Search Results

The paper represents a study of analyses obtained from 656 samples of contaminated crankcase-oil and states the results of cooperative research, the sponsors being the Society, the American Petroleum Institute, the National Automobile Chamber of Commerce, and the Bureau of Standards. Reliable information was sought regarding existent conditions throughout the Country and, since analyses of a large number of samples were a requisite, arrangements were made with service stations located at points representative of the Country's atmospheric and geographical conditions for the collection of samples of contaminated crankcase-oil, a uniform procedure calculated to assure accuracy of the results being enjoined. Each participating service station was requested to select 10 cars, all of the same make, to drain the oil and to refill with new oil.

After quoting statistics that show the alarming increase in thefts of automobiles and analyzing numerous conditions under which automobiles are stolen, the authors discuss locks as theft retardants, saying that the providing and the improvement of locks has always been man's method of seeking security from thieves and comes in naturally for first consideration as the normal course to pursue in working toward adequate theft prevention. The present identification systems in use are mentioned, together with their features of advantage and disadvantage, and numerous practices that owners and drivers can adopt which tend to minimize theft are cited. The early forms of locking device are outlined and statistics are included which show the percentage of cars actually locked when they are equipped with a locking device.

Substitution of scientific data obtained by experiment for the mere opinions long since prevailing about the respective values of arguments pro and con in regard to the interleaf friction of springs, the effectiveness of many leaves versus few leaves, the lubrication of springs and kindred subjects, was the objective of the author and the results he has secured since the start of the experimental work early in 1924 are set forth. Tests were conducted with springs having leaves varying in number from 1 to 14 and, in all cases, both when dry and when copiously lubricated with thin oil. All the variable factors were included during the progress of the experiments, the number of combinations possible being indicated by the fact that about 250 tests were made and more than 50 different springs were used.

Subsequent to a brief review of the development of the worm-gear drive for motor-trucks and the gear-ratios considered most desirable, the author discusses comparatively the worm-gear and the spiral-bevel gear with regard to their application for specific service, as well as with regard to their cost and length of life. It is brought out that the worm-gear is, after all, very similar in action to any sliding, or journal, bearing. A certain amount of involute rolling-action takes place in the action of the gearing, the magnitude of which increases with the gear-ratio; but the primary action is one of sliding of the worm-threads across the gear-teeth. Simple as this fact is, the prejudice fostered by many people against worm-gears can be traced to lack of appreciation of it. Due to the nature of the surfaces in contact, the best obtainable bearing takes the form of a narrow strip running across the gear-tooth, and the bearing pressures obtained are high.

After a brief historical review of the development of worm-gears, the author deals with worms and worm-wheels in detail, presenting the subjects of proper choice of materials, tooth-shapes, worm-gear efficiency, the stresses imposed on worm-gearing and worm-gear axles. Usually, he says, the worm is made of case-hardened steel of S.A.E. No. 1020 grade; however, when the worm-diameter is smaller and the stresses are greater, nickel-steels such as S.A.E. Nos. 2315 and 2320 grades are utilized. The worm should be properly heat-treated and carbonized to produce a glass-hard surface. Grinding of the worm-thread is necessary to remove distortions. Bronze is the only material of which the author knows that will enable the worm-wheel to withstand the high stresses imposed by motor-vehicle axles, and three typical bronze alloys are in common use.

Use of the universal-joint for transmitting power mechanically through an angle has been traced back to about 300 years before Cardan's period and about 400 years before a patent on a universal-joint was granted to Robert Hooke in 1664. The first reference to use of this type of joint is found in a manuscript by Wilars de Honecort, a thirteenth-century architect. A peculiarity of the universal-joint is that, as the two shafts which it unites are rotated when at an angle to each other, it imparts to the driven shaft a non-uniform rotational velocity which becomes very erratic as the angle between the shafts approaches 90 deg. This action has been analyzed by many writers by different methods, two such analyses being cited by the author of the present paper.

The experiences of the author in flying over an air-mail route are graphically portrayed. Although general practices hold for all routes, each route is said to present its own problems; special methods used in flying between any two points are not entirely effective in flying between any other two points. Conditions along the New York City-Cleveland route are therefore described and such topics as lights and beacons, terminal fields, emergency landing-fields, and the various aids in locating the position of the airplane when the beacons are obscured, are discussed. Among these aids are the general appearance of cities and the direction of their main streets, large factories, blast-furnaces, amusement parks, lighted railroad trains, automobile headlights on main highways, railroad roundhouses, mountains, and rivers. In nightflying, much depends on the airplane, which must meet definite requirements.

The equisignal method of airplane signaling consists in receiving signals, sent out by one or more transmitting stations, alternately on two loops the planes of which differ by a certain angle. If the signals obtained on the two loops are equal in intensity, the bisector of the angle between the loops will correspond to the line of sight or of wave propagation. In the development of the apparatus described in this paper, the fundamental idea made use of was that of the old Telefunken compass, which was later used to a considerable extent by the German Navy during the war as an aid to the flight of Zeppelins in their raids on England, and in which the transmitting system consisted of a number of similar directional antennae that could be thrown into the circuit in succession and had directional effects differing in orientation by 10-deg. steps.

The marked advance that has been made in the last 10 years in constructional details and in performance of airplane engines and in airplane performance is reviewed, beginning with the year 1916 when the Curtiss OX-5 eight-cylinder water-cooled engine was brought to its final stage of development. The author describes briefly each type of engine produced successively by the company he represents and tells of the changes that were made to improve the performance. From the 8-cylinder V-type the constructors changed to the 6 and 12-cylinder water-cooled type and are now developing a 9-cylinder air-cooled radial engine that was built in 1925. An important field of usefulness is foreseen for the air-cooled engine.

