National Advisory Committee for Aeronautics (NACA) - 356 Matching Results
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- The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates
- "The theory of Lagrangian multipliers is applied to the problem of finding both upper and lower limits to the true compressive buckling stress of a clamped rectangular plate. The upper and lower limits thus bracket the truss, which cannot be exactly found by the differential-equation approach. The procedure for obtaining the upper limit, which is believed to be new, presents certain advantages over the classical Raleigh-Rite method of finding upper limits" (p. 1).
- Single-Cylinder Oil-Control Tests of Porous Chrome Plated Cylinder Barrels for Radial Air-Cooled Engines
- Report presenting a series of single-cylinder engine tests run to determine a satisfactory method of reducing oil consumption in radial air-cooled engines with flat-face compression rings as standard parts and equipped with cylinder barrels salvaged by porous chrome plating. Testing was conducted using porous chrome-plated cylinders with straight and choke bores with standard flat-face compression rings.
- Flow over a slender body of revolution at supersonic velocities
- "The theory of small disturbances is applied to the calculation of the pressure distribution and drag of a closed body of revolution traveling at supersonic speeds. It is shown that toward the rear of the body the shape of the pressure distribution is similar to that for subsonic flow. For fineness ratios between 10 and 15 the theoretical wave drag is of the same order as probable values of the frictional drag" (p. 1).
- Stresses in and general instability of monocoque cylinders with cutouts 2: calculation of the stresses in a cylinder with a symmetric cutout
- A numerical procedure is presented for the calculation of the stresses in a monocoque cylinder with a cutout. In the procedure the structure is broken up into a great many units; the forces in these units corresponding to specified distortions of the units are calculated; a set of linear equations is established expressing the equilibrium conditions of the units in the distorted state; and the simultaneous linear equations are solved. A fully worked out numerical example, corresponding to the application of a pure bending moment, gave results in good agreement with experiments carried out earlier at the Polytechnic Institute of Brooklyn.
- Stresses in and general instability of monocoque cylinders with cutouts 1: experimental investigation of cylinders with a symmetric cutout subjected to pure bending
- "Ten 24S-T alclad cylinders of 20-inch diameter, 45- or 58-inch length, and 0.012-inch wall thickness, reinforced with 24S-T aluminum alloy stringers and rings were tested in pure bending. In the middle of the compression side of the cylinders there was a cutout extending over 19 inches in the longitudinal direction, and over an angle of 45 degrees, 90 degrees, or 135 degrees in the circumferential direction. The strain in the stringers and in the sheet covering was measured with metal electric strain gages. The stress distribution in the cylinders deviate considerably from the linear law valid for cylinders without a cutout" (p. 1).
- The Development of a Lateral-Control System for Use With Large-Span Flaps
- "A spoiler-type lateral-control system has been developed for use on the Northrop P-61 airplane. The lateral-control system is to be used with large-span flaps and consists of a thin circular arc spoiler, linked with a short-span plain aileron located just outboard of the spoiler. This unconventional lateral-control system has been accepted with enthusiasm by the pilots who have flown the airplane" (p. 1).
- Effect of Mach and Reynolds Numbers on Maximum Lift Coefficient
- Report presenting an investigation of the effects of Mach and Reynolds numbers on the maximum lift coefficient of aircraft. Flight testing was conducted on six airplanes outfitted with measuring tools and flow at various Mach and Reynolds numbers.
- Wind-tunnel investigation of end-plate effects of horizontal tails on a vertical tail compared with available theory
- A vertical-tail model with stub fuselage was tested in combination with various simulated horizontal tails to determine the effect of horizontal-tail span and location on the aerodynamic characteristics of the vertical tail. Available theoretical data on end-plate effects were collected and presented in the form most suitable for design purposes. Reasonable agreement was obtained between the measured and theoretical end-plate effects of horizontal tails on vertical tails, and the data indicated that the end-plate effect was determined more by the location of the horizontal tail than by the span of the horizontal tail. The horizontal tail gave most end-plate effect when located near either tip of the vertical tail and, when located near the base of the vertical tail, the end-plate effect was increased by moving the horizontal tail rearward.
- A Study of Combustion in a Flowing Gas
- Note presenting the results of a preliminary study of combustion in flowing gases and apparatus for obtaining high rates of heat release per unit volume of combustion space are described. Tests were made over a wide range of fuel-air ratios, inlet-mixture velocities, and electrical heat inputs, using propane gas as the fuel. Results indicate that the greater the surface-volume ratio, or the greater the amount of heat addible to the gas stream, the greater the inlet-mixture velocity at which appreciable combustion can be obtained.
