Technical Report Archive and Image Library (TRAIL) - 444 Matching Results

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The aerodynamic forces on slender plane- and cruciform-wing and body combinations

Description: From Introduction: "Since these results were not applicable to the present problem, a theoretical analysis of the aerodynamic properties of slender wing-body combinations was undertaken. The results of this investigation were first reported in reference 5 and were later extended in reference 6 to include cruciform-wing and body combinations. The present report summarizes and extends the theory and results previously presented in these references."
Date: 1950?~
Creator: Spreiter, John R
Partner: UNT Libraries Government Documents Department

Analysis of spanwise temperature distribution in three types of air-cooled turbine blade

Description: From Summary: An approximate method for determining the allowable stress-limited blade-temperature distribution is included, with brief accounts of a method for determining the maximum allowable effective gas temperatures and the cooling-air requirements. Numerical examples that illustrate the use of the various temperature-distribution equations and of the nondimensional charts are also included.
Date: 1950~
Creator: Livingood, John N B & Brown, W Byron
Partner: UNT Libraries Government Documents Department

The application of Green's theorem to the solution of boundary-value problems in linearized supersonic wing theory

Description: From Introduction: "The present paper is restricted to a discussion of wing theory subject to the assumptions of linearized compressible flow. It therefore employs solutions of Laplace's equation and the wave equation for cases where the boundary condition are specified in the plane of the wing."
Date: January 1, 1950
Creator: Heaslet, Max A & Lomax, Harvard
Partner: UNT Libraries Government Documents Department

Application of radial-equilibrium condition to axial-flow compressor and turbine design

Description: Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given. In these methods, the blade loading and the shape of the annular passage wall may be arbitrarily specified.
Date: January 1, 1950
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
Partner: UNT Libraries Government Documents Department

Blockage corrections for three-dimensional-flow closed-throat wind tunnels, with consideration of the effect of compressibility

Description: Theoretical blockage corrections are presented for a body of revolution and for a three-dimensional unswept wing in a circular or rectangular wind tunnel. The theory takes account of the effects of the wake and of the compressibility of the fluid, and is based on the assumption that the dimensions of the model are small in comparison with those of the tunnel throat. Formulas are given for correcting a number of the quantities, such as dynamic pressure and Mach number, measured in wing-tunnel tests. The report presents a summary and unification of the existing literature on the subject.
Date: January 1, 1950
Creator: Herriot, John G
Partner: UNT Libraries Government Documents Department

The calculation of downwash behind supersonic wings with an application to triangular plan forms

Description: A method is developed consistent with the assumptions of small perturbation theory which provides a means of determining the downwash behind a wing in supersonic flow for a known load distribution. The analysis is based upon the use of supersonic doublets which are distributed over the plan form and wake of the wing in a manner determined from the wing loading. The equivalence in subsonic and supersonic flow of the downwash at infinity corresponding to a given load distribution is proved.
Date: January 1, 1950
Creator: Lomax, Harvard; Sluder, Loma & Heaslet, Max A
Partner: UNT Libraries Government Documents Department

Calculation of the aerodynamic loading of swept and unswept flexible wings of arbitrary stiffness

Description: A method is presented for calculating the aerodynamic loading, the divergence speed, and certain stability derivatives of swept and unswept wings and tail surfaces of arbitrary stiffness. Provision is made for using either stiffness curves and root rotation constants or structural influence coefficients in the analysis. Computing forms, tables of numerical constants required in the analysis, and an illustrative example are included to facilitate calculations by means of the method.
Date: January 1, 1950
Creator: Diederich, Franklin W
Partner: UNT Libraries Government Documents Department

Comparative drag measurements at transonic speeds of rectangular sweptback NACA 65-009 airfoils mounted on a freely falling body

