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Technical Paper

GASOLINE VOLATILITY

1926-01-01
260003
Measurement of the volatility of motor fuels by batch distillation is regarded by the author as unsatisfactory, because the carbureted fuel is vaporized in an internal-combustion engine by continuous distillation, hence there is great difficulty in correlating the temperatures of test with those of actual use. Whereas formerly gasoline was produced by batch distillation in the refinery, it is produced now by removing the gasoline from crude oil by continuous distillation or is produced by cracking and continuous fractionation. Therefore the temperatures of production also bear no rational relation to those of test by batch distillation. Similarly, in an engine, fresh gasoline is supplied continuously by the carbureter and is vaporized continuously in the manifold and cylinder, all of the constituents being present at any time in any cross-section of the manifold.
Technical Paper

HOW I FLY AT NIGHT

1926-01-01
260067
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.
Technical Paper

THE STATIONARY AND ROTATING EQUISIGNAL BEACON1

1926-01-01
260066
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.
Technical Paper

WASP AND HORNET RADIAL AIR-COOLED AERONAUTIC ENGINES

1926-01-01
260062
Decision that the fixed radial air-cooled type of aeronautic engine offers the most possibilities in light weight and maximum dependability was arrived at by the company with which the author is connected after a careful and comprehensive engineering analysis of many types of both water-cooled and air-cooled engine and therefore it undertook the development of this type. Because the Navy was desirous of obtaining a 400-hp. direct-drive engine and a 500-hp. engine to drive either direct or geared and because a commercial air-cooled engine to replace the Liberty-12 water-cooled engine was desirable owing to the increased pay-load it would make possible, it was decided to undertake first the development of a 400-hp. engine of this type. Work on the design was started Aug. 1, 1925, and the first engine was finished on Dec. 24, or approximately 5 months later. This engine was named the Wasp.
Technical Paper

PROGRESS IN AIRCRAFT-ENGINE DESIGN

1926-01-01
260063
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.
Technical Paper

A ROOTS-TYPE AIRCRAFT-ENGINE SUPERCHARGER

1926-01-01
260064
Development of the aircraft powerplant has been the greatest single contributing factor to the progress of aviation. A logical field for future development seems to be the improvement of its altitude performance, and the best of the several proposed methods for doing this. Consequently, the Sub-Committee on Powerplants for Aircraft of the National Advisory Committee for Aeronautics recommended that the Roots-type compressor be investigated, and a complete supercharger was built and sent to the Langley Field laboratory for test. The design, principles of operation and characteristics of the Roots-type compressor are described, and its slip-speed due to air leakage past the rotors, its pulsating discharge, type efficiency, and variation in torque are discussed. The Roots-type supercharger built for the National Advisory Committee for Aeronautics, as designed for use with the Liberty-12 engine, is described and illustrated.
Technical Paper

INSPECTION ALONG THE LINE

1926-01-01
260057
Although production has been increased greatly during the last decade by the use of special automatic machinery, conveyors and improved methods, plans for the application of wage incentives to indirect labor have not been widely adopted. Inasmuch as time-studies of some sort of wage-incentive system have served to keep the individual output of direct labor close to its assignment, the assumption is made that the labor of the indirect workers might also be so measured to a standard that the compensation would be governed by the quantity and the quality of the ultimate output. The advantages and functions of inspection are discussed and a method is suggested for establishing a quality-bonus incentive-plan based on the amount of rejected and scrap material per car and the number of inspectors employed per unit of production.
Technical Paper

AIR-COOLED ENGINES IN NAVAL AIRCRAFT

1926-01-01
260060
The purpose of the paper is to point out the basic policies which have resulted in the fostering of air-cooled-engine development by the Navy, and to indicate where the development has led. Two roles played by naval aviation are designated “air service” and “air force.” The former term refers to the functions of naval aircraft which are contributory to the ships of the fleets, such as scouting and the control of gun-fire. The latter term refers to the functions which involve the use of aircraft as an integral and component part of the Navy's striking force, such as combat, bombing and torpedo launching. Seven different types of aircraft are required by the Navy for its different purposes, these being airplanes for training, fighting, observation, scouting, torpedoing, bombing, and patrol use.
Technical Paper

