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Calculated spanwise lift distributions, influence functions, and influence coefficients for unswept wings in subsonic flow

Description: Spanwise lift distributions have been calculated for nineteen unswept wings with various aspect ratios and taper ratios and with a variety of angle-of-attack or twist distributions, including flap and aileron deflections, by means of the Weissinger method with eight control points on the semispan. Also calculated were aerodynamic influence coefficients which pertain to a certain definite set of stations along the span, and several methods are presented for calculating aerodynamic influence func… more
Date: May 5, 1953
Creator: Diederich, Franklin W. & Zlotnick, Martin
Partner: UNT Libraries Government Documents Department
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Effect of Interaction on Landing-Gear Behavior and Dynamic Loads in a Flexible Airplane Structure

Description: "The effects of interaction between a landing gear and a flexible airplane structure on the behavior of the landing gear and the loads in the structure have been studied by treating the equations of motion of the airplane and the landing gear as a coupled system. The landing gear is considered to have nonlinear characteristics typical of conventional gears, namely, velocity-squared damping, polytropic air-compression springing, and exponential tire force-deflection characteristics. For the case… more
Date: May 5, 1955
Creator: Cook, Francis E. & Milwitzky, Benjamin
Partner: UNT Libraries Government Documents Department
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Impingement of Cloud Droplets on a Cylinder and Procedure for Measuring Liquid-Water Content and Droplet Sizes in Supercooled Clouds by Rotating Multicylinder Method

Description: "Evaluation of the rotating multicylinder method for the measurement of droplet-size distribution, volume-median droplet size, and liquid-water content in clouds showed that small uncertainties in the basic data eliminate the distinction between different cloud droplet-size distributions and are a source of large errors in the determination of the droplet size. Calculations of the trajectories of cloud droplets in incompressible and compressible flow fields around a cylinder were performed on a… more
Date: September 5, 1952
Creator: Brun, R. J.; Lewis, W.; Perkins, P. J. & Serafini, J. S.
Partner: UNT Libraries Government Documents Department
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A method for studying the hunting oscillations of an airplane with a simple type of automatic control

Description: "A method is presented for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in the response of the aircraft to the controls. If the steering device is actuated by a simple right-left type of signal, the series of alternating fixed-amplified signals occurring during the hunting may ordinarily be represented by a "square wave." Formulas are given expressing the respon… more
Date: May 5, 1944
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
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Two-dimensional unsteady lift problems in supersonic flight

Description: The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these re… more
Date: December 5, 1947
Creator: Heaslet, Max A. & Lomax, Harvard
Partner: UNT Libraries Government Documents Department
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Laminar mixing of a compressible fluid

Description: From Summary: "A theoretical investigation of the velocity profiles for laminar mixing of a high-velocity stream with a region of fluid at rest has been made assuming that the Prandtl number is unity. A method which involves only quadratures is presented for calculating the velocity profile in the mixing layer for an arbitrary value of the free-stream Mach number. Detailed velocity profiles have been calculated for free-stream Mach numbers of 0, 1, 2, 3, and 5."
Date: January 5, 1949
Creator: Chapman, Dean R.
Partner: UNT Libraries Government Documents Department
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Determination of stresses in gas-turbine disks subjected to plastic flow and creep

Description: A finite-difference method previously presented for computing elastic stresses in rotating disks is extended to include the computation of the disk stresses when plastic flow and creep are considered. A finite-difference method is employed to eliminate numerical integration and to permit nontechnical personnel to make the calculations with a minimum of engineering supervision. Illustrative examples are included to facilitate explanation of the procedure by carrying out the computations on a typ… more
Date: March 5, 1948
Creator: Millenson, M. B. & Manson, S. S.
Partner: UNT Libraries Government Documents Department
open access

Relation between spark-ignition engine knock, detonation waves, and autoignition as shown by high-speed photography

Description: "A critical review of literature bearing on the autoignition and detonation-wave theories of spark-ignition engine knock and on the nature of gas vibrations associated with combustion and knock results in the conclusion that neither the autoignition theory nor the detonation-wave theory is an adequate explanation of spark-ignition engine knock. A knock theory is proposed, combining the autoignition and detonation-wave theories, which introduces the idea that the detonation wave develops in auto… more
Date: December 5, 1945
Creator: Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department
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Experimental investigation of the effect of vertical-tail size and length and of fuselage shape and length on the static lateral stability characteristics of a model with 45 degree sweptback wing and tail surfaces

