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Viewing 4621 to 4650 of 4671
1936-01-01
Technical Paper
360063
W. R. Shimer
1936-01-01
Technical Paper
360134
George J. Mercer
EVOLUTION of body engineering is recalled with the traditional practices of the profession and the difficulty of obtaining information and instruction. Relations and locations of side-sweep, turnunder sweep, and belt line are discussed; definite suggestions are made and design procedure outlined. How the first visual impression or “eye appeal” of a new design affects public acceptance is emphasized, and the special influence of this factor upon women is pointed out. Responses from three authorities in body design to a twelve-point questionnaire on debatable policies and principles give an indication of modern body-design trends and practice.
1936-01-01
Technical Paper
360138
Fred W. Herman
THE introduction to this paper includes definitions of the major items under discussion, and is followed by a discussion of the materials most widely used in metal-aircraft construction and their important physical properties. In the remainder of the paper are described some of the problems encountered in metal construction and the processes that have been developed to facilitate manufacture. The following specific items are discussed: (1) Design, (2) Tooling, including lofting, (3) Fabrication, (4) Assembly, (5) Inspection, and (6) Protective coating. Special equipment and tools are illustrated.
1934-01-01
Technical Paper
340107
C. V. Johnson
THIS paper points out that the shock-absorbing system of the main landing-gear of an airplane must function under the impact of landing and while taxiing on landing fields. The present requirements for impact landing are outlined, and a typical analysis is made to check up a proposed system for a given airplane. The effects of geometrical arrangement of gear, of tire size and of tire rebound are considered. Laboratory methods of testing systems to determine whether the requirements have been met are discussed. The characteristics desired of the shock-absorber system for good taxiing are enumerated, and the effects of various types and arrangements of absorber units on performance are investigated. In conclusion, the paper presents a discussion of the tail-wheel shock-absorber system in which it is brought out that the same criteria that are applied to the main gear apply here, but that the relative importance of various factors is not the same as in the main gear.
1934-01-01
Technical Paper
340095
R. N. Falge
THE prospects for substantially improved headlighting conditions in the future look very promising, Mr. Falge concludes. Assurance of safe headlighting conditions on our roads at night involves the full cooperation of those who build the lamps, those who specify how they shall be used, those who are responsible for their maintenance, and those who use them. The automotive industry, interested technical societies and state enforcement officials have done an excellent job in establishing the fundamental requirements underlying safe headlighting and in developing test specifications to cover them. More than three-quarters of the cars on the road are equipped with headlamps capable of complying with these requirements when properly maintained, adjusted, and used. The stage is all set for the final drive to permit and induce motorists to adjust and use their head-lamps in accordance with this practice. Legislation is needed to specify the multiple-beam practice in all states.
1933-01-01
Technical Paper
330006
Herbert Chase
“IN making these comments,” Mr. Chase says, “I am well aware that engineers are rarely given an opportunity to design a car incorporating even a large proportion of the improvements they would like to see included. “Unless some more or less ‘ideal’ types of construction are visualized, however, there may be no well-considered objective.” Visualizing these “more or less ideal types of construction,” Mr. Chase, in the following paper, throws a blanket indictment at the car designers, says what he thinks about current automobiles in no uncertain terms, and states specifically what he thinks ought to be done about it. Bodies, frames, springs, headlights, seats, engines-no unit of the modern car escapes Mr. Chase's stimulating criticism.
1932-01-01
Technical Paper
320041
Joseph W. Meadowcroft, James J. Paugh
ALL-STEEL welded bodies for passenger-cars have many advantages over composite bodies, among them being fewer parts, doors of only two pieces, no visible outside seams, lower tops for the same headroom, less roof weight, lower center of gravity, greater safety, increased visibility, permanent quiet, economical upkeep and perfect outside lines. Wood and steel react so differently to stress that neither adds much to the strength of the other in a composite structure. Steel alone, welded into a unit structure, is lighter and less bulky. The entire side of the body is stamped from a single sheet, with the openings die formed to reenforce it. Chassis frame and body follow the same lines, so that they reenforce each other and body sills can be omitted. This plan saves 2 in. in height, as compared with some other bodies.
1932-01-01
Technical Paper
320046
George H. Scragg
1932-01-01
Technical Paper
320011
Richard C. Gazley
RECENT developments disclose the existence of a well-defined tendency toward greater accuracy and thoroughness in airplane stress-analysis methods, which serve only as a link between applied loads and allowable loads. This trend has just begun. “Although we may justly look with pride on the aeronautical achievements thus far accomplished,” the author says, “our knowledge and ability are far from being complete or entirely satisfactory.” Hence, he analyzes several recurrent stress-analysis problems and indicates methods leading to their solution, because these seem to be outstanding in their ability to cause trouble for airplane designers. Better understanding is needed of the peculiarities of aircraft structure; such as lack of rigidity, the nature of inertia loads, the effects of flutter and of engine vibration, and the dangers of stress concentration.
