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Aeronautic instruments. Section 2: altitude instruments

Description: This report is Section two of a series of reports on aeronautic instruments (Technical Report nos. 125 to 132, inclusive). This section discusses briefly barometric altitude determinations, and describes in detail the principal types of altimeters and barographs used in aeronautics during the recent war. This is followed by a discussion of performance requirements for such instruments and an account of the methods of testing developed by the Bureau of Standards. The report concludes with a brief account of the results of recent investigations. For accurate measurements of altitude, reference must also be made to thermometer readings of atmospheric temperature, since the altitude is not fixed by atmospheric pressure alone. This matter is discussed in connection with barometric altitude determination.
Date: 1923?
Creator: Mears, A. H.; Henrickson, H. B. & Brombacher, W. G.
Partner: UNT Libraries Government Documents Department

Aeronautic Instruments Section 3: Aircraft Speed Instruments

Description: Part 1 contains a discussion and description of the various types of air speed measuring instruments. The authors then give general specifications and performance requirements with the results of tests on air speed indicators at the Bureau of Standards. Part 2 reports methods and laboratory apparatus used at the Bureau of Standards to make static tests. Methods are also given of combining wind tunnel tests with static tests. Consideration is also given to free flight tests. Part 3 discusses the problem of finding suitable methods for the purpose of measuring the speed of aircraft relative to the ground.
Date: 1923?
Creator: Hunt, Franklin L. & Stearns, H. O.
Partner: UNT Libraries Government Documents Department

Aeronautic Instruments Section 4: Direction Instruments

Description: Part one points out the adequacy of a consideration of the steady state gyroscopic motion as a basis for the discussion of displacements of the gyroscope mounted on an airplane, and develops a simple theory on this basis. Part two describes a new type of stabilizing gyro mounted on top of a spindle by means of a universal joint, the spindle being kept in a vertical position by supporting it as a pendulum of which the bob is the driving motor. Methods of tests and the difficulties in designing a satisfactory and reliable compass for aircraft use in considered in part three. Part four contains a brief general treatment of the important features of construction of aircraft compasses and description of the principal types used.
Date: 1923?~
Creator: Franklin, W. S.; Stillman, M. H.; Sanford, R. L.; Warner, John A. C.; Sylvander, R. C. & Rounds, E. W.
Partner: UNT Libraries Government Documents Department

Aeronautic instruments. Section 5 : power plant instruments

Description: Part 1 gives a general discussion of the uses, principles, construction, and operation of airplane tachometers. Detailed description of all available instruments, both foreign and domestic, are given. Part 2 describes methods of tests and effect of various conditions encountered in airplane flight such as change of temperature, vibration, tilting, and reduced air pressure. Part 3 describes the principal types of distance reading thermometers for aircraft engines, including an explanation of the physical principles involved in the functioning of the instruments and proper filling of the bulbs. Performance requirements and testing methods are given and a discussion of the source of error and results of tests. Part 4 gives methods of tests and calibration, also requirements of gauges of this type for the pressure measurement of the air pressure in gasoline tanks and the engine oil pressure on airplanes. Part 5 describes two types of gasoline gauges, the float type and the pressure type.
Date: 1923
Creator: Washburn, G. E.; Sylvander, R. C.; Mueller, E. F.; Wilhelm, R. M.; Eaton, H. N. & Warner, John A. C.
Partner: UNT Libraries Government Documents Department

Aeronautic instruments. Section 6 : aerial navigation and navigating instruments

Description: This report outlines briefly the methods of aerial navigation which have been developed during the past few years, with a description of the different instruments used. Dead reckoning, the most universal method of aerial navigation, is first discussed. Then follows an outline of the principles of navigation by astronomical observation; a discussion of the practical use of natural horizons, such as sea, land, and cloud, in making extant observations; the use of artificial horizons, including the bubble, pendulum, and gyroscopic types. A description is given of the recent development of the radio direction finder and its application to navigation.
Date: 1923?~
Creator: Eaton, H. N.
Partner: UNT Libraries Government Documents Department

Aeronautic Instruments Section 6: Oxygen Instruments

Description: This report contains statements as to amount of oxygen required at different altitudes and the methods of storing oxygen. The two types of control apparatus - the compressed oxygen type and the liquid oxygen type - are described. Ten different instruments of the compressed type are described, as well as the foreign instruments of the liquid types. The performance and specifications and the results of laboratory tests on all representative types conclude this report.
Date: 1923?~
Creator: Hunt, F. L.
Partner: UNT Libraries Government Documents Department

