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The 6-foot-4-inch wind tunnel at the Washington Navy Yard
Report discussing the 6-foot-4-inch wind tunnel and its auxiliary equipment has proven itself capable of continuous and reliable output of data. The real value of the tunnel will increase as experience is gained in checking the observed tunnel performance against full-scale performance. Such has been the case of the 8- by 8-foot tunnel, and for that reason the comparison in the calibration tests have been presented.
The 300 H.P. Benz Aircraft Engine
This report provides a description of the Benz 300 H.P. aircraft engine containing 12 cylinders placed at a 60° angle. It includes a detailed description of the development of the constructional points, particularly the cylinders, pistons, and connecting rods, as well as the engine fitting, lubrication, oil pumps, bearings, oil tank, fuel pump, carburetors, and cooling system. There are seven pages of illustrative figures at the end of the report.
The 1350 F stress-rupture properties of two wrought alloys and three cast alloys
From Summary: "These properties compare favorably with those of the strongest similar alloys previously investigated. However, compared with a 60Cr-25Fe-15Mo alloy, the three cobalt-chronium-nickel cast alloys are inferior. A correlation of NACA and OSRD (Project NRC-8) data is presented, showing the variation of rupture strengths with temperature in the range of 1350^o to 2000^o for alloys."
N.A.C.A. control position recorder
Report discussing a new instrument is described which is capable of simultaneously recording the position of the three controls of an airplane. The records are taken photographically on a standard N.A.C.A. film drum and the instrument can be quickly installed in any airplane.
N.A.C.A. Langley field wind tunnel apparatusthe tilting manometer
A description is given of a tilting manometer designed to meet the requirements of a manometer for use in the wind tunnel at the Langley Memorial Aeronautical Laboratory. This gauge was designed to meet the requirements of a manometer in use in connection with a static pressure plate to indicate the wind speed in the tunnel. The requirements are noted. The sensitivity of the gauge must be made inversely proportional to the pressure to be measured. The gauge must be accurately and quickly set for any desired pressure. When set at the desired pressure, the extent of variation between the existing and the desired pressures may be readily estimated. In fact, this manometer is quick to adjust, is easy to read, always has the meniscus in the same position, and accurately indicates a large range of air speeds on what is a comparatively compact instrument.
N.A.C.A. recording air speed meter
A new type of air speed meter is described which was designed by the technical staff of the National Advisory Committee for Aeronautics. The instrument consists essentially of a tight metal diaphragm of high natural period which is acted upon by the pressure difference of a pitot-static head. The resulting deflection of this diaphragm is recorded optically on a moving film.
Abnormal grain growth in M-252 and S-816 alloys
Report discussing an experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.
Abnormal grain growth in nickel-base heat-resistant alloys
From Introduction: "The data included in this report for Nimonic 80A alloy, for instance, represent experiments carried out to help clarify a production problem of grain-size control in an alloy which has been extensively used. The general procedure of the investigation was to carry out controlled laboratory experiments on samples of bar stock to find conditions of heating and hot-working which resulted in abnormal grain growth."
Abnormal grain growth in S-816 alloy
From Introduction: "This report presents the results obtained to date of an investigation to establish the fundamental causes of abnormal growth in S-816 alloy under conditions encountered during the forging of blades for the gas turbine of jet engines."
Absolute coefficients and the graphical representation of airfoil characteristics
It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil. The author notes that, on the whole, it appears that the use of natural absolute coefficients in a polar diagram is the logical method for presentation of airfoil characteristics, and that serious consideration should be given to the advisability of adopting this method in all countries, in order to advance uniformity and accuracy in the science of aeronautics.
Absolute dimensions of Karman vortex motion
No Description Available.
Accelerations and passenger harness loads measured in full-scale light-airplane crashes
From Introduction: "Light-airplane accident data, compiled by Crash Injury Research of Cornell University Medical College, indicate that human beings have often withstood declarations in excess of those imposed in airplane crashes involving extensive damage to the airplane structure (ref. 1). This study also correlates the extent of damage to the airplane structure with the injury incurred by the occupants during crash accidents."
Accelerations in transport-airplane crashes
From Introduction: "A study of crash-impact survival in light airplanes is reported in references 1 and 2. A similar study for fighter airplanes is reported in reference 3. This report discusses crash-impact survival in transport airplanes."
Accuracy of approximate methods for predicting pressures on pointed nonlifting bodies of revolution in supersonic flow
No Description Available.
