UNT Libraries Government Documents Department - 423 Matching Results
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- Investigation of Effects of Various Camouflage Paints and Painting Procedures on the Drag Characteristics of an NACA 65(Sub 421)-420, a = 1.0 Airfoil Section
- Bulletin presenting an investigation of the effects of various camouflage paints and painting procedures on the drag characteristics of a 60-inch-chord low-drag airfoil in the NACA two-dimensional low-turbulence pressure tunnel.
- Flight Investigation of Boundary-Layer Control by Suction Slots on an NACA 35-215 Low-Drag Airfoil at High Reynolds Numbers
- Report presenting an investigation of the effectiveness of suction slots as a means of extending the laminar boundary layer in flight at high Reynolds numbers on an NACA 35-215 airfoil. The results showed that, with a slot spacing of about 5 percent of the chord, the laminar boundary layer could be maintained to or slightly beyond 45 percent of the chord.
- High-Altitude Cooling 3: Radiators
- Report details the methods of determining the heat-transfer rate, pressure drop, and drag power of high-altitude radiators. Performance charts are provided for a wide range of design variables.
- Power-Off Tests of the Northrop N9M-2 Tailless Airplane in the 40- by 80-Foot Wind Tunnel
- Report discussing tests on the N9M-2 airplane to evaluate the airplane efficiency factor and to investigate the characteristics of the aeroboost in the elevon control system. The efficiency factor compared reasonably well to conventional airplanes and the aeroboost system and valve-chatter tests were satisfactory.
- Flight Tests of the High-Speed Performance of a P-51B Airplane (AAF No. 43-12105)
- Report discussing testing to check the improvement of 3 or 4 miles per hour in the maximum speed of the P-51B airplane as a result of sealing the wing-gun access doors and flap-spar lightening holes. Large variations in speed were observed during testing, so additional testing and analysis was carried out to determine the effects of various factors that were suspected of contributing to the inconsistency of the plane's performance.
- Analysis of Circular Shell-Supported Frames
- From Summary: "This paper deals with the single problem if circular shell-supported frames subjected to concentrated loadings. A mathematical attack is developed and presented in the form of nondimensional-coefficient curves."
- Investigation of the Behavior of Parallel Two-Dimensional Air Jets
- Report presenting an investigation made of the flow downstream from a two-dimensional grid, formed of parallel rods. The two-dimensional character of the flow was insured by end plates normal to the rods and covering the entire flow field. The nature of the flow was determined primarily by means of total-head measurements.
- Elastic properties of channels with unflanged lightening holes
- Report presenting testing of fifty-eight lightened and five unlightened aluminum-alloy channels as simply supported beams in pure or simple bending produced by loads parallel to the plane of symmetry, and fifty-three lightened and four unlightened aluminum-alloy channels with loads parallel to the back. Four types of testing occurred with various types of support and loading.
- A Least-Squares Procedure for the Solution of the Lifting-Line Integral Equation
- Note presenting a least-squares procedure adapted to numerical calculation for the approximate solution of the Prandtl lifting-line equation. Sufficient data are tabulated to permit a solution of the equation by purely numerical methods for an arbitrary symmetrical variation of the chord and the angle of attack.
- Determination of stress-strain relations from "offset" yield strength values
- Report presenting an investigation of the shape of stress-strain curve for a material, especially when the material is subjected to compression, which may cause materials to become unstable at stresses beyond the elastic range. The ratio of stresses to effective modulus is explored in equation form.
- The Influence of Plastic Deformation and of Heat Treatment on Poisson's Ratio for 18:8 Chromium-Nickel Steel
- Note presenting an effective value of Poisson's ratio for 18:8 Cr-Ni steel computed from values of tensile and torsional moduli of elasticity obtianed in earlier investigations by use of an appropriate formula.
