. Whatever their reasoning, they selected for their first powered flight the exact form of prime mover that continued to power the airplane until the advent of the aircraft gas turbine more than forty years later.
[Footnote 3: In the 1890s the wealthy inventor Sir Hiram Stevens Maxim conducted an experiment of considerable magnitude with a flying machine that utilized a twin-cylinder compound steam powerplant. It was developed to the flight-test stage.]
The indicated solution to their problem of obtaining the engine--and the engine that would seem by all odds most reliable--would have been to have a unit produced to their specifications by one of the best of the experienced engine builders, and to accomplish this, the most effective method would be to use the equivalent of a bid procedure. This they attempted, and sent out a letter of inquiry to a fairly large number of m