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Technical Paper

A Method of Measuring the Cushioning Quality of Tires

1927-01-01
270021
TIRES of high shock-absorbing capacity greatly reduce the blows delivered to roadways by heavy vehicles and the reactions on the vehicles; they also absorb most effectively the shocks in a vertical direction that are the cause of the greatest discomfort to passengers. With a view to making a laboratory study of these shock-absorbing properties of tires, an instrument called a bounce-recorder has been devised and is described. This instrument records the paths followed by tires in passing over obstacles placed in their way. From these records, the vertical acceleration of a tire at any point of its flight can be determined, the purpose of doing so being twofold, namely, to develop an accurate and fairly rapid means of ascertaining the relative shock-absorbing capacities of tires by the acceleration method and to find out whether load-deflection tests made on the Olsen testing-machine could be used for the same purpose.
Technical Paper

The Torque-Equalized Brake

1927-01-01
270020
BRAKE action extends from the foot-pedal through various connections and devices to the point of contact of the braked wheel on the ground but, although brake-development work has been extensive for that portion of the brake mechanism which extends from the foot-pedal up to the point of application of brake pressure, the author says that beyond this point practically no improvement has been made. He says further that a study of brakes and the retarding forces they exert on the road surface reveals the primary cause of brake troubles, and then analyzes the design of an efficient braking-system for automobiles, first outlining the ideally perfect mechanism without regard to mechanical limitations.
Technical Paper

The Constantinesco Torque-Converter

1927-01-01
270019
THE purpose of the mechanism described is to produce an instant and automatically variable torque that is always equal to the resistance encountered while the primary driving engine maintains its speed and torque nearly constant. The principle of operation is illustrated by reference to the action of a stick weighted with a ball at one end and suspended freely by a string at the other so that it can swing as a pendulum. Interference with the swing of the pendulum at any point on the stick results in a transference of part of the inertia force of the ball to other parts of the stick and also alters the amplitude and rate of vibration of all parts. At the same time, pressure is set up at the point of interference. The pressure varies in magnitude with the inertia and is proportional to the change of speed in a unit of time.
Technical Paper

The Electrodeposition of Rubber

1927-01-01
270025
AFTER giving a brief description of the nature of rubber latex and a review of investigations made in Europe of its physico-chemical properties, the author tells of experiments made in Rochester to develop a method for the electrodeposition of rubber particles. These proved that the process was possible but the problem of producing a coating containing all the ingredients requisite in a compound suitable for vulcanizing remained to be solved. The nature of the rubber particles and of rubber after coagulation of the particles is described and the method of rubber-plating as developed is explained. It is stated that the deposit can be built up almost indefinitely and at a very rapid rate; that the composition remains substantially unchanged during coating, and that the current efficiency is remarkably high.
Technical Paper

A Four-Speed Internal-Underdrive Transmission

1927-01-01
270018
ALTHOUGH the enormous demand for automobiles has been met with continual improvement in performance, economy, comfort, and appearance of the vehicle, the development of the transmission has lagged badly for more than a decade. Car-ability has been handicapped by the limitations of the three-ratio gearbox. Notwithstanding that the added car-flexibility, economy and smoothness that result from increasing the number of ratios between the engine and the axle have long been appreciated by engineers, the short-comings of conventional four-speed transmissions, friction drives and two-speed rear-axles having double ring-gears and pinions are many, and the first cost and lack of over-all efficiency of the gasoline-electric drive have prevented their greater use in passenger-car and truck service.
Technical Paper

Cast Iron in Its Relation to the Automotive Industry

1927-01-01
270024
CAST iron is purchased on a basis of price instead of quality, according to the author, who says that this has depreciated the qualities of the material generally and caused engineers to look askance at its application. Combined with such factors is the influence of misinformation about cast iron that has been widely broadcast. Questions regarding the design of patterns and cheaper raw-materials have involved the foundrymen in controversial discussion concerning the influence of various elements to the detriment of the economic condition of the iron industry as well as that of the consumer of castings. Due to the lessening of the consumption of cast iron, the foundry world has inaugurated research to better the quality of cast iron, not only through investigations of raw materials but also by improvement in melting practice.
Technical Paper

Why Does a Car “Pivot”?