- A Fixture for Compressive Tests of Thin Sheet Metal Between Lubricated Steel Guides
- Note presenting a fixture for compressive tests of thin sheet metal. It consists of two hardened steel guides between which the specimen is held by two adjustable clamps. Results and analysis regarding steel versus brass guides, the lubricant film, tests without the subpress, and comparison of tensile tests with compressive tests using steel guides are provided.
- Charts of Thermodynamic Properties of Fluids Encountered in Calculations of Internal Combustion Engine Cycles
- "A single chart has been prepared that simplifies the calculation of the thermodynamic properties of air, various octene-air mixtures, and mixtures of those with their products of combustion at all temperatures below which chemical dissociation becomes unimportant. The chart is based on the use of 1 pound mol of mixture, and examples of its use are given in the form of the calculation of a turbocompressor power plant and a supercharged Otto engine cycle" (p. 1).
- Effect of Sweepback and Aspect Ratio on Longitudinal Stability Characteristics of Wings at Low Speeds
- Note presenting an analysis of the available data on the longitudinal stability characteristics of sweptback wings at low speeds. The analysis indicated that the shape of the pitching-moment curve near the stall for sweptback wings is greatly dependent on the aspect ratio. The addition of a horizontal tail behind the wings may be destabilizing and requires further investigation.
- Measurement of the arithmetic mean velocity of a pulsating flow of high velocity by the hot-wire method
- Report presenting an experimental method of measuring both the arithmetic mean velocity and the instantaneous velocity of pulsating flow and with the instruments developed for this purpose. A circuit for a hot-wire anemometer usable for fluctuating flow is described.
- Two dimensional wind-tunnel investigation of low drag vertical-tail,horizontal-tail, and wing sections equipped with sealed internally balanced control surfaces
- Report presenting a two-dimensional wind-tunnel investigation of three low-drag airfoil sections equipped with sealed internally balanced control surfaces designed for use as vertical-tail, horizontal-tail, and wing sections. Testing included determination of control-surface effectiveness and hinge moments and airfoil section drag characteristics. Results regarding vertical-tail section, horizontal-tail section, wing section, and effect of sudden movement of transition on airplane control-surface characteristics are provided.
- Clamped Long Rectangular Plate Under Combined Axial Load and Normal Pressure
- Note presenting a solution for the buckling load and load carried after buckling of a clamped rectangular plate with a width-length ratio of 1:4 under combined normal pressure and axial load. The results indicate that normal pressure causes a smaller increase in the buckling load of plates with clamped edges than of plates with simply supported edges.
- An Empirical Equation for the Coefficient of Heat Transfer to a Flat Surface From a Plane Heated-Air Jet Directed Tangentially to the Surface
- Note presenting an investigation of the heat transfer to a surface from plane heated-air jets discharged tangentially to the surface was conducted to provide heat-transfer relationships required in the design of heated-air jet installations for aircraft windshield fog prevention. Experimental temperature, velocity, and heat-transfer data were obtained by tests in which the initial jet temperature and velocity were varied.
- Wind-Tunnel Investigation of Boundary-Layer Control by Suction on the NACA 653-418, a = 1.0 Airfoil Section with a 0.29-Airfoil-Chord Double Slotted Flap
- Note presenting tests to find the maximum lift of the NACA 65(sub 3)-418 airfoil section equipped with a 0.29-airfoil-chord double slotted flap and a boundary-layer suction slot located at 0.45 airfoil chord. Results regarding lift characteristics, drag characteristics, and boundary layer and related characteristics are provided.
- Flight tests of experimental beveled-trailing-edge Frise ailerons on a fighter airplane
- Report presenting flight measurements made to determine the characteristics of a pair of experimental ailerons designed to provide a close degree of balance and maintain a linear variation of aileron effectiveness with aileron angle through a large deflection range. Results regarding the small-deflection tests, large-deflection tests, effect of stretch on stick forces, and analysis of extended-span ailerons are provided.
- On Laminar and Turbulent Friction
- Report deals, first with the theory of the laminar friction flow, where the basic concepts of Prandtl's boundary layer theory are represented from mathematical and physical points of view, and a method is indicated by means of which even more complicated cases can be treated with simple mathematical means, at least approximately. An attempt is also made to secure a basis for the computation of the turbulent friction by means of formulas through which the empirical laws of the turbulent pipe resistance can be applied to other problems on friction drag.
