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- Wind Tunnel Investigation of Control-Surface Characteristics 11: Various Large Overhang and Internal-Type Aerodynamic Balances for a Straight- Contour Flap on the NACA 0015 Airfoil
- Report presenting force-test measurements in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the characteristics of several different shaped overhang-type aerodynamic balances applied to a straight-contour flap mounted on an NACA 0015 airfoil. The flap with blunt-nose overhang was overbalanced throughout certain ranges of flap deflection. Results regarding precision, lift, flap hinge moments, pitching moment, and drag are provided.
- Wind Tunnel Investigation of Control Surface Characteristics: [Part] 12 - Various Cover-Plate Alinements on the NACA 0015 Airfoil With a 30 Percent Chord Flap and Large Sealed Internal Balance
- Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel to determine the aerodynamic effects of changing the alignment of the cover plates on a sealed internally balanced flap. Manufacturing imperfections in the alignment of the cover plates with the airfoil contour may have serious effects on the resultant hinge moment of a flap with a sealed internal balance. Results regarding lift, flap hinge moments, pitching moment, and drag are provided.
- Theory and preliminary flight tests of an all-movable vertical tail surface
- Report presenting flight testing of an improved type of all-movable tail surface. The particular arrangement tested provides control-free stability and a stable variation of the control forces during maneuvers. Results regarding rudder effectiveness, directional stability, rudder-free lateral motion, and rudder-free turns are provided.
- Aerodynamic characteristics and flap loads of perforated double split flaps on a rectangular NACA 23012 airfoil
- From Introduction: "The results of the load tests and some additional aerodynamic characteristics of perforated double split flaps on a rectangular NACA 23012 airfoil are given in the present report."
- Wind-tunnel tests of hinge-moment characteristics of spring-tab ailerons
- Report presenting testing in the stability tunnel of two types of spring tab used as balances on a partial-span plain aileron. The tabs were connected to a spring located in the control system so that tab deflection was dependent on the control force.
- Wind-Tunnel Investigation of a Plain Aileron with Various Trailing-Edge Modifications on a Tapered Wing 3: Ailerons with Simple and Spring-Linked Balancing Tabs
- Aerodynamics data are obtained for the design of linked balancing tabs and effect of varied tab span and location to produce suitable lateral control characteristics with reasonable stick pressures for high-speed aircraft. Simple and spring-linked balancing tabs may considerably reduce control pressures if aileron system is designed for low maximum aileron deflection. Spring-linked tabs also decrease variation of stick pressure with speed and impart better controlllability at low speeds.
- An investigation of aircraft heaters 15: the emissivity of several materials
- Report presenting a determination of the mean effective emissivity as a function of temperature for the surfaces of several metals and insulating materials. A description and discussion of the measuring technique is presented. The results are plotted on a variety of graphs.
- The effect of high loading on landing technique and distance, with experimental data for the B-26 airplane
- Report presenting an analysis of the effect of wing loading of the landing flare, which indicated that it had an important effect on landing technique and distance. Results regarding the approach and flare path and ground run are provided.
- Investigation of Drag and Pressure Distribution of Windshields at High Speeds
- Report presenting tests in the 8-foot high-speed wind tunnel to determine the loads and the load distributions at high speeds for a number of windshields of the cockpit-canopy type. Ten windshields of various designs similar to those in general use were included in these tests. Results regarding drag, loads, and design considerations are provided.
- A Theoretical Investigation of the Rolling Oscillations of an Airplane With Ailerons Free
- Report discusses an analysis of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. Information about the aerodynamic balance of the plane and oscillations that may be encountered are included. The effects of friction in the control system is also explored.
- An empirical formula for the critical shear stress of curved sheets
- Report presenting tests to determine the critical shear stress of curved sheets. The empirical formula derived from the tests is applicable to panels with a ratio of radius to thickness of 300 or greater, a central angle of 1 radian or less, and a ratio of arc length to axial length not greater than 1.
- The significance of the time concept in engine detonation
- Report presenting an experimental technique developed by means of which the variables affecting the time element in the detonation process in a spark-ignition engine can be controlled and approximately measured. Results indicated that higher maximum permissible pressures can be used if the rate of compression of the end gas is increased. Suggestions for future study are provided.
