National Advisory Committee for Aeronautics (NACA) - 62 Matching Results

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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."
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.
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).
A Comparison of the Lateral Motion Calculated for Tailless and Conventional Airplanes: Theoretical analysts of lateral dynamic motion of tailless and conventional airplanes was made for fighter and heavy transport. Their reactions to a lateral gust and control power required by each for simple maneuvers were determined and compared. Both types of airplanes require almost identical aileron control power to perform a given maneuver; tailless airplane requires about 1-2 to 1-3 directional control power of conventional airplane. Tailless airplane also shows greatest displacement for a given disturbance and has least damping in oscillatory mode.
Device for Measuring Principal Curvature and Principal Strains on a Nearly Plane Surface: Note presenting a device which makes possible the measurement of principal extreme fiber bending strains over a circular area with a radius of 0.94 inch with a systematic error on 0.1-inch sheet of the order of 0.00003. Equations are presented for computing median fiber strains from the measured curvatures and strains at the surface and from the thickness of the sheet.
Effect of Centrifugal Force on the Elastic Curve of a Vibrating Cantilever Beam: Report presenting the results of a study to determine the effect of rotation on the dynamic-stress distribution in vibrating cantilever beams. Both theoretical and experimental results are obtained by means of stroboscopic photographs and strain gauges. Both types of results indicated that the introduction of centrifugal force had no effect on the maximum dynamic-stress locations in a vibrating cantilever beam fixed at the center of rotation within the investigated speed range.
Effects on Performance of Changing the Division of Work Between Increase of Angular Velocity and Increase of Radius of Rotation in an Impeller: Note presenting the effect on the performance of increasing the angular velocity of an impeller and consequently increasing the amount of work of compression resulting from the angular acceleration of the air in the impeller for four impellers in combination with a vaneless diffuser in a variable-component supercharger test rig of a range of tip speeds. Results regarding a comparison of performance, analysis of volume-flow limitations, and use of blade-inlet relative Mach number as a design parameter are provided.
Exhaust-valve temperatures in a liquid-cooled aircraft-engine cylinder as affected by engine operating variables: 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.
Flight Measurements of Internal Cockpit Pressures in Several Fighter-Type Airplanes: Report presenting flight measurements of internal cockpit pressure in several fighter-type airplanes equipped with conventional or bubble canopies. Data are presented for variation in cockpit pressure with indicated airspeed and angle of sideslip for canopy-closed and canopy-open positions. A method is also included for predicting cockpit pressure in accelerated flight from measurements made in accelerated flight.
Flight Measurements of the Lateral Control Characteristics of Narrow-Chord Ailerons on the Trailing Edge of a Full-Span Slotted Flap: 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.
Foaming Volume and Foam Stability: "A method of measuring foaming volume is described and investigated to establish the critical factors in its operation. Data on foaming volumes and foam stabilities are given for a series of hydrocarbons and for a range of concentrations of aqueous ethylene-glycol solutions. It is shown that the amount of foam formed depends on the machinery of its production as well as on properties of the liquid, whereas the stability of the foam produced, within specified mechanical limitations, is primarily a function of the liquid" (p. 1).
Formulas for additional mass corrections to the moments of inertia of airplanes: "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).
Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2: Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a form designed to be aerodynamically favorable, the ability to operate is at least questionable. This investigation will account for the important practical observation made by Paul Schmidt that the ratio of the effective valve cross-sectional area to the tube cross section may not be of any random magnitude and will explain why at too great flight speeds the jet tube ceases to operate. Chemical an thermodynamic processes (for example, constituents or mode of fuel-air-mixture formation or heat losses) are unimportant in this regard.
Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2: "Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a form designed to be aerodynamically favorable, the ability to operate is at least questionable" (p. 1).
An Improved Continuous-Indicating Dew-Point Meter: 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.
In-line aircraft-engine bearing loads 3: main-bearing loads: Report presenting the application of dimensional analysis to the computation of the main bearing of a V-type in-line aircraft engine. Two crankshafts have been considered, one designed for higher operating speed than the other. Two types of engines are considered: one for regular V-type engines and one for production V-type engines.
