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Accurate Calculation of Multispar Cantilever and Semicantilever Wings With Parallel Webs Under Direct and Indirect Loading
In the present report the computation is actually carried through for the case of parallel spars of equal resistance in bending without direct loading, including plotting of the influence lines; for other cases the method of calculation is explained. The development of large size airplanes can be speeded up by accurate methods of calculation such as this.
The Aerodynamic Characteristics of a Model Wing Having a Split Flap Deflected Downward and Moved to the Rear
"Tests were made on a model wing with three different sized split trailing-edged flaps, in the NACA 7 by 10 foot wind tunnel. The flaps were formed of the lower rear portion of the wing and were rotated downward about axes at their front edges. The lift, drag, and center of pressure were measured with the axis in its original position and also with it moved back in even steps to the trailing edge of the main wing, giving in effect an increase in area. The split flaps when deflected about their original axis locations gave slightly higher maximum lift coefficients than conventional trailing-edge flaps, and the lift coefficients were increased still further by moving the axes toward the rear" (p. 1).
The aerodynamic characteristics of a slotted Clark y wing as affected by the auxiliary airfoil position
From Summary: "Aerodynamic force tests on a slotted Clark Y wing were conducted in a vertical wind tunnel to determine the best position for a given auxiliary airfoil with respect to the main wing. A systematic series of 100 changes in location of the auxiliary airfoil were made to cover all the probable useful ranges of slot gap, slot width, and slot depth. The results of the investigation may be applied to the design of automatic or controlled slots on wings with geometric characteristics similar to the wing tested. The best positions of the auxiliary airfoil were covered by the range of the tests, and the position for desired aerodynamic characteristics may easily be obtained from charts prepared especially for the purpose."
The Aerodynamic Characteristics of Airfoils at Negative Angles of Attack
From Introduction: "The present report gives all the results, including those published in reference 1 and the results of previously un-published tests tests of the airfoils at positive angles of attack."
Aerodynamic characteristics of circular-arc airfoils at high speeds
From Summary: "The aerodynamic characteristics of eight circular-arc airfoils at speeds of 0.5, 0.8, 0.95, and 1.08 times the speed of sound have been determined in an open-jet air stream 2 inches in diameter, using models of 1-inch chord. The lower surface of each airfoil was plane; the upper surface was cylindrical. As compared with the measurements described in NACA-TR-319, the circular-arc airfoils at speeds of 0.95 and 1.08 times the speed of sound are more efficient than airfoils of the R. A. F. or Clark Y families. At a speed of 0.5 times the speed of sound, the thick circular-arc sections are extremely inefficient, but thin sections compare favorably with those of the R. A. F. family. A moderate round of the sharp edges changes the characteristics very little and is in many instances beneficial. The results indicate that the section of the blades of propellers intended for use at high tip-speeds should be of the circular-arc form for the outer part of the blade and should be changed gradually to the R. A. F. or Clark Y form as the hub is approached."
The aerodynamic characteristics of eight very thick airfoils from tests in the variable density wind tunnel
Report presents the results of wind tunnel tests on a group of eight very thick airfoils having sections of the same thickness as those used near the roots of tapered airfoils. The tests were made to study certain discontinuities in the characteristic curves that have been obtained from previous tests of these airfoils, and to compare the characteristics of the different sections at values of the Reynolds number comparable with those attained in flight. The discontinuities were found to disappear as the Reynolds number was increased. The results obtained from the large-scale airfoil, a symmetrical airfoil having a thickness ratio of 21 per cent, has the best general characteristics.
The aerodynamic safety of airplanes
This report presents several hypotheses regarding airplane safety, mainly concerning the nondimensional coefficient of air, speed, acceleration, and wing area on aerodynamic considerations of safety.
Airfoil section characteristics as affected by protuberances
From Introduction: "The present report deals with another phase of the investigation; that is, the effects on airfoil section characteristics of protuberances extending along the entire span from the airfoil surface."
Airplane Flight in the Stratosphere
This brief survey of the problems encountered in high-altitude flight deals in particular with the need for high lift coefficient in the wings, large aspect ratios in the wings, and also the problem of hermetically sealing the cabin.
