National Advisory Committee for Aeronautics (NACA) - 743 Matching Results
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- An Analysis of the Full-Floating Journal Bearing
- Report discussing an analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted.
- An Analysis of the Full-Floating Journal Bearing
- "An analysis of the operating characteristics of a full-floating bearing - a bearing in which a floating sleeve is located between the journal and bearing surfaces - is presented together with charts - from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing to verify some results of the analysis are reported. The floating sleeve can operate over a wide range of speeds for a given shaft speed, the exact value depending principally upon the ratio of clearances and upon the ratio of radii of the bearing" (p. 1).
- Analysis, Verification, and Application of Equations and Procedures for Design of Exhaust-Pipe Shrouds
- Investigations were made to develop a simplified method for designing exhaust-pipe shrouds to provide desired or maximum cooling of exhaust installations. Analysis of heat exchange and pressure drop of an adequate exhaust-pipe shroud system requires equations for predicting design temperatures and pressure drop on cooling air side of system. Present experiments derive such equations for usual straight annular exhaust-pipe shroud systems for both parallel flow and counter flow. Equations and methods presented are believed to be applicable under certain conditions to the design of shrouds for tail pipes of jet engines.
- Analytical and Experimental Investigation of Bolted Joints
- From Introduction: "The present paper contains the development of a recurrence formula for the bolt loads for the simplified case of a symmetrical butt joint with bolts spaced evenly in line with the applied load. The method presented herein is based on the fundamental relationship which was developed in reference 1 between the loads on any two successive bolts. The present paper also gives the results of an experimental investigation conducted to substantiate further the adequacy of the elastic theory as well as to yield additional data on the critical bolt load and the behavior of long joints in the plastic range and at the ultimate load."
- Analytical Comparison of a Standard Turbojet Engine, a Turbojet Engine with a Tail-Pipe Burner, and a Ram-Jet Engine
- From Introduction: "Experimental investigations (reference 1) have shown that in some cases the thrust can be more than doubled by means of tail-pipe burning. A comparison is made of a standard turbojet engine, whose thrust is augmented by tail-pipe burning, and a ram-jet engine. The performance characteristics for the ram-jet engine were computed entirely from theoretical considerations and on the assumption that the burner-inlet velocity was constant."
- An Analytical Investigation of the Heat Losses from a U.S. Navy K-Type Airship
- From Summary: "The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large."
- Analytical Treatment of Normal Condensation Shock
- "The condensation of water vapor in an air has the following consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front" (p. 1).
- An Anaylsis of Control Requirements and Control Parameters for Direct-Coupled Turbojet Engines
- "Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters. An adjustable speed governor was found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of preventing unstable burner operation during steady-state operation" (p. 1).
- Application of an ultraviolet spectrophotometric method to the estimation of alkylnaphthalenes in 10 experimental jet-propulsion fuels
- Report presenting the combustion efficiencies of 10 experimental jet-propulsion fuels that are approximately 200 degrees Fahrenheit cuts of five selected crudes available in large quantities in a turbojet engine combustor at altitude conditions.
- The application of high-temperature strain gauges to the measurement of vibratory stresses in gas-turbine buckets
- The feasibility of measuring the vibration in the buckets of a gas turbine under service conditions of speed and temperature was determined by use of a high temperature wire strain gauge cemented to a modified supercharger turbine bucket. A high-temperature wire strain gauge and the auxiliary mechanical and electrical equipment developed for the investigation are described.
- An application of lifting-surface theory to the prediction of angle-of-attack hinge-moment parameters for aspect ratio 4.5 wings
- Report presenting an investigation made of the angle-of-attack-type loading for an elliptical wing of aspect ratio 4.5 in an attempt to augment existing methods of prediction of finite span angle-of-attack hinge-moment parameters.
