Technical Report Archive & Image Library (TRAIL) - 528 Matching Results
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- Operation of Electrolytic Manganese Pilot Plant: Boulder City, Nevada
- From Introduction: "This report records a chapter in the history of the development of an electrolytic manganese industry in the United States."
- Mineral-Dressing Characteristics of the Red Iron Ores of Birmingham, Alabama
- From Introduction: "The scope of this paper is such that it was deemed advisable to group the contents into several main sections. They are: Section I. Geography and Geology. Section II. Historical Review. (a) Mining and Smelting in Alabama. (b) Milling. (c) Summary of Milling Research. These two sections are primarily a bibliography and summary of the research on the Birmingham Red Mountain ores up to the middle 1940's."
- United States Earthquakes, 1946
- Report discussing earthquake activity in the United States during 1946. The report is broken down by regions and has sections for specific earthquakes.
- Effects of Specific Types of Surface Roughness on Boundary-Layer Transition
- Report presenting tests of two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils.
- Flight Investigation at High Speeds of Profile Drag of Wing of a P-47d Airplane Having Production Surfaces Covered With Camouflage Paint
- Report presenting a flight investigation made at high speeds to determine the profile drag of a P-47D airplane wing with production surfaces covered with camouflage paint. The results indicated that a minimum profile-drag coefficient of 0.0097 was attained for lift coefficients from 0.16 to 0.25 at Mach numbers less than 0.67.
- Tank tests to determine the effect of varying design parameters of planing-tail hulls 2: effect of varying depth of step, angle of after- body keel, length of afterbody chine, and gross load
- From Summary: "The second part of a series of tests made in Langley tank no. 2 to determine the effect of varying design parameters of planing-tail hulls is presented. Results are given to show the effects on resistance characteristics of varying angle of afterbody keel, depth of step, and length of afterbody chine. The effect of varying the gross load is shown for one configuration. The resistance characteristics of planing-tail hulls are compared with those of a conventional flying-boat hull. The forces on the forebody and afterbody of one configuration are compared with the forces on a conventional hull."
- An Empirical Equation for the Coefficient of Heat Transfer to a Flat Surface From a Plane Heated-Air Jet Directed Tangentially to the Surface
- Note presenting an investigation of the heat transfer to a surface from plane heated-air jets discharged tangentially to the surface to provide heat-transfer relationships required in the design of heated-air jet installations for aircraft windshield fog prevention. Experimental temperature, velocity, and heat-transfer data were obtained by tests in which the initial jet temperature and velocity were varied.
- Lightning Discharges to Aircraft and Associated Meteorological Conditions
- A summary is given of information on atmospheric electrical discharges to aircraft and associated meteorological conditions. Information is given that is designed to give a fairly comprehensive view of the underlying principles of meteorology and atmospheric electricity. Of special interest to pilots are lists of procedures of flight conduct and aircraft maintenance recommended foe avoiding or minimizing the hazards of disruptive electrical discharges and other severe conditions near thunderstorms.
- Stress Analysis of Columns and Beam Columns by the Photoelastic Method
- "Principles of similarity and other factors in the design of models for photoelastic testing are discussed. Some approximate theoretical equations, useful in the analysis of results obtained from photoelastic tests are derived. Examples of the use of photoelastic techniques and the analysis of results as applied to uniform and tapered beam columns, circular rings, and statically indeterminate frames, are given. It is concluded that this method is an effective tool for the analysis of structures in which column action is present, particularly in tapered beam columns, and in statically indeterminate structures in which the distribution of loads in the structures is influenced by bending moments due to axial loads in one or more members" (p. 1).
- The Column Strength of Aluminum Alloy 75S-T Extruded Shapes
- "Because the tensile strength and tensile yield strength of alloy 75S-T are appreciably higher than those of the materials used in the tests leading to the use of the straight-line column curve, it appeared advisable to establish the curve of column strength by test rather than by extrapolation of relations determined empirically in the earlier tests. The object of this investigation was to determine the curve of column strength for extruded aluminum alloy 75S-T. In addition to three extruded shapes, a rolled-and-drawn round rod was included" (p. 1).