Airplane Stability in Taxying
The stability analysis of an airplane while rolling is much more simplified to the extent that it can be obtained for numerical data which can be put to practical use in the design of landing gear dimensions. Every landing gear type attains to a critical ground friction coefficient that decides the beginning of instability, i.e., nosing over. This study has, in addition, a certain interest for the use of wheel brakes.
Annual Report of the National Advisory Committee for Aeronautics (17th). Administrative Report Including Technical Report Nos. 365 to 400
Report includes the National Advisory Committee for Aeronautics letter of submittal to the president, congressional report, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
Application of the Theory of Free Jets
Based upon Kirchoff's theory of free jets the flow through different screen arrangements of flat plates, as chiefly encountered with turbines in the cavitation zone is defined. It is shown by experiments that these theoretical results are very well representative in most cases of the conditions of discharge from water in air and consequently by cavitation. In addition, the experiments reveal a picture of the discrepancies between the actual flow and the theory of discharge of air in air (of water in water without cavitation).
Approximate Calculation of Multispar Cantilever and Semicantilever Wings With Parallel Ribs Under Direct and Indirect Loading
A method is presented for approximate static calculation, which is based on the customary assumption of rigid ribs, while taking into account the systematic errors in the calculation results due to this arbitrary assumption. The procedure is given in greater detail for semicantilever and cantilever wings with polygonal spar plan form and for wings under direct loading only. The last example illustrates the advantages of the use of influence lines for such wing structures and their practical interpretation.
Armstrong-Whitworth A.W. 15 "Atlanta" Airplane (British): A Commercial Multiplace Cantilever Monoplane
Circular describing the Armstrong Whitworth XV "Atalanta" airplane, which is a commercial multiplace cantilever monoplane. Details of the wings, landing gear, fuselage, control surfaces, structural design, wing, engine, characteristics, drawings, and photographs are provided.
The Armstrong Whitworth A.W. 16 Military Airplane (British): A Single-Seat Biplane
Circular presenting a description of the A.W. XVI, which is a single-bay staggered biplane of metal construction with a clean external design. A description of the tail unit, control system, cockpit, fuselage, characteristics, performance, drawings, and photographs are provided.
The Ashland Coal Field, Rosebud, Powder River, and Custer Counties, Montana
From introduction: The detailed information concerning the coal deposits of the Ashland field set forth in this report has been obtained in the course of an investigation that has been conducted both as a part of the United States Geological Survey's general systematic study of western coal lands and as an aid in the administration of the public lands. With the information obtained on the location of outcrops, the number, distribution, and thickness of coal beds, the accessibility of the coal, and the thickness of the overburden, the public lands of the region are classified as to their coal value; coal-bearing lands are differentiated from noncoal-bearing lands; and the administration of the coal-land leasing law is facilitated.
Automatic Stability of Airplanes
It is endeavored in this report to give a full outline of the problem of airplane stability and to classify the proposed solutions systematically. Longitudinal stability, which can be studied separately, is considered first. The combination of lateral and directional stabilities, which cannot be separated, will be dealt with later.
The Automotive Ignition Coil
This report gives the results of a series of measurements on the secondary voltage induced in an ignition coil of typical construction under a variety of operating conditions. These results show that the theoretical predictions hitherto made as to the behavior of this type of apparatus are in satisfactory agreement with the observed facts. The large mass of data obtained is here published both for the use of other investigators who may wish to compare them with other theoretical predictions and for the use of automotive engineers who will here find definite experimental results showing the effect of secondary capacity and resistance on the crest voltage produced by ignition apparatus.
The Avro 631 Training Airplane (British): A Two-Seat Light Biplane
Circular describing the Avro 631 training airplane, which is a British two-seat light biplane that is meant to be affordable and small. Details regarding the wings, fuselage, tail unit, landing gear, power plant, accommodation, characteristics, performance, drawings, and photographs are provided.
The Bleriot 137 Military Airplane (French): A Twin-Engine Multiplace Monoplane
Circular presenting a description of the Blériot 137, which is a metal modification of the Bléirot 127. A description of the crew, the equipment, firing tests of the guns, and flight characteristics are provided.
