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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Collection: National Advisory Committee for Aeronautics Collection
Tensile elastic properties of 18:8 chromium-nickel steel as affected by plastic deformation

Tensile elastic properties of 18:8 chromium-nickel steel as affected by plastic deformation

Date: January 1, 1939
Creator: Mcadam, D J & Mebs, R W
Description: The relationship between stress and strain, and between stress and permanent set, for 18:8 alloy as affected by prior plastic deformation is discussed. Hysteresis and creep and their effects on the stress-strain and stress-set curves are also considered, as well as the influence of duration of the rest interval after cold work and the influence of plastic deformation on proof stresses, on the modulus of elasticity at zero stress, and on the curvature of the stress-strain line. A constant (c sub 1) is suggested to represent the variation of the modulus of elasticity with stress.
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Tension fields in originally curved, thin sheets during shearing stresses

Tension fields in originally curved, thin sheets during shearing stresses

Date: August 1, 1935
Creator: Wagner, H & Ballerstedt, W
Description: The analysis of the stresses in the sheet and stiffeners is predicated upon the direction of the wrinkles, particularly the tensile stresses (principal stresses). This analysis and the calculation of stresses after buckling form the subject of the present article. It includes: 1) metal cylinders with closely spaced longitudinal stiffeners; 2) metal cylinders with closely spaced transverse rings.
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Test of an adjustable pitch model propeller at four blade settings

Test of an adjustable pitch model propeller at four blade settings

Date: February 1, 1930
Creator: Lesley, E P
Description: This note describes tests of an adjustable blade metal model propeller, both in a free wind stream and in combination with a model fuselage, at four settings of the blades. The model propeller is designed for a uniform nominal pitch/diameter ratio of .7 and the blade settings used correspond to nominal pitch/diameter ratios of .5, .7, .9, and 1.1 at the .6 radius. The tests show that propellers of this type may be considerably changed in setting from the designed pitch angles and yet give excellent performance. The efficiency realized and power absorbed when blades are set at other than the designed angle, are little different than would be obtained from a propeller with uniform pitch equal to the mean pitch of the propeller under test.
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The testing of airplane fabrics

The testing of airplane fabrics

Date: November 1, 1932
Creator: Schraivogel, Karl
Description: This report considers the determining factors in the choice of airplane fabrics, describes the customary methods of testing and reports some of the experimental results. To sum up briefly the results obtained with the different fabrics, it may be said that increasing the strength of covering fabrics by using coarser yarns ordinarily offers no difficulty, because the weight increment from doping is relatively smaller.
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Tests for the determination of the stress condition in tension fields

Tests for the determination of the stress condition in tension fields

Date: November 1, 1936
Creator: Lahde, R & Wagner, H
Description: The present experiments treat the stress of actual tension fields within the elastic range. They give the magnitude of the flexural stresses due to wrinkling. They also disclose, particularly by slightly exceeded buckling load, the marked unloading - as compared with the tension-field theory - of the uprights as a result of the flexural stiffness of the web plate. The test sheets were clamped at the edges and brought to buckling through shearing and compressive stresses applied in the direction of the long sides.
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Tests for the elimination of tail flutter

Tests for the elimination of tail flutter

Date: June 1, 1933
Creator: Biechteler, Curt
Description: On various low-wing monoplanes the horizontal tail surfaces flutter in flight at large angles of attack and occasionally in curvilinear flight. This flutter leads to torsional vibrations of the rear end of the fuselage, as manifested by vibrations of the control stick. According to the earlier DVL investigations tail flutter is due to the influence, on horizontal tail surfaces, of eddies or vortices shed at large angles of attack by the upper surface of the wing root. The cause of tail flutter on a low-wing monoplane and the means of preventing it are investigated in the present report.
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Tests in the gust tunnel of a model of the XBM-1 airplane

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

Date: October 1, 1939
Creator: Donely, Philip & Shufflebarger, C C
Description: None
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Tests in the Variable-Density Tunnel of Seven Tapered Wings Having N.A.C.A. 230 Mean Lines, Special Report

Tests in the Variable-Density Tunnel of Seven Tapered Wings Having N.A.C.A. 230 Mean Lines, Special Report

Date: August 1, 1937
Creator: Anderson, Raymond F.
Description: At the request of the Materiel Division of the Army Air Corps, seven tapered wings having sections based on the N.A,C.A. 230 mean line were tested in the variable-density wind tunnel, The characteristics of the wings are given.
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Tests in the variable-density wind tunnel of related airfoils having the maximum camber unusually far forward