- A General Method of Selecting Foam Inhibitors
- Note presenting a criterion for selecting foam inhibitors from insoluble liquids that form emulsions with the foaming liquid. By determining the surface tensions of the foaming liquid and of the additive saturated with that liquid and the interfacial tension between them, spreading and entering coefficients may be calculated. A mechanism of foam inhibition is also described.
- A Discussion of the Application of the Prandtl-Glauert Method to Subsonic Compressible Flow Over a Slender Body of Revolution
- Note presenting an analysis of the use of the Prandtl-Glauert method for subsonic potential flow of a compressible fluid. This paper specifically focuses on the difference between the two- and three-dimensional flow when using this method.
- A preliminary study of a propeller powered by gas jets issuing from the blade tips
- From Summary: "Computations are made of the performance of a propeller designed to develop 56 thrust horsepower at 100 miles per hour. The fuel consumption of the jet-operated propeller would be considerably higher than that of a reciprocating engine and a propeller. The lighter weight of the jet-operated propeller will result in a lighter weight of engine plus fuel for short-range flights. A theoretical analysis is made of a propeller powered by gas jets issuing from the blade tips."
- Comparison of relative sensitivities of the knock limits of two fuels to six engine variables
- Report presenting knock testing of a sensitive fuel and a relatively insensitive fuel in a full-scale air-cooled cylinder. Six engine variables were investigated: fuel-air ratio, compression ratio, inlet-air temperature, spark advance, exhaust pressure, and cylinder temperature.
- Flow Tests of an NACA-Designed Supercharger Inlet Elbow and the Effects of Various Components on the Flow Characteristics at the Elbow Outlet
- Note presenting an investigation on a supercharger inlet elbow designed to have a uniform velocity distribution at the outlet with a minimum pressure loss through the bend. The effects of a vane, an impeller-shaft housing, and the combination of the two on the outlet-velocity distribution and total pressure drop through the elbow were determined.
- Methods for Determination and Computation of Flow Patterns of a Compressible Fluid
- Note presenting a well-known method of generating stream functions of an incompressible fluid flow, which involves taking the imaginary part of an analytic function of a complex variable. This paper is specifically devoted to a detailed discussion of performing computations related to obtaining flow patterns of compressible fluid from analytic functions of a compressible fluid. An example is also provided to illustrate the method.
- Performance of Hoods for Aircraft Exhaust-Gas Turbines
- Report presenting the performance of a turbosupercharger turbine with three types of exhaust hood. The results for conical hoods, flat-nozzle hoods, and short-turning-radius hoods are provided.
- Compressive Strength of 24S-T Aluminum-Alloy Flat Panels With Longitudinal Formed Hat-Section Stiffeners
- "Results are presented for a part of a test program on 24S-T aluminum alloy flat compression panels with longitudinal formed hat-section stiffeners. This part of the program is concerned with panels in which the thickness of the stiffener materials is 0.625 times the skin thickness. The results, presented in tabular and graphical form, show the effect of the relative dimensions of the panel on the buckling stress and the average stress at maximum load" (p. 1).
- The Synthesis and Purification of Aromatic Hydrocarbons 1: Butylbenzene
- "A 13-gallon quantity of butylbenzene was synthesized and purified by large-scale preparation of 4-phenyl-1-butene from benzyl-magnesium chloride and allyl chloride with subsequent hydrogenation of the olefin. The physical constants for pure samples of 4-phenyl-1-butene and butylbenzene were determined and the position of the double bond in the olefin was established" (p. 1).
- A Relaxation Procedure for the Stress Analysis of a Continuous Beam-Column Elastically Restrained Against Deflection and Rotation at the Supports
- Note presenting a method of stress analysis for a continuous beam-column supported by deflectional and rotational springs. The principal feature of the method is the use of a relaxation procedure to determine the deflections and rotations of the supports. The shears and moments at the supports and between the supports can then be calculated with the aid of sample equations and graphs.
- The effect of engine variables on the prediction-limited performance of three fuels
- Report presenting preignition-limited performance data for S reference fuel, diisobutylene, and benzene with an engine-heated hot spot on a supercharged CFR engine at 11 sets of engine operating conditions. Results indicated that increases in compression ratio, spark advance, coolant temperature, or inlet-air temperature decreased the preignition-limited indicated mean effective pressure of all three fuels.
