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 Collection: Technical Report Archive and Image Library
Results 15251 - 15260 of 17,421
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The Minimum Induced Drag of Aerofoils

The Minimum Induced Drag of Aerofoils

Date: December 1, 1979
Creator: Munk, M. M.
Description: Equations are derived to demonstrate which distribution of lifting elements result in a minimum amount of aerodynamic drag. The lifting elements were arranged (1) in one line, (2) parallel lying in a transverse plane, and (3) in any direction in a transverse plane. It was shown that the distribution of lift which causes the least drag is reduced to the solution of the problem for systems of airfoils which are situated in a plane perpendicular to the direction of flight.
Contributing Partner: UNT Libraries Government Documents Department
Graphic Construction of Joukowski Wings

Graphic Construction of Joukowski Wings

Date: December 1, 1979
Creator: Trefftz, E.
Description: A plot of the cross sectional outline of a Joukowski wing is presented.
Contributing Partner: UNT Libraries Government Documents Department
Flow and Drag Formulas for Simple Quadrics

Flow and Drag Formulas for Simple Quadrics

Date: December 1, 1979
Creator: Zahm, A. F.
Description: The pressure distribution and resistance found by theory and experiment for simple quadrics fixed in an infinite uniform stream of practically incompressible fluid are calculated. The experimental values pertain to air and some liquids, especially water; the theoretical refer sometimes to perfect, again to viscid fluids. Formulas for the velocity at all points of the flow field are given. Pressure and pressure drag are discussed for a sphere, a round cylinder, the elliptic cylinder, the prolate and oblate spheroid, and the circular disk. The velocity and pressure in an oblique flow are examined.
Contributing Partner: UNT Libraries Government Documents Department
A Procedure for the Design of Air-Heated Ice-Prevention Systems

A Procedure for the Design of Air-Heated Ice-Prevention Systems

Date: June 1, 1954
Creator: Neel, C. B.
Description: A procedure proposed for use in the design of air-heated systems for the continuous prevention of ice formation on airplane components is set forth. Required heat-transfer and air-pressure-loss equations are presented, and methods of selecting appropriate meteorological conditions for flight over specified geographical areas and for the calculation of water-drop-impingement characteristics are suggested. In order to facilitate the design, a simple electrical analogue was devised which solves the complex heat-transfer relationships existing in the thermal-system analysis. The analogue is described and an illustration of its application to design is given.
Contributing Partner: UNT Libraries Government Documents Department
Langley Field wind tunnel apparatus

Langley Field wind tunnel apparatus

Date: January 1, 1922
Creator: Bacon, D L
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Air resistance measurements on actual airplane parts

Air resistance measurements on actual airplane parts

Date: November 1, 1923
Creator: Weiselsberger, C
Description: For the calculation of the parasite resistance of an airplane, a knowledge of the resistance of the individual structural and accessory parts is necessary. The most reliable basis for this is given by tests with actual airplane parts at airspeeds which occur in practice. The data given here relate to the landing gear of a Siemanms-Schuckert DI airplane; the landing gear of a 'Luftfahrzeug-Gesellschaft' airplane (type Roland Dlla); landing gear of a 'Flugzeugbau Friedrichshafen' G airplane; a machine gun, and the exhaust manifold of a 269 HP engine.
Contributing Partner: UNT Libraries Government Documents Department
A preliminary investigation of a new method for testing aerofoils in free flight

A preliminary investigation of a new method for testing aerofoils in free flight

Date: January 1, 1922
Creator: Norton, F H
Description: This report is a description of a new method of testing aerofoils in free flight devised by the National Advisory Committee for Aeronautics. The method consists in lowering below a flying airplane a large inverted aerofoil on three small steel wires in such a way that the lift on the aerofoil always keeps the wires tight. The resultant force is measured by the tension in the wires, and the direction of the resultant by the amount the wing trails backwards. A test was made on an aerofoil of the N.A.C.A. #64 section, 6 ft. in span and the results are compared with a similar section tested in the wind tunnel. This investigation indicates that by the use of suitable recording apparatus aerofoils may be accurately and conveniently tested at a Reynolds number, a velocity and a degree of turbulence, comparable with that on the full-sized airplane. Satisfactory experiments were also made in trailing a sphere and a streamlined body on single wires.
Contributing Partner: UNT Libraries Government Documents Department
Variation in the number of revolutions of air propellers

Variation in the number of revolutions of air propellers

Date: March 1, 1923
Creator: Achenbach, W
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Experiments with fabrics for covering airplane wings, to determine effect of method of installation

Experiments with fabrics for covering airplane wings, to determine effect of method of installation

Date: December 1, 1923
Creator: Proll, A
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Notes on the construction and testing of model airplanes

Notes on the construction and testing of model airplanes

Date: January 1, 1922
Creator: Diehl, Walter S
Description: Here, it is shown that the construction of an airplane model can and should be simplified in order to obtain the most reliable test data. General requirements for model construction are given, keeping in mind that the general purpose of wind tunnel tests on a model airplane is to obtain the aerodynamic characteristics, the static balance, and the efficiency of controls for the particular combination of wings, tail surfaces, fuselage, and landing gear employed in the design. These parts must be exact scale reproductions. Any appreciable variation from scale reproduction must be in the remaining parts of the model, i.e., struts, wires, fittings, control horns, radiators, engines, and the various attachments found exposed to the wind in special airplanes. Interplane bracing is discussed in some detail.
Contributing Partner: UNT Libraries Government Documents Department