UNT Libraries Government Documents Department - 417 Matching Results

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Local instability of columns with I-, Z-, channel, and rectangular-tube sections

Description: From Summary: "Charts are presented for the coefficients in the formulas for the critical compressive stress at which cross-sectional distortion begins in thin-wall columns of I-, Z-, channel, and rectangular-tube sections. The energy method of Timoshenko was used in the theoretical calculations required for the construction of the charts. The deflection equations were carefully selected to give good accuracy. The calculation of the critical compressive stress at stresses above the elastic rang… more
Date: December 1939
Creator: Stowell, Elbridge Z. & Lundquist, Eugene E.
open access

Observations in Flight of the Region of Stalled Flow Over the Blades of an Autogiro Rotor

Description: "The flow over the inner halves of the rotor blades on a Kellet YG-1B autogiro was investigated in flight by making camera records of the motion of silk streamers attached to the upper surfaces of the blades. These records were analyzed to determine the boundaries of the region within which the flow over the blade sections was stalled for various tip-speed ratios. For the sake of comparison, corresponding theoretical boundaries were obtained. Both the size of the stalled area and its rate of gr… more
Date: December 1939
Creator: Bailey, F. J., Jr. & Gustafson, F. B.
open access

Pressure-Distribution Measurements on a Rectangular Wing With a Partial-Span Split Flap in Curved Flight

Description: "Pressure-distribution tests were made on the 32-foot whirling arm of the Daniel Guggenheim Airship Institute of a rectangular wing of NACA 23012 section to determine the rolling and the yawing moment due to angular velocity in yaw. The model was tested at 0 and 5 degree pitch; 0, +/- 5, and +/- 10 degrees yaw; and with no flap and with split flaps 25, 50 and 75 percent of the wing span and deflected 60 degrees. The results are given in the form of span load distributions and as calculated mome… more
Date: December 1939
Creator: Rokus, Frank G.
open access

A Recurrence Formula for Shear-Lag Problems

Description: "The analysis of the bending action in box beams with appreciable shear deformation of the flanges becomes very difficult in the general case of variable cross section and loading. This paper presents a convenient method of solving the problem by the familiar method of dividing the beam into a number of bays that can be assumed to have constant cross section and loading. Application of formerly derived shear-lag formulas leads to a general equation closely analogous in form to the well-known th… more
Date: December 1939
Creator: Kuhn, Paul
open access

Stress concentration around an open circular hole in a plate subjected to bending normal to the plane of the plate

Description: "An aluminum-alloy plate containing an open circular hole of diameter large compared with the thickness of the plate was subjected to bending forces normal to the plane of the plate. Deflection and strain measurements were taken for two different loads. Stress concentrations occurred at the edge of the hole and the maximum stresses were tangential to the hole at the ends of the transverse diameter. The maximum stress at the edge of the hole was 1.59 times the computed stress on the net section … more
Date: December 1939
Creator: Dumont, C.
open access

Corrugated Metal Diaphragms for Aircraft Pressure-Measuring Instruments

Description: Note presenting a description of a large number of corrugated diaphragms of beryllium copper, phosphor bronze, and Z-nickel with geometrically similar outlines but various diameters and thicknesses were formed by hydraulic pressing. The apparatus and technique used in the manufacture, testing, and heat treatment are described. Results regarding pressure-deflection curves, load limit, effect of center reinforcing, snap-action diaphragms, deflection traverse, thickness variations, and concentrate… more
Date: November 1939
Creator: Wildhack, W. A. & Goerke, V. H.
open access

Photoelastic Analysis of Three-Dimensional Stress Systems Using Scattered Light

Description: "A method has been developed for making photoelastic analyses of three-dimensional stress systems by utilizing the polarization phenomena associated with the scattering of light. By this method, the maximum shear and the directions of the three principal stresses at any point within a model can be determined, and the two principal stresses at a free-bounding surface can be separately evaluated. Polarized light is projected into the model through a slit so that it illuminates a plane section" (p… more
Date: November 1939
Creator: Weller, R. & Bussey, J. K.
open access

Pressure-Distribution Investigation of an N.A.C.A. 0009 Airfoil With a 50-Percent-Chord Plain Flap and Three Tabs