- Flight investigation of the cooling characteristics of a two-row radial engine installation 3: engine temperature distribution
- From Summary: "The temperature distribution of a two-row radial engine in a twin-engine airplane has been investigated in a series of flight tests. The test engine was operated over a wide range of conditions at density altitudes of 5000 and 20,000 feet; quantitative results are presented showing the effects of flight and engine variables upon average engine temperature and over-all temperature spread. Discussions of the effect of the variables on the shape of the temperature patterns and on the temperature distribution of individual cylinders are also included."
- Pressure Distributions for Representative Airfoils and Related Profiles
- Note presenting selected pressure-distribution diagrams for a number of conventional and special airfoils. The conventional airfoils include the NACA 22, 44, and 230 series airfoils and Clark Y family and the special airfoils consist of circular-arc sections of several thicknesses and a number of synthetic airfoils. The pressure distributions are in most cases given for several lift coefficients including that at the ideal angle of attack.
- An Electron Microscope Study of Used Nitrated-Steel Piston Rings
- Note presenting a study of the altered surface layers found on nitrided-steel piston rings run in nitrided-steel cylinder barrels in order to determine the physical and chemical characteristics of the altered layers and the mechanism by which the coating layers were formed. An electron and a light microscope were used to study different aspects of the materials.
- Investigation of the Stability of the Laminar Boundary Layer
- Note presenting an investigation of the stability of two-dimensional laminar flows of a gas by the method of small perturbations. The chief emphasis is placed on the case of the laminar boundary layer.
- A method for the determination of air infiltration rates in airplane cabins
- From Summary: "A method for the experimental determination of the rate of infiltration of air into aircraft cabins during flight has been developed and tested. This method consists of releasing a quantity of gas in the cabin and calculating the infiltration rate from the measured rate of change of the gas concentration. The results of the flight tests indicate that after the infiltration rate is established at one altitude and airspeed, the infiltration rates at other altitudes and airspeeds can be calculated."
- Stress Rupture of Heat Resisting Alloys as a Rate Process
- Note presenting the application of the equations of the theory of rate processes to stress rupture in order to predict the experimental stress and temperature dependence of the time for rupture for three heat-resisting alloys. Results regarding stress dependence, temperature dependence of slope factor, and temperature dependence of apparent free energy of activation are provided.
- Strain-Gage Study of Internally Cooled Exhaust Valves Having Various Throat Designs
- Note presenting three internally cooled exhaust valves with the same external dimensions but different throat designs were investigated to determine a method of obtaining increased coolant-flow area with increasing stresses. The valves were statistically loaded to simulate stresses in the throat region caused by valve closure.
- The Synthesis and Purification of Aromatic Hydrocarbons 2: 1, 2, 4-Trimethylbenzene
- Note presenting a new method for the synthesis and purification of a 14-gallon quantity of 1,2,4-trimethylbenzene. The method consists in the chloromethylation of m- and p-xylenes, subsequent formation of ethyl dimethylbenzyl ethers, and hydrogenolysis of the ethers to yield the hydrocarbon. Results regarding chloromethylation of xylene, conversion of dimethylbenzyl chlorides to ethyl dimethylbenzyl ethers, hydrogenolysis of the ethyl dimethylbenzyl ethers, and identification of biproducts are provided.
- Turbosupercharger-Rotor Temperatures in Flight
- Note presenting temperatures of a turbosupercharger rotor measured in flight for a variety of conditions by thermocouples, the leads of which were brought away from the turbine by means of rotating slip rings and stationary brushes. A consistent and almost linear relation was shown between turbine temperature at the outer edge of the rim and the effective exhaust-gas temperature at the surfaces of the blades on three successive flights at cruising power.
- The Synthesis and Purification of Aromatic Hydrocarbons 3: Isobutylbenzene, Sec-Butylebenzene and Tert-Butylbenzene
- Note presenting a description of the synthesis of isobutylbenzene, sec-butylbenzene, and tert-butylbenzene in 11-gallon quantities. The physical properties are tabulated and freezing curves are plotted for the five hydrocarbons.
