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Large deflection of curved plates

Description: Report presenting a treatment of several problems on the large deflections of curved plates with compound curvature. Testing demonstrated that the effective width of the curved plates in longitudinal compression is reduced by the presence of an initial deflection function.
Date: October 1956
Creator: Lew, H. G.; Fox, J. A. & Loo, T. T.
Partner: UNT Libraries Government Documents Department

Bearing strengths of bare and alclad XA75S-T and 24S-T81 aluminum alloy sheet

Description: From Introduction: "A report was recently issued covering an investigation of the bearing properties of the wrought aluminum alloys commonly used in aircraft construction (reference 1). Since this work was undertaken, two new materials, XA75S-T and 24S-T81, have been developed to the commercial stage for aircraft use. The objection of this investigation was to determine the bearing yield and ultimate strengths of these new materials in the form of bare and alclad sheet."
Date: December 1943
Creator: Moore, R. L. & Wescoat, C.
Partner: UNT Libraries Government Documents Department

Determination of plate compressive strengths at elevated temperatures

Description: The results of local-instability tests of h-section plate assemblies and compressive stress-strain tests of extruded 75s-t6 aluminum alloy, obtained to determine flat-plate compressive strength under stabilized elevated temperature conditions, are given for temperatures up to 600 degrees F. The results show that methods available for calculating the critical compressive stress at room temperature can also be used at elevated temperatures if the applicable compressive stress-strain curve for the material is given.
Date: 1950
Creator: Heimerl, George J. & Roberts, William M.
Partner: UNT Libraries Government Documents Department

Effect of pH on strength of resin bonds

Description: Report presenting an investigation to determine the effect of acid on the strength and aging properties of various types of resin bonds for plywood. The pH values of the birch plywoods, flexural and impact strengths before and after aging of birch plywoods bonded with urea-formaldehyde resins and phenolic resins, and delamination properties of birch plywoods bonded with each type of resin are provided.
Date: October 1943
Creator: Rinker, R. C.; Reinhart, F. W. & Kline, G. M.
Partner: UNT Libraries Government Documents Department

Effect of variables in welding technique on the strength of direct-current metal-arc-welded joints in aircraft steel II: repeated-stress tests of joints in SAE 4130 seamless steel tubing

Description: From Summary: "A series of tests were made for the purposes of establishing the effects of several variables in welding technique on the fatigue strength of arc-welded joints in SAE 4130 seamless steel tubing. The variables included type of electrode, speed of welding, current, position, amount of preheat, and other factors which in turn controlled the weld contour, penetration, and depth of the heat-affected zone. A range of joint design was also investigated."
Date: April 1948
Creator: Voldrich, C. B. & Armstrong, E. T.
Partner: UNT Libraries Government Documents Department

Effect of ratio of rivet pitch to rivet diameter on the fatigue strength of riveted joints of 24S-T aluminum alloy sheet

Description: From Summary: "An extensive series of tests were conducted on riveted joints to determine the effect of rivet size and rivet pitch on the fatigue lift of joints subjected to "prying" (combined tensile and bending) loads. For each sheet thickness tested, there appeared to be a value of the ratio of rivet pitch to rivet diameter that would ensure a near maximum of the ratio of fatigue strength to static ultimate strength for the joint."
Date: September 1946
Creator: Crate, Harold; Ochiltree, David W. & Graves, Walter T.
Partner: UNT Libraries Government Documents Department

The properties of three cast polyester resins of Sierracin 212, 212A, and 250A

Description: From Summary: "Physical properties of samples of three cast polyester resins known as Sierracin resins were investigated. Tests were made to determine specific gravity, index of refraction, Rockwell hardness, Tukon indentation hardness, effect of exposure to accelerated and outdoor weathering, Munsell color, resistance to accelerated service tests, crazing resistance under stress, flexural strength, Izod impact strength, and Taber abrasion resistance. Tables of the values obtained for these physical properties are included in the report."
Date: April 23, 1951
Creator: Kline, G. M.
Partner: UNT Libraries Government Documents Department

Synthetic resins in aircraft construction - their composition, properties, present state of development and application to light structures

Description: This report gives a brief review of the properties that have been attained with the synthetic materials with which we are at present familiar. Results of investigations are presented as well as possibilities for construction applications. Endurance strength and bonding tests are also presented.
Date: November 1937
Creator: Riechers, K.
Partner: UNT Libraries Government Documents Department