Description: Directly comparable drag measurements have been made of an airfoil with a conventional rectangular plan form and an airfoil with a sweptback plan form mounted on freely falling bodies. Both airfoils had NACA 65-009 sections and were identical in span, frontal area, and chord perpendicular to the leading edge. The sweptback plan form incorporated a sweepback angle of 45 degrees. The data obtained have been used to establish the relation between the airfoil drag coefficients and the free-stream Mach number over a range of Mach numbers from 0.90 to 1.27. The results of the measurements indicate that the drag of the sweptback plan form is less than 0.3 that of the rectangular plan form at a Mach number of 1.00 and is less than 0.4 that at a Mach number of 1.20.
Date: January 1, 1950
Creator: Mathews, Charles W & Thompson, Jim Rogers
Partner: UNT Libraries Government Documents Department

Critical stress of ring-stiffened cylinders in torsion

Description: A chart in terms of nondimensional parameters is presented for the theoretical critical stress in torsion of simply supported cylinders stiffened by identical equally spaced rings of zero torsional stiffness. The results are obtained by solving the equation of equilibrium by means of the Galerkin method. Comparison of the theoretical results with experimental results indicates that ring-stiffened cylinders buckle, on the average, at a buckling stress about 15 percent below the theoretical buckling stress. (author).
Date: January 1, 1950
Creator: Stein, Manuel; Snaders, J Lyell, Jr & Crate, Harold
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: January 1, 1950
Creator: Heimerl, George J & Roberts, William M
Partner: UNT Libraries Government Documents Department

Direct method of design and stress analysis of rotating disks with temperature gradient

Description: A method is presented for the determination of the contour of disks, typified by those of aircraft gas turbines, to incorporate arbitrary elastic-stress distributions resulting from either centrifugal or combined centrifugal and thermal effects. The specified stress may be radial, tangential, or any combination of the two. Use is made of the finite-difference approach in solving the stress equations, the amount of computation necessary in the evolution of a design being greatly reduced by the judicious selection of point stations by the aid of a design chart. Use of the charts and of a preselected schedule of point stations is also applied to the direct problem of finding the elastic and plastic stress distribution in disks of a given design, thereby effecting a great reduction in the amount of calculation. Illustrative examples are presented to show computational procedures in the determination of a new design and in analyzing an existing design for elastic stress and for stresses resulting from plastic flow.
Date: January 1, 1950
Creator: Manson, S S
Partner: UNT Libraries Government Documents Department

The effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings

Description: An analysis is presented of the effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings with partial-span constant-percent-chord ailerons extending inboard from the wing tip. The geometric variables considered are aspect ratio, taper ratio, aileron span, and aileron chord. The shape of the wing-torsional-stiffness curve is assumed and the twisting moment is considered to result solely from the pressure distribution caused by aileron deflection, so that the necessity of using a successive-approximation method is avoided. Because of the complexity of the equations resulting from the analysis, numerical calculations from the equations are presented in a series of figures. A computational form is provided to be used in conjunction with these figures so that calculations can be made without reference to the analysis.
Date: January 1, 1950
Creator: Tucker, Warren A & Nelson, Robert L
Partner: UNT Libraries Government Documents Department

The effects of variations in Reynolds number between 3.0 x 10sub6 and 25.0 x 10sub6 upon the aerodynamic characteristics of a number of NACA 6-series airfoil sections

Description: Results are presented of an investigation made to determine the two-dimensional lift and drag characteristics of nine NACA 6-series airfoil section at Reynolds numbers of 15.0 x 10sub6, 20.0 x 10sub6, and 25.0 x 10sub6. Also presented are data from NACA Technical Report 824 for the same airfoils at Reynolds numbers of 3.0 x 10sub6, 6.0 x 10sub6, and 9.0 x 10sub6. The airfoils selected represent sections having variations in the airfoil thickness, thickness form, and camber. The characteristics of an airfoil with a split flap were determined in one instance, as was the effect of surface roughness. Qualitative explanations in terms of flow behavior are advanced for the observed types of scale effect.
Date: January 1, 1950
Creator: Loftin, Laurence K, Jr & Bursnall, William J
Partner: UNT Libraries Government Documents Department

