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Acceleration Measurements During Landings of a 1/5.5-Size Dynamic Model of the Columbia XJL-1 Amphibian in Smooth Water and in Waves: Langley Tank Model 208M, TED No. NACA 2336
A 1/5.5-size powered dynamic model of the Columbia XJL-1 amphibian was landed in Langley tank no. 1 in smooth water and in oncoming waves of heights from 2.1 feet to 6.4 feet (full-size) and lengths from 50 feet to 264 feet (full-size). The motions and the vertical accelerations of the model were continuously recorded. The greatest vertical acceleration measured during the smooth-water landings was 3.1g.
An analysis of longitudinal-control problems encountered in flight at transonic speeds with a jet-propelled airplane
From Introduction: "This report presents an analysis based on flight and wind-tunnel test data directed toward the determination of the probable cause of the pitch-up. Wing pressure distribution and stability and control characteristics in the dive are also included."
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.
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).
Comparison of the control-force characteristics of two types of lateral-control system for large airplanes
Report presenting an analysis of wind-tunnel data for two types of lateral-control system for large airplanes in order to determine the control-force characteristics and rolling effectiveness of each system. The two types of control systems explored are a spring-tab aileron and a combination spoiler and guide or pilot-aileron arrangement.
Compressive strength of 24S-T aluminum-alloy flat panels with longitudinal formed hat-section stiffeners having a ratio of stiffener thickness to skin thickness equal to 1.00
Report presenting results for a part of a test program on 24S-T aluminum-alloy flat compression panels with longitudinal formed hat-section stiffeners. This particular part of the program is concerned with panels in which the thickness of the stiffener material is equal to the thickness of the skin. Results regarding the hat-stiffened panels and a comparison of hat-stiffened and Z-stiffened panels are provided.
Cooling Characteristics of the V-1650-7 Engine 2 - Effect of Coolant Conditions on Cylinder Temperatures and Heat Rejection at Several Engine Powers
From Summary: "An investigation has been conducted on a V-1650-7 engine to determine the cylinder temperatures and the coolant and oil heat rejections over a range of coolant flows (50 to 200 gal/min) and oil inlet temperatures (160 to 2150 F) for two values of coolant outlet temperature (250 deg and 275 F) at each of four power conditions ranging from approximately 1100 to 2000 brake horsepower. Data were obtained for several values of block-outlet pressure at each of the two coolant outlet temperatures. A mixture of 30 percent by volume of ethylene glycol and 70-percent water was used as the coolant."
Determination of the Stress Concentration Factor of a Stepped Shaft Stressed in Torsion by Means of Precision Strain Gages
The stress distribution in stepped shafts stressed in torsion is determined by means of the electric precision strain gage the stress concentration factor is ascertained from the measurements. It is shown that the test values always are slightly lower than the values resulting from an approximate formula.
Development and Construction of an Interferometer for Optical Measurements of Density Fields
"A method of interference is described in the present report which promises profitable application in aeronautical research. The physical foundation of the method and a simple method of adjustment are briefly discussed. The special technical construction of the instrument is described which guarantees its use also in the case of vibrations of the surrounding space and permits the investigation of unsteady phenomena" (p. 1).
Dislocation Theory of the Fatigue of Metals
"A dislocation theory of fatigue failure for annealed solid solutions is presented. On the basis of this theory, an equation giving the dependence of the number of cycles for failure on the stress, the temperature, the material parameters, and the frequency is derived for uniformly stressed specimens. The equation is in quantitative agreement with the data" (p. 183).
Effect of variation in diameter and pitch of rivets on compressive strength of panels with Z-section stiffeners: Panels of various lengths with close stiffener spacing
Report presenting an experimental investigation conducted to determine the effect of varying rivet diameter and pitch on the compressive strength of flat 24S-T aluminum-alloy panels with longitudinal Z-section stiffeners of the type for which design charts are available.
The effects of yawing thin pointed wings at supersonic speeds
From Summary: "An approximate relation is derived for the surface velocity potential of thin pointed wings at supersonic speeds when they are contained within the Mach cone from the vertex. This relation is applied to obtain the pressure distributions, the lift and drag coefficients, the center of pressure, and the rolling moments as a function of angle of yaw for the delta wing. Theoretical curves are presented for a Mach number of the square root of 2 to illustrate the relations."
