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open access

Column Strength of Magnesium Alloy AM-57S

Description: Tests were made to determine the column strength of extruded magnesium alloy AM-57S. Column specimens were tested with round ends and with flat ends. It was found that the compressive properties should be used in computations for column strengths rather than the tensile properties because the compressive yield strength was approximately one-half the tensile yield strength. A formula for the column strength of magnesium alloy AM-57S is given.
Date: July 1943
Creator: Holt, M.
open access

Description of Stress-Strain Curves by Three Parameters

Description: "A simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths. Dimensionless charts are derived from this formula for determining the stress-strain curve, the tangent modulus, and the reduced modulus of a material for which these three parameters are given. Comparison with the tensile and compressive data on aluminum-alloy, stainless-steel, and carbon-steel sheet in NACA Technical Note No. 840 indicates… more
Date: July 1943
Creator: Ramberg, Walter & Osgood, William R.
open access

Determination of General Relations for the Behavior of Turbulent Boundary Layers

Description: Report presenting an analysis of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. Results indicate that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter.
Date: July 1943
Creator: von Doenhoff, Albert E. & Tetervin, Neal
open access

Effect of Rivet Pitch Upon the Fatigue Strength of Single-Row Riveted Joints of 0.025- to 0.025-Inch 24S-T Alclad

Description: "S-N curves at the range ratio of 0.2 were experimentally obtained for each of the following values of rivet pitch P as used in a single-row lap joint of 0.025- to 0.025-inch 24S-T alclad with one-eight AN430 round-head rivets: p=0.5, 0.75, 1.0, 1.5. Families of constant rivet pitch curves, which define the fatigue life for specimens studied, were developed. Curves showing the variation of the effective stress concentration factor in fatigue with rivet pitch and maximum load per rivet were also… more
Date: July 1943
Creator: Seliger, Victor
open access

Effect of Turbulence on Air-Flow Measurements Behind Orifice Plates

Description: Report presenting determination of air-flow quantity in front of and behind three orifice plates to determine the errors introduced in the quantity measurements by the turbulence behind the orifice plates. For the orifice plates tested, the results showed that the measurements must be taken 40 to 60 hole diameters downstream from the plates to ensure accuracy.
Date: July 1943
Creator: Nielsen, Jack N.
open access

The effect of xylidines on the corrosiveness of aircraft-engine oil

Description: Report presenting testing to determine the effect of xylidines of the corrosiveness of aircraft-engine oil toward engine bearings as part of an investigation on the suitability of xylidines as an antiknock component in aviation gasoline. Results regarding the loss in bearing weight, corrosion losses, temperature characteristics, and types of corrosion are provided.
Date: July 1943
Creator: Meyrowitz, Emanuel & Olson, Walter T.
open access

Flight Measurements of Compressibility Effects on a Three-Blade Thin Clark Y Propeller Operating at Constant Advance-Diameter Ratio and Blade Angle

Description: Report presenting flight tests of a three-blade thin Clark Y propeller operating at a fixed blade angle of approximately 46.8 degrees at 0.75 radius, at an advance-diameter ratio of 2.37, and at true airplane speeds of approximately 300 and 450 miles per hour. Comparisons of the results at the two different speeds indicated losses in propeller efficiency from 11 to 18 percent at high speed. Report is incomplete.
Date: July 1943
Creator: Vogeley, A. W.
open access

Investigation for the Development of a High-Speed Antiaircraft Tow Target

Description: Report presenting an investigation for the purpose of developing a target which can be towed satisfactorily at high speeds. Testing included drag measurements and visual observations of the stability characteristics of several full-scale and scale models of sleeve-type tow targets. The drag coefficients obtained for the currently used targets were found to be excessively high.
Date: July 1943
Creator: Migotsky, Eugene
open access

Investigation of Methods of Reducing the Temperature Variation Among Cylinders on Air-Cooled Aircraft Engines

Description: Report presenting testing to determine methods for reducing the temperatures of the hot cylinders on air-cooled aircraft engines. A Pratt & Whitney R-1830-43, 14-cylinder engine used for the tests. Results regarding the cooling-air ducts, mixture-enriching tests, additional cooling area, baffle modifications, and an application of the information are provided.
Date: July 1943
Creator: Mueller, William A.
open access