1931-01-01
Technical Paper
310034
Charles Ward Hall
METHODS employed by the author to reduce the weight of the structural frame without sacrificing strength are described in the paper. To obtain this result the best available cross-section must be selected and the members arranged to transmit the load directly to the final supports which should lie approximately in a plane that is parallel to the load vector; also where a bending moment is caused by the loading, the support attachment should produce a moment of the same amount and of opposite sign. Avoiding secondary bending and utilizing the advantages of full continuity over supports can be secured by a simple arrangement of the frame members. Substitution of power tools for hand tools will effect a reduction in assembly costs. Sections suitable for power assembly include closed hollow-sections, which have a high structural efficiency, as well as angles, channels, I-beams and similar shapes.
1930-01-01
Technical Paper
300031
Alfred A. Gassner
1929-01-01
Technical Paper
290066
L. B. RICHARDSON
AT first believed immune, aluminum alloys have been found extremely susceptible to both surface corrosion and intercrystalline corrosion. The latter goes on under paint that has been applied to imperfectly cleaned surfaces, and shows only as blisters. Because of this, it has become commonplace to break with the fingers the ribs and the trailing edges of duralumin lower wings and tail-surfaces. Contact of duralumin with brass or steel hastens corrosion, and protective paint coverings are dissolved by dope where fabric surfaces meet metal parts. All-duralumin structures are not considered suitable for sea-going aircraft unless all joints and seams are of water-tight construction, not only in hulls but in other members of the structure. Corrosion over the land is much less severe. Few manufacturers seem awake to the importance of corrosion. The fight to avoid it should begin with avoiding seams that are difficult to protect and hollow members that cannot be sealed hermetically.
1929-01-01
Technical Paper
290065
J. H. KINDELBERGER
1928-01-01
Technical Paper
280066
GERARD F. VULTEE
THE monocoque type of fuselage construction seems to promise satisfaction of the three requisites of prime importance; namely, high strength-weight ratio, “streamlined” form, and unobstructed interior, according to the author. The conventional method of building a fuselage consists, first, in the construction of a “form” of the required shape, upon which a layer of veneer is fastened. Other layers are applied, and thus a fuselage shell of two or three plies is completed. But the process is expensive and laborious, involving the handling and individual fitting of many small pieces. In the process described by the author, a wooden form of the exact shape of one half of the fuselage body, divided on a vertical plane passing through the center line, is built. This form, or pattern, is next suspended in a large box in which reinforcing bars previously have been woven, and concrete is poured in.
1928-01-01
Technical Paper
280027
C. H. CHATFIELD
AFTER pointing out that the rivalry between the monoplane and the biplane is of long standing, and that each must therefore have some advantages, the author proceeds to the consideration of the question at issue by comparing structural efficiency, aerodynamic characteristics, performance, and certain other features. In structural efficiency the biplane is considered superior both in strength-weight ratio and in rigidity, but the monoplane has the advantage of being better adapted to metal construction. In aerodynamic characteristics the monoplane has the advantage on the basis of wings of the same area and profile, but the lower lift-drag ratio and greater unit weight of the monoplane wing tend to reduce its superiority. World's records in performance are divided between the two types, and in speed the recent Schneider Cup races show the monoplane and the biplane to be about equal.
1928-01-01
Technical Paper
280021
JOHN P. KELLEY
NEARLY all steel used in this process of manufacturing frames comes to the plant in the form of strips, which are rolled to remove curvature and inspected automatically for dimensions. All operations and handling are automatic, except pickling, cleaning and oiling the stock and inspecting the assembled frame, until the enameled frame is ready to be shipped. Economical use of the strip steel is dependent upon an offsetting operation that makes the strip conform to the vertical curves desired in the finished frame. With the aid of illustrations, the author follows the fabricating process through the various lines and other units, until a frame is ready for shipment or storage, within less than 2 hr. after it enters the manufacturing line as strip steel.
1928-01-01
Technical Paper
280030
W. B. STOUT
PSYCHOLOGY of the public, as well as engineering structure and aerodynamics, is involved in commercial aviation. The public has confidence in metal. With quantity production in view, the author and his associates considered costs of production as related to quantity and also costs of maintenance at airports and in the field, and chose metal as the material of construction. Structural members are fashioned from sheet duralumin rather than from tubes and a type of construction was evolved that can be made with the minimum investment in tools, that is cheap to put together and that can be repaired with the smallest amount of equipment and labor. For compression loads, duralumin has a great deal more strength for a given weight than has steel. It cannot be used, however, for compression members in combination with steel in tension members because of the difference in coefficient of expansion.
1928-01-01
Technical Paper
280029
CHARLES WARD HALL
USEFUL load-carrying capacity is a measure of the comparative value of two airplanes of the same size, having identical powerplants, speed, rate of climb and other flying characteristics. It seems to be feasible to combine in the same airplane both the greatest ability to carry useful load and the least cost of construction. Blanked and pressed metal work offers substantial advantage to the extent that parts, particularly sub-assemblies, can be made directly by machine in complete units ready to set in the final assembly. The author shows and describes the methods followed by his organization in forming the members, building the frames and assembling the units of metal aircraft. Trusses are blanked and the web members pressed to ¾-circle form. Dies for long members are variable in length by being made in pieces that can be removed or inserted as desired. Flanged-tube sections are employed for truss chords.