Factors Affecting the Design of Quiet Propellers
"The problems associated with propeller noise and with the design of propellers that are less noisy than those conventionally used are presented. Three aspects of these problems are discussed: acoustical, aerodynamic, and structural. Some of the factors which must be considered in the design of a quiet propeller are outlined" (p. 1).
Flight investigation of the heat requirements for ice prevention on aircraft windshields
Report presenting a flight investigation conducted to establish the heat requirements for ice prevention on aircraft windshields mounted on the forebody of an airplane at several angles. Electrically heated windshields were used in order to provide accurate measuring of heat input to the windshield. Results regarding the quantity of heat provided, amount of water collection, ideal windshield angle, ranges in airplane velocity, and icing conditions are provided.
Flight Investigation of Thrust Augmentation of a Turbojet Engine by Water-Alcohol Injection
Memorandum presenting an investigation of thrust augmentation by the injection of water-alcohol mixtures into the compressor inlets of a turbojet engine with a centrifugal-flow-type compressor at altitudes of sea level, 5000 feet, and 10,000 feet. The investigation was made to determine the water-alcohol mixture and the injection rate for optimum thrust augmentation. At a standard NACA altitude of 10,000 feet and an engine speed of 16,000 rpm, the mixture and injection rate for optimum thrust augmentation was found to be 20-percent alcohol to water by weight injected at a rate of approximately 1.45 pounds per second.
Free-Spinning-Tunnel Tests of a 1/24-Scale Model of the McDonnell XP-88 Airplane with a Conventional Tail
"An investigation of the spin and recovery characteristics of a 1/24-scale model of the McDonnell XP-88 airplane has been conducted in the Langley 20-foot free-spinning tunnel. The effects of control settings and movements on the erect and inverted spin and recovery characteristics of the model in the normal loading were determined. Tests of the model in the long-range loading also were made" (p. 1).
A General Small-Deflection Theory for Flat Sandwich Plates
"A small-deflection theory is developed for the elastic behavior of orthotropic flat plates in which deflections due to shear are taken into account. In this theory, which covers all types of flat sandwich construction, a plate is characterized by seven physical constants (five stiffnesses and two Poisson ratios) of which six are independent. Both the energy expression and the differential equations are developed. Boundary conditions corresponding to simply supported, clamped, and elastically restrained edges are considered" (p. 1).
High-Speed Wind-Tunnel Tests of an NACA 0009-64 Airfoil Having a 33.4-Percent-Chord Flap With an Overhang 20.1 Percent of the Flap Chord
Report presenting testing to investigate the effects of compressibility on a 5-inch-chord NACA 0009-64 airfoil section with a 33.4-percent-chord flap with a nose overhang and an unsealed gap. Flap effectiveness was generally found to increase with Mach number. Results regarding the lift, pitching moment, and hinge moment are provided.
Icing Properties of Noncyclonic Winter Stratus Clouds
Note presenting measurements of the vertical distribution of liquid water concentration and drop size made in winter stratus clouds in the absence of significant cyclonic or frontal activity. The observations indicate that the clouds are formed by turbulent mixing of the lower layers of the atmosphere, resulting in a region of constant specific humidity and adiabatic lapse rates.
Icing Properties of Noncyclonic Winter Stratus Clouds
Note presenting measurements of the vertical distribution of liquid water concentration and drop size in winter stratus clouds in the absence of significant cyclonic or frontal activity. The observations indicate that the clouds are formed by turbulent mixing of the lower layers of the atmosphere, resulting in a region of constant specific humidity and adiabatic lapse rates. Calculations based on the observations were used to construct a graph that gives the liquid water concentration in terms of the temperature at the cloud base and the height above the base.
Investigation of the Aileron and tab of a spring-tab lateral-control system in the Langley 19-foot pressure tunnel
Report presenting tests of a partial-span model of a large bomber-type airplane, which were conducted to provide data on the aerodynamic characteristics of the aileron-tab arrangement and of the wing. Testing occurred to determine the rolling-moment, yawing-moment, and hinge-moment characteristics of the aileron and tab and the effect of midchord wing slots on the characteristics of the wing and aileron and tab. Results regarding the aerodynamic and stalling characteristics of the wing and aerodynamic characteristics of the aileron and tab are provided.