Tests in the variable-density wind tunnel of related airfoils having the maximum camber unusually far forward

Date: January 1, 1936
Creator: Jacobs, Eastman N & Pinkerton, Robert M
Description: A family of related airfoils having the position of maximum camber unusually far forward was investigated in the variable-density tunnel as an extension of the study recently completed of a large number of related airfoils. The new airfoils gave improved characteristics over those previously investigated, especially in regard to the pitching moment. Some of the new sections are markedly superior to well-known and commonly used sections and should replace them in applications requiring a slightly cambered section of moderate thickness having a small pitching-moment coefficient.
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Tests in the variable-density wind tunnel of the NACA 23012 airfoil with plain and split flaps

Tests in the variable-density wind tunnel of the NACA 23012 airfoil with plain and split flaps

Date: January 1, 1939
Creator: Abbott, Ira H & Greenberg, Harry
Description: Section characteristics for use in wing design are presented for the NACA 23012 airfoil with plain and split flaps of 20 percent wing chord at a value of the effective Reynolds number of about 8,000,000. The flap deflections covered a range from 60 degrees upward to 75 degrees downward for the plain flap and from neutral to 90 degrees downward for the split flap. The split flap was aerodynamically superior to the plain flap in producing high maximum lift coefficients and in having lower profile-drag coefficients at high lift coefficients.
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Tests in the Variable Density Wind Tunnel to Investigate the Effects of Scale and Turbulence on Airfoil Characteristics

Tests in the Variable Density Wind Tunnel to Investigate the Effects of Scale and Turbulence on Airfoil Characteristics

Date: February 1, 1931
Creator: Stack, John
Description: The effect of scale and turbulence on the lift and drag of five airfoils the NACA 0006, the NACA 0021, the Clark Y and the USA 35-A, and the USN PS6, have been investigated in the Variable Density Wind Tunnel of the NACA. Tests were made over a wide scale range for only two different conditions of turbulence.
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Tests of 16 related airfoils at high speed

Tests of 16 related airfoils at high speed

Date: January 1, 1935
Creator: Stack, John & Von Doenhoff, Albert E
Description: In order to provide information that might lead to the development of better propeller section, 13 related symmetrical airfoils were tested in the NACA high-speed wind tunnel for a study of the effect of thickness form on the aerodynamic characteristics. The thickness-form variables studies were the value of the maximum thickness, the position along the chord at which the maximum thickness occurs, and the value of the leading-edge radius. The tests were conducted through the low angle-of-attack range for speeds extending from 35 percent of that of sound to slightly in excess of the speed at which a compressibility burble, or breakdown of flow, occurs. The corresponding Reynolds number range is 350,000 to 750,000.
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Tests of a contra-propeller for aircraft

Tests of a contra-propeller for aircraft

Date: November 1, 1938
Creator: Benson, William M
Description: Tests of an 8-blade contra-propeller of 32-inch diameter in combination with a 4-inch, 36-inch diameter adjustable pitch, metal propeller at pitch setting of 15, 25, 35, and 45 degrees at 0.75 R were made. The tests showed a significant increase in effective thrust of the combination over that of the propeller alone for value V/nD somewhat below those for maximum efficiency and without a corresponding increase of power absorbed. From 1/2 percent to 2-1/2 percent in propulsive efficiency was thus gained in this range. In all but one case, however, the peak propulsive efficiency of the combination was found to be from 1 to 2 percent less than that of the propeller alone. Counter torque on the contra-propeller amounted to about 50 percent of the propeller torque.
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Tests of a wing-nacelle-propeller combination at several pitch settings up to 42 degrees

Tests of a wing-nacelle-propeller combination at several pitch settings up to 42 degrees

Date: January 1, 1937
Creator: Windler, Ray
Description: This report presents the results of tests of a 4-foot model of Navy propeller No. 4412 in conjunction with an NACA cowled nacelle mounted ahead of a thick wing in the 20-foot propeller-research tunnel. A range of propeller pitches from 17 degrees to 42 degrees at 0.75r was covered, and for this propeller the efficiency reached a maximum at a pitch setting of 27 degrees; at high pitches the efficiencies were slightly lower. The corrected propulsive efficiency is shown to be independent of the angle of attack for the high-speed and the climbing ranges of flight. A working chart is presented for the selection of similar propellers over a wide range of airplane speed, engine power, and propeller revolution.
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Tests of Airfoils Designed to Delay the Compressibility Burble

