Technical Report Archive and Image Library (TRAIL) - 119 Matching Results

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Wire Suspensions in Wind Tunnel Experiments

Description: The elimination of the rigid supports for models and their replacement by wires constitute a great improvement by rendering negligible the interactions of support. There are disadvantages to wire, namely, the aerodynamic resistance is very large and their use is rather difficult because the whole suspension lacks rigidity and easily becomes distorted. We will here investigate the nature of these distortions, evaluate the errors they entail and describe the methods for taking account of or avoiding them.
Date: December 1925
Creator: Kerneis, Jean
Partner: UNT Libraries Government Documents Department

Potential Flow in Engine Valves

Description: "The extensive applicability of the hydrodynamic theory to the problems of engine construction is clearly shown in the following attempt to determine by exact methods the nature of the flow in valves under variously restricted conditions. Observation shows that two principal kinds of flow occur in simple flat-seated valves. For small valve lifts, the flow is along the horizontal wall and is therefore deflected 90 degrees, but for greater valve lifts the flow separates and forms a free stream, whose angle of deflection naturally increases with increasing lift" (p. 1).
Date: December 1925
Creator: Eck, Bruno
Partner: UNT Libraries Government Documents Department

Light Aeroplane Engine Development

Description: "It has frequently been stated and written that in order to popularize light aircraft the first essential is the production of a reliable engine capable of being easily maintained and having a long life, at the same time selling at a low figure. It is desired to point out the difficulties in the way of realizing this ideal before remarking on the claims of the various types for adoption" (p. 1).
Date: April 1925
Creator: Fell, L. F. R.
Partner: UNT Libraries Government Documents Department

Model Tests With a Systematic Series of 27 Wing Sections at Full Reynolds Number

Description: "A systematic series of 27 wing sections, characterized by a small travel of the center or pressure, have been investigated at 20 atmospheres pressure in the variable density wind tunnel of the National Advisory Committee for Aeronautics. The results are consistent with each other, and indicate that for such "stable" sections a small effective camber, a small effective S-shape and a thickness of 8 to 12 per cent lead to good aerodynamic properties" (p. 3).
Date: 1925
Creator: Munk, Max M. & Miller, Elton W.
Partner: UNT Libraries Government Documents Department

Correcting Horsepower Measurements to a Standard Temperature

Description: This report discusses the relation between the temperature of the air at the entrance to the carburetor and the power developed by the engine. Its scope is limited to a consideration of the range of temperatures likely to result from changes of season, locality, or altitude, since its primary aim is the finding of a satisfactory basis for correcting power measurements to a standard temperature. From the results of over 1,600 tests it is concluded that if calculations be based on the assumption that the indicated horsepower of an engine varies inversely as the square root of the absolute temperature of the carburetor air the values obtained will check closely experimental measurements.
Date: 1925
Creator: Sparrow, Stanwood W.
Partner: UNT Libraries Government Documents Department

Computation of Cantilever Airplane Wings

Description: The purpose of this treatise is, first of all, the determination of the effect of variously loaded spars on one another, since the neglect of this effect would present an economically very unfavorable computation method. The system of spars and cross-bars alone (whether solid or built-up) does not matter at first, the original assumption being that the spars are rigidly braced by the cross-bars.
Date: July 1925
Creator: Thalau, K.
Partner: UNT Libraries Government Documents Department

Pressure Distribution Over the Wings of an MB-3 Airplane in Flight

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" (p. 179).
Date: 1925
Creator: Norton, F. H.
Partner: UNT Libraries Government Documents Department

Calculation of Wing Spars of Variable Cross-Section and Linear Load

Description: "The calculation of wing spars of constant cross-section and load has been thoroughly treated by a large number of authors. Such is not the case,however, regarding the calculation of wing spars whose section and linear load diminish toward the ends, as in wings of trapezoidal contour and decreasing section" (p. 1).
Date: March 1925
Creator: Kirste, Léon
Partner: UNT Libraries Government Documents Department

Atomization of Liquid Fuels Part 2: Description of Apparatus, Fuels Tested, Atomization Experiments, Discharge Measurements, Atomization

Description: This report describes the design and operation of a nozzle to inject fuel into an engine. The design of the nozzle is open, without any compulsory or automatic stop-valve. The fuel injection is regulated simply by the pressure and the adjustment of the fuel pump.
Date: September 1925
Creator: Kuehn, R.
Partner: UNT Libraries Government Documents Department

