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Calorimetric Determination of Constant-Pressure Specific Heats of Carbon Dioxide at Elevated Pressures and Temperatures
Note presenting the measurement of the constant-pressure specific heat of carbon dioxide over the range of pressures and temperatures from ambient conditions to 1000 pounds per square inch gage and 1000 degrees Fahrenheit using a steady-flow calorimeter operating on an open cycle. The results of the tests check the widely accepted spectroscopic data within 1 percent. Results regarding the validity of results, presentation of results, and limitations of the calorimeter are provided.
Date:
December 1952
Creator:
Schrock, Virgil E.
System:
The UNT Digital Library
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.
Date:
May 1946
Creator:
Harrison, L. P.
System:
The UNT Digital Library
Numerical procedures for the calculation of the stresses in monocoques 3: calculation of the bending moments in fuselage frames
"This report deals with the calculation of the bending moments in and the distortions of fuselage rings upon which known concentrated and distributed loads are acting. In the procedure suggested, the ring is divided into a number of beams each having a constant radius of curvature. The forces and moments caused in the end sections of the beams by individual unit displacements of the end sections are listed in a table designated as the operations table in conformity with Southwell's nomenclature. The operations table and the external loads are equivalent to a set of linear equations" (p. 1).
Date:
April 1946
Creator:
Hoff, N. J.; Libby, Paul A. & Klein, Bertram
System:
The UNT Digital Library
Numerical procedures for the calculation of the stresses in monocoques 4: influence coefficients of curved bars for distortions in their own plane
"Formulas for the calculation of influence coefficients of curved beams of constant radius of curvature are presented corresponding to displacements in the plane of curvature. Moreover, numerical values are given in tabular and graphic form for a limited number of values of the parameter involved" (p. 1).
Date:
April 1946
Creator:
Hoff, N. J.; Klein, Bertram & Libby, Paul A.
System:
The UNT Digital Library
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).
Date:
March 1946
Creator:
Ruffner, B. F.
System:
The UNT Digital Library
The theoretical flow of a frictionless, adiabatic, perfect gas inside of a two-dimensional hyperbolic nozzle
Report presenting a study of the two-dimensional flow of a frictionless, adiabatic, perfect gas inside of a two-dimensional hyperbolic nozzle by using numerical methods.
Date:
May 1946
Creator:
Emmons, Howard W.
System:
The UNT Digital Library
Performance tests of wire strain gages 3: calibrations at high tensile strains
Report presenting results of calibration in axial tension over the strain range 0 to 0.03 are presented for 15 types of single element, multistrand wire strain gages. Considerable nonlinearity was observed at strains between 0.0025 and 0.006. Fifty-eight percent of the gages failed by breaking of the strain-sensitive wire at strains less than 0.03.
Date:
December 1945
Creator:
Campbell, William R.
System:
The UNT Digital Library
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).
Date:
January 1946
Creator:
Holt, Marshall & Leary, J. R.
System:
The UNT Digital Library
Axial Fatigue Test at Two Stress Amplitudes of 0.032-Inch 24S-T Sheet Specimens With a Circular Hole
Report presenting testing of the effect of applying a number of cycles of a high fatigue stress followed by a number of cycles of relatively low stress to failure has been investigated on 93 drilled specimens of a 24S-T sheet. The results indicated that any general formula for endurance must take sequence into consideration, which makes overly simple formulas inadequate to describe endurance over varying stress amplitudes.
Date:
July 1945
Creator:
Brueggeman, W. C.; Mayer, M., Jr. & Smith, W. H.
System:
The UNT Digital Library
The Effect of Temperature on Sheet Metals for Airplane Firewalls
Note presenting tests conducted on 5 uncoated steels and 20 steels with various coatings to determine the effect of temperature on the tensile properties and surface characteristics of the metals. The metals were subjected to furnace-heating tests over a range of temperatures for various times and to flame-impingement and airplane-fire tests. Results regarding metals without surface coatings, low carbon steels with surface coatings, and discussion of comparative behaviors regarding the different surface coatings are provided.