Tests of Airfoils Designed to Delay the Compressibility Burble

Date: June 1, 1939
Creator: Stack, John
Description: Development of airfoil sections suitable for high-speed applications has generally been difficult because little was known of the flow phenomenon that occurs at high speeds. A definite critical speed has been found at which serious detrimental flow changes occur that lead to serious losses in lift and large increases in drag. This flow phenomenon, called the compressibility burble, was originally a propeller problem, but with the development of higher speed aircraft serious consideration must be given to other parts of the airplane. Fundamental investigations of high-speed airflow phenomenon have provided new information. An important conclusion of this work has been the determination of the critical speed, that is, the speed at which the compressibility burble occurs. The critical speed was shown to be the translational velocity at which the sum of the translational velocity and the maximum local induced velocity at the surface of the airfoil or other body equals the local speed of sound. Obviously then higher critical speeds can be attained through the development of airfoils that have minimum induced velocity for any given value of the lift coefficient. Presumably, the highest critical speed will be attained by an airfoil that has uniform chordwise distribution of induced velocity ...
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Tests of an N.A.C.A. 23012 Airfoil with a slotted deflector flap

Tests of an N.A.C.A. 23012 Airfoil with a slotted deflector flap

Date: April 1, 1939
Creator: House, R O
Description: Section aerodynamic characteristics of a large-chord N.A.C.A. 23012 airfoil with a slotted deflector flap were obtained in the N.A.C.A. 7- by 10-foot wind tunnel. The characteristics of an N.A.C.A. slotted flap and of a simple split flap are included for comparison. The slotted deflector flap was found to have a somewhat lower maximum lift coefficient and somewhat higher drag at high lift coefficients than the N.A.C.A. slotted flap. The high drag of the open slot with the deflector flap neutral indicates that the slot should be closed for this condition.
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Tests of five full-scale propellers in the presence of a radial and a liquid-cooled engine nacelle, including tests of two spinners

Tests of five full-scale propellers in the presence of a radial and a liquid-cooled engine nacelle, including tests of two spinners

Date: January 1, 1938
Creator: Biermann, David & Hartman, Edwin P
Description: Wind-tunnel tests are reported of five 3-blade 10-foot propellers operating in front of a radial and a liquid-cooled engine nacelle. The range of blade angles investigated extended from 15 degrees to 45 degrees. Two spinners were tested in conjunction with the liquid-cooled engine nacelle. Comparisons are made between propellers having different blade-shank shapes, blades of different thickness, and different airfoil sections. The results show that propellers operating in front of the liquid-cooled engine nacelle had higher take-off efficiencies than when operating in front of the radial engine nacelle; the peak efficiency was higher only when spinners were employed. One spinner increased the propulsive efficiency of the liquid-cooled unit 6 percent for the highest blade-angle setting investigated and less for lower blade angles. The propeller having airfoil sections extending into the hub was superior to one having round blade shanks. The thick propeller having a Clark y section had a higher take-off efficiency than the thinner one, but its maximum efficiency was possibly lower. Of the three blade sections tested, Clark y, R.A.F. 6, and NACA 2400-34, the Clark y was superior for the high-speed condition, but the R.A.F. 6 excelled for the take-off condition.
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Tests of five metal model propellers with various pitch distributions in a free wind stream and in combination with model VE-7 fuselage

Tests of five metal model propellers with various pitch distributions in a free wind stream and in combination with model VE-7 fuselage

Date: January 1, 1930
Creator: Lesley, E P & Reid, Elliott G
Description: This report describes the tests of five adjustable blade metal model propellers both in a free wind stream and in combination with a model fuselage with stub wings. The propellers are of the same form and cross section but have variations in radial distributions of pitch. By making a survey of the radial distribution of air velocity through the propeller plane of the model fuselage it was found that this velocity varies from zero at the hub center to approximately free stream velocity at the blade tip. The tests show that the efficiency of a propeller when operating in the presence of the airplane is, over the working range, generally less than when operating in a free wind stream, but that a propeller with a radial distribution of pitch of the same nature as the radial distribution of air velocity through the propeller plane suffers the smallest loss in efficiency.
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Tests of large airfoils in the propeller research tunnel, including two with corrugated surfaces

Tests of large airfoils in the propeller research tunnel, including two with corrugated surfaces

