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The Method of Characteristics for the Determination of Supersonic Flow Over Bodies of Revolution at Small Angles of Attack

Description: Note presenting the use of the method of characteristics for the determination of the supersonic-flow properties around bodies of revolution at a small angle of attack. The system developed considers the effect of the variation of entropy due to the curved shock and determines a flow that exactly satisfies the boundary conditions in the limits of the simplifications assumed.
Date: February 1949
Creator: Ferri, Antonio
Partner: UNT Libraries Government Documents Department

Method for Evaluating From Shadow or Schlieren Photographs the Pressure Drag in Two-Dimensional or Axially Symmetrical Flow Phenomena With Detached Shock

Description: "A method has been developed for evaluating from shadow or schileren photographs the pressure drag of axially symmetrical bodies at zero angle of attack or of two-dimensional bodies producing detached shock. The method consists in the determination of the flow properties along a characteristic line and the application of the momentum theorem to a stream tube around the body. The method can be applied to the determination of external drag of supersonic inlets with subsonic flow at the entrance of the inlet" (p. 1).
Date: February 1949
Creator: Ferri, Antonio
Partner: UNT Libraries Government Documents Department

Flight Measurements of the Lateral Control Characteristics of Narrow-Chord Ailerons on the Trailing Edge of a Full-Span Slotted Flap

Description: Note presenting results of flight tests made to determine the effect of flap deflection on the lateral control characteristics of a modified Brewster F2A-2 airplane equipped with partial-span narrow-chord ailerons on the trailing edge of a full-span NACA slotted flap. The results indicated that the effectiveness of the ailerons was greatly reduced at flap deflections greater than about 20 degrees.
Date: February 1947
Creator: Sawyer, Richard H.
Partner: UNT Libraries Government Documents Department

De-Icing Effectiveness of External Electric Heaters for Propeller Blades

Description: Note presenting an investigation in the icing research tunnel to determine the icing protection provided by external rubber-clad blade heaters at several icing, heating, and propeller operating conditions. Data are presented to show the effect of propeller speed, ambient-air temperature, liquid-water concentration, heating-power density, duration of heating, and total cycle times on the power requirements and de-icing performance of the blade heaters.
Date: February 1948
Creator: Lewis, James P.
Partner: UNT Libraries Government Documents Department

An Investigation of Sheet-Stiffener Panels Subjected to Compression Loads With Particular Reference to Torsionally Weak Stiffeners

Description: "A total of 183 panel specimens of 24ST aluminum alloy with nominal thickness of 0.020, and 0.040 inch with extruded bulb-angle sections of 12 shapes spaced 4 and 5 inches as stiffeners were tested to obtain the buckling stress and the amplitude of the maximum wave when buckled. Bulb angles from 3 to 27 1/2 inches long were tested as pin-end columns. The experimental data are presented as stress-strain and column curves and in tabular form" (p. 1).
Date: February 1940
Creator: Dunn, Louis G.
Partner: UNT Libraries Government Documents Department

Measurement of the Forces Acting on Gliders in Towed Flight

Description: "The magnitude, the direction, and the fluctuations of tow forces exerted upon gliders by towing them aloft behind an automobile were measured under a variety of conditions covering a range from gentle to severe types of operation. For these tests, the glider towing force did not exceed 1.6 of the gross weight of the glider. V-G records obtained during the towed-flight period as well as during the subsequent return glide to earth showed accelerations in the range from 3 to -1 g. The results of preliminary airplane tow tests are also presented" (p. 1).
Date: February 1940
Creator: Klemperer, W. B.
Partner: UNT Libraries Government Documents Department

Apparent Effect of Inlet Temperature on Adiabatic Efficiency of Centrifugal Compressors

Description: From Introduction: "The results of varying only Reynolds number for several equivalent tip speeds are presented and probable reasons for the apparent variation of adiabatic efficiency with inlet temperature are discussed."
Date: February 1948
Creator: Anderson, Robert J.; Ritter, William K. & Parsons, Shirley R.
Partner: UNT Libraries Government Documents Department

An Improved Continuous-Indicating Dew-Point Meter

Description: Note presenting the development of a continuous-indicating dew-point meter that automatically maintains a mirror surface at the dew point. The instrument was found to have an average accuracy of 1 degrees Fahrenheit over the range of 75 to -45 degrees. The accuracy of the instrument is uncertain at temperatures below 32 degrees Fahrenheit by the difference in vapor-solid and vapor-liquid equilibrium temperatures.
Date: February 1947
Creator: Friswold, Frank A.; Lewis, Ralph D. & Wheeler, R. Clyde, Jr.
Partner: UNT Libraries Government Documents Department