Description: An investigation was made to determine the effects of vertical-tail size and length and of fuselage shape and length on the static lateral stability characteristics of a model with wing and vertical tails having the quarter-chord lines swept back 45 degrees. The results indicate that the directional instability of the various isolated fuselages was about two-thirds as large as that predicted by classical theory.
Date: June 5, 1950
Creator: Queijo, M. J. & Wolhart, Walter D.
Partner: UNT Libraries Government Documents Department
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Calculation of the lateral control of swept and unswept flexible wings of arbitrary stiffness

Description: A method similar to that of NACA rep. 1000 is presented for calculating the effectiveness and the reversal speed of lateral-control devices on swept and unswept wings of arbitrary stiffness. Provision is made for using either stiffness curves and root-rotation constants or structural influence coefficients in the analysis. Computing forms and an illustrative example are included to facilitate calculations by means of the method. The effectiveness of conventional aileron configurations and the m… more
Date: April 5, 1951
Creator: Diederich, Franklin W.
Partner: UNT Libraries Government Documents Department
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A variational theorem for creep with applications to plates and columns

Description: A variational theorem is presented for a body undergoing creep. Solutions to problems of the creep behavior of plates, columns, beams, and shells can be obtained by means of the direct methods of the calculus of variations in conjunction with the stated theorem. The application of the theorem is illustrated for plates and columns by the solution of two sample problems.
Date: March 5, 1957
Creator: Sanders, J. Lyell, Jr.; McComb, Harvey G., Jr. & Schlechte, Floyd R.
Partner: UNT Libraries Government Documents Department
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The response of an airplane to random atmospheric disturbances

Description: The statistical approach to the gust-load problem, which consists in considering flight through turbulent air to be a stationary random process, is extended by including the effect of lateral variation of the instantaneous gust intensity on the aerodynamic forces. The forces obtained in this manner are used in dynamic analyses of rigid and flexible airplanes free to move vertically, in pitch, and in roll. The effect of the interaction of longitudinal, normal, and lateral gusts on the wind stres… more
Date: November 5, 1956
Creator: Diederich, Franklin W.
Partner: UNT Libraries Government Documents Department
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Relation of Turbojet and Ramjet Combustion Efficiency to Second-Order Reaction Kinetics and Fundamental Flame Speed

Description: Theoretical studies of the turbojet and ramjet combustion process are summarized and the resulting equations are applied to experimental data obtained from various combustor tests. The theoretical treatment assumes that one step in the over-all chain of processes which constitute jet-engine combustion is sufficiently slow to be the rate-controlling step that determines combustion efficiency.
Date: August 5, 1957
Creator: Childs, J. Howard; Reynolds, Thaine W. & Graves, Charles C.
Partner: UNT Libraries Government Documents Department
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Average Properties of Compressible Laminar Boundary Layer on Flat Plate With Unsteady Flight Velocity

Description: The time-average characteristics of boundary layers over a flat plate in nearly quasi-steady flow are determined. The plate may be either insulated or isothermal. The time averages are found without specifying the plate velocity explicitly except that it is positive and has an average value.
Date: September 5, 1956
Creator: Moore, Franklin K. & Ostrach, Simon
Partner: UNT Libraries Government Documents Department
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Boron and zirconium from crucible refractories in a complex heat-resistant alloy

Description: In a laboratory study of the factors involved in the influence of induction vacuum melting on 55ni-20cr-15co-4mo-3ti-3al heat resistant alloy, it was found that the major factor was the type of ceramic used as the crucible. The study concluded that trace amounts of boron or zirconium derived from reaction of the melt with the crucible refactories improved creep-rupture properties at 1,600 degrees F. Boron was most effective and, in addition, markedly improved hot-workability.
Date: August 5, 1958
Creator: Decker, R. F.; Rowe, John P. & Freeman, J. W.
Partner: UNT Libraries Government Documents Department
open access

A comparison of the experimental subsonic pressure distributions about several bodies of revolution with pressure distributions computed by means of the linearized theory

Description: "An analysis is made of the effects of compressibility on the pressure coefficients about several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of the linearized equations of compressible flow. The results show that the theoretical methods predict the subsonic pressure-coefficient changes over the central part of the body but do not predict the pressure-coefficient changes near the nose. Extrapola… more
Date: November 5, 1951
Creator: Matthews, Clarence W.
Partner: UNT Libraries Government Documents Department
open access