- Ovalization of Tubes Under Bending and Compression
- "An empirical equation has been developed that gives the approximate amount of ovalization for tubes under bending loads. Tests were made on tubes in the d/t range from 6 to 14, the latter d/t ratio being in the normal landing gear range. Within the range of the series of tests conducted, the increase in ovalization due to a compression load in combination with a bending load was very small" (p. 1).
- Piloting of flying boats with special reference to porpoising and skipping
- From Summary: "The various types of hydrodynamic instability - including porpoising, skipping, and yawing - that may be encountered during take-off or landing of a flying boat are described and the piloting technique required for efficient take-offs and landings is discussed. Suggestions are made for assisting a pilot to become familiar with the take-off and landing qualities of a flying boat that is new to him."
- Bibliography of piston ring lubrication
- Report presenting a survey of the technical information contained in the literature on the subject of lubrication, friction, and wear of aircraft engine piston rings.
- Torsion Test to Failure of a Monocoque Box
- Note presenting a torsion test to failure for a monocoque box of 24S-T aluminum alloy. The box had a rectangular section and was reinforced by Z-stringers, antirolls, bulkheads, and corner posts.
- Numerical procedures for the calculation of the stresses in monocoques 2: diffusion of tensiles stringer loads in reinforced flat panels with cut-outs
- Report presenting experiments with a flat reinforced sheet model, the longitudinals of which were loaded axially. Two groups of sheets, one with one panel and one with two panels, were cut out and the stress distributions in stringers and sheet was measured with electric strain gages.
- Performance tests of wire strain gages 1: calibration factors in tension
- Report presenting calibrations in axial tension over the strain range from 0 to 0.0024 are presented for 15 types of single element multistrand wire strain gages. The majority of the gages showed significant differences between the calibration factors for strain increasing and strain decreasing. Improvement in gage performance after preloading was apparent in most cases.
- A unit laboratory engine oil system providing for a remote indication of oil flow and oil consumption together with blow-by measurement
- From Summary: "A unit oil system and oil-weighing device designed for laboratory engine tests to permit the remote measurement of oil-flow rate and oil consumption is described. The system regulates the oil pressure and temperature and is closed to make possible the accurate measurement of blow-by gas. The oil is weighed by a self-contained diaphragm and pilot-valve assembly, which uses compressed air as the transmitting medium. Several of those unit systems have given satisfactory service for more than a year."
- Axial Fatigue of 10 Airplane Wing-Beam Specimens by the Resonance Method
- Note presenting axial fatigue tests made by the resonance method on 10 specimens from airplane wing beams. The specimens contained several types of stress raiser, such as rivets, holes, fittings, splices, reinforcing plates, and so forth. The results show a greater fatigue stress concentration factor for the wing-beam specimens than for drilled coupons machined from the flanges or for parallel strip coupons containing idle rivets.
- Applicability of Similarity Principles to Structural Models
- "A systematic account is given in part I of the use of dimensional analysis in constructing similarity conditions for models and structures. The analysis covers large deflections, buckling, plastic behavior, and materials with nonlinear stress-strain characteristics, as well as the simpler structural problems" (p. 1).
- Plastic Mountings for Aircraft Windshields
- Note presenting an investigation of several laminated glass windshields to determine their suitability for use in airplanes with pressurized cabins. The various constructions of the extended portions of the windshields which serve for mounting purposes included plastic alone, plastic and one sheet of glass extended, plastic extension reinforced with an aluminum strip, and plastic extension reinforced with a steel strip. The results indicated that the laminated windshields with plastic-mounting extensions reinforced by aluminum or steel were resistant to creep and bursting at pressures of the order that will be encountered in service.
- Simplified Truss Stability Criteria
- Report presenting a note in two parts regarding simplified truss stability criteria. The first part covers the development of simplified criteria for the stability of planar pin-jointed trusses against buckling in the plane of the truss. The second part constitutes a report on tests carried out to verify the validity of the criteria developed in part one.