The Buckling of Parallel Simply Supported Tension and Compression Members Connected by Elastic Deflectional Springs

Description: Note presenting an investigation of the problem of the buckling of parallel simply supported tension and compression members connected by equally stiff and equally spaced elastic deflection springs as an approximation to the problem of the effect of finite stiffness of ribs and tension surface on the buckling load of the compression surface of a wing. Charts relating compressive buckling load, deflectional spring stiffness, and the ratio of the flexural stiffness of the members are given for tension and compression members with various numbers of spans.
Date: February 1949
Creator: Seide, Paul & Eppler, John F.
Partner: UNT Libraries Government Documents Department

The Response of Pressure Measuring Systems to Oscillating Pressures

Description: Note presenting a method for calculating the response and lag in pressure measuring systems subjected to steady-state sinusoidally varying pressures. The pressure system is assumed to consist of an inlet restriction, tubing length, and connected instrument volume. Results of the phase-shift determination are provided.
Date: February 1949
Creator: Taback, Israel
Partner: UNT Libraries Government Documents Department

Two-Stage Supercharging

Description: "The arrangement of the parts and the installation and control problems of the two-stage mechanically driven superchargers for aircraft engines are discussed. Unless an entirely new form of supercharging is developed, there will be a definite need for a two-stage centrifugal supercharger. It is shown that the two-stage mechanically driven supercharger itself is a comparatively simple device; the complications arise from the addition of inter-coolers and controls" (p. 1).
Date: February 1941
Creator: Buck, Richard S.
Partner: UNT Libraries Government Documents Department

Effect of Rotor-Blade Twist and Plan-Form Taper on Helicopter Hovering Performance

Description: Note presenting a theoretical analysis of the hovering performance of rotors with various combinations of twist and plan-form taper in order to estimate the effects of blade twist and taper on rotor efficiency in hovering. The calculations were made with the aid of a strip-analysis procedure similar to that used in propeller analysis, the comparisons being made for rotors of equal solidity.
Date: February 1948
Creator: Gessow, Alfred
Partner: UNT Libraries Government Documents Department

A Generalized Vortex Theory of the Screw Propeller and Its Application

Description: "The vortex theory as presented by the author in earlier papers has been extended to permit the solution of the following problems: (1) the investigation of the relation between thrusts and torque distribution and energy loss as given by the induction of helical vortex sheets and by the parasite drag; (2) the checking of the theorem of Betz of the rigidly behaving helical vortex sheet of minimum induced energy loss; (3) the extension of the theory of the screw propeller of minimum energy loss for the inclusion of parasite-drag distribution along the blades" (p. 1).
Date: February 1940
Creator: Reissner, Hans
Partner: UNT Libraries Government Documents Department

A Generalized Theoretical and Experimental Investigation of the Motions and Hydrodynamic Loads Experienced by V-Bottom Seaplanes During Step-Landing Impacts

Description: Note presenting a theoretical investigation made of the motions and hydrodynamic loads experienced by V-bottom seaplanes during the course of a step-landing impact. In the analysis, the primary flow about the immersed portion of a keeled float or hull is considered to occur in transverse flow planes and the virtual-mass concept is applied to calculate the reaction of the water to the motion of the seaplane. The results are presented in the form of dimensionless curves which may be used to predict the behavior of V-bottom seaplanes at all instants during an impact as well as at the particular instants of maximum acceleration, maximum draft, and rebound.
Date: February 1948
Creator: Milwitzky, Benjamin
Partner: UNT Libraries Government Documents Department

Fatigue Tests on 1/8-inch Aluminum Alloy Rivets

Description: Note presenting an investigation of the fatigue characteristics of riveted joints in aluminum alloy sheet. The purpose of this report is to summarize all the results of fatigue tests that have been made to date in the Aluminum Research Laboratories of lap joints with 1/8-inch aluminum alloy rivets.
Date: February 1945
Creator: Andrews, H. J. & Holt, M.
Partner: UNT Libraries Government Documents Department

