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Bending Stresses Due to Torsion in Cantilever Box Beams

Description: "The paper beings with a brief discussion on the origin of the bending stresses in cantilever box beams under torsion. A critical survey of existing theory is followed by a summary of design formulas; this summary is based on the most complete solution published but omits all refinements considered unnecessary at the present state of development. Strain-gage tests made by NACA to obtained some experimental verification of the formulas are described next. Finally, the formulas are applied to a series of box beams previously static-tested by the U.S. Army Air Corps; the results show that the bending stresses due to torsion are responsible to a large extent for the free-edge type of failure frequently experienced in these tests" (p. 1).
Date: June 1935
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department

Measurements of Recovery Factors and Coefficients of Heat Transfer in a Tube for Subsonic Flow of Air

Description: Note presenting measurements of heat flow to air at subsonic velocities and substantially constant Reynolds number, which show that the heat-transfer coefficient is independent of the difference between the temperature of the heated wall and the adiabatic wall temperature. Recovery factors are measured at the pipe wall for adiabatic flow.
Date: June 1945
Creator: McAdams, William H.; Nicolai, Lloyd A. & Keenan, Joseph H.
Partner: UNT Libraries Government Documents Department

On Solutions for the Transient Response of Beams

Description: Note presenting Williams type modal solutions of the elementary and Timoshenko beam equations for the transient response of several uniform beams to a general applied load. Example computations are shown for a free-free beam subject to various concentrated loads at its center. Results regarding modal solutions, the need for Timoshenko's theory, and numerical solutions are provided.
Date: June 1958
Creator: Leonard, Robert W.
Partner: UNT Libraries Government Documents Department

Investigation of First Stage of Two-Stage Turbine Designed for Free-Vortex Flow

Description: Note presenting an experimental investigation of the first stage of a two-stage turbine designed for free-vortex flow. The results of the investigation showed that highest adiabatic efficiency was attained when the turbine was operating near the design total-pressure ratio. Results regarding power and efficiency, weight rate of gas flow through the turbine, weight-flow distribution at stator-cascade outlets, stator and rotor flow angles at mean radii, radial distribution of flow angle, radial distribution of the rotor-outlet flow angle, radial distribution of the total pressures at the stator-cascade outlet, and radial distribution of rotor-outlet pressure are provided.
Date: June 1950
Creator: Englert, G. W. & Ross, A. O.
Partner: UNT Libraries Government Documents Department

An Investigation of Fretting Corrosion Under Several Conditions of Oxidation

Description: Note presenting a study to gain information as to the fundamental mechanism of fretting corrosion. The specific questions to be answered were whether chemical action played an important role in fretting of metal surfaces and whether any such action would improve the corrosion resistance of the metal investigated. The results indicated that the chemical action is of primary importance in fretting-corrosion effects and oxide formation does not give any protection to the metals but rather increases the rate of wear.
Date: June 1948
Creator: Sakmann, B. W. & Rightmire, B. G.
Partner: UNT Libraries Government Documents Department

Flight Tests at Supersonic Speeds to Determine the Effect of Taper on the Zero-Lift Drag of Sweptback Low-Aspect-Ratio Wings

Description: Note presenting an investigation using rocket-powered models to provide an experimental comparison with linearized theoretical calculations for zero-lift drag of sweptback tapered wings with thin, symmetrical, double-wedge airfoil sections. The linearized theory compared very favorably with the experimental results over most of the test range.
Date: June 1956
Creator: Pittel, Murray
Partner: UNT Libraries Government Documents Department

Investigation of Suction-Slot Shapes for Controlling a Turbulent Boundary Layer

Description: Note presenting tests of three types of boundary-layer-control suction slots in a two-dimensional diffuser to investigate design criterions and to evaluate the practical minimum total-pressure losses. Testing occurred at a velocity of about 100 feet per second with a boundary layer with a displacement thickness of 0.85 inch and a shape parameter of about 1.8.
Date: June 1947
Creator: Pierpont, P. Kenneth
Partner: UNT Libraries Government Documents Department

Investigation of Lateral Control Near the Stall: Flight Tests With High-Wing and Low-Wing Monoplanes of Various Configurations