- Numerical procedures for the calculation of the stresses in monocoques 1: diffusion of tensile stringer loads in reinforced panels
- Report presenting experiments with both curved and flat reinforced sheet models, the longitudinals of which were loaded axially. The stress distribution in longitudinals and sheet was measured with electric strain gages.
- Charts for rapid analysis of 45 degree strain-rosette data
- From Summary: "Charts are presented for rapidly determining the principal strains and stresses, the maximum shear strain and stress, and the orientation of principal axes from data on 45 degree strain rosettes. The charts may be used for analyzing the conventional data consisting of strains measured along three gage lines 45 degrees apart, but their application is more direct if the rosette data are obtained by means of special circuits that require the use of four gages 45 degrees apart."
- An automatic electrical analyzer for 45 degree strain-rosette data
- Report presenting a device that automatically analyses the data from a 45 degree strain rosette. The rosette strains are properly combined by means of an electric circuit to yield a direct meter reading of maximum shear strain and major and minor principal strains.
- The Shear of Aluminum Alloy Driven Rivets as Affected by Increasing D/T Ratios
- "A decrease in shear strengths for increasing D/t ratios was shown in a previous investigation of protruding-head aluminum alloy rivets in double shear conducted at Aluminum Research Laboratories in 1942. Since single shear joints are more common than double shear joints, it was desirable to extend the investigation to single shear joints. This reports describes the results of this investigation of single shear joints and also includes the results of the previous investigation on double shear joints" (p. 1).
- Nondestructive Test Methods for Spot Welds in Aluminum Alloys
- Note presenting the results of a study and research investigation of nondestructive test methods for spot welds in aluminum-alloy sheets. The purpose of the research was to investigate proposed nondestructive test methods for spot welds in aluminum alloys, to determine the feasibility of the tests, and to recommend the research methods found suitable for development and reduction to practical application.
- Effect of Curvature on Strength of Axially Loaded Sheet-Stringer Panels
- Note presenting compressive testing made on twenty-one 24S-T aluminum-alloy sheet-stringer panels 12 inches in length and 16 inches in developed width, reinforced by four Z stringers spaced 4 inches apart. Results regarding strains, buckling, and failure are provided.
- The Effect of Temperature on Sheet Metals for Airplane Firewalls
- Note presenting tests conducted on 5 uncoated steels and 20 steels with various coatings to determine the effect of temperature on the tensile properties and surface characteristics of the metals. The metals were subjected to furnace-heating tests over a range of temperatures for various times and to flame-impingement and airplane-fire tests. Results regarding metals without surface coatings, low carbon steels with surface coatings, and discussion of comparative behaviors regarding the different surface coatings are provided.
- Tests of Airfoils Designed to Delay the Compressibility Burble
- Note presenting a method of deriving certain airfoil shapes that delay certain compressibility phenomena, and the aerodynamic data for a wide range of Mach numbers obtained from tests of the airfoils in the 24-inch high-speed tunnel. The airfoils, which are designated the NACA 16-series, have increased critical Mach number. Results regarding the airfoil comparison, critical speed, minimum drag, and use of the data are provided.
- Development of detonation detector suitable for use in flight
- Report presenting an apparatus for making quantitative measurements of the vibrations excited by detonation in the cylinder head of an aircraft engine. The apparatus consisted of pick-up units, an amplifying system, and a cathode-ray oscillograph with a high-speed-camera recording system. A large number of records were taken under various operating conditions in a single-cylinder aircraft engine.
- Normal Pressure Tests on Unstiffened Flat Plates
- "Flat sheet panels of aluminum alloy (all 17S-T except for two specimens of 24S-T) were tested under normal pressures with clamped edge supports in the structures laboratory of the Guggenheim Aeronautical Laboratory, California Institute of Technology. The thicknesses used ranged from 0.010 to 0.080 inch; the panel sizes ranged from 10 by 10 inches to 10 by 40 inches; and the pressure range was from 0 to 60-pounds-per-square-inch gage. Deflection patterns were measured and maximum tensile strains in the center of the panel were determined by electric strain gages" (p. 1).
