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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Year: 1938
 Collection: Technical Report Archive and Image Library
N.A.C.A. Stall-Warning Device

N.A.C.A. Stall-Warning Device

Date: February 1938
Creator: Thompson, F.L.
Description: With some airplanes the approach to the stall is accompanied by changes in the behavior, such as tail buffeting or changes in the control characteristics of the airplane so that the pilot obtains a warning of the impending stall. Vith other airplanes it is possible to approach the stall without any perceptible warning other than the reading of the air-speed meter, in which case the danger of inadvertent stalling is considerably greater. Although it is not within the scope of this paper to discuss stalling characteristics, it is desired to point out that in general the danger of inadvertent stalling is greatest with those airplanes that behave worse when the stalling occurs; that is, with airplanes in which the stall starts at the wing tips. A warning of the impending stall is desirable in any case, but is particularly desirable with airplanes of the latter type.
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Aerodynamic characteristics of a 4-engine monoplane showing effects of enclosing the engines in the wing and comparisons of tractor- and pusher-propeller arrangements

Aerodynamic characteristics of a 4-engine monoplane showing effects of enclosing the engines in the wing and comparisons of tractor- and pusher-propeller arrangements

Date: April 1, 1938
Creator: Wilson, Herbert A , Jr
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Aerodynamic characteristics of a large number of airfoils tested in the variable-density wind tunnel

Aerodynamic characteristics of a large number of airfoils tested in the variable-density wind tunnel

Date: January 1, 1938
Creator: Pinkerton, Robert M & Greenberg, Harry
Description: The aerodynamic characteristics of a large number of miscellaneous airfoils tested in the variable-density tunnel have been reduced to a comparable form and are published in this report for convenient reference. Plots of the standard characteristics are given in tabular form. Included is a tabulation of important characteristics for the related airfoils reported in NACA report 460. This report, in conjunction with NACA report 610, makes available in comparable and convenient form the aerodynamic data for airfoils tested in the variable-density tunnel since January 1, 1931.
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The aerodynamic characteristics of four full-scale propellers having different plan forms

The aerodynamic characteristics of four full-scale propellers having different plan forms

Date: January 1, 1938
Creator: Hartman, Edwin P & Biermann, David
Description: Tests were made of four propellers, with diameters of 10 feet, having different blade plan forms. One propeller (Navy design no. 5868-r6) was of the usual present-day type and was used as a basis of comparison for the other three, which had unusual plan forms distinguished by the inward (toward the hub) location of the sections having the greatest blade width. It was found that propellers with points of maximum blade width occurring closer to the hub than on the present-day type of blade had higher peak efficiencies but lower take-off efficiencies. This results was found true for a "clean" liquid-cooled engine installation. It appears that some modification could be made to present plan forms which would produce propellers having more satisfactory aerodynamic qualities. The propellers with the inward location of the points of maximum blade width had lower thrust and power coefficients and stalled earlier than the present-day type.
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The aerodynamic characteristics of full-scale propellers having 2, 3, and 4 blades of Clark y and R.A.F. 6 airfoil sections

The aerodynamic characteristics of full-scale propellers having 2, 3, and 4 blades of Clark y and R.A.F. 6 airfoil sections

Date: January 1, 1938
Creator: Hartman, Edwin P & Biermann, David
Description: Aerodynamic tests were made of seven full-scale 10-foot-diameter propellers of recent design comprising three groups. The first group was composed of three propellers having Clark y airfoil sections and the second group was composed of three propellers having R.A.F. 6 airfoil sections, the propellers of each group having 2, 3, and 4 blades. The third group was composed of two propellers, the 2-blade propeller taken from the second group and another propeller having the same airfoil section and number of blades but with the width and thickness 50 percent greater. The tests of these propellers reveal the effect of changes in solidity resulting either from increasing the number of blades or from increasing the blade width propeller design charts and methods of computing propeller thrust are included.
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The aerodynamic drag of five models of side floats N.A.C.A. Models 51-E, 51-F, 51-G, 51-H, 51-J

The aerodynamic drag of five models of side floats N.A.C.A. Models 51-E, 51-F, 51-G, 51-H, 51-J

Date: December 1, 1938
Creator: House, R O
Description: The drag of five models of side floats was measured in the N.A.C.A. 7- by 10-foot wind tunnel. The most promising method of reducing the drag of floats indicated by these tests is lowering the angle at which the floats are rigged. The addition of a step to a float does not always increase the drag in the flying range, floats with steps sometimes having lower drag than similar floats without steps. Making the bow chine no higher than necessary might result in a reduction in air drag because of the lower angle of pitch of the chines. Since side floats are used formally to obtain lateral stability when the seaplane is operating on the water at slow speeds or at rest, greater consideration can be given to factors affecting aerodynamic drag than is possible for other types of floats and hulls.
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Airfoil section characteristics as applied to the prediction of air forces and their distribution on wings

