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  Partner: UNT Libraries Government Documents Department
 Decade: 1920-1929
 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
Stability of the parachute and helicopter

Stability of the parachute and helicopter

Date: January 1, 1920
Creator: Batemen, H
Description: This report deals with an extension of the theory of stability in oscillation to the case of aircraft following a vertical trajectory, and particularly to the oscillations of parachutes.
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Tests on air propellers in yaw

Tests on air propellers in yaw

Date: January 1, 1923
Creator: Durand, W F & Lesley, E P
Description: This report contains the results of tests to determine the thrust (pull) and torque characteristics of air propellers in movement relative to the air in a line oblique to the line of the shaft, and specifically when such angle of obliquity is large, as in the case of helicopter flight with the propeller serving for both sustentation and traction.
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Fuselage stress analysis

Fuselage stress analysis

Date: January 1, 1920
Creator: Warner, Edward P & Miller, Roy G
Description: Report analyzes the stresses in a fuselage of the built-up type in which the shear is taken by diagonal bracing wires. Tests are conducted for landing, flying, and thrust loads.
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Wind tunnel balances

Wind tunnel balances

Date: January 1, 1920
Creator: Warner, Edward P & Norton, F H
Description: Report embodies a description of the balance designed and constructed for the use of the National Advisory Committee for Aeronautics at Langley Field, and also deals with the theory of sensitivity of balances and with the errors to which wind tunnel balances of various types are subject.
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Slip-stream corrections performance computation

Slip-stream corrections performance computation

Date: January 1, 1920
Creator: Warner, Edward P
Description: This report is an analysis of experiments performed by Eiffel on the air velocity in slip stream of a propeller, and also includes a theoretical discussion of the magnitude of the velocity in different propellers.
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Preliminary report on free flight tests

Preliminary report on free flight tests

Date: January 1, 1920
Creator: Warner, E P & Norton, F H
Description: Results are presented for a series of tests made by the Advisory Committee's staff at Langley Field during the summer of 1919 with the objectives of determining the characteristics of airplanes in flight and the extent to which the actual characteristics differ from those predicted from tests on models in the wind tunnel, and of studying the balance of the machines and the forces which must be applied to the controls in order to maintain longitudinal equilibrium.
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Bomb trajectories

Bomb trajectories

Date: January 1, 1920
Creator: Wilson, Edwin Bidwell
Description: The report is a mathematical treatise dealing with the trajectories of bombs of high terminal velocity, dropped from a great altitude.
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The aerodynamic properties of thick aerofoils suitable for internal bracing

The aerodynamic properties of thick aerofoils suitable for internal bracing

Date: January 1, 1920
Creator: Norton, F H
Description: The object of this investigation was to determine the characteristics of various types of wings having sufficient depth to entirely inclose the wing bracing, and also to provide data for the further design of such sections. This type of wing is of interest because it eliminates the resistance of the interplane bracing, a portion of the airplane that sometimes absorbs one-quarter of the total power required to fly, and because these wings may be made to give a very high maximum lift. Results of the investigation of the following subjects are given: (1) effect of changing the upper and lower camber of thick aerofoils of uniform section; (2) effect of thickening the center and thinning the tips of a thin aerofoil; (3) effect of adding a convex lower surface to a tapered section; (4) effect of changing the mean thickness with constant center and tip sections; and (5) effect of varying the chord along the span.
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Construction of models for tests in wind tunnels

Construction of models for tests in wind tunnels

Date: January 1, 1920
Creator: Norton, F H
Description: Report deals with the methods of constructing aerofoils and all other parts of a model airplane, including discussion of the degree of accuracy.
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Diagrams of airplane stability

Diagrams of airplane stability

Date: January 1, 1921
Creator: Batemen, H
Description: In this report a study is made of the effect on longitudinal and lateral oscillations of an airplane of simultaneous variations in two resistance derivatives while the remainder of the derivatives are constant. The results are represented by diagrams in which the two variable resistance derivatives are used as coordinates, and curves are plotted along which the modulus of decay of a long oscillation has a constant value. The same type of analysis is also carried out for the stability of the parachute. In discussing the stability of the helicopter it is concluded that the gyroscopic effect on stability will be greater than in the case of the airplane.
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Analysis of wing truss stresses including the effect of redundancies