- An experimental survey of flow across banks of elliptical and pointed tubes
- Report presenting an experimental survey of the details of the flow of fluids across banks of streamline tubes as a continuation of previous work. Information that clarifies the picture of flow has been obtained by surveys of total, dynamic, and static pressure, and hot-wire cooling surveys of the unheated tubes.
- Single-Cylinder Engine Tests of Porous Chrome-Plated Cylinder Barrels With Special Bore Coatings for Radial Air-Cooled Engines
- Report discussing a series of single-cylinder engine tests to determine the effect of special surface coatings in porous chrome-plated cylinder barrels on oil consumption and ring wear. The coating materials were selected for their bearing and lubrication properties and on their applicability to processing. The surface coatings tested were lead overplates, silver overplates, and colloidal graphite base paint.
- Comparison of various methods for computing drag from wake surveys
- "The various equations for computing profile drag by the momentum method are examined, and the errors arising from complete or partial neglect of compressibility effects in the Jones equation and the Bicknell equation are evaluated. The integrating method of Silverstein and Katzoff is shown to be accurate over a wide range of Mach number and wake shapes" (p. 1).
- Experimental Determination of the Effect of Negative Dihedral on Lateral Stability and Control Characteristics at High Lift Coefficients
- Report presenting the effects of negative dihedral on lateral stability and control characteristics at high lift coefficients determined by flight tests with a model. As the effective dihedral was decreased, the model became increasingly difficult to fly. Results regarding the effect of directional stability and lift coefficient on flight behavior are also provided.
- Comparison of an approximate and an exact method of shear-lag analysis
- Report presenting comparisons between the approximate substitute single-stringer method of shear-lag analysis and the exact solutions, which indicate that for beams of practical proportions the approximate method yields a value for the maximum root stress that exceeds the value obtained by use of the exact solution by less than 10 percent.
- Shear-Lag Tests of Two Box Beams With Corrugated Covers Loaded to Failure
- "Strain measurements were made on the compression side of two box beams with corrugated aluminum-alloy covers loaded to failure. Angles formed from sheet were used for corner flanges in beam 1; whereas extruded angles were used in beam 2. Failure in each beam occurred in the corner angle at a stress that was above the compressive yield stress for the material" (p. 1).
- Additional design charts relating to the stalling of tapered wings
- From Introduction: "The present report, therefore, may be considered a supplement to reference 1. The combined scope of the stall charts of reference 1, designated A, and of the present work, designated B, is summarized in the following table: For the wing with root thickness ratio to 18 was also investigated.
- Flight Investigation of NACA D(Sub S) Cowlings on the XP-42 Airplane 1: High-Inlet-Velocity Cowling with Propeller Cuffs Tested in High-Speed Level Flight
- Report presenting results from a series of flight tests of the maximum speed and cooling characteristics in full-throttle level flight of the XP-42 airplane equipped with a short-nose high-inlet velocity cowling. The results of the tests indicated a maximum speed of 336 miles per hour at 960 horsepower at 25,000 feet. Results regarding maximum speed and pressure and temperatures are provided.
- Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane 3: low-inlet-velocity cowling without fan or propeller cuffs, with axial-flow fan alone, and with two different sets of propeller cuffs
- Report presenting the results of flight measurements of performance and cooling characteristics of the XP-42 airplane equipped with a short-nose low-inlet-velocity cowling. Testing included measurements in level flight and climb of the effects of a spinner-mounted axial-flow fan without propeller cuffs, no fan or cuffs, and two different sets of propeller cuffs.
- Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane 4: high-inlet-velocity cowling tested in climb with and without propeller cuffs and in high-speed level flight without propeller cuffs
- Report presenting flight measurements of the performance and cooling characteristics of a short-nose high-inlet-velocity cowling on the XP-42 for conditions of climb with and without propeller cuffs and for high speed without cuffs. The speed of the airplane was approximately 1 mile per hour greater without propeller cuffs than the previously measured value with cuffs. Results regarding maximum speed, pressures and temperatures, and ground cooling are provided.
- An analysis of the skipping characteristics of some full-size flying boats
- From Introduction: "The purpose of this report is to gather together in one place information on the skipping characteristics of number of flying boats. A graph showing the influence of the hull form on the skipping characteristics is given which should be useful in laying out the proportions of the hull in preliminary design to insure good landing behavior."
- Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane 2: low-inlet-velocity cowling with axial-flow fan and propeller cuffs
- Report presenting results from a series of flight tests of the performance and cooling characteristics in high-speed level flight and in climb of the XP-42 airplane equipped with a short-nose low-inlet-velocity cowling and an axial-flow fan mounted on the spinner. Results regarding maximum speed and pressures and temperatures are provided.
- Wind-Tunnel Tests of a Twin-Engine Model to Determine the Effect of Direction of Propeller Rotation on the Static-Stability Characteristics
- Report presenting tests made in the 7- by 10-foot tunnel to determine the effect of direction of propeller rotation on the static longitudinal and lateral stability characteristics of the scale model of the North American B-28 airplanes. The results of the present investigation indicate that the mode of propeller operation has a considerable effect upon lateral and longitudinal stability and may have an effect upon propulsive efficiency.
- Determination of the Effect of Wing Flexibility on Lateral Maneuverability and a Comparison of Calculated Rolling Effectiveness With Flight Results
- Report presenting an analysis which shows that, when account is taken of sideslip and wing flexibility, the calculated rolling maneuverability of an airplane is in good agreement with the results obtained from flight tests. The method used avoids the complications of successive approximations but is nevertheless believed to be more nearly accurate than other methods based on semirigid-wing assumptions. The method is applied to a wing of tubular shell construction and the procedure is illustrated for a modern pursuit airplane.
- A Procedure for the Shear-Lag Analysis of Box Beams
- Report presenting a procedure for the shear-lag analysis of box beams, such as wing structures. It is based off of a previous method but allows for the separation of the most essential part of the shear-lag analysis.
- Spray Characteristics of a Powered Dynamic Model of a Flying Boat Having a Hull With a Length-Beam Ratio of 9.0
- Report discusses an investigation into the spray characteristics of a twin-engine flying boat model similar to the Boeing XPBB-1 but with a modified length-beam ratio of the hull. The spray characteristics of the modified model compared favorably with the standard XPBB-1 flying boat and no adverse effects on spray characteristics were introduced by modifying the length-beam ratio and hull.
- Tests of Thermal-Electric De-Icing Equipment for Propellers
- "Flights were made in natural icing conditions at the NACA Ice Research Project, Minneapolis, Minn. to test several designs of thermal-electric propeller de-icing blade shoes and a hub-generator design. It was found that a minimum average unit power of 2.5 watts per square inch of blade-shoe area would protect the propeller blades at the test conditions. The most satisfactory blade shoe of the three designs tested extended to the 20-percent-chord point and to 90 percent of the blade radius" (p. 1).
- Altitude Rating of Electrical Apparatus
- "This paper studies the effect of altitude on the ratings of rotating electric machines and after determining the fundamental principles involved, discusses these in relation to the application of such machines in modern aircraft" (p. 1).
- The knock-limited performance of fuel blends containing aromatics 2: isopropylbenzene, benzene, and o-xylene
- Report presenting knock-limited small-scale-engine tests of isopropyl-benzene, benzene, and o-xylene blended individually in various concentrations with selected base fuels. Data were obtained to determine the blending sensitivity, lead susceptibility, and sensitivity of the blends to inlet-air temperatures. Isopropylbenzene was found to be the most effective overall.
- A Method for Welding Sheet Aluminum to SAE 4140 Steel
- Report presenting an investigation of a large variety of different metals used as an intermediate metal between aluminum and steel for the purpose of securing a good bond both from the viewpoint of strength and thermal conductivity. The principal result was that it was found possible to secure a satisfactory bond between aluminum and steel by electroplating the steel with a layer of silver of proper thickness.
- The Two-Dimensional Incompressible Potential Flow Over Corrugated and Distorted Infinite Surfaces
- "The two-dimensional incompressible potential flow over corrugations and bumps of arbitrary shape is derived by conformal transformation. The results are compared with those obtained by the methods of thin-airfoil theory. Some discussion is included of the flow over bumps that protrude both inward and outward from a wall" (p. 1).
- Charts of Pressure, Density, and Temperature Changes at an Abrupt Increase in Cross-Sectional Area of Flow of Compressible Air
- "Equations have been derived for the change in the quantities that define the thermodynamic state of air - pressure, density, and temperature - at an abrupt increase in cross-sectional area of flow of compressible air. Results calculated from these equations are given in a table and are plotted as curves showing the variation of the calculated qualities with the area expansion ratio in terms of the initial Mach number as parameter. Only the subsonic region of flow is considered" (p. 1).