INSTRUMENT FOR MEASURING SURFACE FINISH BY REFLECTED LIGHT

1926-01-01
260059
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.
Technical Paper

THE COST OF OPERATION AND ECONOMIC LIFE OF MOTOR TRUCKS

1926-01-01
260055
In order to flourish, business must operate at a profit. As the margin of profit is daily becoming smaller, costs must be analyzed so that economies can be effected. As a lack of uniformity exists in the methods of arriving at the cost of operation, a brief outline is given of the items that enter into the totals from which operating costs are calculated and also of what constitutes the economic life of a motor vehicle. Selection of the correct type and size of vehicle is of paramount importance; and standardization of the various makes will result in better operation, more efficient inspection, and more economical repair and upkeep. Having then determined the cost of operation of a vehicle, a decision must be made as to the basis on which its economic life can be computed.
Technical Paper

THE MOTOR-TRUCK TIRE IN ITS RELATIONS TO THE VEHICLE AND TO THE ROAD1

1926-01-01
260050
In motor-truck impact-reactions, the unsprung component is generally the major quantity and the force depends on four principal variables: tire equipment, load, speed and road roughness. The tire equipment that utilizes the greater time of duration for the reaction will cause the lower impact-forces. Increases in load, speed and road roughness increase the impact-reaction. Poor tire-equipment on rough roads may cause forces of 35 tons to be borne by both the truck and the road. Pneumatic tires rarely allow reactions greater than twice the static wheel-load. The impact reactions of a six-wheel truck approximate one-half those of an otherwise equivalent four-wheel truck having the same pay-load. Fifty per cent loss in the overall height of the tire multiplies the impact reaction by 2.5. Rolling resistance varies with the speed, the tire equipment and the road surface, and may reach a value of one-sixteenth the wheel-load.
Technical Paper

THE AUTOMOTIVE WORM-GEAR

1926-01-01
260042
Progress in the development of automotive worm-gearing is interestingly outlined. Previously tO 1912, American experience had been limited almost exclusively to the industrial form, generally of the single-thread type. Introduction of the motor truck required a worm for the final-drive but one having entirely different characteristics from that of the industrial gear. Experience in designing these was lacking, however, as was also the special machinery to produce them. In 1913, machinery was imported from England and since that time development has been rapid. First efforts were devoted to simplifying the design of the axle as a whole, studying the problem of getting lubricant to the bearings, heat-treating the parts, and improving the materials of construction.
Technical Paper

TECHNIQUE OF SOUND MEASUREMENTS

1926-01-01
260038
Research methods applied to the inspection of automotive parts for noise-producing causes are analyzed by the author, who notes the increasing tendency toward the use of sound-measuring instruments and discusses first the units of sound intensity and loudness. The dyne per square centimeter is a convenient size of unit for measuring the pressure amplitude of sound-waves, since 1 dyne per sq. cm. lies within the range of amplitudes at which the ear normally functions, being approximately that at one's ear when listening to conversation. In calibrating at high frequencies, the thermophone is used. It consists of a small strip of thin platinum or gold a few centimeters long and about 1 cm. wide through which an alternating current of desired frequency is sent.
Technical Paper

INFLUENCE OF TEMPERATURE, FUEL AND OIL ON CARBON DEPOSITION

1926-01-01
260031
High operating-temperature, the use of the more volatile fuels and a lean air-fuel mixture and the use of lubricating oils of relatively high volatility which contain little carbon-residue all tend to reduce the deposition of carbon in an internal-combustion engine, as indicated by the experimental study reported in this paper. Believing that heat, fuel and oil are the most important factors influencing carbon formation and deposition, the experimenters adopted the method controlling closely the other conditions of operation of a specially designed single-cylinder test-engine and varying the operating temperature and the fuel and oil, allowing the carbon deposit to build up in the normal way during the test periods of 15 and 36-hr. The test engine and control apparatus and the test procedure are described.
Technical Paper

AUDIBILITY ANTI-KNOCK TESTS AND KNOCK-INTENSITY EVALUATION

1926-01-01
260030
Valuable data pertaining to the anti-knock qualities of fuels, combustion-chamber shapes and the efficiency of gasoline dopes are believed to be obtainable by the method described. Several hundred tests have failed to show anything seriously wrong with the method; on the contrary, involved matters such as the relative effect of various anti-knock fuels, anti-knock dopes, altitude, compression, mixture-ratio, and cylinder actions, have become clearer. No apparent reason exists why the method is not applicable to the determination of the relative merits of combustion-chamber shapes, various spark-plug locations and other important considerations necessary to the realization of higher compression-pressure and its accompanying substantial fuel-saving. Further, the incidental information gained concerning engines of present-day compressions is of no small value.
Technical Paper

