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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Serial/Series Title: NACA Technical Reports
 Collection: Technical Report Archive and Image Library
Aircraft woods: their properties, selection, and characteristics

Aircraft woods: their properties, selection, and characteristics

Date: January 1, 1931
Creator: Markwardt, L J
Description: Strength values of various woods for aircraft design for a 15 per cent moisture condition of material and a 3-second duration of stress are presented, and also a discussion of the various factors affecting the values. The toughness-test method of selecting wood is discussed, and a table of acceptance values for several species is given.
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Airfoil pressure distribution investigation in the variable density wind tunnel

Airfoil pressure distribution investigation in the variable density wind tunnel

Date: January 1, 1931
Creator: Jacobs, Eastman N; Stack, John & Pinkerton, Robert M
Description: Report presents the results of wind tunnel tests of pressure distribution measurements over one section each of six airfoils. Pressure distribution diagrams, as well as the integrated characteristics of the airfoils, are given for both a high and a low dynamic scale or, Reynolds number VL/V, for comparison with flight and other wind-tunnel tests, respectively. It is concluded that the scale effect is very important only at angles of attack near the burble. The distribution of pressure over an airfoil having a Joukowski section is compared with the theoretically derived distribution. A further study of the distribution of pressure over all of the airfoils resulted in the development of an approximate method of predicting the pressure distribution along the chord of any normal airfoil for all attitudes within the working range if the distribution at one attitude is known.
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Airfoil section characteristics as affected by protuberances

Airfoil section characteristics as affected by protuberances

Date: January 1, 1934
Creator: Jacobs, Eastman N
Description: The drag and interference caused by protuberance from the surface of an airfoil have been determined in the NACA variable-density wind tunnel at a Reynolds number approximately 3,100,000. The effects of variations of the fore-and-aft position, height, and shape of the protuberance were measured by determining how the airfoil section characteristics were affected by the addition of the various protuberances extending along the entire span of the airfoil. The results provide fundamental data on which to base the prediction of the effects of actual short-span protuberances. The data may also be applied to the design of air brakes and spoilers.
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Airfoil section characteristics as affected by variations of the Reynolds number

Airfoil section characteristics as affected by variations of the Reynolds number

Date: January 1, 1937
Creator: Jacobs, Eastman N & Sherman, Albert
Description: Report presents the results of an investigation of a systematically chosen representative group of related airfoils conducted in the NACA variable-density wind tunnel over a wide range of Reynolds number extending well into the flight range. The tests were made to provide information from which the variations of airfoil section characteristics with changes in the Reynolds number could be inferred and methods of allowing for these variations in practice could be determined. This work is one phase of an extensive and general airfoil investigation being conducted in the variable-density tunnel and extends the previously published researches concerning airfoil characteristics as affected by variations in airfoil profile determined at a single value of the Reynolds number.
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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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Airfoil section data obtained in the NACA variable-density tunnel as affected by support interference and other corrections

Airfoil section data obtained in the NACA variable-density tunnel as affected by support interference and other corrections

Date: January 1, 1939
Creator: Jacobs, Eastman N & Abbott, Ira H
Description: The results of an investigation of the effect of support interference on airfoil drag data obtained in the variable-density tunnel are presented. As a result of the support interference, previously published airfoil data from the variable-density tunnel have shown too large drag coefficients and too large a rate of increase of drag coefficients and too large a rate increase of drag coefficients with airfoil thickness. The practical effect of the corrections on the choice of the optimum section is briefly considered and corrected data for a selected list of airfoils are presented as a convenience to the designer. Methods of correcting published data for other airfoils are presented.
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Airship model tests in the variable density wind tunnel

Airship model tests in the variable density wind tunnel

Date: January 1, 1932
Creator: Abbott, Ira H
Description: This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of airship models. Eight Goodyear-Zeppelin airship models were tested in the original closed-throat tunnel. After the tunnel was rebuilt with an open throat a new model was tested, and one of the Goodyear-Zeppelin models was retested. The results indicate that much may be done to determine the drag of airships from evaluations of the pressure and skin-frictional drags on models tested at large Reynolds number.
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Alternating-current equipment for the measurement of fluctuations of air speed in turbulent flow