Analysis of wing truss stresses including the effect of redundancies

Date: January 1, 1921
Creator: Warner, E P & Miller, R G
Description: Airplane wing trusses are generally designed to contain redundant members (stagger wires and external drag wires) which, according to common practice, are not taken into account in calculations, so as to simplify the stress analysis by rendering the structure statically determinate. A more accurate method, in which the redundancies are included, involves a solution by means of Castigliano's method of least work. For the purpose of demonstrating the practical application of the method of least work this report presents examples for stresses of several cases of loading worked out for a structure similar to that of the Curtiss JN-4h. Case 1 was taken as the condition of velocity of 100 miles per hour combined with the angle of attack of maximum lift. Case 1a assumed the same loading but neglected the distortion of wooden members in the least-work analysis. So little error was involved in case 1a that this simplified method was employed for each succeeding case. Case 2 assumed a diving speed of 120 miles per hour and an angle of attack of no lift. Case 3 was worked out for the conditions imposed by the sand load recommended in NACA technical note no. 6.
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The efficiency of small bearings in instruments of the type used in aircraft

The efficiency of small bearings in instruments of the type used in aircraft

Date: January 1, 1921
Creator: Norton, F H
Description: This report deals with the construction and properties of bearings and pivots for use in instruments. The static and running friction for both thrust and radial loads was determined for a number of conical pivots and cylindrical and ball bearings. The static rocking friction was also measured for several conical and ball bearings under a heavy load, especially to determine their suitability for use in N. P. L. (National Physical Laboratory) type wind tunnel balance. In constructing conical pivots and sockets it was found that the pivots should be hardened and highly polished, preferably with a revolving lap, and that the sockets should be made by punching with a hardened and polished punch. It was found that for a light load the conical pivots give less friction than any other type, and their wearing qualities when hardened are excellent. Very small ball bearings are unsatisfactory because the proportional accuracy of the balls and races is not high enough to insure smooth running. For rocking pivots under heavy loads it was found that a ball-and-socket bearing, consisting of a hemispherical socket and a sphere of smaller diameter concentric with it, with a row of small balls resting between the two, was ...
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Moisture resistant finishes for airplane woods

Moisture resistant finishes for airplane woods

Date: January 1, 1921
Creator: Dunlap, M E
Description: This report describes briefly a series of experiments made at the Forest Products Laboratory, Madison, Wisconsin, to determine the comparative moisture resistance of linseed oil, impregnation treatments, condensation varnishes, oil varnishes, enamels, cellulose varnishes, rubber, electroplated and sprayed metal coatings, and metal-leaf coatings when applied to wood. All coatings except rubber and electroplated metal coatings, which were not developed sufficiently to make them practical, admitted moisture in varying degrees. The most effective and most practical coating was found to be that of aluminum leaf.
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Data on the design of plywood for aircraft

Data on the design of plywood for aircraft

Date: January 1, 1921
Creator: Elmendorf, Armin
Description: This report makes available data which will aid the designer in determining the plywood that is best adapted to various aircraft parts. It gives the results of investigations made by the Forest Products Laboratory of the United States Forest Service at Madison, Wisconsin, for the Army and Navy Departments, and is one of a series of reports on the use of wood in aircraft prepared by the Forest Products Laboratory for publication by the National Advisory Committee for Aeronautics. The object of the study was to determine, through comprehensive tests, the mechanical and physical properties of plywood and how these properties vary with density, number, thickness, arrangement of the plies and direction of grain of the plies.
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Wind tunnel studies in aerodynamic phenomena at high speed

Wind tunnel studies in aerodynamic phenomena at high speed

Date: January 1, 1921
Creator: Caldwell, F W & Fales, E N
Description: A great amount of research and experimental work has been done and fair success obtained in an effort to place airplane and propeller design upon an empirical basis. However, one can not fail to be impressed by the apparent lack of data available toward establishing flow phenomena upon a rational basis, such that they may be interpreted in terms of the laws of physics. With this end in view it was the object of the authors to design a wind tunnel differing from the usual type especially in regard to large power and speed of flow. This report describes the wind tunnel at Mccook Field and gives the results of experiments conducted in testing the efficiency of the wind tunnel.
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Pressure distribution over the wings of an MB-3 airplane in flight

Pressure distribution over the wings of an MB-3 airplane in flight

Date: January 1, 1925
Creator: Norton, F H
Description: This investigation was carried out to determine the distribution of load over the wings of a high speed airplane under all conditions of flight. In particular it was desired to find the pressure distribution during level flight, over the portions of the wings in the slipstream and, during violent maneuvers, over the entire wing surface. The method used consisted in connecting a number of holes in the surface of the wings to recording multiple manometers mounted in the fuselage of the airplane. In this way simultaneous records could be taken on all of the holes for any desired length of time. (author).
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Air forces, moments and damping on model of fleet airship Shenandoah