Knocking Tendency of an Air-Cooled Aircraft-Engine Cylinder With One and With Two Spark Plugs

Description: Report presenting tests conducted with an air-cooled aircraft-engine cylinder to determine the effect on the knocking tendency of cutting out one spark plug when the engine is operating at or near the knock point with two spark plugs firing. The results indicate that cutting out one spark plug will not lead to knock but will actually stop or decrease knock that is occurring with both spark plugs firing.
Date: July 1943
Creator: Spencer, R. C. & Jones, A. W.
open access

Measurements of Friction Coefficients in a Pipe for Subsonic and Supersonic Flow of Air

Description: Report presenting tests of the flow of air through brass tubes with the friction coefficient and incompressible flow relation as the main focus. The analytical relation between friction coefficient, tube length, and Mach number is shown for flow without shock and the conditions for flow with and without shock are delimited.
Date: July 1943
Creator: Keenan, Joseph H. & Neumann, Ernest P.
open access

NACA Mach number indicator for use in high-speed tunnels

Description: Report presenting a description of a device for indicating stream Mach number in a high-speed tunnel. It consists of a mechanism for determining the pressure ratio that Mach number is a function of. The instrument is in service in the 8-foot high-speed tunnel and its accuracy has been found adequate for wind-tunnel requirements.
Date: July 1943
Creator: Smith, Norman F.
open access

NACA Procedure for Flight Tests of Aileron Characteristics of Airplanes

Description: Report describes the standard procedure that NACA used for evaluating the aileron characteristics of airplanes. The variables measured in the testing are rolling velocity, aileron positions, aileron stick forces or tangential wheel force, indicated airspeed, altitude, free-air temperature, and rudder position. The step-by-step flight procedure is described and information regarding evaluation of the control data and general suggestions is included.
Date: July 1943
Creator: Johnson, Harold I.
open access

Porpoising: A Comparison of Theory With Experiment

Description: Report presenting a direct comparison between the observed and the calculated longitudinal dynamic stability of a particular dynamic model of a flying boat moving on the water. Good agreement was obtained between experiment and theory for trim angles in the vicinity of lower limit, at one speed a little above the hump.
Date: July 1943
Creator: Davidson, Kenneth S. M.; Locke, F. W. S., Jr. & Suarez, Anthony
open access

Relation of Preignition and Knock to Allowable Engine Temperatures

Description: "The results are given of an investigation of some of the limitations that now prevent increases in the temperature level of engine cylinder heads, and a review of previous work in the field is included to supplement these results. Attention was given, in particular, to the effects of fuel knock and surface ignition on cylinder temperatures and the effects of cylinder temperatures on performance. Data were obtained from a Wright C9GC air-cooled cylinder and from a Lycoming O-1230 liquid-cooled … more
Date: July 1943
Creator: Biermann, Arnold E. & Corrington, Lester C.
open access

Round Heat-Treated Chromium-Molybdenum-Steel Tubing Under Combined Loads

Description: "The results of tests of round heat-treated chromium-molybdenum-steel tubing are presented. Tests were made on tubing under axial load, bending load, torsional load, combined bending and axial load, combined bending and torsional load, and combined axial, bending, and torsional load. Tensile and compressive tests were made to determine the properties of the material. Formulas are given for the evaluation of the maximum strength of this steel tubing under individual or combined loads" (p. 1).
Date: July 1943
Creator: Osgood, William R.
open access

Some Investigations of the General Instability of Stiffened Metal Cylinders 2: Preliminary Tests of Wire-Braced Specimens and Theoretical Studies

Description: "This is the second of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory… more
Date: July 1943
open access

Some Yawing Tests of a 1/30-Scale Model of the Hull of the XPB2M-1 Flying Boat

Description: Report discusses the results of yawing tests on a model of the complete hull of the XPB2M-1. The tests indicated that there was a tendency toward directional instability in the vicinity of the hump. The researchers concluded that at a certain range, the curves of yawing moment are discontinuous, and this has led to difficulty in preliminary test flights.
Date: July 1943
Creator: Locke, F. W. S., Jr.
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