Latest content added for UNT Digital Library Collection: Technical Report Archive and Image Libraryhttp://digital.library.unt.edu/explore/collections/TRAIL/browse/?start=15250&fq=untl_institution:UNTGD2011-11-11T19:22:00-06:00UNT LibrariesThis is a custom feed for browsing UNT Digital Library Collection: Technical Report Archive and Image LibraryThe Minimum Induced Drag of Aerofoils2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53402/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53402/"><img alt="The Minimum Induced Drag of Aerofoils" title="The Minimum Induced Drag of Aerofoils" src="http://digital.library.unt.edu/ark:/67531/metadc53402/thumbnail/"/></a></p><p>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.</p>Graphic Construction of Joukowski Wings2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53401/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53401/"><img alt="Graphic Construction of Joukowski Wings" title="Graphic Construction of Joukowski Wings" src="http://digital.library.unt.edu/ark:/67531/metadc53401/thumbnail/"/></a></p><p>A plot of the cross sectional outline of a Joukowski wing is presented.</p>Flow and Drag Formulas for Simple Quadrics2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53407/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53407/"><img alt="Flow and Drag Formulas for Simple Quadrics" title="Flow and Drag Formulas for Simple Quadrics" src="http://digital.library.unt.edu/ark:/67531/metadc53407/thumbnail/"/></a></p><p>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.</p>A Procedure for the Design of Air-Heated Ice-Prevention Systems2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53433/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53433/"><img alt="A Procedure for the Design of Air-Heated Ice-Prevention Systems" title="A Procedure for the Design of Air-Heated Ice-Prevention Systems" src="http://digital.library.unt.edu/ark:/67531/metadc53433/thumbnail/"/></a></p><p>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.</p>Langley Field wind tunnel apparatus2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53825/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53825/"><img alt="Langley Field wind tunnel apparatus" title="Langley Field wind tunnel apparatus" src="http://digital.library.unt.edu/ark:/67531/metadc53825/thumbnail/"/></a></p><p>None</p>Air resistance measurements on actual airplane parts2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53822/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53822/"><img alt="Air resistance measurements on actual airplane parts" title="Air resistance measurements on actual airplane parts" src="http://digital.library.unt.edu/ark:/67531/metadc53822/thumbnail/"/></a></p><p>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.</p>A preliminary investigation of a new method for testing aerofoils in free flight2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53821/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53821/"><img alt="A preliminary investigation of a new method for testing aerofoils in free flight" title="A preliminary investigation of a new method for testing aerofoils in free flight" src="http://digital.library.unt.edu/ark:/67531/metadc53821/thumbnail/"/></a></p><p>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.</p>Variation in the number of revolutions of air propellers2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53827/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53827/"><img alt="Variation in the number of revolutions of air propellers" title="Variation in the number of revolutions of air propellers" src="http://digital.library.unt.edu/ark:/67531/metadc53827/thumbnail/"/></a></p><p>None</p>Experiments with fabrics for covering airplane wings, to determine effect of method of installation2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53820/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53820/"><img alt="Experiments with fabrics for covering airplane wings, to determine effect of method of installation" title="Experiments with fabrics for covering airplane wings, to determine effect of method of installation" src="http://digital.library.unt.edu/ark:/67531/metadc53820/thumbnail/"/></a></p><p>None</p>Notes on the construction and testing of model airplanes2011-11-11T19:22:00-06:00http://digital.library.unt.edu/ark:/67531/metadc53828/<p><a href="http://digital.library.unt.edu/ark:/67531/metadc53828/"><img alt="Notes on the construction and testing of model airplanes" title="Notes on the construction and testing of model airplanes" src="http://digital.library.unt.edu/ark:/67531/metadc53828/thumbnail/"/></a></p><p>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.</p>