Air forces, moments and damping on model of fleet airship Shenandoah

Date: January 1, 1926
Creator: Zahm, A F; Smith, R H & Louden, F A
Description: To furnish data for the design of the fleet airship Shenandoah, a model was made and tested in the 8 by 8 foot wind tunnel for wind forces, moments, and damping, under conditions described in this report. The results are given for air of standard density. P=0.00237 slugs per cubic foot with vl/v correction, and with but a brief discussion of the aerodynamic design features of the airship.
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Wing spar stress charts and wing truss proportions

Wing spar stress charts and wing truss proportions

Date: January 1, 1926
Creator: Warner, Edward P
Description: In order to simplify the calculation of beams continuous over three supports, a series of charts have been calculated giving the bending moments at all the critical points and the reactions at all supports for such members. Using these charts as a basis, calculations of equivalent bending moments, representing the total stresses acting in two bay-wing trusses of proportions varying over a wide range, have been determined, both with and without allowance for column effect. This leads finally to the determination of the best proportions for any particular truss or the best strut locations in any particular airplane. The ideal proportions are found to vary with the thickness of the wing section used, the aspect ratio, and the ratio of gap to chord.
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Experimental research on air propellers  IV

Experimental research on air propellers IV

Date: January 1, 1921
Creator: Durand, W F & Lesley, E P
Description: This report states the results of investigations made upon numerous propeller models at the request of the Subcommittee on Aerodynamics, and contains valuable data for those interested in the design of air propellers.
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The decay of a simple eddy

The decay of a simple eddy

Date: January 1, 1923
Creator: Bateman, H
Description: The principal result obtained in this report is a generalization of Taylor's formula for a simple eddy. The discussion of the properties of the eddy indicates that there is a slight analogy between the theory of eddies in a viscous fluid and the quantum theory of radiation. Another exact solution of the equations of motion of viscous fluid yields a result which reminds one of the well-known condition for instability in the case of a horizontally stratified atmosphere.
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The six-component wind balance

The six-component wind balance

Date: January 1, 1923
Creator: Zahm, A F
Description: Dr. Zahm's report is a description of the six-component wind-tunnel balance in use at the Aerodynamic Laboratory, Washington Navy Yard. The description of the balance gives the mechanical details and the method of operation, and is accompanied by line drawings showing the construction of the balance. The balance is of particular interest, as it allows the model to be set up quickly and accurately in roll, pitch, and yaw, without stopping the wind. It is possible to measure automatically, directly, and independently the drag, cross-wind force, and lift; also the rolling, pitching, and yawing moments. It is also possible to make the balance self-recording.
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Standard atmosphere

Standard atmosphere

Date: January 1, 1923
Creator: Gregg, Willis Ray
Description: This report was prepared at the request of the National Advisory Committee for Aeronautics and discusses the need of a standard set of values of pressure, temperature and density at various altitudes and points out the desirability of adopting such values as are most in accord with actual average conditions, in order that corrections in individual cases may be as small as possible. To meet this need, so far as the united states is concerned, all free-air observations obtained by means of kites and balloons at several stations in this country near latitude 40 degrees N., have been used, and average values of pressure, temperature, and density, based upon those observations, have been determined for summer, winter, and the year, and for all altitudes up to 20,000 meters (65,000 feet). These values are presented in tables and graphs in both metric and english units; and in the tables of densities there are also included values of density for other parts of the world, more particularly for Europe. A comparison with these values shows that, except in the lowest levels, the agreement is very satisfactory.
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Analysis of stresses in German airplanes

Analysis of stresses in German airplanes

Date: January 1, 1923
Creator: Hoff, Wilhelm
Description: This report contains an account of the origin of the views and fundamental principles underlying the construction of German airplanes during the war. The report contains a detailed discussion of the aerodynamic principles and their use in determining the strength of airplanes, the analysis of the strength qualities of materials and in the construction, the calculated strength of air flows and a description of tests made in determining the strength of airplanes.
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Internal stresses in laminated construction

Internal stresses in laminated construction

Date: January 1, 1923
Creator: Heim, A L; Knauss, A C & Seutter, Louis
Description: This report reviews the procedure employed in an investigation of the sources and influence of internal stresses in laminated construction, and discusses the influence of shrinkage and swelling stresses caused by atmospheric conditions upon the tensile strength across grain in laminated construction with special reference to airplane propellers. The investigation covered three sources of internal stress, namely, the combination of plain-sawed and quarter-sawed material in the same construction, the gluing together of laminations of different moisture contents, and the gluing together of laminations of different densities. Glued specimens and free specimens, made up under various manufacturing conditions, were subjected to various climatic changes inducing internal stresses and then were tested.
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