1927-01-01
270022
REMARKING the difficulty of explaining logically the strange phenomenon known as the “pivoting” of a car, the author, after presenting citations of actual experiences with various combinations of front-wheel and rear-wheel braking and their tendencies to cause a car to pivot, analyzes pivoting and explains its causes under (a) “dry-roadway” and (b) “skiddy-roadway” conditions. Concerning (a), the author states that when two-thirds of the braking force of a four-wheel-brake system is distributed to the rear wheels, the preponderance of the stopping or braking force will remain active to the rear of the center of gravity of the car, causing a so-called “drag-anchor” effect to counterbalance what is termed the “spin effect,” and no dry-roadway pivot can occur. Since the friction available between the roadway and the tires is comparatively small on a skiddy roadway, the retarding forces at the two sets of wheels should be utilized to their utmost.
Technical Paper

Tires as a Cause of Shimmy

1927-01-01
270023
THE author enumerates and describes various inter-related movements of the front end of the car that are commonly known as automobile shimmy. A long list is given of experiments made in an attempt to correct the trouble. These did not produce consistent results but showed that caster angle acts as a considerable influence, while the influence of camber and toe-in seems to be more on tire wear than on shimmy. Lubrication of springs and conditions affecting the free motion of the steering pivots have some influence but the author sees imperfections in the tires as fundamental causes. The nature of the road is also important, particularly of concrete roads having regularly spaced depressions at joints. Some of the tire imperfections are described and blame is placed on the tire makers for being less thorough in their methods of testing and inspection than are car manufacturers.
Technical Paper

The English Light-Car and Why

1927-01-01
270013
ECONOMIC and other conditions that favored and practically forced the development of the light car in England, and the history of that development, are dealt with at length by the author. He recalls the light cars of the pioneer days of the automobile and then the putting on of weight about 1898 to increase reliability and riding comfort. He comments on the reaction that resulted in the advent of the cyclecar in 1911 and its quick demise because of its failure to perform satisfactorily. The keen interest of the public, however, indicated that a big business could be done in a light, efficient, cheap motor-car if it could be produced in a practical form. Genuinely light cars minus the crudities of the cyclecar began making their appearance and quickly “caught on,” due to the tax on gasoline, low selling prices, and automobile-club competitions giving the public confidence in these vehicles.
Technical Paper

Production of Gasoline Substitutes from Coal

1927-01-01
270010
NO danger exists of the imminent exhaustion of the petroleum reserves of the United States, as is shown by a committee report published early in 1926 by the American Petroleum Institute, from which figures are given in the following paper. It is reasonable to assume that a sufficient supply of oil will be available for all purposes beyond the time when the demand therefor will be reduced by more efficient use of petroleum products or by the production of substitutes for them. The possibility of a future shortage of petroleum fuel suitable for automotive engines, however, and of the production of substitutes to avoid such a contingency, is receiving considerable attention in America and Europe. The author presents a general review of the situation and the status of research in the manufacture of gasoline substitutes from coal, of which enormous quantities remain unmined in this Country.
Technical Paper

Possibilities of the Counterbalanced Connecting-Rod

1927-01-01
270017
IN considering the possibilities of the counterbalanced connecting-rod, the author points out that (a) every automobile engine is dynamically unbalanced; (b) inertia unbalance of two, four and eight-cylinder engines can be eliminated by counterbalancing the connecting-rods; (c) such engines so balanced have a better balance than the conventional six-cylinder engine; (d) the design of counterbalanced connecting-rods is practicable and adds little to the cost of the engine; and (e) if a counterbalanced connecting-rod is used, the single-cylinder engine can be as well balanced as the conventional six-cylinder engine by using the geared-balancer that is described. The fundamentals relating to the foregoing statements are analyzed mathematically. The geared-balancer proposed by the author consists of a pair of small shafts geared to run at crankshaft speed in opposite directions, each shaft carrying a pair of weights that produce a rotating centrifugal-couple.
Technical Paper