- The infrared spectra of spiropentane methylenecyclobutane and 2-methyl-1-butene
- The infrared spectra of spiropentane, methylenecyclobutane, and 2-methyl-1-butene were measured in the region from 3 to 14 microns with a rock salt prism spectrometer of medium dispersion. The pure samples were prepared at the NACA Cleveland Laboratory. The vapors of these three C5 hydrocarbons were investigated at room temperature and at pressures in the range from 80 to 300 millimeters of mercury absolute in a 10-centimeter cell. The spectra were compared with each other and with Ramon spectra for the same compounds.
- The synthesis of methylenecyclobutane, spiropentane, and 2-methyl-1-butene from pentaerythrityl tetrabromide
- From Summary: "Reduction of pentaerythrityl tetrabromide in ethanol with zinc in the presence of sodium carbonate and sodium iodide was found to yield methylenecyclobutane, spiropentane, and 2-methyl-l-butene. Yields were 46 percent methylenecyclobutane, 21 percent spiropentane, and 12 percent 2-methyl-l-butene. The reduction procedure described offers a method of preparing both methylenecyclobutane and spiropentane from the same reaction in yields comparable with individual methods of synthesis previously reported."
- The Synthesis and Purification of Aromatic Hydrocarbons 5: 1-Ethyl-3-Methylbenzene
- "The method used for the synthesis and purification of an 8-gallon quantity of 1-ethyl-3-methylbenzene from m-creosol consists in obtaining m-methylcyclohexanone from m-creosol by hydrogenation followed by oxidation, condensation of the ketone with ethylmagnesium bromide, dehydration of the tertiary alcohol obtained, and the dehydration of the olefins to 1-ethyl-3-methylbenzene. A yield of 28 percent of the theoretical was obtained from 98 percent commercial m-creosol. The physical properties of the 1-ethyl-3-methylbenzene are compared with selected values from the literature" (p. 1).
- Tensile Properties of a Sillimanite Refractory at Elevated Temperatures
- Report presenting an investigation of the tensile strength, stress-to-rupture characteristics, and modulus of elasticity of a sillimanite refractory at various temperatures. The tensile strength varied greatly with temperature.
- Structural hinge-moment increments caused by hinge-axis distortion
- Report presenting an investigation of elevators with three hinges to evaluate the structural hinge-moment increments resulting from changing the elevator angle when the hinge axis is distorted under load. The analytical results are compared to test data obtained for a full-scale semispan fighter-type horizontal tail surface in the 16-foot high-speed tunnel.
- Quantitative Treatment of the Creep of Metals by Dislocation and Rate-Process Theories
- Note presenting an equation for the steady-state rate of creep, which has been derived by applying the theory of dislocations to the creep of pure metals. The form of this equation is in good agreement with empirical equations describing creep rates. A discussion of the way the theory can be applied to alloys, in particular heat-resisting alloys, is also provided.
- Effect of Normal Pressure on Strength of Axially Loaded Sheet-Stringer Panels
- Note presenting tests under combined axial load and normal pressure on 29 24S-T aluminum alloy sheet-stringer panels. Empirical formulas were derived for predicting the effect of normal pressure on the strain for buckling of sheet between stringers. Results of buckling, sheet load, strains, buckling, and failure are provided.
- Column Strength of Aluminum Alloy 14S-T Extruded Shapes and Rod
- Note presenting an investigation of the use of aluminum alloy 14S-T in heavy-duty structural applications and aircraft. The column data presented in this report have been obtained on extruded shapes and on rolled and drawn rod of the alloy.
- Extension of the Chaplygin Proofs on the Existence of Compressible-Flow Solutions to the Supersonic Region
- "It has been known for some time that the velocity of sound is not the upper limit for potential flow. S. A. Chaplygin in his paper "On Gas Jets" (NACA TM No. 1063) carried out some interesting proofs on the existence of solutions and gave proofs relating to maxima and minima of certain functions. In the present paper these proofs are extended to include the supersonic potential air-flow field adjacent to the subsonic region treated by Chaplygin" (p. 1).
- A Condition on the Initial Shock
- "Initial shocks of the type that occur on airfoils at stream Mach numbers less than unity are shown to satisfy a certain condition, namely, that the local Mach number behind the shock wave tends to approach unity. This result is, in nature, similar to the classic condition of Kutta on the circulation" (p. 1).