An investigation of the aerodynamic characteristics of a rotating axial-flow blade grid: Report presenting the results of an experimental investigation of the aerodynamic characteristics of a rotating axial-flow blade grid with pressure-increasing effect. Several techniques of measurement were used, including pressure distribution measurements, pitot tubes, and hot wire wake surveys. Results regarding the lift and pressure drag of the blade sections, aerodynamic characteristics of the blade sections, profile drag, and static pressure are provided.
Lifting-Surface-Theory Aspect-Ratio Corrections to the Lift and Hinge-Moment Parameters for Full-Span Elevators on Horizontal Tail Surfaces: Report presenting a limited number of lifting-surface-theory solutions with chordwise loading resulting from angle of attack, parabolic-arc camber, and flap deflection.
Marine Exposure Tests on Stainless Steel Sheet: Note presenting tidewater and weather-exposure tests on metals used in aircraft. Three distinct research projects were included: aluminum-rich alloys, magnesium-rich alloys, and stainless steels. This paper is a final report on the corrosion tests of stainless steel sheets included in the marine exposure program from 1938 to 1945.
The Monoplane as a Lifting Vortex Surface: "In Prandtl's airfoil theory the monoplane was replaced by a single lifting vortex line and yielded fairly practical results. However, the theory remained restricted to the straight wing. Yawed wings and those curved in flight direction could not be computed with this first approximation; for these the chordwise lift distribution must be taken into consideration. For the two-dimensional problem the transition from the lifting line to the lifting surface has been explained by Birnbaum. In the present report the transition to the three-dimensional problem is undertaken" (p. 1).
Observations on the behavior of some noncircular aluminum alloy sections loaded to failure in torsion: Report presenting an investigation of the strength and stiffness characteristics of noncircular aluminum alloy sections loaded to failure in torsion. Results regarding torque-twist and torque-stress curves and stress-distribution diagrams are provided.
On Combustion in a Turbulent Flow: "The characteristics introduced by the turbulence in the process of the flame propagation are considered. On the basis of geometrical and dimensional considerations an expression is obtained for the velocity of the flame propagation in a flow of large scale of turbulence" (p. 1).
The Oscillating Circular Airfoil on the Basis of Potential Theory: "Proceeding from the thesis by W. Kinner the present report treats the problem of the circular airfoil in uniform airflow executing small oscillations, the amplitudes of which correspond to whole functions of the second degree in x and y. The pressure distribution is secured by means of Prandtl's acceleration potential. It results in a system of linear equations the coefficients of which can be calculated exactly with the aid of exponential functions and Hankel's functions" (p. 1).
Performance of axial-flow fan and compressor blades designed for high loadings: Report presenting an investigation to determine the effects of loading on the performance of axial-flow fan and compressor blades in a test blower. Results regarding verification of the two-dimensional design data and effects of blade roughness are provided.
Pressure-distribution measurements on the rotating blades of a single-stage axial-flow compressor: Investigation of the pressure distribution about the mean-radius section of the rotating blades of a single-stage axial-flow compressor at a blade Mach number of 0.35. The results indicated that the maximum suction pressure for thin low-camber rotor blades was only slightly greater than for the isolated airfoil of the same section. Results regarding the performance of the compressor, performance of the pressure-transfer device, pressure distribution, critical Mach number, and lift characteristics are provided.
Reactions with steel of compounds containing chemical groups used in lubricant additives: Report presenting an investigation of the chemical reactions between steel of a type used in aircraft-engine cylinder barrels and compounds containing reactive groups commonly found in lubricant additives. The products formed by reaction at temperatures from 400 to 650 degrees F were analyzed by reflection electron diffraction. Results regarding the diffraction patterns, a description of the products found, and correlation of the results with results form other investigations are provided.