METALCLAD RIGID AIRSHIP DEVELOPMENT1

1926-01-01
260026
Several years ago some of the most prominent leaders in automotive industries cooperated to form a purely engineering group that had as its primary purpose developing a type of rigid-airship construction in which the public would have confidence. It was conceived that such an airship should be (1) Fireproof (2) Weatherproof (3) Durable and permanent in structure (4) Navigable in practically all kinds of weather (5) Economical in the use of buoyant gas and ballast To meet all of these requirements it was decided, after mature consideration, that a substantially all-metal construction was imperative.
Technical Paper

ECONOMIC SPHERES OF AIRPLANE AND AIRSHIP

1926-01-01
260025
Although the generally accepted spheres of usefulness of the airship and the airplane are usually based on their comparative ranges of operation and their speeds, the suitability of either of these types for a given purpose is primarily dependent on two classes of factors, those fundamentally dissimilar and those roughly similar. Conclusions as to relative usefulness should be based on a consideration of the dissimilar characteristics, which include aerodynamic efficiency, size and comfort. Aerodynamic efficiency governs range and, since it determines fuel consumption, influences the cost of operation. The size required depends on the paying loads that are available for carrying. Comfort concerns passenger-carrying only. As the propeller efficiency, rate of fuel consumption and ratio of weight of fuel carried to gross lift are similar in both types of aircraft, the range must depend on the L/D factor, that is, the ratio of gross lift to thrust.
Technical Paper

SOME FACTORS AFFECTING BRAKE-LINING FRICTION

1926-01-01
260021
Variation of the retarding forces on the brakes of automotive vehicles for a given pedal position or a given pedal pressure is frequently due to the ordinary wear of the brake-linings or other parts and may readily be prevented by periodic inspection and adjustment. Sometimes, however, sudden and serious reduction in retarding ability occurs when the brakes have been applied for comparatively long periods with short cooling-intervals or when the brakes have been wetted or oil has reached the linings. Laboratory tests of braking materials have shown that a marked increase in temperature will generally result in a reduction in the coefficient of friction of asbestos textile brake-lining materials and that oil and water have a similar effect of a temporary character.
Technical Paper

FUNDAMENTAL REASONS UNDERLYING SAFETY COACH DESIGN

1926-01-01
260018
The problem in building the first “safety coach” was to short-cut evolution-to bridge the gap between what the industry had and what it needed. It is the purpose in this paper to consider the broad fundamentals and underlying principles of the Fageol safety-coach which have formed the basis of subsequent modern motorcoach construction, giving particulars of detailed design only to point out and illustrate the methods of definitely meeting the known needs. It was noted that equipment for all types of transportation had undergone a definite evolution, beginning with vehicles designed primarily for some other type of service. The early railroad equipment was adapted from the horse-drawn stagecoach. The first automobiles were literally “horseless carriages.” The first motor-stages were adapted from the touring car or the truck. Either of the latter was good for the purpose it was designed to fulfill-both had great shortcomings in public motor passenger-service.
Technical Paper

GENERAL MOTORS AUTOMOTIVE PROVING GROUNDS

1926-01-01
260017
Layout, facilities and activities relating to making road-tests of motor vehicles at the 1125-acre proving grounds of the General Motors Corporation near Detroit, this tract being designed to provide a place where road conditions are suitable for obtaining data that can be interpreted accurately, compared with similar data and used constructively, are outlined and illustrated. Adequate facilities are provided and ideal road-conditions have been established so that motor-vehicle tests involving endurance, speed, acceleration, hill climbing, riding-quality and other comparative tests can be made. Conditions are such that tests can be repeated from day to day, thus compensating for the variations of the weather and other factors. Complete and conclusive tests can be carried out readily and promptly, and the results are free from guesses and personal opinions. The speed track is 20 ft. wide and nearly 4 miles long. Traffic is in one direction, clockwise.
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