An instrument that utilizes the principles of radio amplification for inspection purposes is described and the experience that led to its development is recounted. It measures the finish polish on metal pieces by light from a microscopic lamp reflected from the surface upon a photoelectric cell, or amplifying bulb, that responds instantaneously to minute variations of light intensity and is connected in a suitable amplifying circuit to a milliammeter. The elements comprising the instrument are enumerated and the circuit diagram used is explained. As the instrument provides a method primarily of comparison, a standard value of the light reflected from a surface of the desired finish is established and the finish of parts to be compared is read from deflections of the milliammeter needle above or below this standard. The purpose of the instrument is to supplant by an accurate mechanical means the uncertain judgment of an inspector who relies upon the physical sense of vision.

Stating that the production of satisfactory gears is one of the most serious problems confronting the automobile builder, the authors give an outline of the practice of producing gears that is used by the company they represent and describe a new method for cutting the rear-axle drive-pinion by using two machines, each machine cutting one side of the teeth. Explanations are given of the various steps in the process and the reasons for stating that this method is not only cheaper but produces gears of higher quality. Numerous suggestions are made for improving gears and axles, and the claim is made that it is doubtful if the spiral-bevel gear has had a fair chance because axles usually have not been designed so that the main consideration was the requirements of the gears.

The effectiveness and the advantages and disadvantages of various substances and compounds that are used or offered in the market for use in the radiators of automotive vehicles as anti-freeze materials are discussed. These include alcohols, glycerine, salts, oils, sugars, and glycols. Properties affecting the suitability of a material or compound, or solutions of them with water to afford protection against freezing at atmospheric temperatures that are likely to be encountered are their heat capacity, freezing-point, boiling-point, specific gravity, viscosity, volatility, solubility, tendency to decompose at the boiling-point, inflammability, corrosive action upon metals, tendency to attack rubber, general availability, and price. The freezing-points of solutions of different materials vary widely at the same concentrations, or proportions to water, and also with variation of their concentration.

The complementary-color headlighting system is based upon the use of differentiated light, that is, light having different wave-lengths. Each head-lamp is oval and contains two paraboloid reflectors, one emitting light through an orange glass filter, the other through one of blue glass. While driving at night, the driver looks through a viewing-filter of transparent glass of the same color as that of the headlight which is in use. The viewing-filters are arranged so that whenever one is used, the headlight of the same color is automatically turned on. When the headlights are not in use, the filters are held in the filter-box and are out of sight. It is the intention that cars traveling in a general direction, say north and east, shall use the blue light; that those traveling south and west shall use the orange light. Each viewing-filter is transparent to the light that is thrown on the road by the headlights of the same car but is opaque to the lights of approaching cars.

Laboratory test-methods of indicating the volatility characteristics and the starting capability of fuels used in internal-combustion engines are described, together with the testing apparatus and procedure, the objective having been the development of a simple method or methods of measuring the volatility of individual samples of motor fuel. The requirements are that the methods be practicable from the standpoint of routine laboratory, give directly the necessary information regarding characteristics of the fuel and be sufficiently precise to permit their use as specification tests. Defining “volatility” as the property of a substance which causes it to be dispersed readily into the air, the author states that volatility as regards fuels is understood to indicate the quantity of fuel that will evaporate into air under definite conditions, so as to be enabled to speak of volatility as a definite quantitative property, and discusses both operating and starting volatility.

No scope available.

No scope available.

Body construction, of a character such that the wooden framework is secured by suitably shaped steel joining-plates and bolts that separate the wooden members ⅛ in. at the joints, is illustrated and described. The outer surface of the body is completely covered with flexible textile fabric or leather-cloth. It is claimed that the effect is to impart to the finished body an easy deformability and to permit it to accommodate itself to distortions of the chassis frame, to which it is rigidly attached. A portion of the English patent specification is quoted, and details of the actual construction practised at the inventor's factory in Paris, Prance, are stated. Due to the absence of steel and to the extreme slenderness of the wooden parts, these bodies are very light. The required wood-working operations are few and simple. Only the minimum machine equipment is needed to fabricate the framework, and no great skill is demanded in its erection.

All-steel automobile bodies are lighter, stronger, roomier, and cheaper than composite bodies having wood framing and metal panels. They are free from squeaks, afford better vision of the road and scenery, take a superior finish with less preliminary work, and permit marked economies in quantity production. Steel has 40 times the strength to resist breakage that wood has and, in bending, may be stressed 7 times as much as wood, hence the cross-sectional area of steel members may be only a small fraction of that of wood members having equal strength. This makes for lightness of construction and reduction of the size of frame members, thereby affording more space in the interior of the body for the passengers and reducing the amount of obstruction to vision.

In determining the characteristics of coiled wire springs, if all the component forces, including those .of torsion, transverse shear, tension, and compression, are considered, the calculation may be complicated and involved, but for practical purposes of design all can be ignored except torsion. The calculation then becomes simple. The underlying principles of the formulas that express the torsional characteristics of an ordinary helical spring are the same as those that govern torsion in a straight shaft; and the fact that the result would be the same if the shaft or wire were twisted in the opposite direction makes it clear why a coiled spring has the same stiffness in either compression or extension so long as all the coils remain open. In Begtrup's formula, as given in the handbooks, the only unknown factor is the modulus G, which is variously stated to be from 10,000,000 to 14,000,000 lb.