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Viewing 19831 to 19860 of 19895
1920-01-01
Technical Paper
200050
C B DRAKE
In view of the inestimable services in the development of standardized transportation rendered to the Army by the Society of Automotive Engineers, particularly during the war, the author believes it important that the Society be acquainted with the intentions and policies of the War Department regarding the engineering development of motor transportation from the viewpoint of the problems and needs of the American Army. The fundamentals of the policies on motor transportation of February, 1919, as approved by the Chief of Staff, are stated and the subsequent changes discussed in some detail. Standardization of chassis as favored by the Army receives specific and lengthy consideration and the Government standardized trucks are commented upon. The standardization of body design and parts specifications are discussed in some detail. It is the policy of the Motor Transport Corps to maintain a thoroughly adequate and efficient engineering branch, which is now operative.
1920-01-01
Technical Paper
200042
V R GAGE
A large number of tests were made in the altitude laboratory of the Bureau of Standards, using aircraft engines. The complete analysis of these tests was conducted under the direction of the Powerplants Committee of the National Advisory Committee for Aeronautics. Many of the engines were of the same make, differing in compression ratio or dimensions. The testing program included determinations of the brake-horsepower at various speeds and altitudes, or air densities, and the friction power, or the power required to operate the engine with no fuel or ignition at various speeds and air densities, with normal operating conditions of oil, water and the like. Some tests included determination of the effect of change of mixture ratio and of air temperature, and of different oils. The difficulties caused by the necessity of using indirect methods to ascertain the effect of various factors are outlined. The test analyses and curves are presented.
1919-01-01
Technical Paper
190025
J B DAVIDSON
THE objects to be obtained in testing tractors are listed, but field testing only is dealt with. Regardless of the attempt of the Society of Automotive Engineers to standardize the practice of drawbar horsepower rating of tractors, the practice followed by the industry is anything but uniform. Drawbar horsepower actually developed in tests at the 1918 National Power-Farming Demonstration, varied from 50 to 200 per cent of the rating. The need of more than 25 per cent reserve, as provided by S. A. E. Standard Practice, is argued. Drawbar pull is suggested as an important part of the rating. Rating of tractors by the number of plows pulled will not be satisfactory, owing to wide variation in soil conditions. To make satisfactory tests an accurate dynamometer is required. The Hyatt and Iowa instruments are described. The importance of care in making tests is emphasized. In the discussion, the Gulley and Giddings recording dynamometers are described.
1919-01-01
Technical Paper
190027
LADISLAS D'ORCY
ON the basis that it is impossible to state the case for either the airship or the heavier-than-air machine without some comparison of the two, the author discusses relatively features, points of merit or superiority and the fields of usefulness thus far disclosed in the rapid development of the craft. Progress since 1914 is outlined, a brief history to date is included and the way prepared for consideration of the possibilities of long-distance flight. A comparison of the features given emphasizes strongly the point that the airplane is mainly a high-speed, short-distance carrier, while the large rigid airship is essentially a medium-speed long-distance carrier. Each type has a distinct sphere of activity; the airship in transcontinental, transoceanic traffic; the airplane in feeding the terminals of the airship with passengers and, possibly, certain kinds of freight.
1919-01-01
Technical Paper
190029
J C HUNSAKER
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.
1919-01-01
Technical Paper
190008
D MCCALL WHITE
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.
1919-01-01
Technical Paper
190018
H C RICHARDSON
1919-01-01
Technical Paper
190019
J H TOWERS
Abstract 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.
1919-01-01
Technical Paper
190003
EDWARD R HEWITT
1919-01-01
Technical Paper
190002
WILLIAM G WALL
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.
1919-01-01
Technical Paper
190059
E A WHITE
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.
1919-01-01
Technical Paper
190057
B F MILLER
The development of the Motor Transport Corps is outlined; the number of motor vehicles for one army at war strength and the number for the proposed peace-strength army with increased motorization are specified and the disposal of surplus motor vehicles is discussed. The problem of keeping uptodate the motor vehicles in service is stated and the cooperation of automotive engineers is requested. The vexatious unsolved problem of spare parts is stressed and solutions are suggested. The question of peace-time training and matters relating to the motor transport reserve are considered in some detail. The motor transport personnel required on a war basis and for a proposed peace army of 509,000 men is enumerated, as well as that of the motor transport reserve corps and the national guard required to bring the proposed peace-time army to war strength.
1919-01-01
Technical Paper
190042
F N G KRANICH
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.