Description: "Pressure-distribution tests of an N.A.C.A. 0009 airfoil with a 50-percent-chord plain flap and three plain tabs, having chords 10, 20, and 30 percent of the flap chord, were made in the N.A.C.A. 4- by 6- foot vertical tunnel. The tests supplied aerodynamic section data that may be applied to the design of horizontal and vertical tail surfaces. The results are presented as resultant-pressure diagrams for the airfoil with the flap and the 20-percent-chord tab" (p. 1).
Date: November 1939
Creator: Street, William G. & Ames, Milton B., Jr.
open access

Pressure-Distribution Measurements on a Tapered Wing With a Partial-Span Split Flap in Curved Flight

Description: "Pressure-distribution tests were made on the 32-foot whirling arm of the Daniel Guggenheim Airship Institute of a tapered wing to determine the rolling and the yawing moments due to an angular velocity in yaw. The model was tested at 0 degree and 5 degree pitch; 0 degree, 5 degree, and 10 degree yaw; and with split flaps covering 25, 50, 75, and 100 percent of the wing span and deflected 60 degrees. The results are given in the form of load distributions and as calculated moment coefficients" … more
Date: November 1939
Creator: Troller, T. & Rokus, F.
open access

Tidewater and Weather-Exposure Tests on Metals Used in Aircraft

Description: "Tidewater and weather-exposure tests on various aluminum alloys, magnesium alloys, and stainless steels are now being conducted by the National Bureau of Standards. Exposures were begun in June 1938 and, according to present plans, are to continue over a 3-year period. The methods of exposure and the materials being investigated are described and the more important results obtained up to the conclusion of the first year's exposure are reported" (p. 1).
Date: November 1939
Creator: Mutchler, Willard & Galvin, W. G.
open access

Experimental Study of Torsional Column Failure

Description: "Thirty-three 24ST aluminum-alloy 2- by 2- by 0.10-inch channels, with lengths ranging from 10 to 90 inches were tested at Stanford University in compression to obtain an experimental verification of the theoretical formulas for torsional failure developed by Eugene E. Lundquist of the N.A.C.A. The observed critical loads and twist-axis locations were sufficiently close to the values obtained from the formulas to establish the substantial validity of the latter. The differences between observed… more
Date: October 1939
Creator: Niles, Alfred S.
open access

Tests in the gust tunnel of a model of the XBM-1 airplane

Description: Report presenting testing of a dynamically scaled model of a Navy XBM-1 biplane in the gust tunnel to provide data for use in determining the structure of atmospheric gusts from measurements of the motions of the full-scale airplane in rough air. Records for two flights for several gradients were evaluated to give histories of events during passage through the gust.
Date: October 1939
Creator: Donely, Philip & Shufflebarger, C. C.
open access

Combined Beam-Column Stresses of Aluminum-Alloy Channel Sections

Description: The results of a research program to obtain design data on the strength of open-channel aluminum-alloy sections subjected to combined column and beam action. The results of the tests of about 70 specimens were graphed for stresses due to axial load and stresses due to bending loading as functions of length to radius of gyration of the specimens. From these graphs a design chart was derived that is suitable for ready use.
Date: September 1939
Creator: Gottlieb, R.; Thompson, T. M. & Witt, E. C.
open access

A flight investigation of the distribution of ice-inhibiting fluids on a propeller blade

Description: Report presenting an investigation of the flow of ice-inhibiting fluids over the blade surfaces of a 12.5-foot-daimeter propeller in flight by discharging dyed fluids at various stations along the leading edges of the blades. The effects on the distribution of varying the fluid composition, the blade-surface roughness, and the orifice design were also observed.
Date: September 1939
Creator: Rodert, Lewis A.
open access

Wind-Tunnel Investigation of an N.A.C.A. 23021 Airfoil With Two Arrangements of a 40-Percent-Chord Slotted Flap

Description: Note presenting an investigation in the 7- by 10-foot wind tunnel of an NACA 23021 airfoil with two arrangements of a 40-percent-chord slotted flap. The effect of slot shape, flap position, and flap deflection on the section aerodynamic characteristics was determined. Results regarding coefficients, precision, plain airfoils, and slotted-flap arrangements are provided.
Date: September 1939
Creator: Duschik, Frank
open access

