UNT Libraries Government Documents Department - 418 Matching Results

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A Study of the Effects of Radii of Gyration and Altitude on Aileron Effectiveness at High Speed: "The variation in the necessary aileron control and in the time required to bank to 45 degrees and 90 degrees with altitude and radii of gyration for a typical fighter or a pursuit airplane have been computed and are presented herein." The lateral motions and impact pressure for several conditions of flight are provided. The report concludes that "the aileron system...should be designed for rolling-moment requirements at high altitude and the hinge-moment limitations at low altitude".
A Subpress for Compressive Tests: "A subpress for compressive tests is described. The subpress was designed primarily for use in developing and investigating methods for testing thin sheet metal in compression. Provision was made for testing fixed-end and flat-end specimens with or without various types of lateral support against buckling. Compressive stress-strain data for a sheet of 0.032-inch 24S-RT aluminum alloy were obtained with the subpress by the pack method and by the single-thickness method" (p. 1).
Summary of an investigation of vanadium and uranium occurrence in Huerfano Park district, Raton Basin area, Huerfano and Costilla counties, Colorado: A report on the SOM-vanadium occurrences of the Huerfano Park District.
Survey of Subsurface Brine-Disposal Systems in Western Kansas Oil Fields: Report issued by the U.S. Bureau of Mines on the disposal of brine from oil field injections. Information on handling and disposing of brine and injection equipment is presented. This report includes tables, and a map.
Syllabus of Clay Testing: Part 1: From Introduction: "This presentation (pt. 1) is what might be termed a qualitative syllabus, in that uses only are indicated, no attempt being made to evaluate a clay quantitatively, that is, to grade for particular uses. In part 2, which is to follow, the work will be amplified both qualitatively and quantitatively. In the first, preliminary tests are made to eliminate from consideration all nonclay minerals or clay minerals containing such large amounts of impurities as to render them unfit for normal uses and also to make a broad general classification of the clay minerals into the kaolinite (shales and clays) and montmorillonite groups. In the second step, the main tests, divided into two general headings, ceramic and noncermaic, are detailed."
Tables of Stiffness and Carry-Over Factor for Flat Rectangular Plates Under Compression: Report presents tables of stiffness and carry-over factor for infinitely long flat plates subjected to a uniformly distributed longitudinal compressive load. The tables can be used to help solve problems in the stability of structures made out of plates under compression.
Tail Buffeting: "An approximate theory of buffeting is here presented, based on the assumption of harmonic disturbing forces. Two cases of buffeting are considered: namely, for a tail angle of attack greater and less than the stalling angle, respectively. On the basis of the tests conducted and the results of foreign investigators, a general analysis is given of the nature of the forced vibrations the possible load limits on the tail, and the methods of elimination of buffeting" (p. 1).
Tank tests of a 1/8-size dynamic model of the PB2Y-3 airplane with increased power: NACA model 131: Report presenting a study of the installation of 1800-horsepower engines in the PB2Y-3 airplane in place of the current 1200-horsepower engines. Stability and spray tests were made to determine the performance of the model on the water when tested at both the present and projected conditions of gross load and engine power. Results regarding aerodynamic tests and hydrodynamic tests are provided.
Tank Tests of a 1/8-Size Dynamic Model of the PB2Y-3 Airplane with Simulated Jet Motors: NACA Models 131J, 131J-1 and 131J-2: Report presenting an investigation to determine the effect of jet motors on the stability of the PB2Y-3 airplane at a gross load of 76,000 pounds. Results regarding Model 131J, Model 131J-1, and Model 131J-2 are provided.
Temperature Coefficient of the Reproduction Factor for Different Lattice Arrangements: The temperature coefficient is calculated for various lattice arrangements, taking into account the variation of [formula], suggested by Fermi. Four contributions are included: leakage, levelling of the dip in thermal neutron density in the lump, resonance absorption, and hardening of the neutrons as they penetrate a metal lump. The departure of neutron temperature from lattice temperature decreases the total coefficient. Values are given for 3 typical piles; in general, the larger the uranium elements, the less stable the pile. A rod lattice tends to be more stable. A pile with metal lumps over 50 lbs. will be unstable.