- Secondary Stresses in Open Box Beams Subjected to Torsion
- In open box beams subjected to torsion, secondary stresses arise owing to lateral bending of the spar caps. The present paper outlines a simple method for estimating the magnitude of these stresses and gives the results of tests of an open box beam in the neighborhood of a discontinuity where the cover changed from the top to the bottom of the box.
- Flight Investigation at High Mach Numbers of Several Methods of Measuring Static Pressure on an Airplane Wing
- Report discusses an investigation into static pressures in subsonic and supersonic flow over an airplane wing as measured by static-pressure tubes, a static-pressure belt, and orifices flush with the wing surface. The results obtained from the three types of measuring devices and a comparison to theoretical calculations are presented.
- Effect of a Trailing-Edge Extension on the Characteristics of a Propeller Section
- Report presenting a convenient technical method to evaluate changes in the airfoil characteristics resulting from an extension of the chord at the trailing edge of a propeller blade section. The method determines the change in the angle of zero lift, the ideal angle of attack, and the difference in these angles as a function of the angle and length of the trailing-edge extension.
- Variation of peak pitching-moment coefficients for six airfoils as affected by compressibility
- Report presenting pressure distribution tests of six NACA 16-series propeller sections with 1-foot chords in the 8-foot high-speed tunnel to determine the compressibility effects on peak section pitching-moment coefficients. Data is presented as curves of peak section pitching-moment coefficient against Mach number, thickness ratio, and camber. The peak pitching-moment coefficients were found to occur in the regions of positive and negative stall.
- Wind-Tunnel Investigation of Control-Surface Characteristics 16: Pressure Distribution Over an NACA 0009 Airfoil With 0.30-Airfoil-Chord Beveled-Trailing-Edge Flaps
- Report discusses pressure-distribution tests of a plain flap with interchangeable beveled trailing edges on an NACA 0009 airfoil. The flap chord was 30 percent of the airfoil chord and the bevel chords were 15 and 20 percent of the flap chord. The purpose of these tests was to supply pressure-distribution data that may be used for structural and aerodynamic design of horizontal and vertical tail surfaces.
- Wind-tunnel investigation of control-surface characteristics 17: beveled-trailing-edge flaps of 0.20, 0.30, and 0.40 airfoil chord on an NACA 0009 airfoil
- Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 0009 airfoil with flaps having chord at 3 locations of the airfoil chord and three degrees of the beveled trailing edges. The results indicated that, with a smooth leading edge, the increased trailing-edge angle on the flaps with sealed gaps decreased the slope of the control-fixed lift curve and the lift effectiveness.
- Some Effects of Propeller Operation on the Distribution of the Load on the Vertical Tail Surface of a Typical Pursuit Airplane
- Report discusses the results of testing on the pressure distribution at several longitudinal sections of the vertical tail surface of the Curtiss P-40K airplane at various angles of attack and angles of yaw and with the propeller removed and propeller operating. Results regarding the chordwise pressure distributions, effects of propeller operation on the spanwise distribution of normal-force coefficient, total normal-force coefficients, and effect of propeller operation on the variation of vertical-tail normal-force coefficients are presented.
- Flutter tests of B-34 fin-rudder-tab system
- From Summary: "Tests on the B-34 fin-rudder-tab assembly were performed in the NACA 8-foot high-speed tunnel. Two cases of tab flutter were studied. It was shown conclusively that the frequency of the original or heavy tab was too low and caused coupling with one of the lower bending frequencies. A general conclusion was made that the tab frequency should be considerably higher than the lower modes of the fin-rudder assembly because there is generally a weaker coupling between the tab and the higher mode responses."
- Maximum Rates of Control Motion Obtained From Ground Tests
- Report discusses the results of testing to determine the maximum rates of control stick (elevator) motion and corresponding maximum stick forces that could be exerted based on experiments with several pilots. The main topics explored were the comparison of the maximum rates of push and pull, maximum rates of push and pull when a mental restriction was placed on the pilot, and maximum rates at which the pilot though he would apply the elevator control forces versus the actual application of forces. Information about experimental procedures and the rig the testing occurred on is included.
