National Advisory Committee for Aeronautics (NACA) - 1,437 Matching Results

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Airscrew Gyroscopic Moments

Description: When flying in a turn or pulling out of a dive, the airscrew exerts a gyroscopic moment on the aircraft, In the case of airscrews with three or more blades, arranged symmetrically, the value of the gyroscopic moment is J(sub x) omega(sub x) omega(sub y), where J(sub x) denotes the axial moment of inertia about the axis of rotation of the airscrew, omega(sub x) the angular upeed of the airscrew about its axis, and omega (sub Y) the rotary speed of the whole aircraft about an axis parallel to the plane of the airscrew (e.g., when pulling up, the transverse axis of the aircraft). The gyroscopic moment then tends to rotate the aircraft about an axis perpendicular to those of the two angular speeds and, in the came of airscrews with three or more blades, is constant during a revolution of the airscrew. With two-bladed airscrews, on the contrary, although the calculate gyroscopic moment represents the mean value in time, it fluctuates about this value with a frequency equal to twice the revolutions per minute. In addition, pulsating moments likewise occur about the other two axes. This fact is known from the theory of the asymmetrical gyro; the calculations that have been carried out for the determination of the various gyroscopic moments, however, mostly require an exact knowledge of the gyro theory. The problem will therefore be approached in another manner based on quite elementary considerations. The considerations are of importance, not only in connection with the gyroscopic moments exerted by the two-bladed airscrew on the aircraft, but also with the stressing of the blades of airscrews with an arbitrary number of blades.
Date: September 1946
Creator: Bock, G.
Partner: UNT Libraries Government Documents Department

"Am" Gasoline Cock

Description: The "AM" cock was designed specially for gasoline pipes on vehicles using internal combustion engines (airplanes, airships, automobiles, tractors, battle "tanks", boats, etc.). The report descirbes the functioning and construction of the device.
Date: February 1923
Partner: UNT Libraries Government Documents Department

The American Airship ZR-3

Description: This airship was built by the Zeppelin Airship Company at Friedrichshafen in 1923-4, for the United States Navy, as the reparations service of the German Government in fulfillment of the treaty of peace. A description of the design, components, flight characteristics, blueprints, and photographs are provided.
Date: November 1924
Creator: Dürr, L.
Partner: UNT Libraries Government Documents Department

Amplitude distribution and energy balance of small disturbances in plate flow

Description: From Introduction: "The present report, therefore, deals first, with the distribution of the amplitude of the disturbance over the flow section, that is, the calculation of the characteristic functions and second, with the study of the energy distribution and energy balance of the disturbance motion. The investigations are based upon the disturbances of the laminar flow past a flat plate which are situated exactly at the boundary between amplification and damping (neutral oscillations)."
Date: April 1950
Creator: Schlichting, H.
Partner: UNT Libraries Government Documents Department

The Analysis of Aircraft Structures as Space Frameworks: Method Based on the Forces in the Longitudinal Members

Description: The following examples do not take up the discussion of viewpoints to be heeded in determining the design of a framework for given external conditions. Rather they are methods for determining the forces in airplane fuselages and wings, though similar considerations are applied to certain simple cases of a different kind. The object of this treatise is to summarize and amplify these considerations from definite viewpoints.
Date: July 1929
Creator: Wagner, Herbert
Partner: UNT Libraries Government Documents Department

Analysis of Experimental Investigations of the Planing Process of the Surface of Water

Description: Pressure distribution and spray measurements were carried out on rectangular flat and V-bottom planing surfaces. Lift, resistance, and center of pressure data are analyzed and it is shown how these values may be computed for the pure planing procees of a flat or V-bottom suface of arbitrary beam, load and speed, the method being illustrated with the aid of an example.
Date: March 1944
Creator: Sottorf, W.
Partner: UNT Libraries Government Documents Department

Analysis of flight and wind-tunnel tests on Udet airplanes with reference to spinning characteristics

Description: This report presents an analysis of results of wind-tunnel tests conducted at the D.V.L. Values were determined for the effectiveness of all the controls at various angles of attack. The autorotation was studied by subjecting the rotating model to an air blast.
Date: March 1929
Creator: Herrmann, H.
Partner: UNT Libraries Government Documents Department

Analysis of Spinning in a Monoplane Wing by the Induction Method as Compared With the Strip Method

Description: The problem of autorotation has been attacked by various authors, in particular Fuchs and Schmidt who applied the so-called strip method which is based upon the assumption that the forces and moments per unit length acting in each section of the wing are equal to those on an infinite cylindrical wing of equal section in an air flow of intensity and direction resulting from the apparent relative motion of this section with respect to the surrounding air. In other words they disregarded the induced velocities, which, however, are of such importance that their omission is bound to result in appreciable errors, as we attempt to prove in this report.
Date: June 1934
Creator: Poggi, L.
Partner: UNT Libraries Government Documents Department