- Theoretical lift and drag of thin triangular wings at supersonic speeds
- "A method is derived for calculating the lift and the drag due to lift of point-forward triangular wings and a restricted series of sweptback wings at supersonic speeds. The elementary or "supersonic sources" solution of the linearized equation of motion is used to find the potential function of a line of doublets. The flow about the triangular flat plate is then obtained by a surface distribution of these doublet lines. The lift-curve slope of triangular wings is found to be a function of the ratio of the tangent of the apex angle to the tangent of the Mach angle" (p. 97).
- Application of the Method of Characteristics to Supersonic Rotational Flow
- "A system for calculating the physical properties of supersonic rotational flow with axial symmetry and supersonic rotational flow in a two-dimensional field was determined by use of the characteristics method. The system was applied to the study of external and internal flow for supersonic inlets with axial symmetry. For a circular conical inlet the shock that occurred at the lip of the inlet became stronger as it approached the axis of the inlet and became a normal shock at the axis" (p. 111).
- Flutter and oscillating air-force calculations for an airfoil in two-dimensional supersonic flow
- A connected account is given of the Possio theory of non-stationary flow for small disturbances in a two-dimensional supersonic flow and of its application to the determination of the aerodynamic forces on an oscillating airfoil. Further application is made to the problem of wing flutter in the degrees of freedom - torsion, bending, and aileron rotations. Numerical tables for flutter calculations are provided for various values of the Mach number greater than unity. Results for bending-torsion wing flutter are shown in figures and are discussed. The static instabilities of divergence and aileron reversal are examined as is a one-degree-of-freedom case of torsional oscillatory instability.
- Summary of lateral-control research
- "A summary has been made of the available information on lateral control. A discussion is given of the criterions used in lateral-control specifications, of the factors involved in obtaining satisfactory lateral control, and of the methods employed in making lateral-control investigations in flight and in wind tunnels. The available data on conventional flap-type ailerons having various types of aerodynamic balance are presented in a form convenient for use in design. The characteristics of spoiler devices and booster mechanisms are discussed" (p. 1).
- The Stability of the Laminar Boundary Layer in a Compressible Fluid
- The present paper is a continuation of a theoretical investigation of the stability of the laminar boundary layer in a compressible fluid. An approximate estimate for the minimum critical Reynolds number, or stability limit, is obtained in terms of the distribution of the kinematic viscosity and the product of the mean density and mean vorticity across the boundary layer. The extension of the results of the stability analysis to laminar boundary-layer gas flows with a pressure gradient in the direction of the free stream is discussed.
- Tank tests to determine the effect on planing-tail hulls of varying length, width, and plan-form taper of afterbody
- Tests were conducted in Langley Tank no. 2 on models of an unconventional flying-boat hull called a planing-tail hull to determine the effects on resistance of varying a number of afterbody parameters. The effects of varying length, width, and plan-form taper of the afterbody are presented. Tests were made with afterbodies of two widths, two lengths, and two tapers. In the tests the depth of step and the angle of afterbody keel were held constant.(author).
- Thin Oblique Airfoils at Supersonic Speed
- "The well-known methods of thin-airfoil theory have been extended to oblique or sweptback airfoils of finite aspect ratio moving at supersonic speeds. The cases considered thus far are symmetrical airfoils at zero lift having plan forms bounded by straight lines. Because of the conical form of the elementary flow fields, the results are comparable in simplicity to the results of the two-dimensional thin-airfoil theory for subsonic speeds" (p. 267).
- Two-Dimensional Irrotational Mixed Subsonic and Supersonic Flow of a Compressible Fluid and the Upper Critical Mach Number
- Note presenting the use of the hodograph method to investigate the problem of flow of a compressible fluid past a body with subsonic flow at infinity. Explicit formulas for numerical calculations are given for the flow about a body, such as an elliptical cylinder, and for the periodic flow such as would exist over a wavy surface.
- Numerical procedures for the calculation of the stresses in monocoques 3: calculation of the bending moments in fuselage frames
- "This report deals with the calculation of the bending moments in and the distortions of fuselage rings upon which known concentrated and distributed loads are acting. In the procedure suggested, the ring is divided into a number of beams each having a constant radius of curvature. The forces and moments caused in the end sections of the beams by individual unit displacements of the end sections are listed in a table designated as the operations table in conformity with Southwell's nomenclature. The operations table and the external loads are equivalent to a set of linear equations" (p. 1).