Notes on the construction and testing of model airplanes

Description: Here, it is shown that the construction of an airplane model can and should be simplified in order to obtain the most reliable test data. General requirements for model construction are given, keeping in mind that the general purpose of wind tunnel tests on a model airplane is to obtain the aerodynamic characteristics, the static balance, and the efficiency of controls for the particular combination of wings, tail surfaces, fuselage, and landing gear employed in the design. These parts must be exact scale reproductions. Any appreciable variation from scale reproduction must be in the remaining parts of the model, i.e., struts, wires, fittings, control horns, radiators, engines, and the various attachments found exposed to the wind in special airplanes. Interplane bracing is discussed in some detail.
Date: January 1922
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department

Restraint provided a flat rectangular plate by a sturdy stiffener along an edge of the plate

Description: From Summary: "A sturdy stiffener is defined as a stiffener of such proportions that it does not suffer cross-sectional distortion when moments are applied to some part of the cross section. When such a stiffener is attached to one edge of a plate, it will resist rotation of that edge of the plate by means of its torsional properties. A formula is given for the restraint coefficient provided the plate by such a stiffener. This coefficient is required for the calculation of the critical compressive stress of the plate."
Date: March 13, 1941
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

A study of the efficiency of high-strength, steel, cellular-core sandwich plates in compression

Description: Structural efficiency curves are presented for high-strength, stainless-steel, cellular-core sandwich plates of various proportions subjected to compressive end loads for temperatures of 80 F and 600 F. Optimum proportions of sandwich plates for any value of the compressive loading intensity can be determined from the curves. The efficiency of steel sandwich plates of optimum proportions is compared with the efficiency of solid plates of high-strength steel and aluminum and titanium alloys at the two temperatures.
Date: September 1956
Creator: Johnson, Aldie E., Jr. & Semonian, Joseph W.
Partner: UNT Libraries Government Documents Department

Mechanical properties of some materials used in airplane construction

Description: Since lightness is desirable in airplane construction, greater stresses must be tolerated than in other kinds of construction. It is therefore necessary to have a more accurate knowledge of the greatest stresses that may occur and of the actual properties of the materials used. The Aeronautic Research Laboratories took the limit of elasticity as the basis of the strength calculations. Many tests were made of different steels, woods, aluminum alloys, and fabrics.
Date: January 1928
Creator: Wolff, E. B. & Van Ewijk, L. J. G.
Partner: UNT Libraries Government Documents Department

Glues used in airplane parts

Description: This report was prepared for the National Advisory Committee for Aeronautics and presents the results of investigations conducted by the Forest Products Laboratory of the United States Forest Service on the manufacture, preparation, application, testing and physical properties of the different types of glues used in wood airplane parts.
Date: 1920
Creator: Allen, S. W. & Truax, T. R.
Partner: UNT Libraries Government Documents Department

Approximate analysis of effects of large deflections and initial twist on torsional stiffness of a cantilever plate subjected to thermal stresses

Description: From Summary: "An approximate analysis of the nonlinear effects of initial twist and large deflections on the torsional stiffness of a cantilever plate subjected to a nonuniform temperature distribution is presented. The Von Karman large-deflection equations are satisfied through the use of a variational principle. The results show that initial twist and applied moments can have significant effects on the changes in stiffness produced by nonuniform heating, particularly in the region of the buckling temperature difference. Results calculated by this approximate analysis are in satisfactory agreement with measured torsional deformations and changes in natural frequency."
Date: May 15, 1957
Creator: Heldenfels, Richard R. & Vosteen, Louis F.
Partner: UNT Libraries Government Documents Department

Approximate analysis of effects of large deflections and initial twist on torsional stiffness of a cantilever plate subjected to thermal stresses

Description: Report presenting an approximate analysis of the nonlinear effects of initial twist and large deflections on the torsional stiffness of a cantilever plate subjected to a nonuniform temperature distribution. The results show that the initial twist and applied moments can have significant effects on the changes in stiffness produced by nonuniform heating. Results regarding the general results of equations and comparison with experiment are provided.
Date: August 1957
Creator: Heldenfels, Richard R. & Vosteen, Louis F.
Partner: UNT Libraries Government Documents Department

The development of German Army airplanes during the war

Description: From Summary: "The author, who was a captain of the Reserves in the Technical Department of the Aviation Division (Board of Airplane Experts) during the war, shows what means were taken for the creation of new airplane types and what tests were employed for trying out their flying properties, capacities and structural reliability. The principal representative types of each of the classes of airplanes are described and the characteristics of the important structural parts are discussed. Data regarding the number of airplanes at the front and the flying efficiency of the various classes of airplanes are given."
Date: June 1921
Creator: Hoff, Wilhelm
Partner: UNT Libraries Government Documents Department