Temperature Effect in Homogeneous Pile: Some idealized considerations of the temperature field in the homogeneous pile are given. It is crudely estimated that the effective mean temperature rise of the pile to be used in calculating the k loss is something like 3/4 the rise in temperature of the slurry in passing through the pile.
Tensile and Compressive Tests of Magnesium Alloy J-1 Sheet: Note presenting tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves for longitudinal and transverse specimens of magnesium alloy J-1 sheets 0.032 and 0.102 inch thick. Significant differences were found between the tensile and compressive stress-strain curves and between the compressive stress-strain curves for the longitudinal and transverse questions.
Test Data on the Shear Strength of Joints Assembled With Round-Head and Brazier-Head Rivets: Report discusses data obtained from testing shear of joints riveted with round-head and brazier-head rivets. The tightness of the rivets is also compared for one value of rivet diameter. The load-displacement curves and comparison of load at various values of permanent displacement are presented for both types of rivets.
Tests in the NACA Two-Dimensional Low-Turbulence Tunnel of Airfoil Sections Designed to Have Small Pitching Moments and High Lift-Drag Ratios: Bulletin presenting the development and testing of airfoil sections that have small or zero pitching-moment coefficients and high lift-drag ratios. Because the new airfoil sections have small pitching moments and low profile-drag coefficients at moderate lift coefficients, they may be suitable for use on the rotor blades of rotating-wing aircraft.
Tests of 10-Inch 24S-T Aluminum-Alloy Shear Panels With 1-1/2-Inch Holes: Report discusses the results of testing on "10-inch shear panels of 24S-T aluminum alloy with 1.5 inch holes to determine the stress concentration at static rupture and the deformation characteristics" (from Summary). The strength of the perforated specimens is compared to the solid specimens and the critical stresses are computed. The stress at which permanent set occurs was also measured.
Tests of a 1/40-Scale Wing-Hull Model and a 1/10-Scale Float-Strut Model of the Hughes-Kaiser Cargo Airplane in the Two-Dimensional Low-Turbulence Pressure Tunnel: Report presenting aerodynamic and hydrodynamic tests of a 1/10-scale wing-hull model and a 1/10-scale float-strut model of the proposed arrangement of the Hughes-Kaiser cargo airplane. The aerodynamic tests were made primarily to study the drag characteristics of these models as originally designed and to determine how the design could be improved. Results regarding the wing-hull model and float-strut model are provided.
Tests of a dynamic model in NACA tank number 1 to determine the effect of length of afterbody, angle of afterbody keel, gross load, and a pointed step on landing and planning stability: Report presenting testing in tank no. 1 to determine the effect of length of afterbody, angle of afterbody keel, and gross load on the limits of stable trims and landing characteristics of a model of a flying boat with conventional steps. The studies were made with four lengths of afterbody, four angles of afterbody keel, and five gross loads. Results regarding the trim limits of stability and landing stability are provided.
Tests of Airfoils Designed to Delay the Compressibility Burble: "Fundamental investigations of compressibility phenomena for airfoils have shown that serious adverse changes of aerodynamic characteristics occur as the local speed over the surface exceeds the local speed of sound. These adverse changes have been delayed to higher free-stream speeds by development of suitable airfoil shapes. The method of deriving such airfoil shapes is described, and aerodynamic data for a wide range of Mach numbers obtained from tests of these airfoils in the Langley 24-inch high-speed tunnel are presented" (p. 1).
