National Advisory Committee for Aeronautics (NACA) - 745 Matching Results

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Effect of wing sweep, taper, and thickness ratio on the transonic drag characteristics of wing-body combinations

Description: Report presenting the transonic drag characteristics of a series of wing-body combinations and their component parts using the free-fall method. The configurations examined had wings of various sweeps and thickness ratios mounted on identical bodies of fineness ratio 12.
Date: December 31, 1948
Creator: Thompson, Jim Rogers & Mathews, Charles W.
Partner: UNT Libraries Government Documents Department

Summary of results of tumbling investigations made in the Langley 20-foot free-spinning tunnel on 14 dynamic models

Description: Report presenting the tumbling characteristics of dynamic models of 14 airplane designs in the free-spinning tunnel for various loadings and configurations. Conventional airplanes were not found to tumble, but tailless and tail-first airplanes might depending on the amount of static longitudinal stability. Results regarding the effect of dimensional and mass characteristics, effect of controls, use of parachutes as a tumble-recovery device, accelerations, and possibility of pilot escape are provided.
Date: December 31, 1948
Creator: Stone, Ralph W., Jr. & Bryant, Robert L.
Partner: UNT Libraries Government Documents Department

One-Dimensional Flows of an Imperfect Diatomic Gas

Description: "With the assumptions that Berthelot's equation of state accounts for molecular size and intermolecular force effects, and that changes in the vibrational heat capacities are given by a Planck term, expressions are developed for analyzing one-dimensional flows of a diatomic gas. The special cases of flow through normal and oblique shocks in free air at sea level are investigated. It is found that up to a Mach number 10 pressure ratio across a normal shock differs by less than 6 percent from its ideal gas value; whereas at Mach numbers above 4 the temperature rise is considerable below and hence the density rise is well above that predicted assuming ideal gas behavior" (p. 239).
Date: December 30, 1948
Creator: Eggers, A. J., Jr.
Partner: UNT Libraries Government Documents Department

An investigation of aileron oscillations at transonic speeds on NACA 23012 and NACA 65-212 airfoils by the wing-flow method

Description: An investigation is being conducted to determine the feasibility of studying aileron buzz by means of the wing-flow method. Two semispan models which had an aspect ratio of 6 and a taper ratio of 2 with quarter-chord half-span mass-balanced ailerons have been used. One had an NACA 23012 airfoil section and the second, an NACA 65-212 airfoil section. The ailerons on both models were subject to buzz over a small range of Mach number near 0.9. Data obtained by wing-flow testing agreed reasonably well with full-scale flight results.
Date: December 29, 1948
Creator: Crane, Harold L.
Partner: UNT Libraries Government Documents Department

Calculation of the aerodynamic loading of flexible wings of arbitrary plan form and stiffness

Description: From Summary: "A method is presented for calculating the aerodynamic loading, the divergence speed, and certain stability derivatives of wings and tail surfaces of arbitrary plan form and stiffness. Provision is made for using either stiffness curves and root-rotation constants or 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: December 24, 1948
Creator: Diederich, Franklin W.
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: December 24, 1948
Creator: Diederich, Franklin W.
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: December 22, 1948
Creator: Heaslet, Max A. & Lomax, Harvard
Partner: UNT Libraries Government Documents Department

Comparison of National Bureau of Standards ceramic coatings L-7C and A-417 on turbine blades in a turbojet engine

Description: Report presenting an investigation to determine which of two ceramic coatings, L-7C and A-417, developed by the National Bureau of Standards is more suitable as a protective coating for turbine blades in a turbojet engine. Four cast Vitallium turbine blades, two coated with each of the ceramics, were installed in a turbine wheel of a turbojet engine and subjected to accelerated cyclic life tests.
Date: December 22, 1948
Creator: Morse, C. Robert
Partner: UNT Libraries Government Documents Department

Preliminary investigation of effects of combustion in ram jet on performance of supersonic diffusers 3: normal-shock diffuser

Description: Report presenting an experimental investigation on a ramjet in the 20-inch supersonic tunnel at a Mach number of 1.92 to determine the effects of combustion on the performance of a basic normal-shock diffuser. Total-pressure recovery with and without combustion was evaluated as a function of outlet-inlet area ratio and fuel flow. A rapid decrease in peak total-pressure recovery was obtained with increasing outlet-inlet area ratio.
Date: December 22, 1948
Creator: Schroeder, Albert H. & Connors, James F.
Partner: UNT Libraries Government Documents Department

Some theoretical low-speed span loading characteristics of swept wings in roll and sideslip