Analysis of stresses in German airplanes

Description: This report contains an account of the origin of the views and fundamental principles underlying the construction of German airplanes during the war. The report contains a detailed discussion of the aerodynamic principles and their use in determining the strength of airplanes, the analysis of the strength qualities of materials and in the construction, the calculated strength of air flows and a description of tests made in determining the strength of airplanes.
Date: 1922
Creator: Hoff, Wilhelm
Partner: UNT Libraries Government Documents Department

Experimental research on air propellers, 2

Description: This report is a continuation of NACA Technical Report 14. It presents the results of an experimental investigation on the performance of air propellers which was divided into five parts, as follows: (1) Tests under conditions of flight on 16 model propellers of different forms, sections, or pitch ratios from those of Technical Report 14; (2) Tests under conditions of flight on one model propeller of variable pitch; (3) Tests under conditions of flight on three sets of right and left hand model propellers in series; (4) Tests on 12 model propellers to determine brake effect or negative thrust at negative slip; (5) Standing thrust and power tests of 67 model propellers.
Date: 1919
Creator: Durand, William F. & Lesley, E. P.
Partner: UNT Libraries Government Documents Department

The general theory of blade screws including propellers, fans, helicopter screws, helicoidal pumps, turbo-motors, and different kinds of helicoidal blades

Description: Report presents a theory which gives a complete picture and an exact quantitative analysis of the whole phenomenon of the working of blade screws, but also unites in a continuous whole the entire scale of states of work conceivable for a blade screw. Chapter 1 is devoted to the establishment of the system of fundamental equations relating to the blade screw. Chapter 2 contains the general discussion of the 16 states of work which may establish themselves for a blade screw. The existence of the vortex ring state and the whirling phenomenon are established. All the fundamental functions which enter the blade-screw theory are submitted to a general analytical discussion. The general outline of the curve of the specific function is examined. Two limited cases of the work of the screw, the screw with a zero constructive pitch and the screw with an infinite constructive pitch, are pointed out. Chapter 3 is devoted to the study of the propulsive screw or propeller. (author).
Date: 1919
Creator: De Bothezat, George
Partner: UNT Libraries Government Documents Department

The strength of one-piece solid, build-up and laminated wood airplane wing beams

Description: The purpose of this report is to summarize the results of all wood airplane wing beams tested to date in the Bureau of Standards Laboratory in order that the various kinds of wood and methods of construction may be compared. All beams tested were of an I section and the majority were somewhat similar in size and cross section to the front wing beam of the Curtiss JN-4 machine. Construction methods may be classed as (1) solid beams cut from solid stock; (2) three-piece beams, built up of three pieces, web and flanges glued together by a tongue-and-groove joint and (3) laminated beams built up of thin laminations of wood glued together.
Date: 1920
Creator: Nelson, John H.
Partner: UNT Libraries Government Documents Department

Development of metal-bonding adhesives with improved heat-resistant properties

Description: From Summary: "Results are reported of current studies at the Forest Products Laboratory to develop a metal-bonding adhesive with greater resistance to temperatures up to 600 degrees Fahrenheit that is easier to use than present ones. Most promising is a formulation of phenol and epoxy resins modified with hexamethylenetetramine and supplied for use as a dry tape supported on a glass-mat base."
Date: May 14, 1954
Creator: Black, John M. & Blomquist, R. F.
Partner: UNT Libraries Government Documents Department

Development of craze and impact resistance in glazing plastics by multiaxial stretching

Description: The loss of strength of cast polymethyl methacrylate plastic as a result of crazing is of considerable importance to the aircraft industry. Because of the critical need for basic information on the nature of crazing and the effects of various treatments and environmental conditions on its incidence and magnitude, an investigation of this phenomenon was undertaken. The following factors were examined: (1) the effect of stress-solvent crazing on tensile strength of polymethyl methacrylate; (2) the critical stress and strain for onset of crazing at various temperatures; (3) the effect of molecular weight on crazing; and (4) the effect of multiaxial stretching on crazing of polymethyl methacrylate and other acrylic glazing materials.
Date: December 28, 1955
Creator: Kline, G. M.; Wolock, I.; Axilrod, B. M.; Sherman, M. A.; George, D. A. & Cohen, V.
Partner: UNT Libraries Government Documents Department