Elastic and plastic buckling of simply supported solid-core sandwich plates in compression

Description: A solution is presented for the problem of the compressive buckling of simply supported, flat, rectangular, solid-core sandwich plates stressed either in the elastic range or in the plastic range. Charts for the analysis of long sandwich plates are presented for plates having face materials of 24s-t3 aluminum alloy, 76s-t6 alclad aluminum alloy, and stainless steel. A comparison of computed and experimental buckling stresses of square solid-core sandwich plates indicates fair agreement between theory and experiment.
Date: January 1, 1950
Creator: Seide, Paul & Stowell, Elbridge Z
Partner: UNT Libraries Government Documents Department

Equilibrium operating performance of axial-flow turbojet engines by means of idealized analysis

Description: A method of predicting equilibrium operating performance of turbojet engines has been developed, with the assumption of simple model processes for the components. Results of the analysis are plotted in terms of dimensionless parameters comprising critical engine dimensions and over-all operating variables. This investigation was made of an engine in which the ratio of axial inlet-air velocity to compressor-tip velocity is constant, which approximates turbojet engines with axial-flow compressors. Experimental correlation of the theory with data from several existing axial-flow-type engines was good and showed close correlation between calculated and measured performance.
Date: January 1, 1950
Creator: Sanders, John C & Chapin, Edward C
Partner: UNT Libraries Government Documents Department

Flight investigation of the effect of various vertical-tail modifications on the directional stability and control characteristics of a propeller-driven fighter airplane

Description: A flight investigation was made to determine the effect of various vertical-tail modifications and of some combinations of these modifications on the directional stability and control characteristics of a propeller-driven fighter airplane. Six different vertical-tail configurations were investigated to determine the lateral-directional oscillation characteristics, the sideslip characteristics, the yaw due to ailerons in rudder-fixed rolls from turns and pull-outs, the trim changes due to speed changes, and the tim changes due to power changes. Results of the tests showed that increasing the aspect ratio of the vertical tail by 40 percent while increasing the area by only 12 percent approximately doubled the directional stability of the airplane. The pilots considered the directional characteristics of the airplane unsatisfactory with original vertical tail but satisfactory with the enlarged vertical tail. The ventral and dorsal fins tested had little effect on the directional stability of the airplane but were effective in eliminating rudder-force reversals in high-engine-power sideslips.
Date: January 1, 1950
Creator: Johnson, Harold I
Partner: UNT Libraries Government Documents Department

Flutter of a uniform wing with an arbitrarily placed mass according to a differential-equation analysis and a comparison with experiment

Description: A method is presented for the calculation of the flutter speed of a uniform wing carrying an arbitrarily placed concentrated mass. The method, an extension of recently published work by Goland and Luke, involves the solution of the differential equations of motion of the wing at flutter speed and therefore does not require the assumption of specific normal modes of vibration. The order of the flutter determinant to be solved by this method depends upon the order of the system of differential equations and not upon the number of modes of vibration involved. The differential equations are solved by operational methods, and a brief discussion of operational methods as applied to boundary-value problems is included in one of two appendixes. A comparison is made with experiment for a wing with a large eccentrically mounted weight and good agreement is obtained. Sample calculations are presented to illustrate the method; and curves of amplitudes of displacement, torque, and shear for a particular case are compared with corresponding curves computed from the first uncoupled normal modes.
Date: January 1, 1950
Creator: Runyan, Harry L & Watkins, Charles E
Partner: UNT Libraries Government Documents Department