Alternating-current equipment for the measurement of fluctuations of air speed in turbulent flow

Date: January 1, 1937
Creator: Mock, W. C., Jr.
Description: Recent electrical and mechanical improvements have been made in the equipment developed at the National Bureau of Standards for measurement of fluctuations of air speed in turbulent flow. Data useful in the design of similar equipment are presented. The design of rectified alternating-current power supplies for such apparatus is treated briefly, and the effect of the power supplies on the performance of the equipment is discussed.
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Altitude-pressure tables based on the United States standard atmosphere

Altitude-pressure tables based on the United States standard atmosphere

Date: January 1, 1936
Creator: Brombacher, W. G.
Description: This report is a revision of the altitude pressure tables of the United States standard atmosphere given in Technical Report No. 246. The altitude range has been extended from 50,000 to 80,000 feet.
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Analysis of 2-spar cantilever wings with special reference to torsion and load transference

Analysis of 2-spar cantilever wings with special reference to torsion and load transference

Date: January 1, 1936
Creator: Kuhn, Paul
Description: This report deals with the analysis of 2-spar cantilever wings in torsion, taking cognizance of the fact that the spars are not independent, but are interconnected by ribs and other structural members. The principles of interaction are briefly explained, showing that the mutual relief action occurring depends on the "pure torsional stiffness" of the wing cross section. Various practical methods of analysis are outlined. The "Friedrichs-Von Karman equations" are shown to require the least amount of labor. Numerical examples by the several methods of analysis are given and the agreement between the calculation and experiment is shown.
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An analysis of lateral stability in power-off flight with charts for use in design

An analysis of lateral stability in power-off flight with charts for use in design

Date: January 1, 1937
Creator: Zimmerman, Charles H
Description: The aerodynamic and mass factors governing lateral stability are discussed and formulas are given for their estimation. Relatively simple relationships between the governing factors and the resulting stability characteristics are presented. A series of charts is included with which approximate stability characteristics may be rapidly estimated. The effects of the various governing factors upon the stability characteristics are discussed in detail. It is pointed out that much additional research is necessary both to correlate stability characteristics with riding, flying, and handling qualities and to provide suitable data for accurate estimates of those characteristics of an airplane while it is in the design stage.
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An analysis of longitudinal stability in power-off flight with charts for use in design

An analysis of longitudinal stability in power-off flight with charts for use in design

Date: January 1, 1936
Creator: Zimmerman, Charles H
Description: This report presents a discussion of longitudinal stability in gliding flight together with a series of charts with which the stability characteristics of any airplane may be readily estimated.
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An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted and measured results

An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted and measured results

Date: January 1, 1937
Creator: Wheatley, John B
Description: Report presents an analysis of the factors that determine the periodic twist of a rotor blade under the action of the air forces on it. The results of the analysis show that the Fourier coefficients of the twist are linear expressions involving only the tip-speed ratio, the pitch setting, the inflow coefficient, the pitching-moment coefficient of the blade airfoil section, and the physical characteristics of the rotor blade and machine. The validity of the analysis was examined by using it to predict the twist of a rotor whose twist characteristics had previously been measured in flight. The agreement between the calculated and experimental results was satisfactory.
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An analytical and experimental study of the effect of periodic blade twist on the thrust, torque, and flapping motion of an autogiro rotor

An analytical and experimental study of the effect of periodic blade twist on the thrust, torque, and flapping motion of an autogiro rotor