- The Analysis of Strains Indicated by Multiple-Strand Resistance-Type Wire Strain Gages Used as Rosettes
- "Methods are given for making the necessary corrections to the strains indicated by multiple-strand resistance-type wire strain gages used singly or as rosettes to measure strains at an angle to the principal strain. The results of tests to determine the validity of the methods of correction are reported" (p. 1).
- Analysis of a thermal ice-prevention system for wing leading-edge landing-light installations
- From Introduction: "A typical ice formation on a wing leading-edge-type light installation is shown in figure 1. Although the primary purpose of this analytic investigation was to determine the practicability of providing a landing-light thermal ice-prevention system which could be incorporated with the wing leading-edge thermal ice-prevention system of the B-17 F airplane, the analysis has been developed in a general form for future application to similar deigns. "
- Tunnel-Wall Corrections to Rolling and Yawing Moments Due to Aileron Deflection in Closed Rectangular Wind Tunnels
- "A method is developed for calculating the tunnel-wall corrections to rolling and yawing moments due to aileron deflection on models in closed rectangular wing tunnels. Graphs are presented which permit a rapid determination of these corrections for models mounted in 7- by 10-foot or 8- by 12-foot wind tunnels. The method is so developed that the corrections may be calculated for the deflection of either aileron alone or both ailerons simultaneously" (p. 1).
- Wind-Tunnel Tests of a Dual-Rotating Propeller Having One Component Locked or Windmilling
- "The effect on the propulsive efficiency of locking or windmilling one propeller of a six-blade dual-rotating propeller installation was determined in the Langley propeller-research tunnel. Tests were made of both pusher and tractor configurations, with the unpowered propeller both leading and following the powered propeller, which was set at a blade angle of 40 degrees. The maximum propulsive efficiency of the powered propeller in combination with the locked or windmilling propeller was, in all cases, lower than that of the powered propeller operating alone" (p. 1).
- Effects of Heat-Capacity Lag in Gas Dynamics
- Report presenting an investigation of the existence of energy dissipations in gas dynamics, which must be attributed to a lag in the vibrational heat capacity of the gas, and most specifically the flow about a very small impact tube. A new method of measuring the relaxation time of gases is introduced in which the total-head defects observed with a specially shaped impact tube are compared with theoretical considerations.
- Determination of Gas Temperatures from the Frequency of Knock-Induced Gas Vibrations in an Internal-Combustion Engine
- Report of a study to develop a method of obtaining gas temperatures from the frequency of knock-induced gas vibrations in an internal-combustion engine cylinder. Temperatures calculated from frequency data were in agreement with temperatures measured by the spectral line-reversal method in previous investigations and were about 700 degrees Fahrenheit lower than temperatures obtained from thermodynamic charts.
- Maximum permissible engine performance of eight representative fuels of 100-octane number
- Report presenting knock-limited performance tests made with eight representative fuels rated at 100-octane number using the CFR aviation method. All eight fuels were mixtures of representative blending agents and bases. Results regarding the effect of inlet-temperature air changes, effect of octane numbers in a full-scale single-cylinder engine, effect of addition of aromatics to the fuels, and type of spark plug used are provided.
- On the plane potential flow past a symmetrical lattice of arbitrary airfoils
- Report presenting a theoretical investigation of the two-dimensional, incompressible potential flow past a symmetrical lattice of airfoils of arbitrary shape. Expressions are given for evaluation of the velocity and pressure distribution at the airfoil boundary.
- Critical combinations of shear and transverse direct stress for an infinitely long flat plate with edges elastically restrained against rotation
- Report presenting an exact solution and a closely concurring approximate energy solution for the buckling of an infinitely long flat plate under combined shear and transverse direct stress with edges elastically restrained against rotation. An appreciable fraction of the critical stress in pure shear may be applied to the plate without any reduction in the transverse compressive stress necessary to produce buckling.
- Compressible potential flow with circulation about a circular cylinder
- Report presenting the potential function for flow, with circulation, of a compressible fluid about a circular cylinder, which is obtained in series form including terms of the order of M(exp 4) where M is the Mach number of the free stream. The equations are used to obtain pressure coefficient as a function of Mach number at a point on the surface of the cylinder for different values of circulation.
- 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.