Free-space oscillating pressures near the tips of rotating propellers

Description: The theory is given for calculating the free-space oscillating pressures associated with a rotating propeller, at any point in space. Because of its complexity this analysis is convenient only for use in the critical region near the propeller tips where the assumptions used by Gutin to simplify his final equations are not valid. Good agreement was found between analytical and experimental results in the tip Mach number range 0.45 to two, three, four, five, six, on eight-blade propellers and for a range of tip clearances from 0.04 to 0.30 times the propeller diameter. If the power coefficient, tip Mach number, and the tip clearance are known for a given propeller, the designer may determine from these charts the average maximum free-space oscillating pressure in the critical region near the plane of rotation. A section of the report is devoted to the fuselage response to these oscillating pressures and indicates some of the factors to be considered in solving the problems of fuselage vibration and noise.
Date: January 1, 1950
Creator: Hubbard, Harvey H & Regier, Arthur A
Partner: UNT Libraries Government Documents Department

Frequency response of linear systems from transient data

Description: Methods are presented that use general correlative time-response input and output data for a linear system to determine the frequency-response function of that system. These methods give an exact description of any linear system for which such transient data are available. Examples are shown of application of a method to both an underdamped and a critically damped exact second-order system, and to an exact first-order system with and without dead time. Experimental data for a turbine-propeller engine showing the response of engine speed to change in propeller-blade angle are presented and analyzed.
Date: January 1, 1950
Creator: Laverne, Melvin E. & Boksenbom, Aaron S.
Partner: UNT Libraries Government Documents Department

Fundamental effects of aging on creep properties of solution-treated low-carbon n-155 alloy

Description: A method is developed whereby the fundamental mechanisms are investigated by which processing, heat treatment, and chemical composition control the properties of alloys at high temperatures. The method used metallographic examination -- both optical and electronic --studies of x-ray diffraction-line widths, intensities, and lattice parameters, and hardness surveys to evaluate fundamental structural conditions. Mechanical properties at high temperatures are then measured and correlated with these measured structural conditions. In accordance with this method, a study was made of the fundamental mechanism by which aging controlled the short-time creep and rupture properties of solution-treated low-carbon n-155 alloy at 1200 degrees F.
Date: January 1, 1950
Creator: Frey, D N; Freeman, J W & White, A E
Partner: UNT Libraries Government Documents Department

Further experiments on the flow and heat transfer in a heated turbulent air jet

Description: Measurements have been made of the mean-total-head and mean-temperature fields in a round turbulent jet with various initial temperatures. The results show that the jet spreads more rapidly as its density becomes lower than that of the receiving medium, even when the difference is not sufficiently great to cause dynamic-pressure function. Rough analytical considerations have given the same relative spread. The effective "turbulent Prandtl number" for a section of the fully developed jet was found to be equal to the true (laminar) Prandtl number within the accuracy measurement.
Date: January 1, 1950
Creator: Corrsin, Stanley & Uberoi, Mahinder S
Partner: UNT Libraries Government Documents Department

General algebraic method applied to control analysis of complex engine types

Description: A general algebraic method of attack on the problem of controlling gas-turbine engines having any number of independent variables was utilized employing operational functions to describe the assumed linear characteristics for the engine, the control, and the other units in the system. Matrices were used to describe the various units of the system, to form a combined system showing all effects, and to form a single condensed matrix showing the principal effects. This method directly led to the conditions on the control system for noninteraction so that any setting disturbance would affect only its corresponding controlled variable. The response-action characteristics were expressed in terms of the control system and the engine characteristics. The ideal control-system characteristics were explicitly determined in terms of any desired response action.
Date: January 1, 1950
Creator: Boksenbom, Aaron S & Hood, Richard
Partner: UNT Libraries Government Documents Department

Icing-protection requirements for reciprocating-engine induction system

Description: Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied. The effects of several factors on the icing characteristics were also studied and included: (1) atmospheric conditions, (2) engine and air-scoop configurations, including light-airplane system, (3) type fuel used, and (4) operating variables, such as power condition, use of a manifold pressure regulator, mixture setting, carburetor heat, and water-alcohol injection. In addition, ice-detection methods were investigated and methods of preventing and removing induction-system ice were studied. Recommendations are given for design and operation with regard to induction-system design.
Date: January 1, 1950
Creator: Coles, Willard D; Rollin, Vern G & Mulholland, Donald R
Partner: UNT Libraries Government Documents Department