Investigation of the pressure-loss characteristics of a turbojet inlet screen
Report presenting the results of an investigation to determine the static-pressure losses and total-pressure distributions of a turbojet inlet screen. The screen was tested in two configurations: one with the vane leading edges square and rough and the other with the vane leading edges rounded. Results regarding the static-pressure-loss coefficient, corrected static-pressure loss, and total-pressure distributions are provided.
Laboratory Investigation of Ice Formation and Elimination in the Induction System of a Large Twin-Engine Cargo Aircraft
"The icing characteristics, the de-icing rate with hot air, and the effect of impact ice on fuel metering and mixture distribution have been determined in a laboratory investigation of that part of the engine induction system consisting of a three-barrel injection-type carburetor and a supercharger housing with spinner-type fuel injection from an 18-cylinder radial engine used on a large twin-engine cargo airplane. The induction system remained ice-free at carburetor-air temperatures above 36 F regardless of the moisture content of the air. Between carburetor-air temperatures of 32 F and 36 F with humidity ratios in excess of saturation, serious throttling ice formed in the carburetor because of expansion cooling of the air; at carburetor-air temperatures below 32 F with humidity ratios in excess of saturation, serious impact-ice formations occurred" (p. 1).
Longitudinal Stability and Control Characteristics of a Semispan Model of the XF7U-1 Tailless Airplane at Transonic Speeds by the NACA Wing-Flow Method, TED No. NACA DE307
From Summary: "An investigation was made by the NACA wing-flow method to determine the longitudinal stability and control characteristics at transonic speeds of a semispan model of the XF7U-1 tailless airplane. The 25-percent chord line of the wing of the model was swept back 35 deg. The airfoil sections of the wing perpendicular to the 25-percent chord line were 12 percent thick. Measurements were made of the normal force and pitching moment through an angle-of-attack range from about -3 deg to 14 deg for several ailavator deflections at Mach numbers from 0.65 to about 1.08."
Longitudinal Stability and Control of High-Speed Airplanes With Particular Reference to Dive Recovery
"An analysis of the effects of compressibility on the longitudinal stability, control, and trim of airplanes flying at high subsonic speeds and a discussion of the causes of and the means for lessening or preventing the diving tendency are presented. Wind-tunnel results for Mach numbers up to 0.90 are included for purposes of illustration and cover several investigations of longitudinal stability and control, airfoil characteristics, dive-recovery aids, and elevator characteristics. Methods are indicated for compensating for the undesirable control tendencies results from the characteristics of the wing at supercritical speeds by the appropriate choice of elevator contour" (p. 1).
Method of designing vaneless diffusers and experimental investigation of certain undetermined parameters
Report presenting a method of designing vaneless diffusers using data given for simple conical diffusers. A family of diffusers with three different cone angles and the same throat height was designed and experimentally studied. A second set of diffusers with varying throats with the best cone angle was also investigated.
Pressure Distribution Measurements on a Turbine Rotor Blade Passing Behind a Turbine Nozzle Lattice
"As a turbine rotor turns, the blades traverse the wake zones of the nozzle vanes. A periodic fluctuation of the pressure distribution around the circumference of the rotor blade is therefore caused. It was desired to investigate quantitatively this effect. At the same time, the magnitude of the force acting upon one profile of the rotor-blade lattice at various positions of this lattice relative to the nozzle lattice was to be determined" (p. 1).
Russian Laminar Flow Airfoils 3rd Part: Measurements on the Profile No. 2315 BIS with Ava-Nose Flap
"The tests on the Russian airfoil 2315 Bis were continued. This airfoil shows, according to Moscow tests, good laminar flow characteristics. Several tests were prepared in the large wind tunnel at Gottingen; partial results were obtained" (p. 1).
The stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds
Report presenting low-aspect-ratio wings with triangular plan form, which are treated on the assumption that the flow potentials in planes at right angles to the long axis of the airfoils are similar to the corresponding two-dimensional potentials. Pressure distributions caused by downward acceleration, pitching, rolling, sideslipping, and yawing are obtained for wings with and without dihedral.