- An Application of Statistical Data in the Development of Gust-Load Criterions
- "In conjunction with assumptions concerning the proportion of time spent at various speeds, statistical gust data were used to determine gust load factors that could be exceeded a given number of times during the operational life of an airplane. The results indicated that present gust load factors might be considerably lowered in certain cases with a consequent decrease in structural weight. Modification of the present criterion, however, must await the accumulation of data not presently available" (p. 1).
- Application of the Analogy Between Water Flow With a Free Surface and Two-Dimensional Compressible Gas Flow
- From Introduction: "The development of the measuring apparatus and techniques is presented herein. The application of the analogy to flows through nozzles and about circular cylinders at subsonic velocities extending into supercritical range is also presented."
- Appreciation and determination of the hydrodynamic qualities of seaplanes
- Report presenting a summary of the hydrodynamic qualities of interest in the normal operation of a seaplane, established over a period of years by model testing and by some knowledge of full-size operation. Results regarding longitudinal stability and control, landing stability, seaworthiness, performances, and lateral stability and control are provided.
- An approximate method for calculating the effect of surface roughness on the drag of an airplane
- From Summary: "A method for computing the effect of surface roughness on the drag coefficient of an airplane is presented. Calculated results using this method are compared with experimental results from both flight and wind-tunnel tests. In general, the agreement is believed satisfactory."
- Axial-flow fan and compressor blade design data on 52.5 degrees stagger and further verification of cascade data by rotor tests
- From Summary: "Previous tests of blower-blade sections have been extended by a series of tests at 52.5 degrees stagger. The results of these tests have been combined with the earlier test results and are presented in new blade design charts which supersede those previously presented. An investigation in a test blower over a range of stagger from 44 degrees to 65 degrees has shown that for blades at a solidity of 1.0, the two-dimensional cascade data predict the turning angle to within 1/2 degrees."
- Bearing strength of some sand-cast magnesium alloys
- Report presenting testing to determine the bearing strength characteristics of some magnesium-alloy sand castings and the relation between those and more commonly determined tensile properties. The primary sand-cast magnesium alloys of interest for aircraft design are AM403, AM260, and AM265. Results of all of the tension, compression, and shear tests are provided in tables.
- Bending Stresses Due to Torsion in a Tapered Box Beam
- Note presenting a method for the calculation of bending stresses due to torsion in a tapered box beam. A special taper was assumed in which all flanges, if extended, would meet at a point. The results obtained by this method were compared with experimental data obtained from tests performed on a tapered box beam.
- Boundary-Induced Upwash for Yawed and Swept-Back Wings in Closed Circular Wind Tunnels
- Report presenting a determination of the tunnel-induced velocities for yawed and swept-back airfoils in a closed circular wind tunnel. Calculations were performed for elemental horseshoe vortices with one tip of the bound vortex on the tunnel axis for a range of yaw angles and bound-vortex lengths.
- Boundary-Layer Momentum Equations for Three-Dimensional Flow
- Note presenting boundary-layer momentum equations for the three-dimensional flow of a fluid with variable density and viscosity in a form similar to the momentum equation for two-dimensional flow. The momentum equations can be reduced to the forms of the three-dimensional momentum equations that have been given recently by Prandtl for a fluid with constant density and viscosity.
- Buckling Stresses of Simply Supported Rectangular Flat Plates in Shear
- "The present paper evaluates the shear buckling stresses of rectangular flat plates with simply supported edges more accurately than previous work on this problem. Both symmetric (odd number of buckles) and antisymmetric (even number of buckles) patterns were considered. A curve is presented from which the critical stresses may be obtained when the dimensions of the plate are known" (p. 1).
- Buffeting of External Fuel Tanks at High Speeds on a Gruman F7F-3 Airplane
- Attempts were made to alleviate the buffeting of external fuel tanks mounted under the wings of a twin-engine Navy fighter airplane. The Mach number at which buffeting began was increased from 0,529 to 0.640 by streamlining the sway braces and by increasing the lateral rigidity of the sway brace system. Further increase of the Mach number, at which buffeting began to 0.725, was obtained by moving the external fuel tank to a position under the fuselage.