Analytical methods for computing the polar curves of airplanes

Description: This report presents a method of calculating polar curves which is at least as precise as graphical methods, but it more rapid. Knowing the wind tunnel test of a wing and the performances of an airplane of the same profile, it is easy to verify the characteristic coefficients and, at the same time, the methods determining induced resistances.
Date: March 1921
Creator: Le Sueur
Partner: UNT Libraries Government Documents Department

Analytical Study of Shimmy of Airplane Wheels

Description: The problem of shimmy of a castering wheel, such as the nose wheel of a tricycle gear airplane, is treated analytically. The flexibility of the tire is considered to be the primary cause of shimmy. The rather simple theory developed agrees rather well with previous experimental results. The author suggests that shimmy may be eliminated through a suitable choice of landing gear dimensions in lieu of a damper.
Date: September 1952
Creator: Bourcier de Carbon, Christian
Partner: UNT Libraries Government Documents Department

Analytical theory of the Campini propulsion system

Description: From Summary: "The present report deals exclusively with the particular jet-propulsion system mentioned in the cited reports. The discussion is limited, for the present, to the analytical study of the efficiency and the consumption for the case of application to aircraft and to the plotting of the practical operating curves secured theoretically by the use of suitable experimental factors."
Date: March 1942
Creator: Campini, S
Partner: UNT Libraries Government Documents Department

Analytical Treatment of Normal Condensation Shock

Description: "The condensation of water vapor in an air has the following consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front" (p. 1).
Date: July 1947
Creator: Heybey
Partner: UNT Libraries Government Documents Department

Apparatus for measurements of time and space correlation

Description: The report describes a brief review is made of improvements to an experimental apparatus for time and space correlation designed for study of turbulence. Included is a description of the control of the measurements and a few particular applications.
Date: April 1955
Creator: Favre, Alexandre; Gaviglio, J & Dumas, R
Partner: UNT Libraries Government Documents Department

The apparent width of the plate in compression

Description: This report discusses an investigation that treats the load capacity of a rectangular plate stressed in compression on one direction (x) beyond the buckling limit and the plate is rotatable (i.e., free from moments) supported at all four sides by bending-resistant beams.
Date: July 1937
Creator: Marguerre, Karl
Partner: UNT Libraries Government Documents Department

Application and testing of transparent plastics used in airplane construction

Description: This report discusses the efforts being made to remove the source of danger to passengers arising from the fracturing of silicate glass and some of the alternatives presented include: single-layer safety glass, multi-layer safety glass, transparent plastic resins.
Date: November 1938
Creator: Riechers, K. & Olms, J.
Partner: UNT Libraries Government Documents Department

Application of the Method of Coordinate Perturbation to Unsteady Duct Flow

Description: The method of coordinate perturbation is applied to the unsteady flow of a compressible fluid in ducts of variable cross section. Solutions, in the form of perturbation series, are obtained for unsteady flows in ducts for which the logarithmic derivative of area variation with respect to the space coordinate is a function of the 'smallness' parameter of the perturbation series. This technique is applied to the problem of the interaction of a disturbance and a shock wave in a diffuser flow. It is found that, for a special choice of the function describing the disturbance, the path of the shock wave can be expressed in closed form to first order. The method is then applied to the determination of the flow field behind a shock wave moving on a prescribed path in the x,t-plane. Perturbation series solutions for quite general paths are developed. The perturbation series solutions are compared with the more exact solutions obtained by the application of the method of characteristics. The approximate solutions are shown to be in reasonably accurate agreement with the solutions obtained by the method of characteristics.
Date: September 1958
Creator: Himmel, Seymour C.
Partner: UNT Libraries Government Documents Department

Application of the Methods of Gas Dynamics to Water Flows With Free Surface 1: Flows With No Energy Dissipation

Description: The application is treated in sufficient detail to facilitate as much as possible its application by the engineer who is less familiar with the subject. The present work was undertaken with two objects in view. In the first place, it is considered as a contribution to the water analogy of gas flows, and secondly, a large portion is devoted to the general theory of the two-dimensional supersonic flows.
Date: March 1940
Creator: Preiswerk, Ernst
Partner: UNT Libraries Government Documents Department

Application of the Methods of Gas Dynamics to Water Flows With Free Surface 2: Flows With Momentum Discontinuities (Hydraulic Jumps)

Description: In this paper an introduction to shock polar diagrams is given which then leads into an examination of water depths in hydraulic jumps. Energy loss during these jumps is considered along with an extended look at elementary solutions of flow. An experimental test set-up is described and the results presented.
Date: March 1940
Creator: Preiswerk, Ernst
Partner: UNT Libraries Government Documents Department

Application of the theory of free jets

Description: Based upon Kirchoff's theory of free jets the flow through different screen arrangements of flat plates, as chiefly encountered with turbines in the cavitation zone is defined. It is shown by experiments that these theoretical results are very well representative in most cases of the conditions of discharge from water in air and consequently by cavitation. In addition, the experiments reveal a picture of the discrepancies between the actual flow and the theory of discharge of air in air (of water in water without cavitation). These discrepancies are explained qualitatively by the mingling processes between the jets and the dead air zones.
Date: April 1932
Creator: Betz, A. & Petersohn, E.
Partner: UNT Libraries Government Documents Department