A Study of Metal Transfer Between Sliding Surfaces
Note presenting a study to determine the nature of the surfaces formed on hardened steel parts during rubbing, notably on piston rings and cylinders during run-in. The technique of measuring the small amounts of material transferred from one rubbing surface to another by making one radioactive is applied to hardened steel surfaces, both nitrided and non-nitrided, and to chromium-plated steel.
A summary and analysis of data on dive-recovery flaps
From Summary: "The results of numerous unrelated tests of dive-recovery flaps are collected in this report and presented in a form suitable for use in the preliminary design of dive-recovery flap installations. Since the data were obtained for airplane models of quite widely varying configurations, and are limited largely to a Mach number of 0.80, it is recommended that each new installation be carefully flight-tested before final approval. A flight-test procedure is outlined which will insure a maximum degree of safety."
Temperatures and Stresses on Hollow Blades For Gas Turbines
"The present treatise reports on theoretical investigations and test-stand measurements which were carried out in the BMW Flugmotoren GMbH in developing the hollow blade for exhaust gas turbines. As an introduction the temperature variation and the stress on a turbine blade for a gas temperature of 900 degrees and circumferential velocities of 600 meters per second are discussed. The assumptions on the heat transfer coefficients at the blade profile are supported by tests on an electrically heated blade model" (p. 1).
A Theory of Unstaggered Airfoil Cascades in Compressible Flow
"By use of the methods of thin airfoil theory, which include effects of compressibility, relations are developed which permit the rapid determination of the pressure distribution over an unstaggered cascade of airfoils of a given profile, and the determination of the profile shape necessary to yield a given pressure distribution for small chord/gap ratios. For incompressible flow the results of the theory are compared with available examples obtained by the more exact method of conformal transformation. Although the theory is developed for small chord/gap ratios, these comparisons show that it may be extended to chord/gap ratios of order unity, at least for low-speed flows" (p. 551).
A Theory of Unstaggered Airfoil Cascades in Compressible Flow
"By use of the methods of thin airfoil theory, which include effects of compressibility, relations are developed which permit the rapid determination of the pressure distribution over an unstaggered cascade of airfoils of a given profile, and the determination of the profile shape necessary to yield a given pressure distribution for small chord gap ratios. For incompressible flow the results of the theory are compared with available examples obtained by the more exact method of conformal transformation. Although the theory is developed for small chord/gap ratios, these comparisons show that it may be extended to chord/gap ratios of order unity, at least for low speed flows" (p. 1).
Voltera's Solution of the Wave Equation as Applied to Three-Dimensional Supersonic Airfoil Problems
"A surface integral is developed which yields solutions of the linearized partial differential equation for supersonic flow. These solutions satisfy boundary conditions arising in wing theory. Particular applications of this general method are made, using acceleration potentials, to flat surfaces and to uniformly loaded lifting surfaces. Rectangular and trapezoidal plan forms are considered along with triangular forms adaptable to swept-forward and swept-back wings. The case of the triangular plan form in sideslip is also included" (p. 1).
Wind-Tunnel Investigations on a Changed Mustang Profile with Nose Flap Force and Pressure-Distribution Measurements
"Measurements are described which were taken in the large wind tunnel of the AVA on a rectangular wing "Mustang 2" with nose flap of a chord of 10 percent. Besides force measurements the results of pressure-distribution measurements are given and compared with those on the same profile "without" nose flap" (p. 1).
Wind-Tunnel Tests of the 1/25-Scale Powered Model of the Martin JRM-1 Airplane. 4 - Tests with Ground Board and with Modified Wing and Hull - TED No. NACA 232, Part 4, Tests with Ground Board and with Modified Wing and Hull, TED No. NACA 232
From Summary: "Wind-tunnel tests were made of a 1/25 scale model of the Martin JRM-1 airplane to determine: (1) The longitudinal stability and control characteristics of the JRM-1 model near the water and lateral and directional stability characteristics with power while moving on the surface of the water, the latter being useful for the design of tip floats; (2) The stability and stalling characteristics of the wing with a modified airfoil contour; (3) Stability characteristics of a hull of larger design gross weight; The test results indicated that the elevator was powerful enough to trim the original model in a landing configuration at any lift coefficient within the specified range of centers of gravity."
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