Tests of Aluminum-Alloy Stiffened-Sheet Specimens Cut From an Airplane Wing: "The specimens used in the present tests were cut from an actual airplane wing of the stressed-skin type. The specimens thus obtained were not representative of the usual type of laboratory specimens because the stiffeners were not exactly parallel nor evenly spaced and, in one case, the skin consisted of pieces of sheet of different thicknesses. The test data obtained indicate that the buckling strain of stiffened curved sheet can be computed with reasonable accuracy by the equation given by Wenzek" (p. 1).
Tests of Exhaust Propulsion Nozzles: "The thrust produced by a variety of exhaust stacks and nozzles, and the effect of these stacks and nozzles on the power of a single-cylinder R-2800 engine were investigated over a wide range of engine speeds and manifold pressures in a series of tests in the Pratt & Whitney experimental test department. From the data obtained it is possible to estimate the optimum form of nozzles and the available thrust for airplanes fitted with R-2800 engines under sea-level conditions" (p. 1).
Tests of flat panels with four types of stiffeners: Report presenting testing of fifty-one aluminum-alloy panels as flat-end columns. The test specimens included all possible combinations of two lengths, four stiffener spacings, and four stiffener designs, and were mostly in duplicate pairs. Results regarding the panel bending tests, panel compression tests, and column tests of individual stiffeners are provided.
Tests of Inverted Spins in the NACA Free-Spinning Tunnels: "Report discusses the results of inverted-spin tests in 44 airplane models in the NACA free-spinning tunnel. Spins were normally steep and recovery by rudder reversal was generally rapid. Pulling the stick back, deflecting ailerons and rudder together, and crossing them all had an effect on the amount of spin encountered and ease of recovery from spin" (p. 1).
Tests of two models representing intermediate inboard and outboard wing sections of the XB-36 airplane: Report presenting testing in the two-dimensional low-turbulence pressure tunnel and the two-dimensional low-turbulence tunnel of two models made by the Consolidated Aircraft Corporation, one of the outboard section and one of the inboard section.
Theoretical Analysis of the Lateral Stability of a Glider Towed by Twin Parallel Towlines: Report discusses a theoretical analysis of the lateral stability characteristics of a glider towed by two parallel towlines, which was correlated with previously reported dynamic flight testing. The glider appears to possess sufficient stability for satisfactory pilotless towed flight. The main factors affecting stability were the dihedral angle of the glider and the length of the towlines.
Theoretical Determination of Axial Fan Performance: "The report presents a method for the computation of axial fan characteristics. The method is based on the assumption that the law of constancy of the circulation along the blade holds, approximately, for all fan conditions for which the blade elements operate at normal angles of attack (up to the stalling angles). Pressure head coefficient K(sub a) and power coefficient K(sub u) for the force components in the axial and tangential directions, respectively, and analogous to the lift and drag coefficients C(sub y) and C(sub x) are conveniently introduced" (p. 1).
A Theoretical Investigation of Longitudinal Stability of Airplane with Free Controls Including Effect of Friction in Control System: "The relation between the elevator hinge-moment parameters and the control-forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short-period oscillations is shown as a series of boundaries giving the limits of the stable region in terms of the elevator hinge-moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considered" (p. 1).
A Theoretical Investigation of the Lateral Oscillations of an Airplane With Free Rudder With Special Reference to the Effect of Friction: Report presenting charts showing the variation in dynamic stability with the rudder hinge-moment characteristics. A stabilizing rudder floating tendency combined with a high degree of aerodynamic balance is shown to lead to oscillations of increasing amplitude.
A Theoretical Investigation of the Lateral Oscillations of an Airplane With Free Rudder With Special Reference to the Effect of Friction: "Charts showing the variation in dynamic stability with the rudder hinge-moment characteristics are presented. A stabilizing rudder floating tendency combined with a high degree of aerodynamic balance is shown to lead to oscillations of increasing amplitude. This dynamic instability is increased by viscous-friction in the rudder control system" (p. 147).