Scale Effect and Optimum Relations for Sea Surface Planning: "From the general dimensional and mechanical similarity theory it follows that a condition of steady motion of a given shape\bottom with constant speed on the surface of water is determined by four nondimensional parameters. By considering the various systems of independent parameters which are applied in theory and practice and special tests, there is determined their mutual relations and their suitability as planning characteristics. In studying the scale effect on the basis of the Prnndtl formula for the friction coefficient for a turbulent condition the order of magnitude is given of the error in applying the model data to full scale in the case of a single-step bottom" (p. 1).
Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-Front Travel, and Cylinder Pressure Rise: Note presenting an investigation conducted on a full-scale air-cooled cylinder in order to establish an effective means of maintaining maximum-economy spark timing with varying engine operating conditions. Variable fuel-air ratio runs were conducted in which relations were determined between the spark timing and basic factors in engine operation, flame-front travel, and cylinder pressure rise. An instrument for controlling spark timing was developed that automatically maintained maximum-economy spark timing with varying engine operating conditions.
Static and Dynamic Creep Properties of Laminated Plastics for Various Types of Stress: Note presenting creep tests of five laminated plastics to determine the relative creep properties of these materials when subjected to various types of static and dynamic stresses. Results regarding the static tests, repeated stress tests, and creep tests are provided. The results indicated that the relative values of the mechanical properties of the laminates in tension, compression, bending, and torsion are not in the same order for all types of tests.
Two-dimensional wind-tunnel investigation of four types of high-lift flap on an NACA 65-210 airfoil section: Report presenting an investigation in the two-dimensional low-turbulence tunnel to develop flap configurations for maximum lift of the NACA 65-210 airfoil section equipped with four types of high-lift flap. Lift and pitching-moment data were obtained for the optimum configurations. Results regarding the optimum configurations for maximum lift, scale effect, effect of roughness, pitching moments, and comparison of flaps are provided.
Computed Performance of a Composite Engine Based on Experimental Data for a Single-Cylinder Conventional Aircraft Engine Converted to Compression-Ignition Operation: Memorandum presenting a determination of the performance of a single-cylinder spark-ignition engine modified to operate on a compression-ignition cycle with a compression ratio of 8.0. Experimental data were obtained at an inlet-manifold pressure of 100 inches of mercury absolute, fuel-air ratios of 0.040 and 0.025, and engine exhaust pressures of 30 to 100 inches of mercury absolute. Results regarding single-cylinder-engine experimental data and full-scale-engine calculations are provided.
Knock-limited power outputs from a CFR engine using internal coolants 3: four alkyl amines, three alkanolamines six amides, and eight heterocyclic compounds: Report presenting investigations to determine the antiknock effectiveness of various additive-water solutions used as internal coolants in conjunction with AN-F-28, Amendment-2, fuel in a modified CFR engine.
Knock-Limited Power Outputs from a CFR Engine Using Internal Coolants 3 - Four Alkyl Amines, Three Alkanolamines, Six Amides, and Eight Heterocyclic Compounds: An investigation of the antiknock effectiveness of various additive-water solutions when used as internal coolants has been conducted at the NACA Cleveland laboratory. Nine compounds have been previously run in a CFR engine and the results are presented. In an effort to find a good anti-knock-coolant additive with more desirable physical properties than those of the nine compounds previously investigated, water solutions of four alkyl amines, three alkanolamines, six amides, and eight heterocyclic compounds were investigated and the results are presented.
High-Speed Load Distribution of the Wing of a 3/16-Scale Model of the Douglas XSB2D-1 Airplane with Flaps Deflected: "The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of the Douglas XSB2D-1 airplane. Comparisons are made between the root bending moment and section torsional moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending moment coefficients but considerable disagreement for the torsional moment coefficients, the measured moments being greater than the analytical moments. The effects of Mach number on both the bending moment and torsional moment coefficients were small" (p. 1).
