The steam plane is constructed throughout of duralumin, the extremely light aluminum alloy which has been wed used successfully in airplane construction in this country. The engine is an adaptation of the Diesel engine, now extensively employed in the United States Navy. It burns a combination of crude oil and other oils, which is broken up under a forced air feed and sprayed against the boiler. Here it Ignites, giving terrific heat considering the relatively small quantity of oil consumed in the operation. ten gallons of oil are said to be sufficient to run the plane's 750 horsepower engine for eight hours. American aviation engineers are inclined to question this statement, as well as the report that only 1000 pounds of water are used in a flight of 95 hours. They do agree that the principles employed in the new plane are likely to lead to important developments.
The water used to generate steam in the new plane is carried in the metal wings in compartments so arranged that the water may be shifted to "trim ship" if desired. The steam is condensed after exhaust and conveyed back to the wings in the form of water.
George W. Lewis, M. E., executive officer of the National Advisory Committee on Aeronautics, says that the U.S. government has done considerable experimental work on steam power for airplanes, but has met with only partial success because of the problem of condensing water without the use of heavy equipment. For the heavier-than-air machine he believes steam power does not look encouraging at this time but ultimately will be of considerable use in propelling dirigibles. Lewis and other aeronautical engineers in the navy agree that steam is the apex of efficiency and that its thorough reliability under practically every condition makes it a fertile field for experimentation.