Atomization of Liquid Fuels Part 1: Relation Between Atomization and Combustion, Methods Employed for Determining the Size of Particles and Small Drops, Choice of Experimental Method

Description: In the present treatise we will consider chiefly the problem of solid injection in comparison with air injection. On leaving the valve or nozzle through one or more small openings, the fuel is split up into innumerable fine drops, which penetrate the combustion chamber in divergent directions in the form of a conical jet. The efficiency of this jet is judged from the following three viewpoints: 1) with respect to the fineness of atomization; 2) with respect to the direction or distribution of sprayed particles; 3) with respect to the penetration of the particles.
Date: September 1925
Creator: Kuehn
Partner: UNT Libraries Government Documents Department

Theory of Flapping Flight

Description: "Before attempting to construct a human-powered aircraft, the aviator will first try to post himself theoretically on the possible method of operating the flapping wings. This report will present a graphic and mathematical method, which renders it possible to determine the power required, so far as it can be done on the basis of the wing dimensions. We will first consider the form of the flight path through the air" (p. 1).
Date: October 1925
Creator: Lippisch, Alexander
Partner: UNT Libraries Government Documents Department

An Introduction to the Helicopter

Description: It is the object of this report to review briefly the aerodynamic and construction data already available regarding helicopters and to set forth the difficulties which must be met.
Date: 1925
Creator: Klemin, Alexander
Partner: UNT Libraries Government Documents Department

Strength Calculations on Airplanes

Description: "Every strength calculation, including those on airplanes, must be preceded by a determination of the forces to be taken into account. In the following discussion, it will be assumed that the magnitudes of these forces are known and that it is only a question of how, on the basis of these known forces, to meet the prescribed conditions on the one hand and the practical requirements on the other" (p. 1).
Date: December 1925
Creator: Baumann, A.
Partner: UNT Libraries Government Documents Department

Inertia Factors of Ellipsoids for Use in Airship Design

Description: "This report is based on a study made by the writer as a member of the Special Committee on Design of Army Semirigid Airship RS-1 appointed by the National Advisory Committee for Aeronautics. The increasing interest in airships has made the problem of the potential flow of a fluid about an ellipsoid of considerable practical importance. The theory of this type of motion is very fully given by Horace Lamb in his "Hydrodynamics," and applications to the theory of airships by many other writers" (p. 3).
Date: 1925
Creator: Tuckerman, L. B.
Partner: UNT Libraries Government Documents Department

[Memorandums on the Subject of Joukowski Wings]

Description: In the first article, in connection with a lecture on the hydrodynamic basis of flight and the potential flow about a Joukowski wing, the pressure distribution on several wings is computed and plotted. The diagrams of the pressure distributions are presented accompanied with a qualitative discussion of the pressure distribution. In the second article, the the cross-sectional outline (or profile) a Joukowski wing are plotted.
Date: October 1925
Creator: Blumenthal, Otto & Trefftz, E.
Partner: UNT Libraries Government Documents Department

Elements of the Wing Section Theory and of the Wing Theory

Description: This report contains those results of the theory of wings and of wing sections which are of immediate practical value. They are proved and demonstrated by the use of the simple conceptions of "kinetic energy" and "momentum" only, familiar to every engineer; and not by introducing "isogonal transformations" and "vortices," which latter mathematical methods are not essential to the theory and better are used only in papers intended for mathematicians and special experts.
Date: 1925
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Determination of Turning Characteristics of an Airship by Means of a Camera Obscura

Description: This investigation was carried out by the National Advisory Committee at Langley Field for the purpose of determining the adaptability of the camera obscura to the securing of turning characteristics of airships, and also of obtaining some of those characteristics of the C-7 airship. The method consisted in flying the airship in circling flight over a camera obscura and photographing it at known time intervals. The results show that the method used is highly satisfactory and that for the particular maneuver employed the turning diameter is 1,240 feet, corresponding to a turning coefficient of 6.4, and that the position of zero angle of yaw is at the nose of the airship.
Date: 1925
Creator: Crowley, J. W., Jr. & Freeman, R. G.
Partner: UNT Libraries Government Documents Department