- The effect of geometric dihedral on the aerodynamic characteristics of a 40 degree swept-back wing of aspect ratio 3
- Report presenting force tests at low Reynolds numbers to determine the effect of changes in the geometric dihedral on the aerodynamic characteristics of a wing of aspect ratio 3 with an angle of sweepback of 40 degrees measured at the quarter-chord line. Results regarding lift characteristics, pitching-moment characteristics, rolling-moment characteristics, and yawing moment and lateral force are provided.
- Steady- and intermittent-flow coefficients of poppet intake valves
- Report presenting flow coefficients of an intake valve, seat, and port combination were measured under steady- and intermittent-flow conditions. Tests were conducted at large and small pressure drops over an engine-speed range of 800 to 3600 rpm.
- Thermodynamic Charts for the Computation of Combustion and Mixture Temperatures at Constant Pressure
- Report presenting charts for calculating the combustion temperatures and temperature changes involved in constant-pressure thermodynamic processes of air and the products of combustion of air and hydrocarbon fuels. Examples for different types of fuel and temperature calculation using the charts are also provided.
- Comparison of Static Strengths of Machine Countersunk Riveted Joints in 24S-T, X75S-T, and Alclad 75S-T Sheet
- Note presenting static tests made on machine-countersunk riveted joints in 24S-T, X75S-T, and Alclad 75S-T sheet using A17S-T and 24S-T rivets. In order to intensify the cutting action of the rivets, all specimens were made with the depth of countersink just equal to the thickness of the sheet.
- The Synthesis and Purification of Aromatic Hydrocarbons 4: 1,2,3-Trimethylbenzene
- "A six gallon quantity of 1,2,3-trimethylbenezene was prepared and purified in a four-step synthesis involving the condensation of 1,3-pentadiene with crotonaldehyde. The dimethylcyclohexencarboxaldehydes formed were hydrogenated to give the corresponding isomeric dimethylcyclohexylcarbinols. The dehydration of the carbinols and the subsequent dehydrogenation of the trimethylcyclohexenes yielded the 1,2,3-trimethylbenzene. The overall yield was 24 percent; the physical properties of the materials are given" (p. 1).
- Wake studies of eight model propellers
- Report presenting an investigation of the influences of shank form and pitch distribution on the characteristics of constant-speed propellers as determine from the wakes of eight model propellers. The experiments show that an improvement in efficiency occurs from the substitution of faired shanks for round ones, which is caused by disproportionate local augmentations of thrust and torque. Results regarding a comparison with force tests, method of comparing performance characteristics, effects of shank form, effects of pitch distribution, independence of blade elements, and section lift characteristics are provided.
- The Fatigue Characteristics of Bolted Lap Joints of 24S-T Alclad Sheet Materials
- Report presenting fatigue testing to determine the effect of bolt fit on the lifetime of lap joints of 24S-T Alclad sheet of various thicknesses joined by steel bolts and designed for sheet failure under repeated loading. Results regarding joints with countersunk bolts, joints with bolts drawn to high initial torque, joints with bolts of different diameters, multibolt joints with nonuniform bolt fit, fatigue strength of the sheet material, friction in bolted lap joints, and bolt slip during testing are provided.
- Flutter and oscillating air-force calculations for an airfoil in a two-dimensional supersonic flow
- An account is given of the Possio theory of non stationary flow for small disturbances in a two-dimensional supersonic flow and of its application to determination of the aerodynamic forces on an oscillating airfoil. Further application is made to the problem of wing flutter in the degrees of freedom - torsion, bending, and aileron torsion. Numerical tables for flutter calculations are provided for numerous values of the Mach number greater than unity. Results for bending-torsion wing flutter are discussed. The static instabilities of divergence and aileron reversal are examined as is a one degree of freedom case of torsional oscillatory instability.
- Flight Investigation of the Effect of a Local Change in Wing Contour on Chordwise Pressure Distribution at High Speeds
- Report presenting testing in high-speed flight with a fighter airplane to determine the effect of chordwise pressure distribution resulting from a minor modification in the contour of the wing upper surface. A faired bulge was added to the contour and chordwise pressure distributions were obtained on the original and modified contours.