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The additional-mass effect of plates as determined by experiments
From Introduction: "The apparent increase in the inertia properties of a body moving in a fluid medium has been called the additional-mass effect. This report presents a resume of test procedures and results of experimental determinations of the additional-mass effect of flat plates. In addition to data obtained from various foreign sources and from a NACA investigation in 1933, the results of tests recently conducted by the National Advisory Committee for Aeronautics are included."
Additional power-on wind-tunnel tests of the 1/8-scale model of the Brewster F2A airplane with full-span slotted flaps
"Additional tests as recommended in reference 1 were made in the 7- by 10-foot wind tunnel of the 1/8-scale model of the Brewster F2A airplane to determine the angle of attack of horizontal tail and the elevator angles required for trim with flaps down" (p. 1).
Aerodynamic Characteristics of a Slot-Lip Aileron and Slotted Flap for Dive Brakes
From Introduction: "As a part of this investigation, a study is being made of test results obtained during the development of devices designed primarily for other purposes, such as high lift or lateral control, but which may also be used for dive control. These results have been reanalyzed and are herein presented in a form that should make them convenient for design purposes."
Aerodynamic Factors Affecting the Ability of a Pilot to Return an Airplane to Level From a Banked Attitude by Use of the Rudder Alone and Without Change of Heading
Report presenting a study of the aerodynamic factors upon which the ability to perform the maneuver depends in an attempt to obtain a better understanding of the conditions involved and, if possible, to evolve criterions that may be used during design.
The aerodynamics of a wind-tunnel fan
From Introduction: "This paper deals only with the aerodynamics of the fan proper and demonstrates the manner in which the radial distribution of axial velocity of fluid through a fan is governed by geometry of the fan itself."
Air Transport by Gliders: Some Technical Observations
This short analysis may be useful in determining the real tactical possibilities of "glider trains" and in adopting the course to be followed in possible studies of these questions. In this analysis most prominent are: (a) the power required for the train in level flight; (b) its speed; (c) climb; and (d) the type of airplane best suited for towing as well as design requirements for transport gliders.
Aluminum-Zinc-Magnesium-Copper Casting Alloys
From Introduction: "This paper contains data on the mechanical properties of sand-cast test bars having a considerable range in zinc, magnesium, and copper content and more detailed data on the properties and foundry characteristics of an aluminum-zinc-magnesium-copper alloy having a preferred composition for high strength and ductility."
Analyses of Washington Coals: Supplement to Technical Paper 491
Report issued by the Bureau of Mines discussing the technological advances made in the mining industry between 1931 and 1941. Mechanized methods for mining operations are presented. This report includes tables, illustrations, and a map.
Analysis of Ground Effect on the Lifting Airscrew
"A study is presented of ground effect as applied to the lifting airscrew of the type used in modern gyroplanes and helicopters. The mathematical analysis of the problem has been verified by tests made of three rotor models in the presence of a large circular "ground plane." The results of the study are presented in the form of convenient charts" (p. 1).
Analytical Determination of Control System Pulley-Axis Angles
From Introduction: "The ideas developed in this paper are presented as a means of saving the designer's time and as a method of reduction of control-system friction by an accurate calculation of pulley-axis angles without the errors and difficult checking incident to any graphical method."
An analytical study of wing and tail loads associated with an elevator deflection
From Introduction: "The present paper covers step 1 of the outlined investigation, includes methods of computing the variation of wing and tail loads, and gives numerical results of the application of the theory to the BT-9B airplane. Finally, theoretical formulas are developed and charts are given for computing the maximum increments of wing load, the down-tail load, and the up-tail load following a given elevator displacement."
Annual Report of Research and Technologic Work on Coal: Fiscal Year 1941
Report issued by the U.S. Bureau of Mines discussing the annual report over the research and technology of coal during 1941. As stated in the foreword, "these investigations increase our fund of exact knowledge on the properties and composition of American coals and lead to better methods in mining, preparing, storing, and utilizing coal" (p. 4). This report includes tables, illustrations, photographs, and a map.