Wind-Tunnel Investigation of Effect of Yawing on Lateral-Stability Characteristics 2: Rectangular N.A.C.A. 23012 Wing with a Circular Fuselage and a Fin

Description: Note presenting testing of an N.A.C.A. 23012 rectangular wing with rounded tips in combination with a fuselage of circular cross section at several angles of yaw in the NACA 7- by 10-foot wind tunnel. The model was tested as a high-wing, a midwing, and a low-wing monoplane; for each wing location, tests were made with two amounts of dihedral and with partial-span split flaps. Results regarding the wing and fuselage, fin and fuselage, and wing, fuselage, and fin are provided.
Date: September 1939
Creator: Bamber, M. J. & House, R. O.
open access

Adhesion of Ice in Its Relation to the De-Icing of Airplanes

Description: 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 l… more
Date: August 1939
Creator: Rothrick, A. M. & Selden, R. F.
open access

Compression-ignition engine performance with undoped and doped fuel oils and alcohol mixtures

Description: From Summary: "Several fuel oils, doped fuel oils, and mixtures of alcohol and fuel oil were tested in a high-speed, single-cylinder, compression-ignition engine to determine power output, fuel consumption, and ignition and combustion characteristics. Fuel oils or doped fuel oils of high octane number had shorter ignition lags, lower rates of pressure rise, and gave smoother engine operation than fuel oils or doped fuel oils of low octane number."
Date: August 1939
Creator: Moore, Charles S. & Foster, Hampton H.
open access

Compressive Tests of a Monocoque Box

Description: "A monocoque box specimen of aluminum alloy was subjected to end compression and the strains in the stringers were measured up to loads at which permanent set became noticeable. The stringer strains at low loads agreed closely with those computed from the assumption of uniform stress distribution. Buckling of the 0.026-inch sheet between stringers and of the 0.075-inch shear web took place at stresses in accord with theoretical values" (p. 1).
Date: August 1939
Creator: Ramberg, Walter; McPherson, Albert E. & Levy, Sam
open access

The Effects of Surface Waviness and of Rib Stitching on Wing Drag

Description: "Surface waviness and rib stitching have been investigated as part of a series of tests to determine the effects on wing drag of common surface irregularities. The tests were made in the N.A.C.A. 8-foot high-speed wind tunnel at Reynolds Numbers up to 17,000,000. The results of the tests showed that the waviness common to airplane wings will cause no serious increase in drag unless the waviness exists on the forward part of the wing, where it may cause premature transition or premature compress… more
Date: August 1939
Creator: Hood, Manley J.
open access

Flight Tests of N.A.C.A. Nose-Slot Cowlings on the BFC-1 Airplane

Description: "The results of flight tests of four nose-slot cowling designs with several variations in each design are presented. The tests were made in the process of developing the nose-slot cowling. The results demonstrate that a nose-slot cowling may be successfully applied to an airplane and that it utilizes the increased slipstream velocity of low-speed operation to produce increased cooling pressure across the engine" (p. 1).
Date: August 1939
Creator: Stickle, George W.
open access

Local Instability of Centrally Loaded Columns of Channel Section and Z-Section

Description: "Charts are presented for the coefficients in formulas for the critical compressive stress at which cross-sectional distortion begins in a thin-wall member with either a channel section or a Z-section with identical flanges. The energy method of Timoshenko was used in the theoretical calculations required for the construction of the charts. The deflection equations were carefully selected to give good accuracy. The calculation of the critical compressive stress at stresses beyond the elastic ra… more
Date: August 1939
Creator: Lundquist, Eugene E.
open access

Tank Tests to Determine the Effects of the Chine Flare of a Flying-Boat Hull N.A.C.A. Model Series 62 and 69

Description: Note presenting testing of twenty-two models of flying-boat hulls for the purpose of determining the effects on water resistance and spray of 13 variations in the transverse section of the bottom of the forebody and of three variations in the form of the afterbody. Generally, the effect of chine flare on the resistance was small, although the resistance of force with chine flare was generally less than the resistance of the form without chine flare.
Date: August 1939
Creator: Bell, Joe W. & Olson, Roland E.
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