Date:
December 1944
Creator:
Mutchler, Willard
System:
The UNT Digital Library
Fatigue Tests on 1/8-inch Aluminum Alloy Rivets
Note presenting an investigation of the fatigue characteristics of riveted joints in aluminum alloy sheet. The purpose of this report is to summarize all the results of fatigue tests that have been made to date in the Aluminum Research Laboratories of lap joints with 1/8-inch aluminum alloy rivets.
Date:
February 1945
Creator:
Andrews, H. J. & Holt, M.
System:
The UNT Digital Library
Performance tests of wire strain gages 2: calibration factors in compression
Report presenting the results of calibrations in axial compression over the strain range 0 to 0.0021 for 15 types of single element multistrand wire strain gages. The majority of gages showed significant differences between the calibration factors for strain increasing and strain decreasing. The majority of the gages were found to have slightly lower factors in compression than in tension.
Date:
September 1945
Creator:
Campbell, William R.
System:
The UNT Digital Library
Effect of Aging Aircraft Structures on Magnesium Parts
Note presenting an analysis of a procedure for artificially aging assemblies and subassemblies to improve the strength properties of the wrought aluminum alloys comprising their principal structure. Information is given on the magnesium alloys which may be present. The forms in which magnesium alloys may be encountered are casings, extrusions, forgings, and sheet.
Date:
April 1945
Creator:
Winston, A. W.
System:
The UNT Digital Library
Bearing strengths of 75S-T aluminum-alloy sheet and extruded angle
Report presenting an investigation to determine the bearing yield and ultimate strengths of 75S-T alloy in sheet form in both with- and across-grain directions and extruded angle in the longitudinal direction. Ratios of bearing to tensile properties were also determined.
Date:
February 1945
Creator:
Wescoat, C. & Moore, R. L.
System:
The UNT Digital Library
An approximate method for determining the displacement effects and viscous drag of laminar boundary layers in two-dimensional hypersonic flow
From Summary: "A simplified approximate theory is presented by means of which the laminar boundary layer over an insulated two-dimensional surface may be calculated, a linear velocity profile being assumed, and an estimate made of its effect in changing the pressure distribution over the profile upon which the boundary layer is formed. Skin friction is also determined. Comparisons of results from this theory are made with experimental results at a Mach number of 6.86 and a Reynolds number of 980,000."
Date:
September 1952
Creator:
Bertram, Mitchel H.
System:
The UNT Digital Library
The Chemical Action of Oils on Single Crystals of Metals
Note presenting a study of the chemical action of oils on large single crystals of metals in the presence of various gases, with special emphasis placed on the influence of crystal plane. The studies primarily have been concerned with four metals: silver, copper, lead, and iron and four types of oil: pure hydrocarbons with mineral oil as representative, oiliness agents with stearic acid as representative, chemical polishing agents with tricresyl phosphate as representative, and commercial oils with new and used aviation oils as representatives. The methods used in preparing large single crystals of various metals are briefly discussed.
Date:
November 1945
Creator:
Gwathmey, A. T.; Leidheiser, H. & Smith, G. P.
System:
The UNT Digital Library
Nondestructive Measurement of Residual and Enforced Stresses by Means of X-Ray Diffraction 2: Some Applications to Aircraft Problems
Note presenting tests on the use of x-ray diffraction methods for determining surface stress distributions in notched tensile bars and in the vicinity of a welded joint in aircraft steel tubing. Data on the effects of stress and degree of notching on the principal stresses and stress-concentration factors for flat notched tensile-test specimens were obtained.
Date:
November 1945
Creator:
Sachs, George; Smith, Charles S.; Lubahn, Jack D.; Davis, Gordon E. & Ebert, Lynn J.