Annual Report of the Mining Division, Fiscal Year 1941
Report issued by the U.S. Bureau of Mines on the annual study of the work done by the Mining Division. Investigations, operations, and projects completed during the fiscal year are discussed. This report includes tables, and photographs.
Annual Report of the National Advisory Committee for Aeronautics (26th). Administrative Report Including Technical Report Nos. 681 to 703
Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
An apparatus for measuring rates of discharge of a fuel-injection system
From Introduction: "An apparatus that gives a quick and an accurate measurement of the rate of discharge has been has been designed by the NACA and is described in this report."
Attwater's Prairie Chicken, its Life History and Management
Summary of the Attwater's prairie chicken, including differences versus other prairie chickens, habits, habitat, limiting factors, management, and threat of extinction due to exploitation by man.
Bending of Rectangular Plates With Large Deflections
"The solution of Von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to Von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, Mcpherson, and Levy" (p. 1).
Boundary Layer Removal by Suction
Flight-test data and wind-tunnel data on suction profiles are substantially in agreement. The lift values found in the model test can be actually flown and used as a basis for the design. To visualize the action of the suction, the flow conditions with and without suction on the upper surface were photographed; figures 12 to 15 are sections of the film.
Buckling Tests on Eccentrically Loaded Beam Columns
"Formulas are obtained for computing the buckling load of rods eccentrically loaded at each end, the computation being extended in particular to the inelastic range. The test results are graphically presented on three sets of curves. Two of these, at least for the elastic range, are independent of the material tested. The third set, which is independent of the material, possesses greater clearness and is therefore used for comparing the test results with the theoretical" (p. 1).
The Calculation of Span Load Distributions of Swept-Back Wings
"Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9" (p. 1).
Characteristics of Naca 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps
"At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord split flaps, deflected 60 degrees, in the center of the wing and having flat span to wing span ratios of 0.3, 0.5, 0.7, and 1.0, respectively" (p. 1).
Characteristics of NACA 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps
"At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord spit flaps, deflected 60 deg span ratios of 0.3, 0.5, 0.7 and 1.0 respectively. In order to get data from which to calculate the characteristics of the flapped wing, the investigation was extended to include tests of the four rectangular airfoils of the NACA 4400R series (4409R, 4412R, 4415R, and 4418R) with full-span 0.2 chord, trailing edge split flaps deflected 60 deg" (p. 1).
Coal-Mine Accidents in the United States, 1938
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.
Collecting and Examining Subsurface Samples of Petroleum
Report issued by the Bureau of Mines discussing subsurface samples of petroleum. As stated in the scope of report, "the Bureau of Mines has developed special equipment and procedures for obtaining samples of petroleum under pressure from the bottom of wells and for examining these samples in the laboratory" (p. 4). This report includes tables, illustrations, and a photograph.
Combined Beam-Column Stresses of Aluminum-Alloy Channel Sections
"The results of tests of 65 specimens of aluminum-alloy channel sections are graphed for stresses due to axial and bending loads as functions of the ratio of length of specimen to its radius of gyration, and from these data a suggested design chart is derived that is suitable for ready use" (p. 1).
Comparison of Automatic Control Systems
This report deals with a reciprocal comparison of an automatic pressure control, an automatic rpm control, an automatic temperature control, and an automatic directional control. It shows the difference between the "faultproof" regulator and the actual regulator which is subject to faults, and develops this difference as far as possible in a parallel manner with regard to the control systems under consideration. Such as analysis affords, particularly in its extension to the faults of the actual regulator, a deep insight into the mechanism of the regulator process.
Comparison of Intercooler Characteristics
"A method is presented of comparing the performance, weight, and general dimensional characteristics of inter-coolers. The performance and dimensional characteristics covered in the comparisons are cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width. A method of presenting intercooler data is described in which two types of charts are plotted; (1) A performance chart setting forth all the important characteristics of a given intercooler and (2) a replot of these characteristics for a number of intercoolers intended to assist in making a selection to satisfy a given set of installation conditions" (p. 1).