Airfoil section characteristics as applied to the prediction of air forces and their distribution on wings

Date: January 1, 1938
Creator: Jacobs, Eastman N & Rhode, R V
Description: The results of previous reports dealing with airfoil section characteristics and span load distribution data are coordinated into a method for determining the air forces and their distribution on airplane wings. Formulas are given from which the resultant force distribution may be combined to find the wing aerodynamic center and pitching moment. The force distribution may also be resolved to determine the distribution of chord and beam components. The forces are resolved in such a manner that it is unnecessary to take the induced drag into account. An illustration of the method is given for a monoplane and a biplane for the conditions of steady flight and a sharp-edge gust. The force determination is completed by outlining a procedure for finding the distribution of load along the chord of airfoil sections.
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Application and testing of transparent plastics used in airplane construction

Application and testing of transparent plastics used in airplane construction

Date: November 1, 1938
Creator: Riechers, K & Olms, J
Description: This report concerns the efforts being made to remove the source of danger to passengers arising from the fracturing of silicate glass. Some of the alternatives presented include: single-layer safety glass, multi-layer safety glass, transparent plastic resins. Some of the resins considered are celluloid, cellulose acetates, and mixtures of polymers.
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Approximate stress analysis of multistringer beams with shear deformation of the flanges

Approximate stress analysis of multistringer beams with shear deformation of the flanges

Date: January 1, 1938
Creator: Kuhn, Paul
Description: The problem of the skin-stringer combinations used as axially loaded panels or as covers for box beams is considered from the point of view of the practical stress analyst. By a simple substitution the problem is reduced to the problem of the single-stringer structure, which has been treated in NACA Report no. 608. The method of making this substitution is essentially empirical; in order to justify it, comparisons are shown between calculations and strain-gage tests of three beams tested by the author and of one compression panel and three beams tested and reported elsewhere.
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Auto-ignition and combustion of diesel fuel in a constant-volume bomb

Auto-ignition and combustion of diesel fuel in a constant-volume bomb

Date: January 1, 1938
Creator: Selden, Robert F
Description: Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag could not be greatly decreased by exceeding the compression-ignition engines. In order to obtain the best combustion and thermal efficiency, it was desirable to use the longest ignition lag consistent with a permissible rate of pressure rise.
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Behavior of a plate strip under shear and compressive stresses beyond the buckling limit

Behavior of a plate strip under shear and compressive stresses beyond the buckling limit

Date: July 1, 1938
Creator: Kromm, A & Marguerre, K
Description: The present report is an extension of previous theoretical investigations on the elastic behavior of a plate under compression and shear in the region above the critical. The main object is the clarification of the behavior immediately above the buckling limit since no theoretical expressions for this range have thus far been found and since experimentally, too, any degree of regularity in the behavior of the plate in the range between the critical load and about three to four times the critical, is discernible only with difficulty.
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Behavior of static pressure heads at high speeds

Behavior of static pressure heads at high speeds

Date: June 1, 1938
Creator: Danielzig, Helmut
Description: These tests proved the practicability of static pressure heads at speeds up to 400 km/h (248.5 mph). It weighs 6.5 kg or 2.5 times as much as the old head. The position of the pressure head below the airplane was determined by bearing method at different speeds and for different lengths of suspension. It was established that for the measured speed range a 20 to 24 meter suspension length was sufficient to assure a minimum distance of 6 meters from the airplane without introducing any appreciable errors in the results due to wrong static pressure.
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The buckling of curved tension-field girders

The buckling of curved tension-field girders

Date: January 1, 1938
Creator: Limpert, G
Description: The present paper reports on experiments made to determine the buckling load under shear of circular curved tension-field webs. The buckling load of the webs may be expressed with reference to the buckling load of the stiffeners. It is found that within the explored range the buckling load is approximately twice as great as that of the identically stiffened flat wall of equal web depth.
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Calculation of load distribution in stiffened cylindrical shells

Calculation of load distribution in stiffened cylindrical shells

Date: June 1, 1938
Creator: Ebner, H & Koller, H
Description: Thin-walled shells with strong longitudinal and transverse stiffening (for example, stressed-skin fuselages and wings) may, under certain simplifying assumptions, be treated as static systems with finite redundancies. In this report the underlying basis for this method of treatment of the problem is presented and a computation procedure for stiffened cylindrical shells with curved sheet panels indicated. A detailed discussion of the force distribution due to applied concentrated forces is given, and the discussion illustrated by numerical examples which refer to an experimentally determined circular cylindrical shell.
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Calculation of the chordwise load distribution over airfoil sections with plain, split, or serially hinged trailing-edge flaps

Calculation of the chordwise load distribution over airfoil sections with plain, split, or serially hinged trailing-edge flaps