The Breda 32 Commercial Airplane (Italian): A Three-Engine All-Metal Low-Wing Monoplane
Circular presenting a description of the Breda 32, which is a commercial airplane with three engines and an all-metal construction. Details regarding the design, components, flight qualities, drawings, and photographs are provided.
The Breguet 410 and 411 Military Airplanes (French): Multiplace Sesquiplane Fighters
Circular presenting a description of the Breguet 410 and 411 military airplanes, which are both multiplace sesquiplane fighter aircraft. Details of the design, components, flying qualities, drawings, and photographs are provided.
The C.A.M.S. 80 Amphibian (French): An Observation Monoplane
Circular presenting a description of the C.A.M.S. 80, which is a shipboard or observation patrol, light-bombing, long-range amphibian. Details of the hull, landing gear, wing, tail surfaces, power plant, front cockpit, pilot's compartment, photographer's compartment, radio cabinet, rear gunner's cockpit, stern compartment, and flying qualities are provided.
Calculation of Potential Flow Past Airship Bodies in Yaw
An outline of Von Karman's method of computing the potential flow of airships in yaw by means of partially constant dipolar superposition on the axis of the body is followed by several considerations for beginning and end of the superposition. Then this method is improved by postulating a continuous, in part linearly variable dipolar superposition on the axis. The second main part of the report brings the calculation of the potential flow by means of sources and sinks, arranged on the surface of the airship body.
The characteristics of 78 related airfoil sections from tests in the variable-density wind tunnel
An investigation of a large group of related airfoils was made in the NACA variable-density wind tunnel at a large value of the Reynolds number. The tests were made to provide data that may be directly employed for a rational choice of the most suitable airfoil section for a given application. The variation of the aerodynamic characteristics with variations in thickness and mean-line form were systematically studied. (author).
The Characteristics of a Clark Y Wing Model Equipped With Several Forms of Low-Drag Fixed Slots
This investigation was undertaken to develop a low-drag fixed slot for an airplane wing which would avoid the complications and maintenance difficulties of the present movable-type Handley Page slot. Tests were conducted on a series of fixed slots in an attempt to reduce the minimum drag coefficient without decreasing the maximum lift coefficient or the stalling angle of the slotted wing. The tests were made in the NACA 5-foot vertical wind tunnel on a Clark Y basic section having a 10-inch chord.
Characteristics of an airfoil as affected by fabric sag
"This report presents the results of tests made at a high value of the Reynolds Number in the N.A.C.A. variable-density wind tunnel to determine the aerodynamic characteristics of an airfoil as affected by fabric sag. Tests were made of two Gottingen 387 airfoils, one having the usual smooth surface and the other having a surface modified to simulate two types of fabric sag. The results of these tests indicate that the usual sagging of the wind covering between ribs has a very small effect on the aerodynamic characteristics of an airfoil" (p. 1).
Characteristics of Clark Y airfoils of small aspect ratios
This report presents the results of a series of wind tunnel tests showing the force, moment, and autorotational characteristics of Clark Y airfoils having aspect ratios varying from 0.5 to 3. An airfoil of rectangular plan form was tested with rectangular tips, flared tips, and semicircular tips. Tests were also made on one airfoil of circular plan form and two airfoils of elliptical plan form. The tests revealed a marked delay of the stall and a decided increase in values of maximum lift coefficient and maximum resultant force coefficient for aspect ratios of the order of 1 as compared with values for aspect ratios of 2 and 3.
Characteristics of Two Sharp-Nosed Airfoils Having Reduced Spinning Tendencies
"According to Mr. L.D. Bell, of the Consolidated Aircraft Corporation, certain undesirable spinning characteristics of a commercial airplane were eliminated by the addition of a filler to the forward part of the wing to give it a sharp leading edge. To ascertain what aerodynamic effects result from such a change of section, two airfoils having sharp leading edges were tested in the variable-density wind tunnel. Both sections were derived by modifying the Gott. 398. The tests, which were made at a large value of the Reynolds Number, were carried to very large angles of attack to provide data for application to flight at angles of attack well beyond the stall" (p. 1).
