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Technical Paper

AUTOMOTIVE APPLICATIONS OF MARINE ENGINES IN THE WAR

1919-01-01
190004
THE application of the marine internal-combustion engine to the British ML class of 80-footers and to the American 110-ft. class of submarine chasers, undoubtedly constituted the most important development along this line of automotive work. With a hull form similar to that of an enlarged runabout, driven by a pair of six-cylinder Standard marine engines rated at 220 b.-hp. at 460 r.p.m., the boats of the ML class averaged about 20 knots. A total of 720 boats of this type were built and the class as a whole proved very satisfactory. In the development of the 110-ft. SC class, the requirement of seaworthiness was made of greater importance than speed. Each boat carried three six-cylinder Standard engines identical with those used in the British boats, driving them at about 17 knots. Although rather uncomfortable, as in the case of any small vessel, the 110-ft. boats proved wonderfully successful in heavy weather; about 450 of this class were built. The 220-b.
Technical Paper

THE STORY OF THE UNITED STATES STANDARD TRUCK

1919-01-01
190009
THE United States was practically unprepared in the field of military motor-transport at the beginning of the war. Due largely to the cooperation of the Society of Automotive Engineers and its members individually, this handicap was overcome and a position stronger in this respect than that of any of the other belligerents was attained. The early efforts and the cooperation between the Society and the various Government departments are described, especially with reference to the Quartermaster Corps which at that time had charge of all motor transportation. Regarding the Class B truck, it is shown that the Society acted as a point of contact between the various members of the industry and the War Department and, although not fostering any program or plan of its own, it was largely responsible for the success of the standardization program conceived and carried out by the Army.
Technical Paper

A COMPARISON OF AIRPLANE AND AUTOMOBILE ENGINES

1919-01-01
190006
ANY aggregation of parts assembled to obtain a mechanical result is a series of compromises. The relative importance of the objectives governs the nature of the compromise. The major objectives to be considered in the design of airplane engines are (1) Reliability (2) Small weight per horsepower (3) Economy of fuel and oil consumption (4) Carburetion that permits of easy starting; maximum power through a range of 30 per cent of the speed range; and idling at one-quarter maximum speed without danger of stalling (5) Ability to deliver full power through a small speed range without excessive vibration (6) Complete local cylinder-cooling under conditions of high mean effective pressure (7) Compactness The automobile engine must have (1) Reliability (2) Silence (3) Carburetion that accomplishes proper and even firing in all cylinders under varying throttle conditions, through speeds covering more than 90 per cent of the speed range of the engine.
Technical Paper

HIGH-SPEED HIGH-EFFICIENCY ENGINES

1919-01-01
190008
ENGINEERS have different ideas regarding highly efficient and moderately efficient engines, but designers dare not ignore the fact that the public requires today a small very high-speed engine, with good torque at low speeds, and capable of revolving efficiently at very high speeds. These two characteristics are difficult to attain, since in practice one is really opposed to the other. To obtain high speeds with power, the valve areas, valve parts, carbureter, etc., should not be restricted in any way, while to get a good mixture at low speed with heavy torque means a different valve-setting and more or less restricted port and valve areas, etc., to secure high gas velocities. The author states that the fundamentals of high-speed engines are high volumetric efficiency; high compression, to aid in obtaining rapid combustion at high speeds, and light reciprocating and rotating parts, to secure high mechanical efficiency.
Technical Paper

PROBABLE EFFECT ON AUTOMOBILE DESIGN OF EXPERIENCE WITH WAR AIRPLANES

1919-01-01
190007
THE impression that recent aircraft experience should have taught engineers how to revolutionize automobile construction and performance, is not warranted by the facts involved. Aircraft and automobiles both embody powerplants, transmission mechanisms, running gear, bodies and controls, but their functions are entirely different. The controls of an airplane, except in work on the ground, act upon a gas, whereas with an automobile the resistant medium is a relatively solid surface. Similarly, the prime function of the fuselage is strength, weight considerations resulting in paying scant attention to comfort and convenience, which are the first requirements of an automobile body. Aircraft running-gear is designed for landing on special fields, and is not in use the major portion of the time. The running-gear is the backbone of an automobile, in use continuously for support, propulsion and steering; hence its utterly different design.
Technical Paper

HEAT-FLOW THROUGH CYLINDER WALLS

1918-01-01
180008
Modern requirements have already forced the rotative speed of high-duty gas and oil engines to a point where the difficulty of heat-flow control, especially with cast iron cylinders, tends to arrest further progress in this direction. In view of this inherent limitation the art of high-speed engine design can best be advanced, not by continued experimental exploration, but rather by first establishing the basic principles underlying heat-flow effects. The purpose of the present paper is to demonstrate that every internal-combustion engine of given size and type has a safe speed limit and that this can be predetermined upon a rational heat-flow basis. This paper provides an explicit method of procedure, by means of which the design characteristics of a normal gas or oil engine can be critically analyzed for heat-flow effects.
Technical Paper

SOME PROBLEMS IN AIRPLANE CONSTRUCTION

1917-01-01
170001
The authors advance for discussion some important problems in the construction of airplanes for military use in this country. The functions of military airplanes designed for strategical and tactical reconnaissance, control of artillery fire and for pursuit are outlined. Problems in construction with reference to the two-propeller system, methods of reducing vibration, application of starting motors, details of the gasoline supply-system, metal construction for airplanes, flexible piping, desirable characteristics of mufflers, shock absorbers, landing gear, fire safety-devices, control of cooling-water temperature, variable camber wings, variable pitch propellers and propeller stresses, are all given consideration. The paper is concluded with suggestions for improvement in design relating to the use of bearing shims, the rigidity of crankcase castings, interchangeability of parts and better detail construction in the oiling, ignition, fuel supply and cooling systems.
Technical Paper