Comparison of stress-strain curves obtained by single-thickness and pack methods
Report presenting an apparatus for supporting a single thickness of sheet against buckling so that its compressive yield strength can be determined by the single-thickness method. The results of testing are compared with those from two other methods. This method results in substantial cost savings as compared to the pack method.
Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel
"The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces" (p. 1).
Compressibility Effects in Aeronautical Engineering
"Compressible-flow research, while a relatively new field in aeronautics, is very old, dating back almost to the development of the first firearm. Over the last hundred years, researches have been conducted in the ballistics field, but these results have been of practically no use in aeronautical engineering because the phenomena that have been studied have been the more or less steady supersonic condition of flow. Some work that has been done in connection with steam turbines, particularly nozzle studies, has been of value, In general, however, understanding of compressible-flow phenomena has been very incomplete and permitted no real basis for the solution of aeronautical engineering problems in which.the flow is likely to be unsteady because regions of both subsonic and supersonic speeds may occur" (p. 1).
Compression tests of some 17S-T aluminum-alloy specimens of I cross section
Report presenting testing of specimens cut from a specially extruded I-beam of 17S-T aluminum alloy with one flange wider than the other under axial compression. Only the two longest specimens failed as columns, while the shorter ones failed by local buckling. The agreement between experimental and calculated values of critical stress can be improved by considering the effect of restraint at the loaded edges of the web and adopting a more accurate buckling treatment beyond the elastic range.
The Compressive Yield Strength of Extruded Shapes of 24ST Aluminum Alloy
The following report discusses an investigation that was made to determine the tensile and the compressive properties of a large number of 24ST extruded shapes selected at random from commercial production in order to investigate the interrelation of these properties.
Contribution to the Aerodynamics of Rotating-Wing Aircraft: Part 2
"The interrelations established in an earlier report (NACA-TM-921) are used to study the best assumptions for hovering and horizontal flight. The effect of the twisted and tapered blade on the rotor efficiency is analyzed and the gliding coefficient at different stages (from autogyro to helicopter) of horizontal flight compared. To the extent that model or full-scale test data are available, they are included in the comparison" (p. 1).
Contributions to the Data on Theoretical Metallurgy: [Part] 9. The Entropies of Inorganic Substances. Revision (1940) of Data and Methods of Calculation
From Introduction: "This bulletin originally was planned as a second revision of the first member of this series, the first revision (249) having appeared in 1936; however, because of requests for the explanatory, section of the first bulletin from those teaching thermodynamics, it was decided to combine the information in the first bulletin and its revision with the data that have appeared since 1935 and to repeat the explanatory material in somewhat more detail. The purpose of this bulletin is therefore to give the available values of the entropies at 298.1 degrees K. of the elements and inorganic compounds, together with enough explanation of the methods employed in calculating entropies to make the results comprehensible."
The Conversion of UF4 to U3Os
Methods of conversion of UF4 to U3O8 by fusion with ammonium oxalate dihydrate and other salts are described.
Cooling and Performance Tests of a Continental A-75 Engine
Note presenting an investigation to determine the performance of a small airplane with two Continental A-75 air-cooled engines enclosed in the wings. The object of the tests was to determine the quantity of air and the pressure difference required for satisfactory cooling of the engine at sea level and at altitude. The engine could be cooled satisfactorily at sea level with wide-open throttle and maximum-power mixture with a pressure difference of 4.5 inches of water and 1.06 pounds of cooling air per second.
Cooling Effects of an Airplane Equipped With an NACA Cowling and a Wing-Duct Cooling System
Report presenting cooling tests of a Northrop A-17A attack airplane equipped with a conventional NACA cowling and then with a wing-duct cooling system. Ground cooling for the wing-duct system without cowl flap was better than for the cowling with flap, but was improved by installing a cowl flap. Satisfactory temperatures were maintained in climb and high-speed flight, but a greater quantity of cooling air was needed for the wing-duct system.
Correction of the Lifting-Line Theory for the Effect of the Chord
"It is shown that a simple correction for the chord of a finite wing can be deduced from the three-dimensional potential flow around an elliptic plate. When this flow is compared with the flow around a section of an endless plate, it is found that the edge velocity is reduced by the factor 1/E, where E is the ratio of the semiperimeter to the span. Applying this correction to the circulation brings the theoretical lift into closer agreement with experiments" (p. 1).