- Buffeting of External Fuel Tanks at High Speeds on a Grumman F7F-3 Airplane
- Attempts were made to alleviate the buffeting of external fuel tanks mounted under the wings of a twin-engine Navy fighter plane. The Mach number at which the buffeting began was increased from 0.529 to 0.640 by streamlining the sway braces and increasing the lateral rigidity of the sway brace system. Further increases of the Mach number, at which buffeting began to 0.725, was obtained by moving the external fuel tank to a position under the fuselage.
- Calculation of compressible flows past aerodynamic shapes by use of the streamline curvature
- "A simple approximate method is given for the calculation of isentropic irrotational flows past symmetrical airfoils, including mixed subsonic-supersonic flows. The method is based on the choice of suitable values for the streamline curvature in the flow field and the subsequent integration of the equations of motion. The method yields limiting solutions for potential flow. The effect of circulation is considered" (p. 1).
- The Calculation of Compressible Flows with Local Regions of Supersonic Velocity
- This report addresses a method for the approximate calculation of compressible flows about profiles with local regions of supersonic velocity. The flow around a slender profile is treated as an example.
- The calculation of drag for airfoil sections and bodies of revolution at subcritical speeds
- Report presenting a method for calculating the drag, in a real compressible fluid and at subcritical Mach numbers, of airfoil sections at arbitrary life coefficients and of bodies of revolution at zero angle of attack. The values of drag coefficient are compared with values obtained for the same configurations by other methods. The differences between the results are found to lie withint he limits of accuracy of current experimental techniques.
- The Calculation of the Heat Required for Wing Thermal Ice Prevention in Specified Icing Conditions
- Note presenting a verification of previously derived equations for calculating the rate of heat transfer from airfoils in icing conditions, which have come about as a result of an investigation of the meteorological conditions conducive to the formation of ice on aircraft and a study of the process of airfoil thermal ice prevention. The results indicated that knowledge of these components has increased to a point where the design of heated wings on a fundamental, wet-air basis can now be undertaken with reasonable certainty.
- Calculation of the Pressure Distribution on Bodies of Revolution in the Subsonic Flow of a Gas Part 1 - Axially Symmetrical Flow
- "The present report concerns a method of computing the velocity and pressure distributions on bodies of revolution in axially symmetrical flow in the subsonic range. The differential equation for the velocity potential Phi of a compressible fluid motion is linearized tn the conventional manner, and then put in the form Delta(Phi) = 0 by affine transformation. The quantity Phi represents the velocity potential of a fictitious incompressible flow, for which a constant superposition of sources by sections is secured by a method patterned after von Karman which must comply with the boundary condition delta(phi)/delta(n) = 0 at the originally specified contour" (p. 1).
- Calculation of Wing Bending Moments and Tail Loads Resulting from the Jettison of Wing Tips During a Symmetrical Pull-Up
- "A preliminary analytical investigation was made to determine the feasibility of the basic idea of controlled failure points as safety valves for the primary airplane structure. The present analysis considers the possibilities of the breakable wing tip which, in failing as a weak link, would relieve the bending moments on the wing structure. The analysis was carried out by computing the time histories of the wing and stabilizer angle of attack in a 10g pull-up for an XF8F airplane with tips fixed and comparing the results with those for the same maneuver, that is, elevator motion but with tips jettisoned at 8g" (p. 1).
- Calculations and Experimental Investigations on the Feed-Power Requirement of Airplanes With Boundary-Layer Control
- "Calculations and test results are given about the feed-power requirement of airplanes with boundary-layer control. Curves and formulas for the rough estimate of pressure-loss and feed-power requirement are set up for the investigated arrangements which differ structurally and aerodynamically. According to these results the feed power for three different designs is calculated at the end of the report" (p. 1).