1927-01-01
Technical Paper
270050
ALFRED W. DEVINE
IT is common practice to provide single-filament motor-vehicle head-lamps with but one focus-adjusting mechanism. The advisability of incorporating also a vertical-focusing mechanism in two-filament tilting-beam head-lamps has been a subject of discussion. The intent of State laws is to require the proper use of lighting equipment that meets the legal requirements. Focusing is the most difficult obstacle in the way of practical enforcement of the laws. Types of focusing mechanism are described and the effect of the use of each type on the instructions issued by State motor-vehicle departments is explained at some length. Movement of the light source by the use of the different types of mechanism for focusing head-lamps is described to explain complications that attend the use of multiple adjusting-mechanisms. Head-lamps can be designed with a focal zone, instead of a focal point, so that they will be less sensitive to filament positioning.
1927-01-01
Technical Paper
270072
LAWRENCE B. RICHARDSON
Abstract MORE and more is being demanded of Navy airplanes beyond the requirements of commercial planes. Catapulting and deck landings are required of some planes and corrosion must be guarded against. Bombers and fighting planes each have their special requirements, and planes must be able to land safely on either land or water. The most important developments in aerodynamics now going on are to restrict the travel of the center of pressure of the wings as the angle of attack changes; but widespread adoption of slotted wings and other results of experimental development may be expected. Metal is being used more than formerly in structural work but there are as yet no all-metal service-types in the Navy. Chrome-molybdenum steel is replacing mild carbon-steel in the tubular frames of fuselages, and there is a tendency to seek substitutes for welded joints. Duralumin is slowly replacing steel where welding is not required, but its adoption is retarded because of corrosion.
1927-01-01
Technical Paper
270065
J. A. ROCHÉ
1927-01-01
Technical Paper
270066
R. D. WEYERBACHER
1926-01-01
Technical Paper
260067
Wesley L. Smith
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.
1926-01-01
Technical Paper
260065
ADOLPH ROHRBACH
Reduction of cost and of the time required to construct airplanes and seaplanes by applying so-called shipbuilding practice to their fabrication, embodying late types of production methods, are discussed by the author, who says that the company he represents adheres to a number of technical principles to reduce to the minimum the risk of designing and constructing new types. The technical principles refer to general arrangement and to layout, as well as to the detail design of many parts of the planes. They include also very careful and minute preparation for the actual workshop construction by the supplying of perfect workshop-drawings and by proper organization of the technical departments. The paper outlines the technical principles, including reasons for their adoption, and then describes the organization of the work of construction. Wing-loading and power-loading are discussed, and the statement is made that the company builds monoplanes only.
1926-01-01
Technical Paper
260053
K. D. CHAMBERS
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.
1926-01-01
Technical Paper
260026
RALPH H UPSON
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.
1926-01-01
Technical Paper
260022
WALTER D'ARCY RYAN
Subsequent to reviewing the circumstances responsible for the present complicated situation existing with respect to satisfactory automobile-headlighting, the author says that headlights glare if they are adjusted for range and that, when adjusted for non-glare, they have no range; hence, careful tests were made on a number of the best types of approved headlight and lens in use. The units were set-up in pairs, in operating position as to height and interval and were tested at a range of 100 ft. with a 1-m. (39.37-in.) hemisphere having an aperture 21 in. square, corresponding to 1 deg. at 100 ft. All the lamps were held at proper current-value throughout the tests, and it was demonstrated by the tests that the reflectors of the parabolic type and others of similar characteristics that have proved to be unsatisfactory during many years past must be abandoned.
1925-01-01
Technical Paper
250055
W D'A Ryan
Although agreeing in general with the sentiments expressed by Mr. Crane and Mr. Hunt, exception is taken to the statement that the solution of the headlighting problem is to be found in diffused lighting, because it has not sufficient range, is too glaring and is too dangerous in a fog. The trouble is said to lie not in the specifications but in the devices that they are supposed to cover. Suggestions are offered regarding modifications that might advantageously be made in the present specifications, and a detailed summation is given of the requirements considered essential to a first-class headlight. The statement is added that a headlight embodying all the points enumerated, while at the same time using a 21-cp. bulb, has already been perfected.
1925-01-01
Technical Paper
250054
J H HUNT
Two points are cited as illustrating the difficulty of enforcing the present regulations, namely, (a) the variation in the angle of the headlight beam caused by the compression of the springs when the loading of the car is changed from no load to full load and (b) the variation of the tilting of the beam caused by the pitching of the car on an ordinary road, the effect being similar to that produced by flashes of lightning in a pitch-dark night. Denial is made of the author's alleged advocacy of diffused lighting and comparison is made of the distribution-curves obtained with frosted bulbs and those obtained with fairly good lamps conforming to the Society's specifications.
Viewing 4621 to 4650 of 4671