- Flight tests of various tail modifications on the Brewster XSBA-1 airplane 3: measurements of flying qualities with tail configuration 3
- Report presenting a series of tests on the Brewster XSBA-1 airplane to determine the effects of various tail modifications. Some of the modifications include variations of the chord of the elevator and rudder while the span and total area of the surfaces are kept constant and variations of the total area of the vertical tail surface. Results regarding the longitudinal stability and control and lateral stability and control are provided.
- Wind-Tunnel Investigation of an NACA 23021 Airfoil With a 0.32-Airfoil-Chord Double Slotted Flap
- Report discusses an investigation to determine the aerodynamic section characteristics of an NACA 23021 airfoil with a double slotted flap with a chord 32 percent of the airfoil chord with the flaps at various positions. The maximum section lift coefficient, profile-drag coefficient, flap positioning, and effects of deflecting or removing the lower lip are described.
- Analysis of Available Data on Control Surfaces Having Plain-Overhang and Frise Balances
- From Introduction: "The present paper deals with control surfaces having plain-overhang and Frise balances."
- An Automatically Variable Control Linkage and Its Effect on the Lateral-Control Characteristics of a High-Speed Fighter Airplane
- Report discusses an analysis and preliminary design of a control linkage that varies automatically with dynamic pressure. The advantages of the device, including greater lateral control than a fixed control linkage without additional aerodynamic balance, are detailed. The effect of variable linkage on lateral-control characteristics is also described.
- Airfoil Section Data From Tests of 10 Practical-Construction Sections of Helicopter Rotor Blades Submitted by the Sikorsky Aircraft Division, United Aircraft Corporation
- Report presenting 10 practical-construction models of sections of helicopter rotor blades tested in the NACA two-dimensional low-turbulence pressure tunnel at atmospheric pressure. Lift, drag, and pitching-moment characteristics of blades representing the present method of construction of the YR-4A helicopter were determined.
- Effect of Compressibility on Pressure Distribution Over an Airfoil With a Slotted Frise Aileron
- Pressure distribution measurements were made over an airfoil with slotted Frise aileron up to 0.76 Mach at various angles of attack and aileron defections. Section characteristics were determined from these pressure data. Results indicated loss of aileron rolling power for deflections ranging from -12 Degrees to -19 Degrees.
- Wind Tunnel Investigation of the Effects of Slot Shape and Flap Location on the Characteristics of a Low-Drag Airfoil Equipped with a 0.25-Chord Slotted Flap
- Tests were conducted at dynamic pressure of 50 lb per square foot with lift drag and pitch moment measurements throughout useful angle of attack range for constant flap deflection and position of a low-drag airfoil. Two slots were investigated and practical flap paths were selected for each Slot shape had a negligible effect on the maximum lift coefficient flap deflected, the rounded-entry slot had lower profile drag.
- Aerodynamic Characteristics of the NACA 747A315 and 747A415 Airfoils From Tests in the NACA Two-Dimensional Low-Turbulence Pressure Tunnel
- Report presenting two low-drag airfoils, the NACA 747A315 and the NACA 747A415, which are designed to have reduced pitching moments about the quarter-chord point and moderately high values of the design lift coefficient and are tested in the tow-dimensional low-turbulence pressure tunnel.
- Drag measurements at high Reynolds numbers of a 100-inch-chord NACA 23016 practical construction wing section submitted by Chance Vought Aircraft Company
- Report presenting drag measurements in the two-dimensional low-turbulence tunnel of an available 100-inch-chord model of the NACA 23016 wing section. Results regarding the curves of section drag coefficient plotted against Reynolds number for various surface conditions and lift coefficients, variation of drag coefficient with lift coefficient, and effects of skin friction are provided.