The accuracy of the substitute-stringer approach for determining the bending frequencies of multistringer box beams
No Description Available.
An accurate and rapid method for the design of supersonic nozzles
From Introduction: "This report presents a computational procedure which provides for the rapid and accurate calculation of any streamline in a series of special flows. Detailed information is given on the boundary conditions and equations used for computing the characteristic nets and stream function."
An accurate method of measuring the moments of inertia of airplanes
From Summary: "This note contains a description of an improved apparatus and procedure used by the NACA for determining the moments of inertia of airplanes. The method used, based on the pendulum theory, is similar to that previously used, but a recent investigation of its accuracy has resulted in the improvements described herein. The error, when using the new apparatus and procedure, has been found to be of the order of 1 per cent."
Achievement of continuous wall curvature in design of two-dimensional symmetrical supersonic nozzles
No Description Available.
Acoustic analysis of ram-jet buzz
From Introduction: "The surging of a system containing a centrifugal- or axial-flow compressor (e.g., refs. 1 to 4) is an example of self-sustained oscillation. Inlets designed for supersonic jet engines also have been observed to induce oscillations (e.g., refs. 5 to 11) which are usually referred to as "buzz." The origin of buzz in ram-jet engines is the subject of the present report."
Acoustic radiation from two-dimensional rectangular cutouts in aerodynamic surfaces
From Introduction: "The experiments in high-speed flow showed that an intense, high-frequency acoustic radiation is an essential feature of the problem. Consequently, a study of the acoustic field (involving schlieren observations and frequency and intensity measurements) was undertaken. This report presents the salient features of the study, which was mainly exploratory."
Acoustic, thrust, and drag characteristics of several full-scale noise suppressors for turbojet engines
From Introduction: " Considerable analytical and experimental research has been done to find means of reducing the noise levels of the turbojet transports. Noise levels can be decreased by engine redesign to reduce the jet-exit velocity (ref. 1), proper flight-climb techniques (ref. 2), and the use of noise-suppression exhaust nozzles (refs. 3 to 5). The present report is concerned with the last method."
Acoustical treatment for the NACA 8- by 6-foot supersonic propulsion wind tunnel
From Introduction: "This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory."
Adaptation of aeronautical engines to high altitude flying
Report discussing Issues and techniques relative to the adaptation of aircraft engines to high altitude flight. Covered here are the limits of engine output, modifications and characteristics of high altitude engines, the influence of air density on the proportions of fuel mixtures, methods of varying the proportions of fuel mixtures, the automatic prevention of fuel waste, and the design and application of air pressure regulators to high altitude flying. Summary: 1. Limits of engine output. 2. High altitude engines. 3. Influence of air density on proportions of mixture. 4. Methods of varying proportions of mixture. 5. Automatic prevention of fuel waste. 6. Design and application of air pressure regulators to high altitude flying.
Adaptor for measuring principal strains with Tuckerman strain gage
Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.
Additional static and fatigue tests of high-strength aluminum-alloy bolted joints
From Introduction: "Early in 1951 the National Advisory Committee for Aeronautics published, as Technical Note 2276 (ref. 1), a report by the Aluminum Research Laboratories of the Aluminum Company of America on the results of static and fatigue tests of high-strength aluminum alloy monobloc specimens and bolted joints. In view of special interest shown by several aircraft companies, certain expansions of the test program were undertaken by the Aluminum Research Laboratories and are reported herein."
Adhesion of ice in its relation to the de-icing of airplanes
From Summary: "The various possible means of preventing ice adhesion on airplane surfaces are critically reviewed. Results are presented of tests of the adhesives forces between ice and various solid and liquid forces. It is concluded that the de-icing of airplane wings by heat from engine exhaust shows sufficient promise to warrant full-scale tests. For propellers, at least, and possibly for certain small areas such as windshields, radio masts, etc. the use of de-icing or adhesion-preventing liquids will provide the best means of protection."
Advantages of oxide films as bases for aluminum pigmented surface coatings for aluminum alloys
Report discussing both laboratory and weather-exposure corrosion tests showed conclusively that the protection afforded by aluminum pigmented spar varnish coatings applied to previously anodized aluminum surfaces was greatly superior to that afforded by the same coatings applied to surfaces which had simply been cleaned free from grease and not anodized.