1918-01-01
Technical Paper
180009
GEORGE T STRITE
1918-01-01
Technical Paper
180001
V E CLARK
1918-01-01
Technical Paper
180042
F W FENN
1918-01-01
Technical Paper
180047
D W Taylor
1917-01-01
Technical Paper
170006
N. W. AKIMOFF
The author believes that an incompatibility exists between the results achieved in this country by the growth of the automobile industry and the almost complete lack of rational data on the most essential elements of kinetics relating to the modern automobile. He submits considerations that can be used in establishing a rational theory of spring suspension in general. A few words are devoted to the first principles of dynamics of springs, to damping, kinematic features of harmonic motion, energy consumption and shock absorbers. An introductory problem, involving an imaginary one-wheel “elemental car”, meant for purely inductive purposes, is then analyzed. Finally the main problem is presented in the form of an analysis of a skeleton-car, spring-suspended and simplified as much as possible.
1917-01-01
Technical Paper
170001
V. E. CLARK, T. F. DODD, O. E. STRAHLMANN
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.
1917-01-01
Technical Paper
170025
Amaury De La Grange
The author describes in a general way the three classes of battleplanes-the fighting, the reconnaisance and the bombing machines-and outlines the service for which each type is best fitted. The tests of engines and airplanes, prior to acceptance for the French Army, are cited. Among the difficulties of construction, those relating to the plane itself are relatively less serious than those relating to the engine. The greatest difficulty is to secure a reliable engine weighing only about 2 lb. per hp. The qualities of rotary and fixed-type engines are compared. The paper is concluded with a few remarks about aviators and mechanics and the relation of one to the other. The author has reserved some of his most interesting observations for the discussion, in which he describes vividly some actual airplane attacks and refers to night flying and night landing, concluding with suggestions as to “what America must do.”
1917-01-01
Technical Paper
170028
H. L. HORNING
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.
1917-01-01
Technical Paper
170026
J. W. SEDDON
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.
1917-01-01
Technical Paper
170015
WALTER T. FISHLEIGH
1917-01-01
Technical Paper
170052
WALTER C. KEYS
After pointing out the existing dearth of easily workable data and formulas covering automobile suspensions, the author mentions the elements that contribute to riding comfort. He then outlines what he considers a good suspension, tabulating the spring dimensions of five hypothetical cars, typical of those on the American market. Curves of spring deflection are included in the paper. Functions of rear springs, the damping effect essential in good suspensions, “thin leaf” springs and spring lubrication are next discussed. In conclusion the author covers means of improving a car's riding qualities and cites a very interesting test for determining spring performance by means of the impressions made on a photographic plate by light from electric lamps mounted on wheels and fenders of an automobile and on the passengers.
1917-01-01
Technical Paper
170049
F. H. CRAVEN
After a few general introductory remarks the author outlines the operating requirements for tractors, and takes up the matter of the proper sizes of tractors, stated in horsepowers per given number of plows. The use of lower-grade fuels, value of water in the engine, cylinder construction, methods of lubrication and design of drive-wheels are the subjects covered by the balance of the paper.
1917-01-01
Technical Paper
170035
FRED P. STEELE
1917-01-01
Technical Paper
170032
DENT PARRETT
1917-01-01
Technical Paper
170033
H. C. Buffington
1917-01-01
Technical Paper
170039
ARNOLD P. YERKES
The author first considers the size of farm on which tractors can be used profitably. Confining his remarks to certain of the central and north central states, he points out the fact that there is a strong tendency for farms from 20 to 100 acres to be combined with others to make units of a more efficient size for the application of modern farming methods. Farms from 100 to 500 acres, representing 65 per cent of the total farm acreage, are the greatest users of tractors. Farms over 500 acres contain 25 per cent of the farm land, and also represent an important tractor market. Efficient sizes of tractors are next treated; three and four-plow sizes are generally preferred. Belt work, representing 50 per cent of a typical tractor's work, and other special duties performed by the tractor are next referred to.
1916-01-01
Technical Paper
160042
Frank E. Watts
The author confines his discussion to engines used on pleasure cars, inasmuch as practically all commercial vehicles use the four-cylinder type. The performance expected of their cars by automobile owners is outlined, particularly as regards performance, durability and maintenance cost. In-asmuch as the horsepower required is often determined by the acceleration demanded, the argument in favor of four-cylinder engines is based mainly on a comparison of its acceleration performance with those of engines having a larger number of cylinders. A number of acceleration curves are given for these engines. The paper next considers smoothness of operation at low, medium and high running speeds, asserting that the decrease in inertia forces due to lighter reciprocating parts has made it possible to increase the speed and thus reduce remarkably the vibration of the four-cylinder engine.
Viewing 19831 to 19860 of 19895