- The theoretical flow of a frictionless, adiabatic, perfect gas inside of a two-dimensional hyperbolic nozzle
- Report presenting a study of the two-dimensional flow of a frictionless, adiabatic, perfect gas inside of a two-dimensional hyperbolic nozzle by using numerical methods.
- The High-Speed Characteristics of Several Flaps and Spoilers on the Upper Surface of the Horizontal Stabilizer of a Model of a Radial-Engine Pursuit Airplane
- Report discussing an investigation into several types and sizes of flaps and spoilers located forward of the elevators on the upper surface of the horizontal stabilizer of a model of a radial-engine pursuit airplane. Information about the elevator characteristics, elevator-fixed and elevator-free balance lift coefficient, and trim drag coefficient for a range of Mach numbers is provided.
- Aerodynamic Data for a Wing Section of the Republic XF-12 Airplane Equipped With a Double Slotted Flap
- Report presenting an investigation in the two-dimensional low-turbulence tunnels for the purpose of developing an optimum flap configuration for maximum lift on an airfoil section for the Republic XF-12 airplane equipped with a double slotted flap. Lift and flap loads were obtained at several flap deflections for two flap paths. Results regarding lift, drag, and flap loads are provided.
- Two-Dimensional Wind-Tunnel Investigation of Two NACA Low-Drag Airfoil Sections Equipped With Slotted Flaps and a Plain NACA Low-Drag Airfoil Section for XF6U-L Airplane
- Report discussing the results of testing to determine the aerodynamic characteristics of three NACA-designed airfoil sections, some with flaps equipped. The tests included determination of the aerodynamic characteristics of the airfoils in smooth conditions and with standard roughness applied to the leading edge. Lift tests were also carried out at a range of flap deflections.
- Aerodynamic Characteristics of Four NACA Airfoil Sections Designed for Helicopter Rotor Blades
- "The purpose of the present work is to extend the previous investigation and to derive additional airfoil sections designed to minimize the undesirable characteristics of the previously tested airfoils. The tests of these additional airfoils were made in the Langley two-dimensional low-turbulence tunnel (LTT)" (p. 2).
- Wind-Tunnel Investigation of an NACA 66-Series 16-Percent-Thick Low-Drag Tapered Wing With Fowler and Split Flaps
- Report presenting testing to determine the aerodynamic characteristics of an NACA 66-series 16-percent-thick low-drag tapered wing with Fowler and split flaps. The wing had a straight trialing edge and a constant-chord center section. Results regarding lift and pitching-moment characteristics and stalling characteristics are provided.
- Effect of Compressibility on the Pressure and Forces Acting on a Modified NACA 65,3-019 Airfoil Having a 0.20-Chord Flap
- "An investigation has been conducted in the Langley rectangular high-speed tunnel to determine the effect of compressibility on the pressure distribution for a modified NACA 65,3-019 airfoil having a 0.20-chord flap. The investigation was made for an angle-of-attack range extending from -2 to 12 deg at .20 flap deflections from 0 to -12 deg. Test data were obtained for Mach numbers from 0.28 to approximately 0.74" (p. 1).
- Some Notes on the Effects of Jet-Exit Design on Static Longitudinal Stability
- Report discussing several types of jet-exit designs, including normal, beveled, and unsymmetrical shapes, and their effect on the stability characteristics of the aircraft. No deviation of the jet center line from its exposed path is likely to be obtained if a jet exist is used that is normal to the flow. Having a tilted or asymmetrical exit was found to adversely affect the stability of the aircraft.
- A correlation of loadings and afterbody length-beam ratios of various flying-boat hulls
- "The gross weight, beam, and afterbody length of 12 contemporary flying boats and amphibians with pointed afterbodies are tabulated and correlated. For most of the hulls considered, the afterbody length-beam ratios are shown to be directly proportion to the gross-load coefficients" (p. 1).
- Tests of Cast Aluminum-Alloy Mixed-Flow Impellers
- "A machined mixed-flow centrifugal impeller of a relatively complex passage shape was used as a pattern to cast a number of aluminum-alloy impellers from two aluminum-base alloys (designated alloys 1 and 2) by the 'lost wax' process. An investigation was conducted to determine whether these cast impellers, could be considered satisfactory for use in compressors. The investigation included preliminary examination, physical tests, metallurgical examination, and performance tests" (p. 1).
- An Experimental Investigation of Flow Conditions in the Vicinity of an NACA D(Sub S)-Type Cowling
- Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.