Experiments to Determine Neighborhood Reactions to Light Airplanes With and Without External Noise Reduction

Description: "The work reported was part of a program of experimentation with external noise reduction on light airplanes. This particular study was in effect a byproduct survey conceived to utilize already available equipment and personnel to further the findings of the original research and to determine reactions in populated neighborhoods to light aircraft with and without noise-reduction equipment. The findings indicate that at the 10 sites within and about metropolitan Boston the degree of noise reduct… more
Date: May 5, 1950
Creator: Elwell, Fred S.
Partner: UNT Libraries Government Documents Department
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Diffusion of heat from a line source in isotropic turbulence

Description: "An experimental and analytical study has been made of some features of the turbulent heat diffusion behind a line heated wire stretched perpendicular to a flowing isotropic turbulence. The mean temperature distributions have been measured with systematic variations in wind speed, size of turbulence-producing grid, and downstream location of heat source. The nature of the temperature fluctuation field has been studied" (p. 1).
Date: June 5, 1951
Creator: Uberoi, Mahinder S. & Corrsin, Stanley
Partner: UNT Libraries Government Documents Department
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A method of calibrating airspeed installations on airplanes at transonic and supersonic speeds by the use of accelerometer and attitude-angle measurements

Description: A method is described for calibrating airspeed installation on airplanes at transonic and supersonic speeds in vertical-plane maneuvers in which use is made of measurements of normal and longitudinal accelerations and attitude angle. In this method all the required instrumentation is carried within the airplane. An analytical study of the effects of various sources of error on the accuracy of an airspeed calibration by the accelerometer method indicated that the required measurements can be mad… more
Date: December 5, 1952
Creator: Zalovcik, John A.; Lina, Lindsay J. & Trant, James P., Jr.
Partner: UNT Libraries Government Documents Department
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Design of NACA Cowlings for Radial Air-Cooled Engines

Description: "The information on the propeller-cowling-nacelle combinations, presented in Technical Reports nos. 592, 593, and 596 and in Technical Note 620, is applied to the practical design of NACA cowlings. The main emphasis is placed on the method of obtaining the dimensions of the cowling; consequently, the physical functioning of each part of the cowling is treated very briefly. A practical method of designing cowlings and some examples are presented" (p. 383).
Date: March 5, 1938
Creator: Stickle, George W.
Partner: UNT Libraries Government Documents Department
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Cooling on the front of an air-cooled engine cylinder in a conventional engine cowling

Description: Measurements were made of the cooling on the fronts of model cylinders in a conventional cowling for cooling in both the ground and the cruising conditions. The mechanisms of front and rear cooling are essentially different. Cooling on the rear baffled part of the cylinders continually increases with increasing fin width. For the front of the cylinder, an optimum fin width was found to exist beyond which an increase in width reduced the heat transfer. The heat transfer coefficient on the front … more
Date: April 5, 1939
Creator: Brevoort, M. J. & Joyner, U. T.
Partner: UNT Libraries Government Documents Department
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Interference of Tail Surfaces and Wing and Fuselage from Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel

Description: "An investigation of the interference associated with tail surfaces added to wing-fuselage combinations was included in the interference program in progress in the NACA variable-density tunnel. The results indicate that, in aerodynamically clean combinations, the increment of the high-speed drag can be estimated from section characteristics within useful limits of accuracy. The interference appears mainly as effects on the downwash angle and as losses in the tail effectiveness and varies with t… more
Date: November 5, 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department
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Auto-Ignition and Combustion of Diesel Fuel in a Constant-Volume Bomb

Description: Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag cou… more
Date: October 5, 1937
Creator: Selden, Robert F.
Partner: UNT Libraries Government Documents Department
open access

Reduction of hinge moments of airplane control surfaces by tabs

Description: This report presents the results of an investigation conducted in the NACA 7 by 10-foot wind tunnel of control surfaces equipped with tabs for reducing the control forces or trimming the aircraft. Two sizes of ordinary ailerons with several sizes of attached and inset tabs were tested on a Clark y wing. Tabs were also tested in combination with auxiliary balances of the horn and paddle types, and with a frise balance aileron.
Date: February 5, 1935
Creator: Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
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