System:
The UNT Digital Library
Analytical study of transmission of load from skin to stiffeners and rings of pressurized cabin structure
From Introduction: "The investigations in this paper were made to obtain more generalized mathematical analyses of monocoque structure subjected to internal pressure. It is also assumed that the principle of superposition can be applied, so that stress analysis of a structure with combined internal pressure and external load can be made without excessive complication."
Date:
October 1945
Creator:
Pian, Theodore Hsueh-Huang
System:
The UNT Digital Library
Column Strength of Extruded Magnesium Alloys AM-C58S and AM-C58S-T5
"Tests have previously been made to determine the column strength of magnesium alloy AM-C58S-T5 extruded rod, but these few data were not considered a satisfactorily wide basis for establishing a general formula for the column strength of this alloy. It was therefore decided to make additional tests on a number of extruded sections of magnesium alloy AM-C58S-T5 with some tests on AM-C58S for comparison" (p. 1).
Date:
December 1945
Creator:
Leary, J. R. & Holt, Marshall
System:
The UNT Digital Library
Data on Material Properties and Panel Compressive Strength of a Plastic-Bonded Material of Glass Cloth and Canvas
Results are presented of tests for determining the tensile, compressive, and bending properties of a material of plastic-bonding glass cloth and canvas layers. In addition, 10 panel specimens were tested in compression. Although the material is not satisfactory for primary structural use in aircraft when compared on a strength-weight basis with other materials in common use, there appears to be potential strength in the material that will require research for development. These points are considered in some detail in the concluding discussion of the report. An appendix shows that a higher tensile strength can be obtained by changes in the type of weave used in the glass-cloth reinforcement.
Date:
December 1944
Creator:
Zender, George W.; Schuette, Evan H. & Weinberger, Robert A.
System:
The UNT Digital Library
Tests of Airfoils Designed to Delay the Compressibility Burble
Note presenting a method of deriving certain airfoil shapes that delay certain compressibility phenomena, and the aerodynamic data for a wide range of Mach numbers obtained from tests of the airfoils in the 24-inch high-speed tunnel. The airfoils, which are designated the NACA 16-series, have increased critical Mach number. Results regarding the airfoil comparison, critical speed, minimum drag, and use of the data are provided.
Date:
December 1944
Creator:
Stack, John
System:
The UNT Digital Library
Heat transfer from a hemisphere-cylinder equipped with flow-separation spikes
Average heat-transfer, temperature-recovery, and pressure-distribution measurements were obtained over the hemispherical nose of a body of revolution both with and without flow-separation spikes. The tests, conducted in a range of Reynolds numbers from 1.55 to 9.85 x 10(5) and from Mach number 0.12 to 5.04, indicated that in supersonic flow the addition of spikes approximately doubles the rate of heat transfer, regardless of spike length.
Date:
September 1954
Creator:
Stalder, Jackson R. & Nielsen, Helmer V.
System:
The UNT Digital Library
Nondestructive Measurement of Residual and Enforced Stresses by Means of X-Ray Diffraction 1: Correlated Abstract of the Literature
Note presenting a study of the stress measurements by means of the x-ray diffraction method, which have found considerable application in solving both commercial and laboratory problems. Two problems related to x-ray diffraction are studied and a literature review is conducted.
Date:
September 1945
Creator:
Sachs, George; Smith, Charles S.; Lubahn, Jack D.; Davis, Gordon E. & Ebert, Lynn J.
System:
The UNT Digital Library
Properties of some expanded plastics and other low-density materials
Report presenting an investigation of various mechanical and physical properties of several expanded plastics and other low-density materials of interest for aircraft applications, such as heat insulation or the core of a sandwich material. The materials in the investigation included cellulose acetate plastic, polystyrene, a urea-formaldehyde resin, a zein product, hard rubber, balsa wood, and cellular glass.
Date:
September 1945
Creator:
Axilrod, Benjamin M. & Koenig, Evelyn
System:
The UNT Digital Library