Tank Tests of a 1/7-Size Dynamic Model of the Grumman XJR2F-1 Amphibian to Determine the Effect of Slotted- and Split-Type Flaps on Take-Off Stability - NACA Model 212, TED No. NACA 2378: From Summary: "Additional tests of a 1/7-size model of the Grumman XJR2F-1 amphibian were made in Langley tank no. 1 to compare the behavior during take-off of the model equipped with split- and slotted-type flaps. The slotted flag had a large effect on locating the forward center-of-gravity limits for stable take-offs. Stable take-offs within the normal operating range of positions of the center of gravity could be made with the split flaps deflected 45 degrees or with the slotted flaps deflected less than 20 degrees."
Cyclic Engine Test of Cast Vitallium Turbine Buckets - I: "An investigation was conducted to correlate the engine service performance of cast Vitallium turbine buckets with standard laboratory metallurgical data. Data were obtained from four I-40 turbine wheels of Timken alloy with cast Vitallium buckets. In order to accelerate bucket deterioration, the turbine wheels were subjected to 20-minute cycles consisting of 5 minutes at idle and 15 minutes at rated speed" (p. 1).
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."
The interdependence of various types of autoignition and knock: A study of the relations existing among pin-point autoignition, homogeneous autoignition, and knock has been made by means of the NACA high-speed camera and the full-view combustion apparatus. High-speed photographic records of combustion, together with corresponding pressure-time traces, of benzene, 2,2,3-trimethylbutane, S-4, and M-4 fuels at various engine conditions have shown the engine conditions under which each of these phenomena occur and the relation of these phenomena to one another.
Two-Dimensional Wind-Tunnel Investigation of Modified NACA 65(sub 112)-111 Airfoil with 35-Percent-Chord Slotted Flap to Determine Pitching-Moment Characteristics and Effects of Roughness: From Summary: "An investigation has been made in the Langley two-dimensional low-turbulence pressure tunnel to develop the optimum configuration of a 0.35-chord slotted flap on an NACA 65(sub 1120)-111 airfoil section modified by removing the trailing-edge cusp. The section pitching-moment characteristics and the effects of standard roughness on the section characteristics were determined for the flap retracted at Reynolds numbers ranging from 3.0 x 10(exp 6) to 9.0 x 10(exp 6)."
Computed Temperature Distribution and Cooling of Solid Gas-Turbine Blades: "Computations were made to determine the temperature distribution and cooling of solid gas-turbine blades.A range of temperatures was used from 1500 degrees to 2500 degrees F, blade-root temperatures from 100 degrees to 1000 degrees F, blade thermal conductivity from 8 to 220 BTU/(hr)(sq ft)(degrees F/ft), and net gas to metal heat transfer coefficients from 75 to 250 BTU/(hr)(sq ft)(degrees F)" (p. 1).
Cooling of Gas Turbines 1 - Effects of Addition of Fins to Blade Tips and Rotor, Admission of Cooling Air Through Part of Nozzles, and Change in Thermal Conductivity of Turbine Components: "An analysis was developed for calculating the radial temperature distribution in a gas turbine with only the temperatures of the gas and the cooling air and the surface heat-transfer coefficient known. This analysis was applied to determine the temperatures of a complete wheel of a conventional single-stage impulse exhaust-gas turbine. The temperatures were first calculated for the case of the turbine operating at design conditions of speed, gas flow, etc. and with only the customary cooling arising from exposure of the outer blade flange and one face of the rotor to the air" (p. 1).
Cooling of Gas Turbines, 3, Analysis of Rotor and Blade Temperatures in Liquid-Cooled Gas Turbines: A theoretical analysis of the radial temperature distribution through the rotor and constant cross sectional area blades near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the rotor and blade temperatures of a specific turbine using a gas flow of 55 pounds per second, a coolant flow of 6.42 pounds per second, and an average coolant temperature of 200 degrees F. The effect of using kerosene, water, and ethylene glycol was determined. The effect of varying blade length and coolant passage lengths with water as the coolant was also determined. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.