The aerodynamic analysis of the gyroplane rotating-wing system
From Summary: "An aerodynamic analysis of the gyroplane rotating-wing system is presented herein. This system consists of a freely rotating rotor in which opposite blades are rigidly connected and allowed to rotate or feather freely about their span axis. Equations have been derived for the lift, the lift-drag ratio, the angle of attack, the feathering angles, and the rolling and pitching moments of a gyroplane rotor in terms of its basic parameters. Curves of lift-drag ratio against lift coefficient have been calculated for a typical case, showing the effect of varying the pitch angle, the solidarity, and the average blade-section drag coefficient. The analysis expresses satisfactorily the qualitative relations between the rotor characteristics and the rotor parameters. As disclosed by this investigation, the aerodynamic principles of the gyroplane are sound, and further research on this wing system is justified."
The aerodynamic behavior of a harmonically oscillating finite sweptback wing in supersonic flow
From Introduction: "The paper treats the case of a finite wing with leading edge ahead of the Mach line."
Aerodynamic characteristics and flying qualities of a tailless triangular-wing airplane configuration as obtained from flights of rocket-propelled models at transonic and supersonic speeds
Report discussing a flight investigation of rocket-powered models of a tailless triangular-wing airplane configuration was made through the transonic and low supersonic speed range at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. An analysis of the aerodynamic coefficients, stability derivatives, and flying qualities based on the results obtained from the successful flight tests of three models is presented.
Aerodynamic characteristics at Reynolds numbers of 3.0 x 10(exp 6) and 6.0 x 10(exp 6) of three airfoil sections formed by cutting off various amounts from the rear portion of the NACA 0012 airfoil section
No Description Available.
Aerodynamic characteristics of 15 NACA airfoil sections at seven Reynolds numbers from 0.7 x 10(exp 6) to 9.0 x 10(exp 6)
No Description Available.
Aerodynamic characteristics of a circular cylinder at Mach number 6.86 and angles of attack up to 90 degrees
Pressure-distribution and force tests of a circular cylinder have been made in the Langley 11-inch hypersonic tunnel at a Mach number of 6.88, a Reynolds number of 129,000, and angles of attack up to 90 degrees. The results are compared with the hypersonic approximation of Grimminger, Williams, and Young and a simple modification of the Newtonian flow theory. An evaluation of the crossflow theory is made through comparison of present results with available crossflow Mach number drag coefficients.
The aerodynamic characteristics of a model wing having a split flap deflected downward and moved to the rear
From Summary: "Tests were made on a model wing with three different sized split trailing-edged flaps, in the NACA 7 by 10 foot wind tunnel. The flaps were formed of the lower rear portion of the wing and were rotated downward about axes at their front edges. The lift, drag, and center of pressure were measured with the axis in its original position and also with it moved back in even steps to the trailing edge of the main wing, giving in effect an increase in area. The split flaps when deflected about their original axis locations gave slightly higher maximum lift coefficients than conventional trailing-edge flaps, and the lift coefficients were increased still further by moving the axes toward the rear. The highest value of C(sub L max), which was obtained with the largest flap hinged at 90 per cent of the chord from the leading edge, was 2.52 as compared with 1.27 for the basic wing."
Aerodynamic characteristics of a number of modified NACA four-digit-series airfoil sections
No Description Available.
Aerodynamic characteristics of a refined deep-step planing-tail flying-boat hull with various forebody and afterbody shapes
From Introduction: "The results of one phase of this investigation, presented in reference 1, have indicated that hull drag can be reduced without causing large changes in aerodynamic stability and hydrodynamic performance by the use of high length-beam ratios. Another phase of the investigation, reference 2, indicated that hulls of the deep-step planning-tail type have much lower air drag than the conventional type of hull and about the same aerodynamic stability; tank tests, reference 3, have indicated that this type of hull also has hydrodynamic performance equal to and in some respects superior to the conventional type of hull. Unpublished tank tests have indicated that the hull models presented in the present paper (with the possible exception of the forebody alone for which data are not available) will have acceptable hydrodynamic performance."
Aerodynamic characteristics of a small-scale shrouded propeller at angles of attack from 0 to 90 degrees
No Description Available.
Aerodynamic characteristics of a two-blade NACA 10-(3)(062)-045 propeller and of a two-blade NACA 10-(3)(08)-045 propeller
Report discussing characteristics are given for the two-blade NACA 10-(3)(062)-045 propeller and for the two-blade NACA 10-(3)(08)-045 propeller over a range of advance ratio from 0.5 to 3.8, through a blade-angle range from 20 degrees to 55 degrees measured at the 0.75 radius. Maximum efficiencies of the order of 91.5 to 92 percent were obtained for the propellers. The propeller with the thinner airfoil sections over the outboard portion of the blades, the NACA 10-(3)(062)-045 propeller, had lower losses at high tip speeds, the difference amounting to about 5 percent at a helical tip Mach number of 1.10.