Date: January 1, 1937
Creator: Wheatley, John B
Description: An analysis is made of the influence on autogiro rotor characteristics of a periodic blade twist that varies with the azimuth position of the rotor blade and the results are compared with experimental data. The analysis expresses the influence of this type of twist upon the thrust, torque, and flapping motion of the rotor. The check against experimental data shows that the periodic twist has a pronounced influence on the flapping motion and that this influence is accurately predicted by the analysis. The influence of the twist upon the thrust and torque could be demonstrated only indirectly, but its importance is indicated.
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Application of practical hydrodynamics to airship design

Application of practical hydrodynamics to airship design

Date: January 1, 1933
Creator: Upson, Ralph H & Klikoff, W A
Description: The purpose of the first two parts of this report is to present in concise format all the formulas required for computation of the hydrodynamic forces, so that they can be easily computed for either straight or curvilinear flight. Improved approximations are also introduced having a high degree of accuracy throughout the entire range of practical proportions. The remaining two parts of the report are devoted respectively to stability and skin friction, as functions of the same hydrodynamic forces.
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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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The automotive ignition coil

The automotive ignition coil

Date: January 1, 1932
Creator: Darnell, T. H.
Description: This report gives the results of a series of measurements on the secondary voltage induced in an ignition coil of typical construction under a variety of operating conditions. These results show that the theoretical predictions hitherto made as to the behavior of this type of apparatus are in satisfactory agreement with the observed facts. The large mass of data obtained is here published both for the use of other investigators who may wish to compare them with other theoretical predictions and for the use of automotive engineers who will here find definite experimental results showing the effect of secondary capacity and resistance on the crest voltage produced by ignition apparatus.
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Blower cooling of finned cylinders

Blower cooling of finned cylinders

Date: January 1, 1937
Creator: Schey, Oscar W & Ellerbrock, Herman H , Jr
Description: Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.
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Calculated and measured pressure distributions over the midspan section of the NACA 4412 airfoil

Calculated and measured pressure distributions over the midspan section of the NACA 4412 airfoil

Date: January 1, 1937
Creator: Pinkerton, Robert M
Description: Pressures were simultaneously measured in the variable-density tunnel at 54 orifices distributed over the midspan section of 5 by 30 inch rectangular model of the NACA 4412 airfoil at 17 angles of attack ranging from -20 degrees to 30 degrees at a Reynolds number of approximately 3,000,000. Accurate data were thus obtained for studying the deviations of the results of potential-flow theory from measured results. The results of the analysis and a discussion of the experimental technique are presented.
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The calculation of take-off run

The calculation of take-off run

Date: January 1934
Creator: Diehl, Walter S.
Description: A comparatively simple method of calculating length of take-off run is developed from the assumption of a linear variation in net accelerating force with air speed and it is shown that the error involved is negligible.
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Calculation of the aerodynamic characteristics of tapered wings with partial-span flaps

Calculation of the aerodynamic characteristics of tapered wings with partial-span flaps

Date: January 1, 1939
Creator: Person, Henry A & Anderson, Raymond F
Description: Factors derived from wing theory are presented. By means of these factors, the angle of zero lift, the lift-curve slope, the pitching moment, the aerodynamic-center position, and the induced drag of tapered wings with partial-span flaps may be calculated. The factors are given for wings of aspect ratios 6 and 10 , of taper ratios from 0.25 to 1.00, and with flaps of various length. An example is presented of the method of application of the factors. Fair agreement with experimental results is shown for two wings of different taper ratio having plain flaps of various spacing.
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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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The characteristics of 78 related airfoil sections from tests in the variable-density wind tunnel

The characteristics of 78 related airfoil sections from tests in the variable-density wind tunnel

Date: January 1, 1933
Creator: Jacobs, Eastman N; Ward, Kenneth E & Pinkerton, Robert M
Description: An investigation of a large group of related airfoils was made in the NACA variable-density wind tunnel at a large value of the Reynolds number. The tests were made to provide data that may be directly employed for a rational choice of the most suitable airfoil section for a given application. The variation of the aerodynamic characteristics with variations in thickness and mean-line form were systematically studied. (author).
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