Description: Report presenting the results of flight tests with several typical light aircraft. Flight tests were made with one airplane with two different horizontal tail configurations in an attempt to provide an arrangement that would give optimum conditions with regard to the effect of power change on longitudinal trim near the stall. The results are intended to provide quantitative flight-test information which may be useful to designers in attempting to provide for adequate low-speed control and which may be correlated with analytical analyses.
Date: June 1956
Creator: Weick, Fred E. & Abramson, H. Norman
Partner: UNT Libraries Government Documents Department

Investigation of Plastic Behavior of Binary Aluminum Alloys by Internal-Friction Methods

Description: Note presenting an investigation indicated that nominal additions of 0.1, 1.0, and 5.0 weight percent copper and magnesium to aluminum have significant effects on damping behavior. An internal-friction peak at abotu 125 degrees Celsius was observed in aluminum containing 1 percent copper and is believed to result from the interaction of dislocations and impurity particles. The internal friction during plastic deformation was sensitive to strain rate, amount of strain, alloy content, heat treatment, temperature, and the frequency at which the measurements are made.
Date: June 1956
Creator: Maringer, R. E.; Marsh, L. L. & Manning, G. K.
Partner: UNT Libraries Government Documents Department

Investigation of Statistical Nature of Fatigue Properties

Description: Note presenting an experimental program to study the subject of metal fatigue and to determine and evaluate the fundamental factors which influence the behavior. The statistics of the fatigue-fracture curves and endurance limits were determined for a variety of metals and the effects of some metallurgical factors on the statistical nature of fatigue properties were shown.
Date: June 1952
Creator: Epremian, E. & Mehl, R. F.
Partner: UNT Libraries Government Documents Department

Simplified Procedures and Charts for the Rapid Estimation of Bending Frequencies of Rotating Beams

Description: Note presenting a Rayleigh energy approach utilizing the bending mode of the nonrotating beam in the determination of the bending frequency of the rotating beam, which is evaluated and is found to give good practical results for helicopter blades. Charts are presented for the rapid estimation of the first three bending frequencies for rotating and nonrotating cantilever and hinged beams.
Date: June 1955
Creator: Yntema, Robert T.
Partner: UNT Libraries Government Documents Department

A Small Pirani Gage for Measurements of Nonsteady Low Pressures

Description: Note presenting a precise, stable, rapid-response Pirani gage that can be used to precisely measure low absolute pressures such as ones found in supersonic wind tunnels. A theoretical analysis of the gage is given and may be used as a guide in the design, application, and evaluation of such a gage.
Date: June 1953
Creator: Pilny, M. John
Partner: UNT Libraries Government Documents Department

Some Linear Dynamics of Two-Spool Turbojet Engines

Description: Note presenting general equations for the linear responses of inner- and outer-spool speed to change in turbine-inlet temperature and exhaust-nozzle area are derived and evaluated from hypothetical two-spool-engine characteristics at design speed. Experimental corroboration of analysis is also provided in the form of response to fuel flow, response to exhaust-nozzle area, and response to turbine-inlet temperature are provided.
Date: June 1956
Creator: Novik, David
Partner: UNT Libraries Government Documents Department

A Simplified Method for Determining From Flight Data the Rate of Change of Yawing-Moment Coefficient With Sideslip

Description: Note presenting a method by which the directional stability derivative, which is the rate of change of yawing-moment coefficient with sideslip angle, can be evaluated for a conventional airplane from flight records of a lateral or directional oscillation. When applied to conventional airplanes flying at low to moderate lift coefficients, the assumptions involved in this simplified method produce negligible error.
Date: June 1946
Creator: Bishop, Robert C. & Lomax, Harvard
Partner: UNT Libraries Government Documents Department

Theoretical Investigation of the Supersonic Lift and Drag of Thin, Sweptback Wings With Increased Sweep Near the Root

Description: Note presenting formulas derived by the use of linearized theory for the lift and drag due to lift, at supersonic speeds, of thin, flat wings with a discontinuity in the leading-edge sweep, the inboard portion of the leading-edge being very highly swept an the outboard portion less so. The lift-curve slope and drag have been calculated for several families of wings, all with straight trailing edges.
Date: June 1953
Creator: Cohen, Doris & Friedman, Morris D.
Partner: UNT Libraries Government Documents Department

Theoretical Investigation of Velocity Diagrams of a Single-Stage Turbine for a Turbojet Engine at Maximum Thrust Per Square Foot Turbine Frontal Area