The aerodynamic characteristics of airfoils as affected by surface roughness
From Summary: "The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated at high values of the Reynolds number in a variable density wind tunnel. Tests were made on a number of National Advisory Committee for Aeronautics (NACA) 0012 airfoil models on which the nature of the surface was varied from a rough to a very smooth finish. The effect on the airfoil characteristics of varying the location of a rough area in the region of the leading edge was also investigated. Airfoils with surfaces simulating lap joints were also tested. Measurable adverse effects were found to be caused by small irregularities in airfoil surfaces which might ordinarily be overlooked. The flow is sensitive to small irregularities of approximately 0.0002c in depth near the leading edge. The tests made on the surfaces simulating lap joints indicated that such surfaces cause small adverse effects. Additional data from earlier tests of another symmetrical airfoil are also included to indicate the variation of the maximum lift coefficient with the Reynolds number for an airfoil with a polished surface and with a very rough one."
The aerodynamic characteristics of airfoils at negative angles of attack
From Introduction: "The present report gives all the results, including those published in reference 1 and the results of previously un-published tests tests of the airfoils at positive angles of attack."
The aerodynamic characteristics of an aspect-ratio-20 wing having thick airfoil sections and employing boundary-layer control by suction
No Description Available.
Aerodynamic characteristics of anemometer cups
From Introduction: "The investigation was intended to cover the characteristics of individual cups and of similar cups mounted on complete cup wheals. This report treats the static tests run on the individual cups."
Aerodynamic characteristics of damping screens
From Summary: "The experimental investigation of damping screens described herein was undertaken primarily to test theories of the effects of damping screens and to obtain information on the performance of screens in oblique flow. The characteristics investigated include the damping of longitudinal and lateral components of turbulence, the effect of screens on scale, the conditions for the production of turbulence and eddies by screens, and the damping of spatial variations of mean speed."
Aerodynamic characteristics of NACA 0012 airfoil section at angles of attack from 0 degrees to 180 degrees
No Description Available.
Aerodynamic characteristics of several 6-percent-thick airfoils at angles of attack from 0 degrees to 20 degrees at high subsonic speeds
No Description Available.
Aerodynamic characteristics of several airfoils of low aspect ratio
From Summary: "This paper presents the results of wind-tunnel tests of several airfoils of low aspect ratio. The airfoils included three circular Clark Y airfoils with different amounts of dihedral, two Clark Y airfoils with slots in their portions, and three flat-plate airfoils. Lift, drag, and pitching-moment characteristics of the slotted airfoils with slots open and closed; pitching moment characteristics of one of the slotted airfoils with slots open and closed; and lift characteristics of the flat-plate airfoils are included. The results reveal a definite improvement of lift, drag, and pitching-moment characteristics with increase in dihedral of the circular Clark Y wing. Lift characteristics near the stall were found to depend markedly on the shape of the extreme tip but were not greatly affected by slots through the after portion of the airfoils. Changes in plan form of the flat-plate airfoils gave erroneous indications of the effect to be expected from changes in plan form of an airfoil of Clark Y section. The minimum drag characteristics of the circular Clark Y airfoils were found to be substantially the same as for a Clark Y airfoil of conventional aspect ratio."
The aerodynamic characteristics of six commonly used Airfoils over a large range of positive and negative angles of attack
From Summary: "This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values."
Aerodynamic characteristics of the NACA 8-H-12 airfoil section at six Reynolds numbers from 1.8 x 10(exp 6) to 11.0 x 10(exp 6).
No Description Available.
Aerodynamic characteristics of the NACA 64-010 and 0010-1.10 40/1.051 airfoil sections at Mach numbers from 0.30 to 0.85 and Reynolds numbers from 4.0 x 10(exp. 6) to 8.0 x 10(exp. 6)
No Description Available.
Aerodynamic characteristics of three deep-step planing-tail flying-boat hulls and a transverse-step hull with extended afterbody
From Summary: "An investigation was made to determine the aerodynamic characteristics in the presence of a wing of three-step planning-tail flying-boat hulls which differed only in the amount of step fairing. The purpose of comparison, tests were also made of a transverse-step hull with an extended afterbody."