These experiences merely confirmed the opinions of American manufacturers that the preparations for the production of any aviation engine of foreign design—if any such suitable and adequate engine could be found—would require at least as much time as to design and tool up for the production of an American engine. When to this was added the necessity of waiting for several weeks or months for a decision on the part of our aviation authorities, either in the United States or in Europe, as to which of the many types of engines then in use by the allies should be put into production here, procuring and shipping to this country suitable samples, drawings, and specifications, negotiating with foreign owners for rights to manufacture, etc., there was but one answer to be made on this score, and that was to design and build an all-American engine.
Another factor in the decision was that of our distance from France, a fact making it necessary for us to simplify as much as possible the problem of furnishing repair parts. At the time we entered the war the British air service was using or developing 37 different makes of engines, while France had 46. Should we be lured into any such situation it might have disastrous results, if only because of the difficulties of ocean transportation. Germany was practically concentrating upon not more than 8 engines. The obvious thing for us to do was to produce as few types of engines as possible, thus making simpler the problem of manufacturing repair parts and shipping them to the front.
With these considerations in mind, the Equipment Division of the Signal Corps in May of 1917 determined to go ahead with the design and production of a standard engine for the fighting forces of the aviation branch of the Army. In the engineering field two men stood out who combined in themselves experience in designing internal-combustion engines which approached nearest to combat engines, with experience also in large quantity production.
J. G. Vincent, with the engineering staff of the Packard Motor Car Co., had for approximately two years been engaged in research work, developing several types of 12-cylinder aviation engines of approximately 125 to 225 horsepower, which, however, were not suitable for military purposes because of their weight per horsepower. This work had resulted in the acquirement of a large amount of data and information which would be invaluable in the design of such an engine as the one proposed; and also had resulted in the upbuilding of an efficient experimental organization. He had also had wide experience in designing internal-combustion motors for quantity production.
E. J. Hall, of the Hall-Scott Motor Car Co., for eight years had been developing and latterly producing several types of aeronautical engines, which he had delivered into the service of several foreign governments, including Russia, Norway, China, Japan, Australia, Canada, and England. He had also completed and tested a 12-cylinder engine of 300 horsepower, which, however, was of too great weight per horsepower to be suitable in its form at that time for military purposes. He had thus acquired a large experience and fund of information covering the proper areas and materials for engine parts, and proper methods of tests to be applied to such engines, and in addition he had general experience in quantity production. All of this information and experience was of invaluable assistance not only in designing the new engine, but in determining its essential metallurgical and manufacturing specifications.
These two men were thus qualified in talent and in practice to lay down on paper the lines and dimensions of the proposed engine, an engine that would meet the Army's requirements and still be readily capable of prompt quantity production. They had in their hands the power to draw freely upon the past experience and achievement of practically the entire world for any features they might decide to install in the model power plant to be produced. And this applied not only to the patented features of American motors, but also of foreign engines; for each man had exhaustively studied the leading European engines, including the Mercedes upon which Germany largely pinned her faith up to the end of the war.
With respect to American motor patents, an interesting situation had arisen in the automobile industry. The leading producers of motor cars were in an association which had adopted an arrangement known as the cross-licensing agreement. Under this agreement all patents taken out by the various producers (with a few exceptions) were thrown into a pool upon which any producer at will was permitted to draw without payment of royalties.
A similar arrangement was adopted with respect to the Liberty engine, except that the Government pledged itself to pay an agreed royalty for the use of patents. Thus the engineers designing the engine might reach out and take what they pleased regardless of patent rights. The result was likely to be a composite type embracing the best features of the best engines ever built. Theoretically, at least, a super-engine ought to result from such an effort.
The ideal aviation engine should produce a maximum of power with a minimum of weight; it must run at its maximum power during a large proportion of its operating time, a thing that an automobile motor seldom, if ever, does for more than a few minutes at a time; and it should consume oil and fuel economically to conserve space and weight on the airplane.
Such was the problem, the design of an engine to meet these requirements, that confronted these two engineers when they were called to Washington and asked to undertake the work.