Development of Inboard Nacelle for the XB-36 Airplane: From Summary: "A series of investigations of several 1/14-scale models of an inboard nacelle for the XB-36 airplane was made in the Langley two-dimensional low-turbulence tunnels. The purpose of these investigations was to develop a low-drag wing-nacelle pusher combination which incorporated an internal air-flow system. As a result of these investigations, a nacelle was developed which had external drag coefficients considerably lower than the original basic form with the external nacelle drag approximately one-half to two-thirds of those of conventional tractor designs. The largest reductions in drag resulted from sealing the gaps between the wing flaps and nacelle, reducing the thickness of the nacelle training-edge lip, and bringing the under-wing air inlet to the wing leading edge."
Investigation of Pressure Losses in Several Turbosupercharger Nozzle Hoses: Memorandum presenting surveys of the impact pressure of the flow to obtain information for determining pressure losses in four different turbosupercharger nozzle boxes. The data indicated substantial differences in total head loss among the boxes and the existence of sharply defined high-loss regions in portions of the nozzle annulus.
Theoretical Evaluation of Methods of Cooling the Blades of Gas Turbines: A study was made of heat transfer in turbine blades and the effects on blade temperature of cooling the blade root and tip, changing the dimensions of the blades, raising the cycle temperatures, insulating with ceramics, and cooling by circulation of air or water through hollow blades. The results indicated that cooling of the root of the blade, shortening the blade, and cooling hollow blades internally with air or liquid offer possibilities of substantial increases in permissible gas temperatures.
Full-Scale Investigation of the Maximum Lift and Flow Characteristics of an Airplane Having Approximately Triangular Plan Form: Report discussing an investigation of the DM-1 glider, which has an approximately triangular plan form, with auxiliary studies of a model of triangular wings. The pitching-moment coefficient, drag coefficient, and angle of attack with the lift coefficient are provided. Results indicated that the angles of descent without power are likely to be prohibitive and airplanes with the tested type of wings will not be able to land safely without power.
Investigation of Rim Cracking in Turbine Wheels with Welded Blades: Rim cracking in turbine wheels with welded blades was evaluated. The problem is explained on the basis of the occurrence of plastic flow in the rim during transient starting conditions when thermal compressive stresses resulting from high-temperature gradients exceed the proportional elastic limit of the material.
Aerodynamic Characteristics at High Speeds of Full-Scale Propellers Having Different Shank Designs: "Tests of two 10-foot-diameter two-blade propellers which differed only in shank design have been made in the Langley 16-foot high-speed tunnel. The propellers are designated by their blade design numbers, NACA 10-(5)(08)-03, which had aerodynamically efficient airfoil shank sections, and NACA 10-(5)(08)-03R which had thick cylindrical shank sections typical of conventional blades. The propellers mere tested on a 2000-horsepower dynamometer through a range of blade-angles from 20 degrees to 55 degrees at various rotational speeds and at airspeeds up to 496 miles per hour" (p. 1).
Comparison of Wind-Tunnel Predictions with Flight Measurements of the Longitudinal-Stability and -Control Characteristics of a Douglas BTD-1 Airplane: "Low Mach number longitudinal-stability and control characteristics as predicted by use of wind tunnel data from a powered 3/16-scale model are compared with flight test measurements of a Navy BTD-1 airplane. The accuracy of the wind tunnel data and the discrepancies involved in attempting to correlate with flight data are discussed and analyzed. The comparison showed that wind tunnel predictions were, in general, in good agreement with flight test data" (p. 1).
Flight Comparison of Performance and Cooling Characteristics of Exhaust-Ejector Installation with Exhaust-Collector-Ring Installation: Flight and ground investigations have been made to compare an exhaust-ejector installation with a standard exhaust-collector-ring installation on air-cooled aircraft engines in a twin-engine airplane. The ground investigation allowed that, whereas the standard engine would have overheated above 600 horsepower, the engine with exhaust ejectors cooled at take-off operating conditions at zero ram. The exhaust ejectors provided as much cooling with cowl flaps closed as the conventional cowl flaps induced when full open at low airspeeds. The propulsive thrust of the exhaust-ejector installation was calculated to be slightly less than the thrust of the collector-ring-installation.

National Advisory Committee for Aeronautics (NACA) - 62 Matching Results

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