- Calculations of the supersonic wave drag of nonlifting wings with arbitrary sweepback and aspect ratio : wings swept behind the Mach lines
- Report presenting calculations of the supersonic wave drag at zero lift for a series of wings with thin symmetrical biconvex sections with untapered plan forms and various angles of sweepback and aspect ratios.
- Calculations of the Supersonic Wave Drag of Nonlifting Wings with Arbitrary Sweepback and Aspect Ratio: Wings Swept Behind the Mach Lines
- "On the basis of a recently developed theory for finite sweptback wings at supersonic speeds, calculations of the supersonic wave drag at zero lift were made for a series of wings having thin symmetrical biconvex sections with untapered plan forms and various angles of sweepback and aspect ratios. The results are presented in a unified form so that a single chart permits the direct determination of the wave drag for this family of airfoils for an extensive range of aspect ratio and sweepback angle for stream Mach numbers up to a value corresponding to that at which the Mach line coincides with the wing leading edge. The calculations showed that in general the wave-drag coefficient decreased with increasing sweepback" (p. 1).
- Calibration and Measurement in Turbulence Research by the Hot-Wire Method
- "The problem of turbulence in aerodynamics is at present being attacked both theoretically and experimentally. In view of the fact however that purely theoretical considerations have not thus far led to satisfactory results the experimental treatment of the problem is of great importance. Among the different measuring procedures the hot wire methods are so far recognized as the most suitable for investigating the turbulence structure" (p. 1).
- Canopy loads investigation for the F6F-3 airplane
- Report presenting an investigation of surface static pressures over the outer and inner surfaces of the cockpit canopies on the Grumman F6F-3, Curtiss SB2C-4E, and Grumman F8F-1 airplanes in the full-scale tunnel. Results regarding the external pressure distribution and internal static pressure are provided.
- Changes Found on Run-in and Scuffed Surfaces of Steel Chrome Plate, and Cast Iron
- Note presenting a study of run-in and scuffed steel, chrome-plate, and cast-iron surfaces. X-ray and electronic diffraction techniques, micro-hardness determinations, and microscopy were used. The surface changes varied and wer efound to include three classes: chemical reaction, hardening, and crystallite-size alteration.
- Characteristics of a 15-Percent-Chord and a 35-Percent-Chord Plain Flap on the NACA 0006 Airfoil Section at High Subsonic Speeds
- Memorandum presenting wind-tunnel tests to determine the aerodynamic characteristics of a 15-percent- and a 35-percent-chord plain trailing-edge flap on the NACA 0006 airfoil section. Simultaneous measurements of section lift, drag, and pitching moment were made over a range of Mach numbers, angles of attack, and flap deflections.
- Charts for determining the characteristics of sharp-nose airfoils in two-dimensional flow at supersonic speeds
- Solutions of the Hugoniot shock equations and Meyer expansion equations are plotted in such a manner as to permit the pressure distribution, the local Mach number, and the angles of shock waves on arbitrary sharp-nose airfoils at supersonic speeds to be obtained directly. (author).
- Charts for stress analysis of reinforced circular cylinders under lateral loads
- Report presenting charts with coefficients for the stress analysis of a reinforced circular cylinder. They allow for the rapid determination of sheer flows and direct stresses in the sheet of a cylinder as well as the shear forces, axial forces, and bending moments in the rings. Separate charts are also given for three basic ring loadings.
- Charts for the Determination of Supersonic Air Flow Against Inclined Planes and Axially Symmetric Cones
- Report presenting a set of charts for the convenient determination of flow conditions behind a shock wave and at the surface of inclined planes and axially symmetric cones located in a uniform frictionless supersonic air stream. Shock angle, static-pressure coefficient, static-pressure ratio, total-pressure ratio, Mach number ratio, and velocity ratio for two-dimensional and conical flow fields are plotted for a range of free-stream Mach numbers.
- Charts for the Minimum-Weight Design of Multiweb Wings in Bending
- Report presenting a method for the calculation of the buckling stress of a multiweb wing in bending as well as design charts based on this method for the minimum-weight design of 24S-T aluminum alloy sheets, extruded 75S-T aluminum alloy, and extruded 0-1HTA magnesium alloy. An example of the use of the charts is also provided.
