Report presenting an investigation of the two-dimensional aerodynamic characteristics of three airfoil sections formed by removing various portions of the original chord from the trailing edge of the NACA 0012 airfoil section. Results regarding lift, drag, and pitching moment and aerodynamic center are provided.
From Summary: "The experimental investigation of damping screens described herein was undertaken primarily to test theories of the effects of damping screens and to obtain information on the performance of screens in oblique flow. The characteristics investigated include the damping of longitudinal and lateral components of turbulence, the effect of screens on scale, the conditions for the production of turbulence and eddies by screens, and the damping of spatial variations of mean speed."
From Introduction: "The fundamental integral equation for the pressure distribution on an oscillating thin airfoil moving at subsonic speed has been derived by Possio in reference 1. Collocation procedures have been used by Possio, Frazer, and Skan, and others to obtain lift and moment on an oscillating first plate. An important contribution has been made by Dietze (see reference 2 and 3), who has developed an iterative procedure for numerical solution of Possio's integral equation."
From Introduction: "This investigation provides general information on the magnitudes and directions of the aerodynamic forces and moments acting on a fighter airplane in fully developed spins. The investigation includes the determination of the effects on the aerodynamic forces and moments of varied rudder setting with and against the spin, of tail modifications, and of deflected flaps and lowered landing gear."
"The first basic problem that must be solved before control synthesis can proceed is that of determining the dynamic characteristics of the engine. Accordingly, an analysis of the dynamic behavior of the turbojet engine with tail-pipe burning was made at the NACA Lewis laboratory and is presented herein" (p. 1).
From Introduction: "In the present paper, general ejector equations (see reference 4 or 5) and certain assumptions with regard to flow conditions and pressure losses have been utilized to calculate the running times of induction blowdown supersonic tunnels operating in the mentioned Mach number range."
From Introduction: "The primary purpose of the investigation described in the present report is to formulate a method which is of value for quantitative calculations of base pressure on airfoils and bodies without boat-tailing. Part I consists of a detailed study of the base pressure in two-dimensional and axially-symmetric inviscid flow. In part II a semi-empirical theory is formulated since the results of part I indicate that an inviscid-flow theory cannot possibly be satisfactory for quantitative calculations of a viscous flow."
From Introduction: "The design of turbojet-engine control systems is intimately related to the dynamic characteristics of the engine and has advanced to the stage where theoretically correct control constants can be determined for fixed dynamic properties (references 1 and 2). The use of the thermodynamic equations presupposes that the engine processes are quansi-static. Such an assumption is shown to be valid for a turbojet engine in references 3 and 4.
From Introduction: "Experimental investigations of air-induction systems in which the air flows of two intakes join in a common duct have inducted that many of these systems are subject to air-flow instability at low inlet-velocity ratios. Therefore, an analysis has been made to determine a proper basis for an explanation and to provide a more quantitative explanation of the flow instability and the flow reversal. This report presents the results of this analysis."
From Introduction: "In the present report an analysis was undertaken to arrive at a mathematical formula by which the shear strengths of honeycomb core materials could be calculated. Experimental verification of the formula of the present paper was obtained by tests of honeycomb-type sheets of resin-impregated paper; two groups of specimens were tested, each of which represented a different resin-impregation treatment of the basic paper."
Report presenting an analysis of normal-acceleration and airspeed data on several transport airplanes of a four-engine type during postwar commerical operations on trans-Pacific and Caribbean-South American routes of the same airlines. The results indicate that the acceleration increment corresponding to the limit-gust-load-factor increment may be exceed about twice in all of the flight miles for each route. Results regarding accelerations, flight loads, gust encounters, and speeds are provided.
Note presenting equations derived for the prediction of velocity distributions for fully developed adiabtic turbulent flow in smooth tubes; both the incompressible and compressible flow cases were treated. The analysis produced a single equation that represents flow in both the conventional buffer layer and the laminar layer. The results for fully developed flow were correlated by using conventional dimensionless velocity and distance parameters, and agreed closely with those of Nikuradse and other investigators.
Report presenting a theoretical treatment of absorption problems that considers the following cases: radiation is normal to an absorber with plane parallel surfaces, radiations are of several polyenergetic types, induced radioactive isotopes decay to stable atoms in multistep decay processes, and radiations from the absorber affect the time-dependency of the source activity. Radiation from intermediate isotopes can become more dangerous than the original activity, so the entire range of radiations must be accounted for.
Note presenting the application of the Laplace transformation to the solution of the lateral and longitudinal stability equations. The expressions for the time history of the motion in response to a sinusoidal control motion are derived for the general case in which all initial measurements are assumed different from zero.
From Summary: "The methods used in the application of the wire-mesh plotting device to find the flow pattern about a cascade of airfoils in compressible inviscid flow and some mathematical checks that increase the accuracy of this application are described. Results for two typical turbine-blade cascades are shown to compare well with experimental data. A method of utilizing the wire mesh to design turbine blades with a prescribed pressure distribution in incompressible flow is presented."