The altitude effect on air speed indicators 2

Description: In an investigation described in NACA Technical Report 110, it was shown that under certain conditions, particularly for the relatively low-speed flight of airships, the data obtained were not sufficiently accurate. This report describes an investigation in which the data obtained were sufficiently accurate and complete to enable the viscosity correction to be deduced quantitatively for a number of the air-speed pressure nozzles in common use. The report opens with a discussion of the theory of the performance of air-speed nozzles and of the calibration of the indicators, from which the theory of the altitude correction is developed. Then follows the determination of the performance characteristics of the nozzles and calibration constants used for the indicators. In the latter half of the report, the viscosity correction is computed for the Zahm Pitot-venturi nozzles.
Date: 1923?~
Creator: Eaton, H. N. & MacNair, W. A.
Partner: UNT Libraries Government Documents Department

Applications of Modern Hydrodynamics to Aeronautics

Description: The report gives, rather briefly, in part one an introduction to hydrodynamics which is designed to give those who have not yet been actively concerned with this science such a grasp of the theoretical underlying principles that they can follow the subsequent developments. In part two there follows a separate discussion of the different questions to be considered, in which the theory of aerofoils claims the greatest portion of the space. The last part is devoted to the application of the aerofoil theory to screw propellers. A table giving the most important quantities is at the end of the report. A short reference list of the literature on the subject and also a table of contents are added.
Date: 1923
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Bending moments, envelope, and cable stresses in non-rigid airships

Description: This report describes the theory of calculating the principal stresses in the envelope of a nonrigid airship used by the Bureau of Aeronautics, United States Navy. The principal stresses are due to the gas pressure and the unequal distribution of weight and buoyancy, and the concentrated loads from the car suspension cables. The second part of the report deals with the variations of tensions in the car suspension cables of any type of airship, with special reference to the rigid type, due to the propeller thrust or the inclination of the airship longitudinally.
Date: January 1923
Creator: Burgess, C. P.
Partner: UNT Libraries Government Documents Department

A Constant Pressure Bomb

Description: "This report describes a new optical method of unusual simplicity and of good accuracy suitable to study the kinetics of gaseous reactions. The device is the complement of the spherical bomb of constant volume, and extends the applicability of the relationship, pv=rt for gaseous equilibrium conditions, to the use of both factors p and v. The method substitutes for the mechanical complications of a manometer placed at some distance from the seat of reaction the possibility of allowing the radiant effects of reaction to record themselves directly upon a sensitive film" (p. 3).
Date: 1923
Creator: Stevens, F. W.
Partner: UNT Libraries Government Documents Department

Control in Circling Flight

Description: "This investigation was undertaken for the purpose of developing instruments that would record the forces and positions of all three controls, and to obtain data on the behavior of an airplane in turns. All the work was done on a standard rigged JN4H (airplane no. 2 of National Advisory Committee for Aeronautics, report no. 70). It was found that the airplane was longitudinally unstable and nose heavy; that it was laterally unstable, probably due to too little dihedral; and that it was directionally unstable, due to insufficient fin area, this last being very serious, for in case of a loss of rudder control the airplane immediately whips into a spin from which there is no way of getting it out" (p. 71).
Date: 1923
Creator: Norton, F. H. & Allen, E. T.
Partner: UNT Libraries Government Documents Department

Controllability and Maneuverability of Airplanes

Description: This investigation was conducted for the purpose of studying the behavior of the JN4H airplane in free flight under the action of its controls and from this to arrive at satisfactory definitions and coefficients for controllability and maneuverability. The method consisted in recording the angular velocity about the three axes, together with the air speed, control positions, and acceleration.
Date: 1923
Creator: Norton, F. H. & Brown, W. G.
Partner: UNT Libraries Government Documents Department

Damping Coefficients Due to Tail Surfaces in Aircraft

Description: "The object of the investigation described in this report was to compare the damping coefficients of an airfoil as calculated from a knowledge of the static characteristics of the section with those obtained experimentally with an oscillation. The damping coefficients as obtained, according to the conventional notation, can be considered either as due to pitching or as due to yawing, the oscillation in these experiments being so arranged that the surfaces oscillate about a vertical axis. This is in reality the case when the influence is yawing about the standard Z-axis, but it can also be considered as a pitching motion when the model is so rigged that its standard Y-axis becomes vertical" (p. 118).
Date: January 1, 1923
Creator: Chu, Lynn
Partner: UNT Libraries Government Documents Department