A Theoretical Investigation of the Rolling Oscillations of an Airplane With Ailerons Free: "An analysis is made of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. The present analysis supersedes the aileron investigation contained in NACA Technical Report no. 709. The equations of motion are first written to include yawing and sideslipping, and it is demonstrated that the principal effects of freeing the ailerons can be determined without regard to these motions" (p. 255).
Theory and preliminary flight tests of an all-movable vertical tail surface: Report presenting flight testing of an improved type of all-movable tail surface. The particular arrangement tested provides control-free stability and a stable variation of the control forces during maneuvers. Results regarding rudder effectiveness, directional stability, rudder-free lateral motion, and rudder-free turns are provided.
Theory of Mechanical Oscillations of Rotors With Two Hinged Blades: Report discusses an investigation into the mechanical stability of a rotor with two vertically hinged blades mounted on symmetrical supports of equal stiffness and mass. Information about the instability regions and effect of damping is included. The two-blade rotor was found to have two shaft-critical speeds at which instability can occur as well as a second region at which self-excited vibrations occur.
Theory of Self-Excited Mechanical Oscillations of Hinged Rotor Blades: "Vibrations of rotary-wing aircraft may derive their energy from the rotation of the rotor rather than from the air forces. A theoretical analysis of these vibrations is described and methods for its application are explained herein" (p. 1). Information about self-excited speed range and shaft-critical speed are provided for any rotor with more than two blades.
Thermodynamic Design of Double-Panel, Air-Heated Windshields for Ice Prevention: Report details the development of design equations for double-panel, air-heated windshields with ice prevention properties. The application of the equations and suggestions for experimental flight testing are described.
Time Variation of Percent Distribution of Fission Activity in Bombarded Uranyl Nitrate: "In this report are presented three figures which show how the relative activities (expressed as percentages of total activity) of the individual fission elements (produced by neutron bombardment of uranyl nitrate) vary with cooling time."
Time-velocity-altitude relations for an airplane diving in a standard atmosphere: Report presenting the determination of time-velocity-altitude relations for airplanes diving in standard atmosphere, which replaces several previous technical reports.
Torsion of flanged members with cross sections restrained against warping: "The longitudinal stresses and the stiffness of flange members - I-beams, channels, and Z-bars - were investigated when these members were subjected to torque with constraint against cross-sectional warping. Measured angles of rotation agreed with corresponding calculated values in which the torsion bending factor of the cross section was involved; the agreement was better for the I-beam and the Z-bar than for the channel. Longitudinal stresses measured at the mid-span were found to agree with the calculated values that involved unit warping as well as the torsion-bending factors: the channel showed the greatest discrepancy between measured and calculated values" (p. 1).
Torsion tests of 24S-T aluminum-alloy noncircular bar and tubing: From Summary: "Tests of 24S-T aluminum alloy have been made to determine the yield and ultimate strengths in torsion of noncircular bar and tubing. An approximate basis for predicting these torsional strength characteristics has been indicated. The results show that the torsional stiffness and maximum shearing stresses within the elastic range may be computed quite closely by means of existing formulas based on mathematical analysis and the membrane analogy."
Torsional Elastic Properties of 18:8 Chromium-Nickel Steel as Affected by Plastic Deformation and by Heat Treatment: Note presenting a study made of the relationship between torsional stress, strain, and permanent set for 18:8 chromium-nickel steel in the annealed, half-hard, and hard conditions. The influence of plastic extension, plastic torsion, and annealing temperature on the torsional elastic properties is discussed.
Torsional strength of aluminum-alloy round tubing: Report presenting an analysis of existing data on aluminum-alloy tubing with a wide range of plastic properties in order to establish a useful empirical relationship between tensile yield and ultimate strengths, diameter-thickness ratios, and torsional strengths within the range of plastic buckling.
The Toxicity of Fluorine: The following report discusses the toxicity of fluorine as described in literature on fluorine intoxication and case studies of Roholm's experimental observations.