Pressure Distributions for Representative Airfoils and Related Profiles

Description: Note presenting selected pressure-distribution diagrams for a number of conventional and special airfoils. The conventional airfoils include the NACA 22, 44, and 230 series airfoils and Clark Y family and the special airfoils consist of circular-arc sections of several thicknesses and a number of synthetic airfoils. The pressure distributions are in most cases given for several lift coefficients including that at the ideal angle of attack.
Date: February 1946
Creator: Theodorsen, Theodore & Naiman, Irven
Partner: UNT Libraries Government Documents Department

The Influence of the Aerodynamic Span Effect on the Magnitude of the Torsional-Divergence Velocity and on the Shape of the Corresponding Deflection Mode

Description: "A procedure which takes into account the aerodynamic span effect is given for the determination of the torsional-divergence velocities of monoplanes. The explicit solutions obtained in several cases indicate that the aerodynamic span effect may increase the divergence velocities found by means of the section-force theory by as much as 17 to 40 percent. It is found that the magnitude of the effect increases with increasing degree of stiffness taper and decreases with increasing degree of chord taper" (p. 1).
Date: February 1944
Creator: Hildebrand, Francis B. & Reissner, Eric
Partner: UNT Libraries Government Documents Department

Determination of stress-strain relations from "offset" yield strength values

Description: Report presenting an investigation of the shape of stress-strain curve for a material, especially when the material is subjected to compression, which may cause materials to become unstable at stresses beyond the elastic range. The ratio of stresses to effective modulus is explored in equation form.
Date: February 1944
Creator: Hill, H. N.
Partner: UNT Libraries Government Documents Department

Exhaust-valve temperatures in a liquid-cooled aircraft-engine cylinder as affected by engine operating variables

Description: Report presenting an investigation of the operating temperatures of sodium-cooled exhaust valves in a liquid-cooled cylinder for a large variety of engine conditions by means of a thermocouple embedded in the valve head. The engine operating variables that affected the valve temperature most for a given percentage change in the operating variable included fuel-air ratio, indicated mean effective pressure, compression ratio, and spark advance. Results regarding temperature variations in constant engine conditions, effect of engine operating variables on exhaust-valve temperatures, and exhaust-valve temperatures at which preignition was encountered are provided.
Date: February 1947
Creator: Sutor, Alois T.; Corrington, Lester C. & Dudugjian, Carl
Partner: UNT Libraries Government Documents Department

An application of Falkner's surface-loading method to predictions of hinge-moment parameters for swept-back wings

Description: Report presenting an application of the Falkner lifting-surface-theory method to predicting hinge-moment and lift parameters for sweptback plan forms in order to develop an analogue to the existing lifting-surface-theory procedure for prediction of these parameters on unswept plan forms. For two specific plan forms, the hinge-moment predictions based on the Falkner method were not in good agreement with experimental values.
Date: February 1948
Creator: Jones, Arthur L. & Sluder, Loma
Partner: UNT Libraries Government Documents Department

Elastic and plastic buckling of simply supported metalite type sandwich plates in compression

Description: Report presenting a solution for the problem of the compressive buckling of simply supported, flat, rectangular, Metalite type sandwich plates stressed either in the elastic or plastic range. Charts for the analysis of long sandwich plates are provided for plates with face materials of 24S-T3 aluminum alloy, 75S-T6 Alclad aluminum alloy, and stainless steel.
Date: February 1949
Creator: Seide, Paul & Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Formulas for additional mass corrections to the moments of inertia of airplanes

Description: "Formulas are presented for the calculation of the additional mass corrections to the moments of inertia of airplanes. These formulas are of particular value in converting the virtual moments of inertia of airplanes or models experimentally determined in air to the true moments of inertia. A correlation of additional moments of inertia calculated by these formulas with experimental additional moments of inertia obtained from vacuum chamber tests of 40 spin-tunnel models indicates that formulas give satisfactory estimations of the additional moments of inertia" (p. 1).
Date: February 1947
Creator: Malvestuto, Frank S., Jr. & Gale, Lawrence J.
Partner: UNT Libraries Government Documents Department

Triangular wings cambered and twisted to support specified distributions of lift at supersonic speeds

Description: Report presenting an application of the linearized supersonic flow theory to the calculation of the camber and twist required for various lift distributions on a triangular wing with leading edges behind the Mach cone. Several specific examples are used and plots of the cambered surfaces, corresponding lift distributions, and values of the theoretical drag coefficients are presented.
Date: February 1949
Creator: Baldwin, Barrett S., Jr.
Partner: UNT Libraries Government Documents Department