From Summary: "Aerodynamic influence coefficients for symmetrically loaded wings of arbitrary plan form in subsonic flow are derived from a simple empirical method of estimating spanwise lift distributions. The application of the coefficients to an aeroelastic analysis is discussed."
From Introduction: "The present paper introduces the approximate method by means of which it is possible to calculate the pressures in the tip region of a rectangular with a symmetrical circular-arc section to a higher degree of accuracy than is possible with the usual linear methods."
Note presenting a method of visualizing air-flow patterns by observing the motion of finely divided particles of balsa wood introduced into the air. Photographic results obtained by this method for small-scale models of several helicopter rotor configurations in the static-thrust condition are presented. The results indicate the feasibility of using the balsa-dust technique for obtaining useful qualitative information on the air-flow patterns for transient conditions as well as for steady-state conditions.
"Differential equations and boundary conditions are derived for the bending and buckling of sandwich plates. The buckling load is calculated for a simply supported plate subjected to edgewise compression. The formulas are evaluated numerically and the results are plotted in a diagram" (p. 1).
Report presenting a metallographic study of the interface between various elements and titanium carbide. Hardness measurements of the different elemental combinations are also provided.
Note presenting a wind-tunnel investigation of the NACA 64A010 airfoil section to determine the boundary-layer and stalling characteristics at low speed. The tests were made at a Reynolds number of 4.1 million and included force measurements, pressure-distribution measurements, flow studies by the liquid-film technique, and boundary-layer measurements.
Report presenting boundary-layer measurements in the transonic and supersonic regions of a channel with maximum cross-sectional dimensions 3.84 by 10 inches and designed by potential-flow methods for a uniform Mach number of 2.08. Results regarding the Mach number distribution along the channel, temperature recovery and Prandtl number, boundary layer development, skin-friction coefficient, and secondary flows are provided.
Note presenting an investigation of the laminar boundary layer on a cooled 20 degree cone at Mach numbers of 1.5 and 2.0 to determine the variation of the position of transition with surface temperature for both constant surface temperatures and surface temperatures that increased toward the rear of the cone. The increase in the extent of the laminar boundary layer for uniform surface temperatures was found to be directly proportional to the difference between the surface and recovery temperatures.
Note presenting an analysis of the performance of basic, reheat, regenerative, and regenerative-plus-reheat turbine-propeller engines. The analysis covered an overall range of flight speeds, altitudes, and turbine-inlet temperatures for a range of compressor pressure ratios.
Report presenting exact and approximate methods based on linearized supersonic flow theory for the calculation of the velocity potential and the downwash from thin wings of arbitrary plan form. The applicability of the method inherently depends on a knowledge of the load distribution over the plan form of the wing.
Report presenting a method that has been developed for the calculation of the natural coupled or uncoupled frequencies and modes of a structure with modifications directly from the known modes and frequencies of the unmodified structure. The method is advantageous when the modes and frequencies of the unmodified structure either are known or are required along with the modes and frequencies of the structure with various modifications.
Note presenting a method of calculating two-dimensional compressible flows past thin airfoils with particular reference to the transonic speed range. The method is based on the integral form of the equation of continuity and on the intrinsic form, in terms of the streamline curvature, of the irrotationality condition.
Report presenting a method for calculating the pressure drop of a high-speed compressible fluid in a constant-area duct under the simultaneous action of friction and heat transfer. The temperature distribution assumed in the development of the working chart can be made to closely approximate, in on one or two steps, the temperature distributions found in the cooling passages of ramjet and tail-pipe-burner combustion chambers.
Note presenting charts for estimating the downwash behind wings in a supersonic stream. The wing plan forms for which compositions are made include rectangular wings with reduced aspect ratios of 2, 4, 8, and 12; trapezoidal wings with reduced aspect ratios ranging from 2 to 12.8 and taper ratios of 1/2 and 1/4; and triangular wings with reduced aspect ratios of 8 and 12. A procedure is indicated to correct for the displacement and the distortion of the trailing vortex sheet.
"The equation of vertical motion for an airplane in gusty air is simplified in order that its solution is a function of only two parameters, namely, the mass parameter of the airplane and the shape of the gust the airplane is penetrating. The solutions of the equation are presented in the form of charts that can be used for estimating rapidly and easily the acceleration ratios encountered by airplanes with different mass parameters penetrating a sharp-edge gust, a gust of arbitrary shape, or a triangular gust.
Report presenting charts that permit the determination of enthalpy change for various processes regarding the thermodynamic data of gas properties. Some examples using the charts to solve problems are provided.
Note presenting comparative data on the volume of foam and stability of foams of aeronautical lubricating oils produced at 100 degrees Celsius by the air-bubbling method. All of the data were obtained with the same foam meter, by a standard technique, and at various rates of air flow. Results regarding the reproducibility of foam tests and treatment of data are provided.
Report presenting a critical comparison between experimental and theoretical results for the aerodynamic characteristics of wings at supersonic flight speeds. The lift, pitching moment, and drag characteristics of several families of wings of varying plan form and section in the wind tunnel and compared with values predicted by the three-dimensional linear theory.
