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THIS article, written shortly after the signing of the armistice, deals with the Naval aviation situation at the outbreak of war and its development during the war, ending with a brief discussion of the probable future lines of development. Figures are given showing the expansion occurring during the nineteen months of warfare, and the different ways in which the various types of aircraft were used. Future development is treated briefly, but that logical assumptions were made is indicated by the fact that the year which has elapsed since the article was written has shown a very decided trend along the lines indicated.

THE Navy Department established the Naval Aircraft Factory (a) to assure a part, at least, of its aircraft supply; (b) to obtain cost data for the Department's guidance in dealing with private manufacturers, and (c) to have under its own control a factory capable of producing experimental work. The history of this development is given in some detail, including statistics of size, valuations and output.

THE rapid development of heavy-duty trucks and farm tractors has made it necessary for manufacturers of engines used in such automotive apparatus to face problems regarding which there is no past experience to fall back upon. The necessity in both types of engine for maximum strength in all parts carrying excessive loads constitutes a problem of great importance, but in addition to it are others of the proper utilization of fuels at present available, lubrication under excessive load conditions over long periods of time; and, of nearly as much importance, the relation of fuels to lubricants and the effect of fuels upon lubricants. Moreover, information is to be acquired regarding the value of prospective fuels as power producers, the effects they have upon engines, lubricants, etc., comparisons of cost and the like. The tests recorded in the paper were made in an endeavor to ascertain some of these unknown values.

THE ordinary governor used on trucks and tractors is essentially a one-speed device. It gives good results at one speed, but at higher speeds “hunting” develops and at lower speeds governing is less accurate. This is because the spring must be stiff enough for maximum speed, and hence four times stiffer than it should be for half speed. The paper shows by calculations and curves the best results that can possibly be obtained; also, curves from a test showing what results are actually obtained with one well-known governor. Two new types of governor are described; in which the position of the spring is varied for different speeds. Theoretical curves also are presented and the results of tests, indicating that the new types produce the same character of curve at 800 as at 1600 r.p.m.

The paper treats the subject of ability from the point of view of its relation to the present trend in motor-truck design, setting forth some of the fundamental considerations involved. An ability formula when applied to automotive vehicles is to determine a “factor of experience” from which engine sizes and gear ratios can be calculated. While passenger-car performance is measured in terms of speed and acceleration, the latter are not the most important considerations in motor trucks, the speed of which is limited by the use of a governor. Wind resistance also is negligible at truck speeds. Practically the only resistances to be overcome by a motor truck are road friction and the force of gravity. Both road and grade resistance are in direct proportion to weight carried and are usually expressed in terms of pounds per pound.

THE author believes a more thorough understanding of the functions and use of drawbar implements is necessary. The tractor is incidental to agriculture. The implements used with tractors do the actual work and the tractor is a means to that end. Many tractors are sold on the quality of work done by the implements, and not because of their own work. Many a tractor is condemned because the implement combination is not correct. The amount of draft of plows must be thoroughly understood. Good plowing requires considerably more power than poor plowing, although done at the same depth and width. Turning the same number of square inches of furrow section will in one case require from 20 to 30 per cent more power than in another.

THE design of a modification of the Class B Government standardized truck engine is presented, the principal object being a saving in weight without sacrificing either durability or safety factors. The crankcase design is rigid, but the metal is distributed so that the weight will be a minimum. The crankshafts are made of chrome-nickel steel of an elastic limit of 120,000 lb. per sq. in., which further carries out the idea of durability with low weight. The connecting-rod length is slightly more than twice that of the stroke, and this, with light-weight pistons, obviates vibration, without adding weight to the engine on account of increased cylinder height. The flywheel and bell-housing diameters were selected with a view to securing enough flywheel weight for smooth running without increasing the engine weight materially. All-steel supports reduce breakage of arms to a minimum. The manifolds are carefully designed to give economical performance, even with low-grade fuels.