Clinker Formation as Related to the Fusibility of Coal Ash
From Introduction Arrangement of Report: "The results of this investigation are presented in two main divisions. The first part covers the chemical and physical tests on average samples of the coals used-chemical analysis, float-and-sink tests to determine distribution of the ash, determination of the forms of sulphur, chemical analyses of the ash, and ash-fusabilibity determinations. The second part covers the clinkering studies and the comparisons of the results with the ash-fusibilty and other tests."
Coal-Mine Accidents in the United States, 1930
Report compiled by the U.S. Bureau of Mines including statistics on fatal and non-fatal accidents in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary.
Combustion of Gaseous Mixtures
This report not only presents matters of practical importance in the classification of engine fuels, for which other means have proved inadequate, but also makes a few suggestions. It confirms the results of Withrow and Boyd which localize the explosive wave in the last portions of the mixture burned. This being the case, it may be assumed that the greater the normal combustion, the less the energy developed in the explosive form. In order to combat the detonation, it is therefore necessary to try to render the normal combustion swift and complete, as produced in carbureted mixtures containing benzene (benzol), in which the flame propagation, beginning at the spark, yields a progressive and pronounced darkening on the photographic film.
Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines
"The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined" (p. 1).
Comparative Performance of a Powerplus Vane-Type Supercharger and an N.A.C.A. Roots-Type Supercharger
"This report presents the results of tests of a Powerplus supercharger and a comparison of its performance with the performance previously obtained with an N.A.C.A. Roots-type supercharger. The Powerplus supercharger is a positive displacement blower of the vane type having mechanically operated vanes, the movement of which is controlled by slots and eccentrics. The supercharger was tested at a range of pressure differences from 0 to 15 inches of mercury and at speeds from 500 to 2,500 r.p.m." (p. 1).
A comparison between the theoretical and measured longitudinal stability characteristics of an airplane
This report covers an investigation of the application of the theory of dynamic longitudinal stability, based on the assumption of small oscillations, to oscillations an airplane is likely to undergo in flight. The investigation was conducted with a small parasol monoplane for the fixed-stick condition. The period and damping of longitudinal oscillations were determined by direct measurements of oscillations in flight and also by calculation in which the factors that enter the theoretical stability equation were determined in flight. A comparison of the above-mentioned characteristics obtained by these two methods indicates that the theory is applicable to the conditions encountered in flight.
Compression-ignition engine tests of several fuels
"The tests reported in this paper were made to devise simple engine tests which would rate fuels as to their comparative value and their suitability for the operating conditions of the individual engine on which the tests are made. Three commercial fuels were used in two test engines having combustion chambers with and without effective air flow. Strictly comparative performance tests gave almost identical results for the three fuels. Analysis of indicator cards allowed a differentiation between fuels on a basis of rates of combustion" (p. 1).
The Compressive Strength of Duralumin Columns of Equal Angle Section
"This report presents a chart giving the compressive strength of duralumin columns of equal angle section. The data used in the construction of the chart were obtained from various published sources and were correlated with theory in the range where secondary failure occurred. Appendices are included giving excerpts from Army and Navy specifications for duralumin and approximate formulas for the properties of the equal angle section" (p. 1).
Considerations of air flow in combustion chambers of high-speed compression-ignition engines
The air flow in combustion chambers is divided into three fundamental classes - induced, forced, and residual. A generalized resume is given of the present status of air flow investigations and of the work done at this and other laboratories to determine the direction and velocity of air movement in auxiliary and integral combustion chambers. The effects of air flow on engine performance are mentioned to show that although air flow improves the combustion efficiency, considerable induction, friction, and thermal losses must be guarded against.
Contributions to the Data on Theoretical Metallurgy: [Part] 1. The Entropies of Inorganic Substances
From Introduction: "The present work is an attempt to collect all the available data referring to one important thermodynamic property and to supply sufficient discussion to make the results readily usable by metallurgists. In the study of chemical or metallurgical reactions two factors have predominant importance-the free energy of reaction and the speed of reaction. The subject of this publication is so closely allied to the former that may be well to consider briefly some of the uses to which free-energy data may be put."