Description: The Weissinger method for determining additional span loading for incompressible flow is used to find the damping in roll, the lateral center of pressure of the rolling for wing plan forms of various aspect ratios, taper ratios, and sweep angles. In addition, the applicability of the method to the determination of certain other aerodynamic derivatives is investigated, and corrections for the first-order effects of compressibility are indicated. The agreement obtained between experimentally and theoretically determined values for the aerodynamic coefficients indicates that the method of Weissinger is well suited to the calculation of such resulting aerodynamic derivatives of wings as do not involve considerations of tip suction.
Date: December 22, 1948
Creator: Bird, John D.
Partner: UNT Libraries Government Documents Department

Linear Theory of Boundary Effects in Open Wind Tunnels With Finite Jet Lengths

Description: "In the first part, the boundary conditions for an open wind tunnel (incompressible flow) are examined with special reference to the effects of the closed entrance and exit sections. In the second part, solutions are derived for four types of two-dimensional open tunnels, including one in which the pressures on the two free surfaces are not equal. In the third part, a general method is given for calculating the boundary effect in an open circular wind tunnel of finite jet length" (p. 509).
Date: December 20, 1948
Creator: Katzoff, S.; Gardner, Clifford S.; Diesendruck, Leo & Eisenstadt, Bertram J.
Partner: UNT Libraries Government Documents Department

Longitudinal-stability investigation of high-lift and stall-control devices on a 52 degree sweptback wing with and without fuselage and horizontal tail at a Reynolds number of 6.8 x 10(exp 6).

Description: Contains low-speed longitudinal stability characteristics of a 52 degree sweptback wing of aspect ratio 2.88, taper ratio 0.625, and NACA 64 (sub 1)-112 airfoil sections normal to the 0.282-chord line, in combination with split flaps, leading-edge flaps, and upper-surface fences. Low-wing and midwing-fuselage aerodynamic characteristics are presented with and without a horizontal tail at various vertical locations. Tests were conducted at a Reynolds number of 6.8 x 10(exp 6).
Date: December 20, 1948
Creator: Foster, Gerald V. & Fitzpatrick, James E.
Partner: UNT Libraries Government Documents Department

Comparison of Theoretical and Experimental Heat-Transfer Characteristics of Bodies of Revolution at Supersonic Speeds

Description: "An investigation of the three important factors that determine convective heat-transfer characteristics at supersonic speeds, location boundary-layer transition, recovery factor, and heat-transfer parameter has been performed at Mach numbers from 1.49 to 1.18. The bodies of revolution that were tested had, in most cases, laminar boundary layers, and the test results have been compared with available theory. Boundary-layer transition was found to be affected by heat transfer" (p. 1301).
Date: December 17, 1948
Creator: Scherrer, Richard
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of horizontal tails 3: unswept and 35 degrees swept-back plan forms of aspect ratio 6

Description: Report presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of two semispan horizontal tails with unswept and 35 degree sweptback plan forms. Test results are provided for models with and without standard roughness on their leading edges and with sealed and unsealed radius-nose elevators. Results regarding effectiveness and hinge-moment parameters, static longitudinal stability, effect of standard roughness, and effect of removing the elevator nose seal are provided.
Date: December 17, 1948
Creator: Dods, Jules B., Jr.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Investigation of Horizontal Tails 4: Unswept Plan Form of Aspect Ratio 2 and a Two-Dimensional Model

Description: Memorandum presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of a horizontal-tail model of aspect ratio 2 with an unswept plan form and of a two-dimensional model. The two-dimensional model provides data which can be used as the basis for computing the three-dimensional lift and hinge-moment parameters by the lifting-surface-theory procedure. Results regarding the effectiveness and hinge-moment parameters, static longitudinal stability, scale effect, effect of standard roughness, and effect of removing the elevator nose seal are provided.
Date: December 16, 1948
Creator: Dods, Jules B., Jr.
Partner: UNT Libraries Government Documents Department

Performance of Allison Model 400-C6 Turbojet-Engine Compressor, 1: Over-All Performance Characteristics of Compressor at Equivalent Impeller Speeds of 6000, 7000, and 8500 RPM