- Charts Showing Relations Among Primary Aerodynamic Variables for Helicopter-Performance Estimation
- "In order to facilitate solutions of the general problem of helicopter selection, the aerodynamic performance of rotors is presented in the form of charts showing relations between primary design and performance variables. By the use of conventional helicopter theory, certain variables are plotted and other variables are considered fixed. Charts constructed in such a manner show typical results, trends, and limits of helicopter performance" (p. 1).
- Coefficient of Friction, Oil Flow and Heat Balance of a Full-Journal Bearing
- Memorandum presenting the coefficient of friction, oil flow, and heat balance of a full-journal bearing.
- Collection and Analysis of Hinge-Moment Data on Control-Surface Tabs
- Report presenting an analysis of wind-tunnel data on the hinge-moment characteristics of control-surface tabs. Results regarding the correlation of section data, correlation of finite-span data, and effect of Mach number are provided.
- Collection and analysis of wind-tunnel data on the characteristics of isolated tail surfaces with and without end plates
- Report presenting the aerodynamic characteristics of 19 isolated tail surfaces, which have been determined by wind tunnel tests. Testing was also made of rectangular airfoils of various aspect ratios with and without double end plates of various shapes. The analysis indicated that the slope of the lift curve could be predicted within 10 percent for all models by use of lifting-surface-theory equations.
- A collection of the collapsed results of general tank tests of miscellaneous flying-boat-hull models
- Presented here are the summary charts of the collapsed results of general tank tests of about 100 flying boat hull models. These summary charts are intended to be used as an engineering tool to enable a flying boat designer to grasp more quickly the significance of various hull form parameters as they influence his particular airplane. The form in which the charts are prepared is discussed in some detail in order to make them clearer to the designer. This is a data report, and no attempt has been made to produce conclusions or correlations of the usual sort. However, some generalizations are put forward on the various methods in which summary charts may be used.
- Column and Plate Compressive Strengths of Aircraft Structural Materials: Extruded 0-1HTA Magnesium Alloy
- Column and plate compressive strengths of extruded 0-1HTA magnesium alloy were determined both within and beyond the elastic range from tests of flat end H-section columns and from local instability tests of H-, Z-, and channel section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.
- The Combination of Internal-Combustion Engine and Gas Turbine
- "While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given" (p. 1).
- Combustion-efficiency investigation of special fuels in single tubular-type combustor at simulated altitude conditions
- Report presenting a combustion-efficiency investigation of 10 special straight-run distillate fuels in an individual tubular-type combustor unit of a 14-unit assembly at two simulated engine operating conditions. These distillates were obtained from various crude oils and consisted of hydrocarbon mixtures with distillations temperature varying from 93 to 690 degrees Fahrenheit. Comparison of temperature measurements obtained from two locations in the exhaust duct showed that under certain operating conditions the flame extended beyond the turbine position.
- Comparative Drag Measurements at Transonic Speeds of 6-Percent-Thick Airfoils of Symmetrical Double-Wedge and Circular-Arc Sections From Tests by the NACA Wing-Flow Method
- Report presenting comparative drag measurements at zero lift at transonic speeds for two sharp-leading-edge airfoils using the NACA wing-flow method. One airfoil had a symmetrical circular-arc section and one had a symmetrical double-wedge section. The primary difference in the drag characteristics of the two airfoils at zero lift is the earlier drag rise of the double-wedge section.
- Comparative Drag Measurements at Transonic Speeds of an NACA 65-006 Airfoil and a Symmetrical Circular-Arc Airfoil
- Report presenting measurements made at transonic speeds by the freely-falling-body method to compare the drag of a rectangular plan-form airfoil of aspect ratio 7.6 with an NACA 65-006 airfoil section. Results regarding the velocity measurements, base-pressure measurements, and airfoil drag measurements are provided.