Date: January 1, 1938
Creator: Allen, H Julian
Description: A method is presented for the rapid calculation of the incremental chordwise normal-force distribution over an airfoil section due to the deflection of a plain flap or tab, a split flap, or a serially hinged flap. This report is intended as a supplement to NACA Report no. 631, wherein a method is presented for the calculation of the chordwise normal-force distribution over an airfoil without a flap or, as it may be considered, an airfoil with flap (or flaps) neutral. The method enables the determination of the form and magnitude of the incremental normal-force distribution to be made for an airfoil-flap combination for which the section characteristics have been determined. A method is included for the calculation of the flap normal-force and hinge-moment coefficients without necessitating a determination of the normal-force distribution.
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Carbonizing Properties of West Virginia Coals and Blends of Coals From the Alma, Cedar Grove, Dorothy Powellton A, Eagle, Pocahontas and Beckley Beds

Carbonizing Properties of West Virginia Coals and Blends of Coals From the Alma, Cedar Grove, Dorothy Powellton A, Eagle, Pocahontas and Beckley Beds

Date: 1938
Creator: Fieldner, A. C.; Davis J. D.; Selvig, W. A.; Thiessen, R.; Reynolds, D. A.; Holmes, C. R. et al.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Coal-Mine Accidents in the United States, 1935

Coal-Mine Accidents in the United States, 1935

Date: 1938
Creator: Adams, W. W.; Geyer, L. E. & Parry, M. G.
Description: Report compiled by the U.S. Bureau of Mines including statistics on fatal and non-fatal accidents in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary.
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Column strength of tubes elastically restrained against rotation at the ends

Column strength of tubes elastically restrained against rotation at the ends

Date: January 1, 1938
Creator: Osgood, William R
Description: Report presents the results of a study made of the effects of known end restraint on commercially available round and streamline tubing of chromium-molybdenum steel, duralumin, stainless steel, and heat-treated chromium-molybdenum steel; and a more accurate method than any previously available, but still a practical method, was developed for designing compression members in riveted or welded structures, particularly aircraft. Two hundred specimens were tested as short, medium-length, and long columns with freely supported ends or elastically restrained ends. Tensile and compressive tests were made on each piece of original tubing from which column specimens were cut.
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Comparative flight and full-scale wind-tunnel measurements of the maximum lift of an airplane

Comparative flight and full-scale wind-tunnel measurements of the maximum lift of an airplane

Date: January 1, 1938
Creator: Silverstein, Abe; Katzoff, S & Hootman, James A
Description: Determinations of the power-off maximum lift of a Fairchild 22 airplane were made in the NACA full-scale wind tunnel and in flight. The results from the two types of test were in satisfactory agreement. It was found that, when the airplane was rotated positively in pitch through the angle of stall at rates of the order of 0.1 degree per second, the maximum lift coefficient was considerably higher than that obtained in the standard tests, in which the forces are measured with the angles of attack fixed. Scale effect on the maximum lift coefficient was also investigated.
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Comparison of free-spinning wind-tunnel results with corresponding full-scale spin results

Comparison of free-spinning wind-tunnel results with corresponding full-scale spin results

Date: December 1, 1938
Creator: NEIHOUSE A I
Description: None
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Composition of Coal Tar and Light Oil

Composition of Coal Tar and Light Oil

Date: 1938
Creator: Fisher, C. H.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Compressible flow about symmetrical Joukowski profiles

Compressible flow about symmetrical Joukowski profiles

Date: January 1, 1938
Creator: Kaplan, Carl
Description: The method of Poggi is employed for the determination of the effects of compressibility upon the flow past an obstacle. A general expression for the velocity increment due to compressibility is obtained. The general result holds whatever the shape of the obstacle; but, in order to obtain the complete solution, it is necessary to know a certain Fourier expansion of the square of the velocity of flow past the obstacle. An application is made to the case flow of a symmetrical Joukowski profile with a sharp trailing edge, fixed in a stream of an arbitrary angle of attack and with the circulation determined by the Kutta condition. The results are obtained in a closed form and are exact insofar as the second approximation to the compressible flow is concerned, the first approximation being the result for the corresponding incompressible flow. Formulas for lift and moment analogous to the Blasius formulas in incompressible flow are developed and are applied to thin symmetrical Joukowski profiles for small angles of attack.
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Compression struts with nonprogressively variable moment of inertia

Compression struts with nonprogressively variable moment of inertia

Date: May 1, 1938
Creator: Radomski, B
Description: The buckling failure conditions for a bar with nonprogressively variable moment of inertia J(sub n), although constant over length l(sub n), are developed.
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The conversion of energy in a radiator

The conversion of energy in a radiator

Date: July 1, 1938
Creator: Weise, A
Description: It was a worthwhile task to research methods to lower the cooling drag of radiators. And the success of these efforts has been so great that without this research the modern high-speed airplane would have decidedly inferior performance. It is the purpose of this report to give a comprehensive discussion of all the fundamental principles and phenomena that offer a key to understanding modern cooling problems.
Contributing Partner: UNT Libraries Government Documents Department
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