- An Investigation of Cowl-Flap and Cowl-Outlet Designs for the Boeing B-29 Power-Plant Installation
- Report discussing an investigation into cowl-flap and cowl-outlet designs for the B-29 in order to determine the effects of cowling performance of different types of flaps and elements of flaps. Details of the available pressure drop and cooling-air pressure-drop distribution are also provided.
- Aerodynamics of the carburetor air scoop and the engine cowling of a single-engine torpedo-bomber-type airplane
- From Introduction: "An investigation of the power-plant installation of a single-engine torpedo-bomber-type airplane has been conducted in the NACA Cleveland altitude wind tunnel at the request of the Bureau of Aeronautics, Navy Department. A similar investigation was previously conducted on a three-tenths scale mock-up of the forward portion of the fuselage of this airplane in the Langley 20-foot tunnel. (See reference 1)."
- Tests of the Jet-Motor Air-Intake Duct System on a 1/4-Scale Stub-Wing Model of a Pursuit-Type Airplane
- Report discussing the characteristics of the jet-motor air-intake duct system for a pursuit-type airplane with modifications to the duct system. Details of its effects on the Mach number, high pressure recovery, drag, and simplicity of the system are provided. Problems regarding the flow condition through the ducts and some potential modifications to prevent further issues are also described.
- Air-Flow and Performance Characteristics of Engine-Stage Supercharger of a Double-Row Radial Aircraft Engine 2: Effect of Design Variables
- Report presenting an investigation to determine the effect of the location of the diffuser vanes with respect to the supercharger outlets and the effect of flow conditions at the impeller inlet on the air-flow distribution in the outlets of the engine-stage supercharger of an 18-cylinder double-row radial aircraft engine. The effect of flow conditions at the impeller inlet was investigated by distorting the flow at the inlet and noting the effect in the supercharger outlets. Results regarding the diffuser effect and inlet effect are provided.
- Hydraulic Characteristics of the NACA Injection Impeller
- Report discussing a mock-up injection impeller created to investigate the hydraulic characteristics and limitations of the NACA injection impeller currently in use. Information about the form and magnitude of critical factors of fuel-transfer leakage and peripheral fuel distribution is provided as well as the effects of design variations of components on hydraulic characteristics. Several revisions in portions of the impeller are suggested to improve its fuel-transfer, fuel-pumping, and fuel-equalizing characteristics.
- The Effect of Liquid and Ice Particles on the Erosion of a Supercharger-Inlet Cover and Diffuser Vanes
- Report discussing the results of accelerated erosion tests to determine the separate effects of the passage of fuel, water, and ice particles through a supercharger. Recommendations for preventing erosion are provided, including materials choice and joint design.
- Ground-Stand Cooling Investigation of an R-2600-22 Engine in a PBM-3D Nacelle
- Report discussing an investigation of the cooling characteristics of an R-2600-22 engine installed in a PBM-3D nacelle. The investigation explored the general cooling characteristics by the NACA cooling-correlation method and an investigation of specific points on the engine cylinder where cooling was critical, including the exhaust-valve-crown and number 3 cylinder.
- Annual Report of the National Advisory Committee for Aeronautics (28th). Administrative Report Including Technical Report Nos. 727 to 751
- Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
- Investigations of Effects of Surface Temperature and Single Roughness Elements on Boundary-Layer Transition
- "The laminar boundary layer and the position of the transition point were investigated on a heated flat plate. It was found that the Reynolds number of transition decreased as the temperature of the plate is increased. It is shown from simple qualitative analytical considerations that the effect of variable viscosity in the boundary layer due to the temperature difference produces a velocity profile with an inflection point if the wall temperature is higher than the free-stream temperature" (p. 587).
- A Thermodynamic Study of the Turbojet Engine
- "Charts are presented for computing thrust, fuel consumption, and other performance values of a turbojet engine for any given set of operating conditions and component efficiencies. The effects of pressure losses in the inlet duct and the combustion chamber, of variation in physical properties of the gas as it passes through the system, of reheating of the gas due to turbine losses, and of change in mass flow by the addition of fuel are included. The principle performance chart shows the effects of primary variables and correction charts provide the effects of secondary variables and of turbine-loss reheat on the performance of the system" (p. 599).
- Summary of Drag Characteristics of Practical-Construction Wing Sections
- "The effect of several parameters on the drag characteristics of practical-construction wing sections have been considered and evaluated. The effects considered were those of surface roughness, surface waviness, compressive load, and de-icers. The data were obtained from a number of tests in the Langley two-dimensional low-turbulence tunnels" (p. 359).