America's Munitions 1917-1918

by Benedict Crowell; United States. War Department

The Liberty engine was America's distinctive contribution to the war in the air, and her chief one. The engine was developed in those first chaotic weeks of preparation of 1917, when our knowledge of planes, instruments, and armament as then known in Europe was still a thing of the future. The manufacture of engines for any aeronautical purpose was one which we might approach with confidence. We possessed in the United States motor engineering talent at least as great as any in Europe, while in facilities for manufacture—in plants which had built our millions of automobile engines—no other part of the world could compare with us. Therefore, while waiting word from Europe as to the best type of wings, fuselages, instruments and the like, we went ahead to produce for ourselves a new, typically American engine which would uphold the prestige of America in actual battle.

Many Americans have doubtless wondered why we built our own engine instead of adopting one or more of the highly developed European engines then at hand; and no doubt our course in this vital matter has sometimes been set down to mere pride in our ability and to an unwillingness to follow the lead of other nations in a science in which we ourselves were preeminent—the science of building light internal-combustion engines. But national pride, aside from giving us confidence that our efforts in this direction would be successful, had little other weight in the decision. There were other reasons, and paramount ones, reasons leading directly from the necessity for the United States to arrive at her maximum aerial effort in a minimum of time, that irresistibly compelled the aircraft production organization to design a standard American engine. Let us examine some of these considerations.

If there was anything to be observed from this side of the Atlantic with respect to the tendencies of aircraft evolution in Europe it was that the horsepowers of the engines were continually increasing, these expansions coming almost from month to month as newer and newer types and sizes of engines were brought out by the European inventors. It was evident to us that there was not a single foreign engine then in use on the western front that was likely to survive the test of time. Each might be expected to have its brief day of supremacy, only to be superseded by something more modern and more powerful.

Yet time was an element to which in this country we must give grave consideration. To produce in quantities such as we were capable of producing would ordinarily require a year of maximum industrial effort to equip our manufacturing plants with the machines, tools, and skilled workmen necessary for the production of parts. The finished articles would under normal circumstances begin coming in quantity during the second year of our program. It would have been fatal to "tool up" our plants for the manufacture of equipment that would be out of date by the time we began producing it a year later.

The obvious course for the United States to adopt, not only with engines but with all sorts of aeronautical equipment, was to come into the manufacturing competition not abreast with European progress but several strides ahead of it, so that when we appeared on the field it would be with equipment a little in advance in type and efficiency of anything the rest of the world had to offer.

This factor of time was a strong element in the decision to produce a standard American engine, since with the possible exception of the Rolls-Royce there was no engine in Europe of sufficient horsepower and proved reliability to guarantee that it would retain its serviceability for the necessary two years upon which we must reckon. There was no other course that we could safely adopt.

But there were other conditions that influenced our conclusion. We believed that we could design and produce an engine much more quickly and with much better results than we could copy and produce any approved foreign model. This proved to be true in actual experience. Along with the production of Liberty engines we went into the quantity manufacture of a number of European engines in this country; and the experience of our engineers and factory executives in this work was anything but pleasant. Among others we produced in American factories the Gnome, the Hispano-Suiza, Le Rhone, and the Bugatti engines.

Now European manufacture of mechanical appliances differs from ours largely in the degree to which the human equation is allowed to enter the shop. In continental practice much of the metallurgical specifications and also of the details of mechanical measurements, limits of requisite accuracy, variations which can be allowed, etc., are not put on paper in detail for the guidance of operators, but are confided to the recollections of the individual workmen. A machine comes in its parts to the assembly room of a foreign factory, and after that it is subject to adjustments on the part of the skilled workmen before its operation is successful. It must be tinkered with before it will go, so to speak. Nothing of the sort is known in an American factory. When standard parts come together for assembly the calibrations must have been so exact that the machine will function perfectly when it is brought together; and assembling becomes mere routine. Thus when we came to adopt foreign plans and attempt to adapt them to our practices, we encountered trouble and delay.

Thirteen months were required to adapt the Hispano-Suiza 150-horsepower engine to our factory methods and to get the first engine from production tools, while eight months were similarly spent in producing the Le Rhone 80-horsepower engines. Both of these engines had been in production in European factories for a long time, and we had the advantage of all the assistance which the foreign manufacturers could give us.