The Controls at Low Hinge Moments
A very stable airplane remains very maneuverable when the hinge moments of the controls remain inferior to those obtained with the conventional forms and when the wing lift at high angles has been improved. From this point of view, elevators balanced by recoil of the hinge, and slotted wings present some interesting features. The results of testing with several different types of wings and tail surfaces are provided.
Crater Wells, Richland Gas Field, Louisiana
Technical paper issued by the Bureau of Mines over "the history of the craters in the Richland gas field. The data have been collected at various times over a period of four years. The equipment and methods of control are discussed, and photographs show the surface conditions at various intervals in the life of the craters" (p. 1). This paper includes tables, maps, photographs, and illustrations.
The Crystal Cavities of the New Jersey Zeolite Region
From abstract: The crystal cavities present in the mineral complex of the New Jersey traprock region have long excited the interest of mineralogists. In 1914 Fenner made the first detailed and comprehensive study of these cavities and suggested that babingtonite was the original mineral. Soon after this anhydrite was found occupying parts of some of the cavities at one of the quarries. At this time, too, Wherry concluded that glauberite was the original mineral of some of the cavities because of his studies of similar crystal cavities in Triassic shale at different places.
The D.H. "Fox Moth" Commercial Airplane (British): A Three-Passenger Light Cabin Biplane
Circular describing the D.H. 83 "Fox Moth", which is a three-passenger light cabin biplane that is considered a commercial airplane despite taking many of its components from the company's existing two-seat touring and training light airplanes. A description of these components, design, flight characteristics, performance, drawings, and photographs are provided.
Determination of Stresses and Deformations of Aircraft Propellers
A method is described for testing the strength of propellers of any shape. It is shown that the shape of the propeller greatly affects the stresses, and that great caution must be exercised if the relieving effect of the centrifugal force, which exists in every propeller with a straight blade axis, is to be increased by curving the blade axis. In a numerical example, the calculation is made for a certain revolution speed at which the actual distortion is then measured. The results of the calculation agree satisfactorily with the experimental results.
Development of Tailless and All-Wing Gliders and Airplanes
Tailless airplanes are characterized by having all their control surfaces, especially the elevator, incorporated in the wings. This paper provides a discussion of the history of their development and current state of development.
Disintegration of a Liquid Jet
This report presents an experimental determination of the process of disintegration and atomization in its simplest form, and the influence of the physical properties of the liquid to be atomized on the disintegration of the jet. Particular attention was paid to the investigation of the process of atomization.
The Dornier Do K Commercial Airplane (German): A High-Wing Cantilever Monoplane
Report presenting a description of the Dornier Do K commercial airplane. Details of the construction, design, wing, fuselage, tail, and landing gear are provided.
The drag of two streamline bodies as affected by protuberances and appendages
This report presents the results of wind tunnel tests of two airship models conducted to determine the drag coefficients at zero pitch, and the effect of fins and cars and of flat and streamlined protuberances located at various positions along the hull. During the investigation the stern of one model was rounded off to produce a blunter shape. The extreme range of the Reynolds number based on the over-all length of the models was from 1,300,000 to 33,000,000. At large values of the Reynolds number the streamlined protuberance affected the drag very little, and the additional drag caused by the flat protuberance was less than the calculated drag by the protuberance alone. The fins and cars together increased the bare-hull drag about 20 per cent.
Drag Tests of 4/9-Scale Model Engine Nacelles With Various Cowlings
"Results are given of drag tests of 4/9-scale model radial air-cooled engine nacelles made as a part of a general investigation of wing-nacelle-propeller interference. A small nacelle of the type commonly used with exposed engine cylinders was tested with various forms of cowling over the cylinders. The effects of cowling-ring position and of angle of ring chord to the thrust line were investigated. An N.A.C.A. cowled nacelle and a smooth body were also tested. The results are given at 50, 75, and 100 miles per hour for -5 degrees, 0 degrees, 5 degrees, 10 degrees, 15 degrees angle of pitch" (p. 1).
The Dreieck I Tailless Airplane (German): A Low-Wing Cantilever Monoplane
Circular presenting a description of the Dreieck I tailless airplane, which has been shown to have excellent flying qualities. Information regarding the design and flight characteristics are provided.
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