THE design and construction of airships in the United States was inaugurated by the Navy in 1917, with the B class of sixteen small airships. These were built for training and coast patrol. They were used to train 150 pilots and covered 140,000 miles of patrol without loss of life. The following year the C class of twice the size was brought out and proved very successful. The development of airship construction has progressed rapidly, but because of such a delayed beginning, the United States is still very far behind England and Germany. In particular, the large rigid airships of the Zeppelin type have not yet been attempted here, but their use during the war by the German navy, as scouts over the North Sea, indicates that they are necessary to a modern fleet. A short account is given of the German North Sea air organization, showing the seaplane bases laid out to cooperate with the airships.

EVERY plow in use should have 10 b.-hp. available. Every tractor engine should deliver continuously at least 33 hp. If the 330-cu. in. engine mentioned were as good as a Liberty airplane engine, it could deliver 57 hp. at 1000 r.p.m. The horsepower actually obtained is as follows: 41.5 in the laboratory 33.0 at the factory 29.0 when burning gasoline 23.0 when burning kerosene 21.0 with poor piston-rings 19.0 with poor spark-plugs 9.5 available at the drawbar The great engineering problem of the future lies between the 57 and the 23 hp. From 19 to 9.5 hp. is the manufacturer's problem. The main difficulties, as outlined by the figures given, lie in the combustion chamber and its ability to dissipate the surplus heat, and in the limitations of fuel. There will be no need for refiners to continue to break up the heavier fuels by processes already so successful, if by ingenuity and good understanding of thermodynamics these can be made to burn in present-day engines.

THE author's observations cover the period immediately following the war when, as a member of a party of representative guests of the British and French governments, he toured England, meeting Government officials and talking on industrial matters; visited Scotland's shipbuilding and coal areas; viewed the battle area, aircraft, automobile and tractor factories in France; and traveled in Italy, later returning to England to inspect factories, conduct investigations and review Government activities. The enormous expansion of the automotive industry factories of the Allied nations is emphasized and their organization and methods briefly described, with running comment on comparative practice in the United States. Factory production methods in England are mentioned, as well as working conditions and welfare work there. Considerable information relating to post-war automobile designs and to motor-truck and tractor practice is given.

Naval aircraft are distinctively American types. Only one foreign seaplane was copied by the United States during the war, and when finally put into production it resembled the British prototype in externals only. While the Navy does a large part of its own designing and building through a corps of naval constructors, its theory of manufacture is to assemble parts procured from separate makers, and private design and construction are encouraged by contracting with builders. Available talent both in and out of the service and the facilities of parts makers, the new materials developed during the war and organized engineering which drove the entire process toward speedy results were appropriated by the Navy. The NC flying boat is typical of U. S. Navy practice. In the same way the dirigible C-5 is a purely American type. The development of really large flying craft before 1917 was held back because no suitable engine had been designed. When the 350-hp.

The author considers the adaptation of farming implements to the farm tractor the most important engineering problem confronting tractor manufacturers. The problems are intricate in their ramifications, all-inclusive in their scope and fundamental. They can never be solved by theoretical discussion and laboratory tests alone. Extensive field experiments are needed with the machines operated by the farmers themselves. It is the implement which does the work. The mold-board plow and the disk harrow are standard for soil preparation; the oscillating sickle, the reel and the knotter-head for harvesting; the revolving toothed cylinder and the oscillating rack for threshing. Power must be transmitted to these fundamental devices. The automotive tractor fills a place in the farm power field not successfully covered heretofore by any single prime mover.

In the past the majority of trucks have been equipped with wood wheels. These gave good service, but the results demanded under strenuous modern conditions seem, the author states, to make the substitution of steel wheels on medium and heavy-duty trucks imperative. Truck engineers and builders seem to recognize the fact, but to hesitate to make the change, chiefly because a metal wheel is somewhat higher in first cost and because some designs have not as yet rendered the service expected of them. The service return of metal wheels is given from the records and reports of the London General Omnibus Co. and the Fifth Avenue Coach Co., both of which use steel wheels exclusively. The added mileage is in excess of wood-wheel service and exceptional tire mileage is shown. The author states briefly the arguments for the hollow-spoke, hollow-rim, the hollow full-flaring spoke and the integral-hub metal wheels.