Note presenting the results of axial fatigue tests conducted on 0.032-inch-thick flat-sheet specimens of bare and alclad 24S-T3 aluminum alloy to determine the effect of frequency of loading on the fatigue strengths of these materials. The number of cycles to failure varied from about 150 to over 10,000,000 and tests were conducted using completely reversed axial load at two frequencies of loading.
Note presenting the results of spin-tunnel investigations compared with corresponding full-scale results for 60 different airplane designs. The purpose of the comparison was to determine the reliability of the model results in predicting full-scale spin and recovery characteristics. Results regarding the recovery characteristics, angle of attack, rate of rotation, altitude loss per revolution, angle of wing tilt, and emergency spin-recovery parachutes are provided.
Note presenting pressure-distribution measurements made on a 5-inch-chord NACA 0012 airfoil at zero angle of attack in the Langley rectangular high-speed tunnel, a 4- by 18-inch closed-throat tunnel, and compared with results calculated by Emmons for an equivalent airfoil-channel configuration by using the relaxation method.
Note presenting an investigation to compare the dynamic lateral control characteristics provided by step plug ailerons with those provided by conventional flap ailerons on a sweptback-wing model. The model used had a 38 degree sweptback wing with an aspect ratio of 3 and a taper ratio of 0.5.
Report presenting heat-transfer measurements on an air-cooled 20 degree cone with a laminar boundary layer at Mach number 2.02. The surface temperature in the instrumented area on the cone was essentially constant at all test conditions, but the area was preceded by severe surface-temperature gradients.
Report presenting a smooth-water-landing investigation with a small seaplane to obtain experimental wing-bending-moment time histories together with time histories of the various parameters necessary for the prediction of wing bending moments during hydrodynamic impact. Experimental results were compared with calculated results, including inertia-load effects and the effects of air-load variation during impact.
Note presenting a simplified extension of the Prandtl-Glauert compressibility correction for isolated airfoils, which was obtained for airfoils in cascade with axial air inlet by considering the total lift coefficient of a cascade to be composed of the sum of two components. Results regarding theoretical variations, experimental correlation, and design application are provided.
"Results are presented of compressive stress-strain tests of titanium sheet at temperatures from room temperature up to 800 degrees Fahrenheit, exposure times of 1/2 to 2 hours, and strain rates of 0.002 to 0.006 per minute. The results show that titanium has favorable compressive properties, comparable to those in tension, up through 800 degrees Fahrenheit. Marked anisotropy in compression was also noted" (p. 1).
Report presenting a method of relating the effects of fuel-air ratio on the knock-limited charge flow and power of a supercharged engine with those of compression ratio and inlet-air temperature. Knock data obtained in a CFR engine over a wide range of conditions were correlated with eight fuels: 28-R fuel, aviation alkylate, S reference fuel, diisopropyl, triptane, cyclohexane, cyclopentane, and triptene.
Report presenting a study of the correlation between molecular structure and physical properties of high-density hydrocarbons, including the net heat of combustion, melting point, boiling point, density, and kinematic viscosity. They are evaluated for their use as a fuel, especially in planes that are required to have smaller fuel tanks.
Report presenting data from five reference reports and correlate the available heat-transfer and friction data on plane fin surfaces that are interrupted and staggered in successive rows in the fluid-flow direction. A single heat-transfer correlation equation was obtained that satisfactory represents the heat-transfer data over the entire range of conditions investigated.
Report presenting solutions for the elastic buckling stress of flat rectangular plates with simply supported or fixed ends when loaded as columns. The procedure for determining the critical stress of plate columns with intermediate end fixities is also given.
Report presenting an investigation of the cooling characteristics of a multicylinder liquid-cooled engine of 1650-cubic-inch displacement. The results showing the variation of the cylinder-head temperature and the coolant heat rejection with the pertinent engine and coolant variables are provided. Data included a variety of engine power outputs, engine speeds, manifold pressure, fuel-air ratio, inlet-air temperature, ignition timing, exhaust pressure, coolant flow, composition, temperature, and pressure.
From Summary: "Interferograms were taken of the flow around a sphere at Mach numbers of 1.30 and 1.62. The results of the evaluation of these interferograms are shown as plots of contours of constant density ratio in the flow field around the sphere and as the distribution of flow variables along the axis of symmetry between the shock wave and the sphere. In appendixes the theory of the analysis is reviewed, sources of error are discussed, and the detailed procedure used in the evaluation of interferograms is described."
Note presenting an investigation of the design requirements and heat-transfer characteristics of exposed-wire instruments to be used for steady-state measurements at transonic and supersonic speeds. Design criterions, construction details, and typical response behavior are presented.
Report presenting the results of several years of experience of operation of a small water channel, which has shown that the hydraulic analogy can be used successfully to demonstrate many two-dimensional compressible-flow phenomena.
Report presenting wind-tunnel testing to determine the temperature-recovery factors for laminar, transitional, and turbulent boundary layers on a flat plate.
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