Chains for Front-End Drives

1927-01-01
270016
TOOTHED and friction-gearing are said by the author to be the two distinct classes of power transmission between two shafts, and the silent chain he describes is in the toothed-gearing class according to his statement, since it has a fixed speed-ratio and causes a bearing pressure that varies almost directly with the power transmitted. It is argued that, because of its elasticity and the peculiar method of contact with the teeth of the sprocket, the silent chain constitutes a medium that absorbs shocks and variations in angular velocity, and has a bearing action similar to that of a belt. The improved silent chain is made of stamped, arch-shaped link-plates assembled in alternate succession and joined by pins that act as bearings. The spacing of the pins forms the “pitch” of the chain. When assembled, the chain can be considered a flexible gear or rack.
Technical Paper

Timing-Gear Development

1927-01-01
270015
AFTER outlining the present status of the forms of drive for timing-gear trains, the author describes modifications of gear design made by the company he represents to overcome noise that involve lengthening gear-teeth for a given pitch. Various modifications in this regard were made and one having 16-pitch teeth with 12-pitch length had 10,000 miles of use in fourth speed without developing excessive wear. A further development resulting from experiments was the use of case-hardened timing-gears for motorcoach engines, such usage being thought to provide the most extreme conditions. Characteristics of so-called anti-stub gears are stated and predictions are made as to the future of timing-gear practice.
Technical Paper

Development of the Silent Timing-Gear

1927-01-01
270014
ACCORDING to the author, gear clatter and clash caused by metal-to-metal contact develops into an annoying whir or howl at high gear-speeds, and a material was sought that is flexible and resilient enough to absorb the vibrations or change their frequency to a pitch inaudible to the average human ear. Since vibrations in the crank, the cam and the generator shafts are transmitted to the timing-gears, which run at high speeds, a material was needed that would silence the consequent noise and provide a noiseless timing-gear train. A great variety of materials was investigated and the development of laminated, phenolic, condensation products resulted; these have proved mainly suitable for timing-gear-blank stock and stock for other gears such as those suitable for crankshafts and generator shafts. A further development was that of the flexible-web cam-gear made of the composition material.
Technical Paper

Service Aviation, Aeronautical Engineering and Commercial Aviation

1927-01-01
270068
INFLUENCE that the research and development work done in aeronautics by the naval and military services has had in the advancement of design and construction of airplanes and aircraft engines suitable for commercial operations is pointed out and exemplified by citing a few instances of direct adaptability of military types of airplane to commercial uses. Nearly all of this work would have been done much later or not at all if the airplane had been purely a commercial vehicle, but the constructor for purely commercial purposes and the commercial operator have had the benefit of it. Major fundamentals, such as speed, safety, reliability and economy, are the same in both types of aviation; divergencies between the requirements for the two kinds of service begin to appear in materiel, personnel, or methods of operation only at a somewhat advanced stage of evolution.
Technical Paper

Problems in Transport-Airplane Design

1927-01-01
270069
MAJOR problems that have been encountered in the operation under contract of that portion of the Transcontinental Air Mail line between Chicago and San Francisco are outlined and discussed briefly. The more serious difficulties cited are: first, the operation of a single type of airplane from points at altitudes as great as 6400 ft. as well as at sea level, together with the fact that, in the case of this particular line, the heaviest loads are carried between the points of greatest altitude; second, the proper design of cowling and manifolding for the operation of the air-cooled radial engine at the extremes of temperature that are encountered throughout the year; and, third, the need for an engine that is geared down to the propeller or an engine delivering its normal power at a lower engine-speed.
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