BURNING KEROSENE IN TRACTOR ENGINES

1917-01-01
170031
The author states as his object a review of what has been done and what must be done to make tractors successful in operating on low-grade fuels, especially kerosene. He takes up in order the four principal methods in common use of applying heat to vaporize kerosene, pointing out the advantages and disadvantages of each method and of its modifications. The author then cites various experiments with different types of carbureters in burning kerosene, drawing at length upon his own experience in this connection. He cites difficulties with gas distribution, manifold condensation, pistons and spark-plugs and points out that carbureter design is inseparable from considerations of tractor engine and manifold design. That better progress has not been made in the past in developing kerosene-burning tractor engines is stated to be largely owing to the fact that there has not been sufficient cooperation between engine and carbureter manufacturers.
Technical Paper

LESSONS OF THE WAR IN TRUCK DESIGN

1917-01-01
170027
The title of this paper fully indicates its scope. The author presents an intimate picture of conditions prevailing at the war front which affect the operation and maintenance of war trucks, and these two factors in turn indicate the trend that design should take. The training of the mechanical transport personnel of the Army is also gone into at some length. The English and American trucks used earlier in the war consisted of about nineteen different makes and forty-two totally different models, resulting in a very serious problem of providing spare parts and maintenance in general. In the British Army transportation comes under an Army Service Corps officer called the Director of Transport and Supplies. At the outbreak of the war these officers had had little mechanical experience, horses being employed principally. In the French Army motor vehicles were used to a greater extent before the war, under the artillery command.
Technical Paper

THE FARM TRACTOR AS RELATED TO THE FOOD PROBLEM

1917-01-01
170028
The author first points out how increasing population and rising standards of living have increased the demand for foodstuffs and how such industrial activities as are brought about by the present conflict magnify the seriousness of the food problem, not only by withdrawing workers from the farms, but also by increasing food consumption on the part of those engaged in the speeded-up industries in order to supply the increased human energy required. The author then passes to a discussion of the tractor as a means for increasing the food supply by taking the place of withdrawn labor and cheapening production. Several charts show the effect of increased individual activity on food consumption, the relation of food consumption to standards of living and the growth of population, the variation of food demand during political activities during the past century, and the relation of the cost per calorie of various cereals.
Technical Paper

BUILDING SUBMARINE CHASERS BY STANDARDIZED METHODS

1917-01-01
170030
The author outlines the history of the 550 submarine chasers built for the British Government between April, 1915, and November, 1916, and attributes the success of the undertaking largely to scientific standardization. He cites some of the early difficulties in obtaining supplies and tells how they were met, and mentions how and why the fabrication was carried out in this country and the assembly made in Canada. The paper concludes with citation of the principal dimensions of the boats, power, speed and cruising radius. In the course of the discussion the author refers further to the power plant and mentions some of the war-time duties of this type of craft.
Technical Paper

DESIGN AND PRODUCTION OF AIRCRAFT IN TIME OF WAR

1917-01-01
170026
Starting with the statement that command of the air in warfare rests largely with the side that produces the best single-seater fighter, the author proceeds to outline some of the problems confronting the designer of fighting airplanes, and particularly the smaller ones. Considering better performance and better fighting qualities as the main desiderata, the author discusses means of obtaining them by: (1) increasing the horsepower-weight ratio; (2) decreasing the wing or structure resistances; (3) devising a new arrangement of the supporting planes, with regard to the position of pilot or crew, or by a combination of the above. Considerable space is devoted to methods of decreasing wing resistance, principally by employing low-resistance aerofoils, and the shaping of wing tips is also referred to.
Technical Paper

SOME ESSENTIAL FEATURES OF HIGH SPEED ENGINES

1917-01-01
170004
The author outlines methods for producing high-speed engines with high mean effective pressure and gives data resulting from several years' experimental work. He discusses the desirable stroke-bore ratios; valve area, weight, dimensions, location and timing; compression ratios; ignition requirements; and the location and means for operating camshafts and other valve-actuating mechanism. Data are given regarding the best material and dimensions for pistons and the desirable number of rings. The physical characteristics of alloy steel desirable for use in connecting-rods are mentioned. Similar data, including dimensions and factors controlling the construction of the crankshaft and its bearings are included. The relation of the inertia stresses set up by reciprocating parts to those due to the explosion and compression pressure on the piston head is indicated, and the maximum total stress deduced.
Technical Paper

DYNAMIC BALANCING OF ROTATING PARTS

1917-01-01
170005
The author points out the necessity of obtaining dynamic or running balance of rotating parts, especially in automobile-engine construction. He discusses the manifestations of the lack of static and running balance, such as vibration and high bearing pressures. Formulas are supplied for calculating bending moments and centrifugal forces in a crankshaft that is out of balance. Methods for obtaining static balance are described and the possible conditions existing after static balance is obtained are treated, with especial reference to the existence of one or more couples. Descriptions are given of two representative machines that are used to locate couples and correct for them. The principles of operation are made clear and advantages and disadvantages of each type are brought out fully.
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