In a rapid and illuminating sketch of the early work done in electricity and magnetism the subtle and close connection between pure research and so-called industrial research is shown. Building on the work of Faraday, Maxwell and Hertz, Marconi, in our day, had the confidence to do the practical thing. From the Hertz oscillating system he passed to grounded antennas at both sending and receiving stations. From the well-understood tuning of electrical circuits and the coherer of Professor Branly he secured increased efficiency and selectivity. Mr. Edison, following the early work of J. J. Thomson at Cambridge University, England, devised the first practical application of the electron apparatus, the Edison relay. The vacuum tube became in the radio field an amplifier, an oscillator and a modulator, the audion. In addition to these interesting developments are the Poulsen arc, the Alexanderson alternator and other alternators of German design.

Iron rust is caused by electrolytic action between the various constituents of iron or steel in the presence of moisture and impurities. It is a continuous process; a coating of rust does not protect the metal underneath. The principal requirements of a rust-prevention process as applied to automobiles, aircraft and other machined and hardened parts are that it (1) Prevent rusting under normal use (2) Prevent the spreading of rust (3) Make no change in dimensions or fits (4) Make no alterations in physical properties (5) Be permanent for the life of the part (6) Be easy and quick of application (7) Be commercially practicable as to cost Of the most familiar rust-proofing processes, the cold, the hot and the high-temperature, the last is eliminated by requirements (3) and (4), while the cold processes and also japanning are eliminated by (2), (3) and (5). There remain three hot processes, the Parker, the Coslett and the Guerini.

The factors included in the commercial airplane problem are the practical use that can be made of airplanes, the volume of business that can be expected, the necessary changes from present military types to make an efficient commercial airplane and what the future holds for this new means of transportation. The requirements for passenger transportation, airmail and general express service, are first discussed in detail, consideration then being given to other possibilities such as aerial photography and map-making, the aerial transportation of mineral ores, sport and miscellaneous usage. Changes in the present equipment of engines and airplanes to make them suitable for commercial use are outlined, and special features of aerial navigation, landing fields and legal questions are mentioned.

Airships were not generally considered important before the war. Many thought they would never become practical as a means of transportation. The proper conception of what an airship is having first been explained, the three principal ways in which progress has been made are specified as weight-saving, improvement of overall propulsion efficiency and decreasing resistance and increase in size. The last mentioned feature is discussed in some detail, the conclusion being that practically anything is possible, given an airship of sufficient size. The future needs of airship development are then considered, such as more suitable engines, multiple powerplants, dependability, the development of better fabric and better landing and hangar facilities.

The necessity for a powerful heavy-duty truck with power transmitted through all four wheels was apparent shortly after the United States became involved in the war. An intensive study of the four-wheel-drive situation finally resulted in the design of the Ordnance four-wheel-drive truck and the modified form known as the artillery wheeled tractor. Seven factors influencing the preparation of the specifications are stated and discussed. The determination of proper gear ratios is analyzed. The considerations leading to the adoption of the universal-joint type of driving-shaft are mentioned and its application commented upon. Ten specific points of internal interchangeability of the mechanism are enumerated.

THE author presents a brief description of the design of some of the principal vehicles used in motorizing the artillery, as developed by the Ordnance Department. A few of the vehicles are described, including gun mounts that were being developed at the time of the signing of the armistice. The relative merits of the different types of equipment are discussed.

THE track-laying type of vehicle is, of course, old. The emergency which brought the modern “tank” into existence was the menace of the machine-gun. The tank is simply a device that can approach closely and destroy the gun or its crew. It is fundamentally a man killer, and its strongest points are speed and mobility. It is now an indispensable arm of the military service. The writer gives a rapid résumé of the fantastic period in design, the early work done on heavy armored cars and the reasons for concentrating on the track-laying type of vehicle. The American type of track was adopted as a foundation and from this and around it France, England and the United States have developed the tanks known through successful use in the war. The British are to be credited with producing the first practical fighting machine of this type. France has two types of machine, one mechanically driven and the other with electric drive, both small.