Description: Note presenting an exploratory velocity-diagram analysis made in order to establish the aerodynamic requirements of a single-stage, axial-flow turbine which satisfies the conditions of maximum thrust per square foot of turbine frontal area in a turbojet engine. The investigation was made over a range of turbine mean blade speeds and inlet temperatures, fixed flight conditions, and a constant centrifugal stress at the root of the rotor blading. A comparison was made employing conventional turbine aerodynamic design limits for one set of conditions from the analysis.
Date: June 1952
Creator: Cohen, Leo
Partner: UNT Libraries Government Documents Department

Torsion and Transverse Bending of Cantilever Plates

Description: "The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included" (p. 1).
Date: June 1951
Creator: Reissner, Eric & Stein, Manuel
Partner: UNT Libraries Government Documents Department

Identification of Aircraft by Rockwell Test

Description: A large number of tests were made on tubes of 1025 and 4130X steel, in various diameters and wall thicknesses, and after diverse heat treatments. The Rockwell B scale was employed, as being the best suited to the ranges of hardness encountered. Only satisfactory chrome molybdenum tubes were found to show a hardness in excess of 90-B after normalizing.
Date: June 1930
Creator: Knerr, Horace
Partner: UNT Libraries Government Documents Department

Propeller Design 4: A Simple Method for Determining the Strength of Propellers

Description: "The object of this report, the last of a series of four on propeller design, is to describe a simple method for determining whether the strength of a propeller of a standard form is sufficient for safe operation. An approximate method of stress analysis is also given" (p. 1).
Date: June 1926
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

Measurement of Heat Transfer in the Turbulent Boundary Layer on a Flat Plate in a Supersonic Flow and Comparison With Skin-Friction Results

Description: "Local heat-transfer rates on the surface of a heated flat plate at zero incidence to an air stream flowing at Mach numbers of 1.69 and 2.27 are presented. The Reynolds number range for both Mach numbers was 1 million to 10 million. Surface temperatures were maintained near recovery temperature. It was found that the variation of heat transfer with Mach number was in agreement with previously reported variations of directly measured skin friction with Mach number on unheated bodies" (p. 1).
Date: June 1954
Creator: Pappas, C. C.
Partner: UNT Libraries Government Documents Department

Fundamental Study of Erosion Caused by Steep Pressure Waves

Description: "A fundamental study of erosion caused by steep pressure waves has been carried out. It is believed that the study gives an insight to the possible causes of damage in high-speed sleeve bearings. In particular, the effect on annealed copper surfaces of steep-fronted pressure waves in oil has been studied, the general conclusion being that cavitation of the oil is the probable cause of damage" (p .1).
Date: June 1954
Creator: Rightmire, B. G. & Bonneville, J. M.
Partner: UNT Libraries Government Documents Department

Effect of Open Circular Holes on Tensile Strength and Elongation of Sheet Specimens of a Magnesium Alloy

Description: Note presenting an investigation of the effect of open circular holes on the tensile strength and elongation of sheet specimens of magnesium alloy AM-C52S in both the annealed and hard-rolled condition. Tests were made to study the effect of variable ratio of hole diameter to total specimen width and the effect of spacing and arrangement of the holes.
Date: June 1952
Creator: Barker, R. S.
Partner: UNT Libraries Government Documents Department

Heat Transfer in Isotropic Turbulence During the Final Period of Decay

Description: Note presenting a consideration of the problem of heat transfer in isotropic turbulence with a constant mean temperature gradient during the final period of decay. The temperature field is ultimately found to become independent of the initial conditions on the temperature and have characteristics determined only by the mean temperature gradient, the physical properties of the fluid, and the characteristics of the turbulence.
Date: June 1958
Creator: Dunn, D. W. & Reid, W. H.
Partner: UNT Libraries Government Documents Department

Estimation of Compressible Boundary-Layer Growth Over Insulated Surfaces With Pressure Gradient

Description: Note presenting the incompressible boundary-layer theory of Truckenbrodt extended using a modified Stewartson-type transformation to include compressible boundary-layer development over insulated surfaces. The method is applicable to two-dimensional and axisymmetric, laminar and turbulent boundary layer, and accounts for the pressure gradient along the wall for both compressible and incompressible flow. Some experimental measurements of the boundary layer on small axisymmetric bodies on the wall of a supersonic wind tunnel compared with theoretical predictions.
Date: June 1957
Creator: Englert, Gerald W.
Partner: UNT Libraries Government Documents Department