The decay of a simple eddy

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.
Date: 1923
Creator: Bateman, H.
Partner: UNT Libraries Government Documents Department

Diaphragms for Aeronautic Instruments

Description: This investigation was carried out at the request of the National Advisory Committee for Aeronautics and comprises an outline of historical developments and theoretical principles, together with a discussion of expedients for making the most effective use of existing diaphragms actuated by the hydrostatic pressure form an essential element of a great variety instruments for aeronautic and other technical purposes. The various physical data needed as a foundation for rational methods of diaphragm design have not, however, been available hitherto except in the most fragmentary form.
Date: 1923
Creator: Hersey, M. D.
Partner: UNT Libraries Government Documents Department

The drag of C class airship hull with varying length of cylindric midships

Description: A model of the C class airship hull, when severed at its major section and provided with a cylindric mid-body of variable length, had its air resistance increased about in proportion to the length of the mid-body up to 3 diameters, and in about the manner to be expected from the increase of skin friction on this variable length. For greater length the drag increased less and less rapidly.
Date: 1923
Creator: Zahm, A. F.; Smith, R. H. & Hill, G. C.
Partner: UNT Libraries Government Documents Department

The Drag of Zeppelin Airships

Description: This report is a discussion of the results of tests with Zeppelin airships, in which the propellers were stopped as quickly as possible while the airship was in full flight. In this paper the author refers to the theory involved in these tests and calls attention to one scientifically interesting fact which can be derived from the tests and which has not yet been noted. The most important question concerning the tests is: does the negative acceleration of an airship with stopped propellers supply proper data for determining the drag of the airship when in uniform flight?
Date: 1923
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Experimental research on air propellers, 5

Description: In previous reports on experimental research on air propellers, by W. F. Durand and E. P. Lesley, as contained in the National Advisory Committee for Aeronautics reports nos. 14, 30, and 64, the investigations were made progressively and each without reference to results given in preceding reports and covering only information relating to forms perhaps adjacent in geometrical form and proportion. This report is a review of the entire series of results of the preceding reports with a view of examining through graphical and other appropriate means the nature of the history of the characteristics of operation as related to the systematic variations in characteristics of forms, etc., through the series of such characteristics.
Date: 1923
Creator: Durand, W. F. & Lesley, E. P.
Partner: UNT Libraries Government Documents Department

General Biplane Theory

Description: "This report deals with the air forces on biplane cellule. The first part of the report deals with the two-dimensional problem neglecting viscosity. The second part deals with the influence of the lateral dimensions. It is found that the loss of lift due to induction is almost unchanged, whether the biplane is staggered or not. In the third part conclusions from previous investigations are drawn, viscosity and experimental experience are brought in, and the method is simplified for practical application" (p. 5).
Date: 1923
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

The general efficiency curve for air propellers

Description: This report presents a formula which may be used to obtain a "general efficiency curve" in addition to the well-known maximum efficiency curve. These two curves, when modified somewhat by experimental data, enable performance calculations to be made without detailed knowledge of the propeller. The curves may also be used to estimate the improvement in efficiency due to reduction gearing, or to judge the performance of a new propeller design.
Date: 1923
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department

General Theory of Thin Wing Sections

Description: "This report contains a new, simple method of calculating the air forces to which thin wings are subjected at small angles of attack, if their curvature is not too great. Two simple integrals are the result. They contain only the coordinates of the wing section" (p. 3).
Date: 1923
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Internal Stresses in Laminated Construction

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" (p. 327).
Date: 1923
Creator: Heim, A. L.; Knauss, A. C. & Seutter, Louis
Partner: UNT Libraries Government Documents Department

Lift and drag effects of wing-tip rake

Description: This report deals with a description and report of tests carried out at the Washington Navy Yard on models of the RAF-6, albatross and Slone airfoils to determine the effectiveness of the conventional wing-trailing edge being always longer than the leading edge. The results are compared with the values computed by standard formulae in use at the time the tests were conducted.
Date: 1923
Creator: Zahm, A. F.; Bear, R. M. & Hill, G. C.
Partner: UNT Libraries Government Documents Department