Description: The Allison model 400-C6 compressor was operated at an inlet pressure of 12 inches of mercury absolute ana ambient inlet temperature at equivalent impeller speeds of 6000, 7000, and 8500 rpm. Additional runs at an equivalent speed of 7000 rpm and ambient inlet temperature were made at inlet pressures from 7 to 22 inches of mercury absolute. The results of this investigation are compared with those of the 533-A-23 compressors. For the speeds investigated, the Allison model 400-C6 compressor had a maximum adiabatic temperature-rise efficiency of 0.768 at an equivalent speed of 7000 rpm; the corresponding equivalent weight flow was 45.0 pounds per second and the pressure ratio was 1.83. At an equivalent impeller speed of 8500 rpm, the maximum equivalent weight flow was 61.6 pounds per second and the peak pressure ratio of 2.38 occurred at an equivalent weight flow of 52.2 pounds per 1 second and an adiabatic temperature-rise efficiency of 0.714. At an equivalent speed of 7000 rpm, increasing the compressor- inlet pressure increased the maximum equivalent weight flow and the pressure ratio.
Date: December 15, 1948
Creator: Kovach, Karl & Withee, Joseph R., Jr.
Partner: UNT Libraries Government Documents Department

Altitude-wind-tunnel investigation of tail-pipe burning with a Westinghouse X24C-4B axial-flow turbojet engine

Description: From Summary: "Thrust augmentation of an axial-flow type turbojet engine by burning fuel in the tail pipe has been investigated in the NACA Cleveland altitude wind tunnel. The performance was determined over a range of simulated flight conditions and tail-pipe fuel flows. The engine tail pipe was modified for the investigation to reduce the gas velocity at the inlet of the tail-pipe combustion chamber and to provide an adequate seat for the flame; four such modifications were investigated."
Date: December 13, 1948
Creator: Fleming, William A. & Wallner, Lewis E.
Partner: UNT Libraries Government Documents Department

Linearized compressible-flow theory for sonic flight speeds

Description: The partial differential equation for the perturbation velocity potential is examined for free-stream Mach numbers close to and equal to one. It is found that, under the assumptions of linearized theory, solutions can be found consistent with the theory for lifting-surface problems both in stationary three-dimensional flow and in unsteady two-dimensional flow. Several examples are solved including a three dimensional swept-back wing and two dimensional harmonically-oscillating wing, both for a free stream Mach number equal to one. Momentum relations for the evaluation of wave and vortex drag are also discussed. (author).
Date: December 12, 1948
Creator: Heaslet, Max A.; Lomax, Harvard & Spreiter, John R.
Partner: UNT Libraries Government Documents Department

Altitude-Wind-Tunnel Investigation of a 3000-Pound-Thrust Axial-Flow Turbojet Engine, 7, Pressure and Temperature Distributions

Description: Temperature and pressure distributions for an original and modified 3000 pound thrust axial flow turbojet engine were investigated. Data are included for a range of simulated altitudes from 5000 to 45000 feet, Mach numbers from 0.24 to 1.08, and corrected engine speeds from 10,550 to 13,359 rpm.
Date: December 10, 1948
Creator: Saari, Martin J. & Prince, William R.
Partner: UNT Libraries Government Documents Department

Note on the Importance of Imperfect-Gas Effects and Variation of Heat Capacities on the Isentropic Flow of Gases

Description: "The errors involved in using the perfect-gas law pv = RT and the assumption of constant heat capacities are evaluated. The basic equations of gas flows taking into account these phenomena separately and at the same time are presented" (p. 1).
Date: December 10, 1948
Creator: Donaldson, Coleman duP.
Partner: UNT Libraries Government Documents Department

The effect of negative dihedral, tip droop, and wing-tip shape on the low-speed aerodynamic characteristics of a complete model having a 45 degrees sweptback wing

Description: "An investigation has been conducted in the Langley 300 MPH 7- by 10-foot tunnel to determine the effect of negative dihedral, tip droop, and wing-tip shape on the low-speed aerodynamic characteristics of a complete model having a 45 degrees sweptback wing. Longitudinal and lateral stability characteristics were obtained for the model with and without tail surfaces" (p .1).
Date: December 6, 1948
Creator: Spearman, M. Leroy & Becht, Robert E.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics at subsonic and supersonic Mach numbers of a thin triangular wing of aspect ratio 2 2: maximum thickness at midchord

Description: "The lift, drag, and pitching-moment characteristics of a triangular wing, having an aspect ratio of 2 and a symmetrical double-wedge profile of 5-percent-chord maximum thickness at midchord, have been evaluated from wind-tunnel tests at Mach numbers from 0.50 to 0.975 and from 1.09 to 1.49 and at Reynolds numbers ranging from 0.67 to 0.85 million. The lift, drag, and pitching-moment coefficients of the triangular wing with a leading-edge sweepback of approximately 63 degrees did not exhibit the irregular variations with Mach number at high subsonic and low supersonic Mach numbers that are characteristic of unswept wings. The lift-curve slope increased steadily with Mach number below unity and declined slowly beyond the Mach number of 1.13" (p. 1).
Date: December 3, 1948
Creator: Walker, Harold J. & Berggren, Robert E.
Partner: UNT Libraries Government Documents Department