The Creep of Laminated Synthetic Resin Plastics
"The long-time loading strength of a number of laminated synthetic resin plastics was ascertained and the effect of molding pressure and resin content determined. The best value was observed with a 30 to 40 percent resin content. The long-time loading strength also increases with increasing molding pressure up to 250 kg/cm(exp 2); a further rise in pressure affords no further substantial improvement" (p. 1)..
Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.
Critical Compressive Stress for Flat Rectangular Plates Supported Along all Edges and Elastically Restrained Against Rotation Along the Unloaded Edges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.
Critical Compressive Stress for Outstanding Flanges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given.
Critical Compressive Stress for Outstanding Flanges
"A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the Loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for the construction of the chart are given" (p. 1).
Critical Speeds and Profile Drag of the Inboard Sections of a Conventional Propeller
Report presenting the section critical speeds and profile drags of the shank and hub sections of a propeller used on a current liquid-cooled-engine pursuit type of airplane. Results indicated that serious adverse compressibility effects can be expected at speeds of about 400 miles per hour. Suitable fairings for shank and hub sections were found to be necessary for maximum propulsive efficiency.
Cylinder Barrel Cooling With Bonded Preformed Copper Fins
Report presenting testing of preformed copper fins which were furnace-brazed to a steel-cylinder barrel. The barrel was electrically heated and blower-cooled to determine heat overall heat-transfer coefficient. Information regarding potential future adaptations of the fins are provided.
Damping characteristics of dashpots
An investigation of the damping characteristics of dashpots was carried out combining theory and experiment. Laminar flow was assumed and three equations for the steady velocity of a piston moving in a cylinder filled with liquid were derived. In the first equation, the piston was assumed coaxial in the cylinder and, in the second equation, the piston was assumed eccentric in the cylinder with an element of the piston in contact with the cylinder wall. The third equation is for a piston of circular cross section in an elliptical cylinder. Experiments showed that the piston is normally eccentric in the cylinder. The pistons tested were 1.25 and 2 inches in diameter 0.062 to 1.00 inch long, and the clearances varied from 1.36 to 5.16 x 10 to the 3rd power inch. The difference in pressure on the two sides of the piston varied from about 2 to 55 pounds per square inch. The piston velocities for each assembly were measured with damping liquids of three different viscosities. At high piston velocities, when turbulent flow exists, the observed velocities were much lower than the velocities calculated on the basis of laminar flow. Results for a wide range of Reynolds numbers are presented in graphical form.
Design charts for cross-flow tubular intercoolers charge-across-tube type
Report presenting equations relating the various dimensions, air mass flow, and performance of a cross-flow tubular intercooler in which the charge flows across and the cooling air through the tubes. Design charts are presented from which the intercooler design characteristics and performance can be quickly determined.
Design charts for cross-flow tubular intercoolers charge-through-tube type
Report presenting equations relating the various dimensions, air weight flow, and performance of a cross-flow tubular intercooler in which the charge flows through and the cooling air across the tubes. A method of determining and presenting the performance of a given intercooler at various operating conditions is indicated. Results regarding the cooling effectiveness equation, effect of primary intercooler variables, design charts, effect of tube arrangement on intercooler characteristics, and performance charts are provided.
The Design of Jet Pumps
This report shows that by applying both energy and impulse theorems the optimum throat dimension of the mixing nozzle and the best shape of intake can be predicted approximately in a relatively simple manner. The necessary length of the mixing nozzle follows from Prandtl's turbulent mixing theory. The calculations are carried out for the mixing of similar and dissimilar fluids.
Design of Nozzles for the Individual Cylinder Exhaust Jet Propulsion System
Report presenting an examination of the design of exhaust-stack nozzles for individual cylinder exhaust-gas jet propulsion and the results of tests on the effect of nozzle area on jet thrust and engine power. A satisfactory method of correlatig the test data for various engine-operating conditions is developed.
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