Date: January 1, 1930
Creator: Wood, Donald H
Description: This report gives the results of the tests of seven 2 by 12 foot airfoils (Clark Y, smooth and corrugated, Gottingen 398, N.A.C.A. M-6, and N.A.C.A. 84). The tests were made in the propeller research tunnel of the National Advisory Committee for Aeronautics at Reynolds numbers up to 2,000,000. The Clark Y airfoil was tested with three degrees of surface smoothness. Corrugating the surface causes a flattening of the lift curve at the burble point and an increase in drag at small flying angles.
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Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 24

Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 24

Date: January 1, 1932
Creator: Jacobs, Eastman N & WARD KENNETH E
Description: This note is the fifth of a series covering an investigation of a number of related airfoils. It presents the results obtained from tests of a group of six low-cambered airfoils in the variable-density wind tunnel. The mean camber lines are identical for the six airfoils and are of such a form that the maximum mean camber is 2 per cent of the chord and is at a position 0.4 of the chord behind the loading edge. The airfoils differ in thickness only, the maximum-thickness/chord ratios being 0.06, 0.09, 0.12, 0.15, 0.18, and 0.21. The results have been presented in the form of both infinite and finite aspect-ratio characteristics. The values of C(sub L) max/C(sub d) degrees min for this group of airfoils are among the highest thus far obtained, the minimum profile drags being approximately equal to those for the symmetrical series of corresponding thickness, while the maximum lift coefficients are considerably higher.
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Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 43 and 63

Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 43 and 63

Date: September 1, 1931
Creator: Jacobs, Eastman N & Pinkerton, Robert M
Description: This note is one of a series covering an investigation of a family of related airfoils. It gives in preliminary form the results obtained from tests in the N.A.C.A. Variable-Density Wind Tunnel of two groups of six airfoils each. One group, the 43 series, has a maximum mean camber of 4 per cent of the chord at a position 0.3 of the chord from the leading edge; the other group, the 63 series, has a maximum mean camber of 6 per cent of the chord at the same position. The members within each group differ only in maximum thickness, the maximum thickness/chord ratios being:0.06, 0.09, 0.12, 0.15, 0.18, and 0.21. The results are analyzed with a view to indicating the variation of the aerodynamic characteristics with profile thickness for airfoils having a certain mean camber line.
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Tests of N.A.C.A. airfoils in the variable density wind tunnel Series 44 and 64

Tests of N.A.C.A. airfoils in the variable density wind tunnel Series 44 and 64

Date: December 1, 1931
Creator: Jacobs, Eastman N & Pinkerton, Robert M
Description: This note is one of a series covering an investigation of a number of related airfoils. It presents the results obtained from tests in the N.A.C.A. Variable Density Wind Tunnel of two groups of six airfoils each. One group, the 44 series, has a maximum mean camber of 4 percent of the chord at a position 0.4 of the chord behind the leading edge and the other group, the 64 series, has a maximum mean camber of 6 percent of the chord at the same position. The members within each group differ only in maximum thickness, the maximum thickness/chord ratios being: 0.06, 0.09, 0.12, 0.15, 0.18, and 0.21. The results are analyzed with a view to indicating the variation of the aerodynamic characteristics with profile thickness for airfoils having a certain mean camber line form.
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Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 45 and 65

Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 45 and 65

Date: September 1, 1931
Creator: Jacobs, Eastman N & Pinkerton, Robert M
Description: This note is one of a series covering an investigation of a number of related airfoils. It presents the results obtained from tests in N.A.C.A. Variable-Density Wind Tunnel of two groups of six airfoils each. One group, the 45 series, has a maximum mean camber of 4 per cent of the chord at a position 0.5 of the chord behind the leading edge, and the other group, the 65 series, has a maximum mean camber of 6 per cent of the chord at the same position. The members within each group differ only in maximum thickness, the maximum thickness/chord ratios being: 0.06, 0.09, 0.12, 0.15, 0.18, and 0.21. The results are analyzed with a view to indicating the variation of the aerodynamic characteristics with profile thickness for airfoils having a certain mean camber line form.
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Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 230.

Tests of N.A.C.A. airfoils in the variable-density wind tunnel Series 230.

Date: May 1, 1936
Creator: Jacobs, Eastman N & Pinkerton, Robert M
Description: The results of tests of six airfoils having the N.A.C.A. 230 mean line and varying in thickness from 0.06c to 0.21c are presented. These results agree with previous findings in showing that aerodynamically the best section is one of moderate thickness. The data are of value mainly in connection with the design of tapered wings having sections based on the N.A.C.A. 230 mean line.
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