Transition Between Laminar and Turbulent Flow by Transverse Contamination: Note presenting tests carried out on a flat plate in a low-turbulence constant-pressure tunnel, which showed that the transition between laminar and turbulent flow could be caused in a normally laminar region by a process of transverse contamination.
Trends in the Use of Energy in the Western States, With Particular Reference to Coal: Report issued by the U.S. Bureau of Mines on energy consumption in the western United States. A focus on coal as the primary energy source is presented. This report includes tables, graphs, maps, and illustrations.
Turbulent Flow Between Rotating Cylinders: "The turbulent air flow between rotating cylinders was investigated. The distributions of mean speed and of turbulence were measured in the gap between a rotating inner and a stationary outer cylinder. The measurements led to the conclusion that the turbulent flow in the gap cannot be considered two dimensional, but that a particular type of secondary motion takes place. It is shown that the experimentally found velocity distribution can be fully understood under the assumption that this secondary motion consists of three-dimensional ring-shape vortices" (p. 1).
Turbulent Friction in the Boundary Layer of a Flat Plate in a Two-Dimensional Compressible Flow at High Speeds: "In the present report an investigation is made on a flat plate in a two-dimensional compressible flow of the effect of compressibility and heating on the turbulent frictional drag coefficient in the boundary layer of an airfoil or wing radiator. The analysis is based on the Prandtl-Karman theory of the turbulent boundary later and the Stodola-Crocco, theorem on the linear relation between the total energy of the flow and its velocity. Formulas are obtained for the velocity distribution and the frictional drag law in a turbulent boundary later with the compressibility effect and heat transfer taken into account" (p. 1).
United States Earthquakes, 1943: Report discussing earthquake activity in the United States during 1943. The report is broken down by regions and has sections for specific earthquakes.
The Use of a Retractable Planing Flap Instead of a Fixed Step on a Seaplane: Report presents and discusses the improvements in hydrodynamic and aerodynamic performance of a seaplane with a retractable planing flap instead of a conventional main step. A type of flap that could be used is described and tested for hydrodynamic stability. Results regarding the trim limits of stability, limiting positions of the center of gravity, and skipping are provided.
Use of Stagnation Temperature in Calculating Rate of Heat Transfer in Aircraft Heat Exchangers: "Theoretical and experimental investigations of the effect of frictional heat on the rate of heat transmission at high fluid velocities are briefly reviewed. On the basis of these investigations, calculations are made which show that the use of the stagnation temperature of the cooling air as the effective temperature for heat transfer in an aircraft heat exchanger is sufficiently accurate" (p. 1).
Use of Wetting Agents in Reducing Dust Produced by Wet Drilling in Basalt: Report issued by the U.S. Bureau of Mines on wet-drilling tests using two different wetting agents. Amounts are listed in the results. This report includes tables, and illustrations.
The Vapor Phase Hydrolysis of the Trichlorides of Lanthanum, Praseodymium, Samarium, and Americium: The following report studies the reactions of vapor phase hydrolysis of the trichlorides of lanthanum, praseodymium, samarium, and americium with gas mixtures of HCl and H2O passing over the solid materials mounted on a cantilever-type quartz fiber microbalance. This report calculates the values of the heats and entropies of the reactions, as well as the heat formation of LaCl3, 1254.9 kcal mol-(-1) that was obtained by determining the heat of the solution of La metal in 1.5M HCl.
Vibration Surveys of the P-40 Rudder and Fin-Rudder Assembly: "The following surveys on the vibration response of the P-40 rudder and fin-rudder assembly were conducted during the fall of 1942 for the purpose of obtaining information on the flutter characteristics of high-speed airplanes of known performance. The tests on the rudder alone were made with the rudder suspended in a floating condition; the tests on the fin-rudder unit were made with the fin rigidly fastened to a concrete base" (p. 1). A variety of figures and diagrams for the assembly are provided.

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