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On the Design of Airfoils in Which the Transition of the Boundary Layer Is Delayed

Description: Memorandum examining the phenomenon of airfoil drag, which is related almost exclusively to skin friction at high speed flight conditions. The primary way to reduce drag is to delay the transition from laminar to turbulent flow in the boundary layer along the surface. A particular airflow design that may delay transition and therefore have fewer problems related to drag are provided.
Date: October 1952
Creator: Tani, Itiro
Partner: UNT Libraries Government Documents Department

Influence of Struts and Stays on the Speed of an Airplane

Description: Report presenting an experiment in the Rechlin airdrome in the fall of 1918 to determine the influence of struts and stays on the speed of an airplane. Results indicated that only a slight increase in horizontal speed was shown in a stayless airplane, but it had considerably greater climbing speed.
Date: October 1921
Creator: Heidelberg, V.
Partner: UNT Libraries Government Documents Department

Some Remarks Concerning Soaring Flight

Description: The publication of the following details is due to the desire of the editor to have the problems of soaring flight treated on the occasion of the Rhone Soaring Flight Contest. Soaring flight is defined as motorless flight without loss of height. Some calculations are provided in order to maximize the potential effects of wind and air currents.
Date: October 1921
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Air Transport Economics

Description: Report presenting an exploration of the costs of operation for commercial airlines operating in Europe at the time of the report.
Date: October 1922
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department

Training of Aeronautical Engineers

Description: The requirements and preliminary coursework for aeronautical engineering are discussed. Some of the specific mechanical engineering properties that must be understood are provided. The report is incomplete.
Date: October 1922
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department

Deflection of Propeller Blades While Running

Description: "The forces acting on the blades of a propeller proceed from the mass of the propeller and the resistance of the surrounding medium. The magnitude, direction and point of application of the resultant to the propeller blade is of prime importance for the strength calculation. Since it was obviously impracticable to bring any kind of testing device near the revolving propeller, not so much on account of the element of danger as on account of the resulting considerable disturbance of the air flow, the deflection in both cases was photographically recorded and subsequently measured at leisure" (p. 1).
Date: October 1922
Creator: Katzmayr, R.
Partner: UNT Libraries Government Documents Department

Effect of Periodic Changes of Angle of Attack on Behavior of Airfoils

Description: This report presents the results of a series of experiments, which gave some quantitative results on the effect of periodic changes in the direction of the relative air flow against airfoils. The first series of experiments concerned how the angle of attack of the wing model was changed by causing the latter to oscillate about an axis parallel to the span and at right angles to the air flow. The second series embraced all the experiments in which the direction of the air flow itself was periodically changed.
Date: October 1922
Creator: Katzmayr, R.
Partner: UNT Libraries Government Documents Department

Computative examination of bending strength of girders originally curved and subjected to longitudinal compression

Description: This report examines the stipulation contained in the 1918 BLV, that a girder subjected to longitudinal compression under the influence of half of the specified breaking load, along with Euler bending safety with an initial deflection of 1/200 of the length of the girder can, at most, be subjected to half the stipulated breaking strength.
Date: October 1922
Creator: Hoff, Wilhelm
Partner: UNT Libraries Government Documents Department

The Wing With a Pointed Tip

Description: In airplane construction generally one finds an almost exclusive use of wing tips that are practically square end but occasionally those with large rounded tips. For use as a cantilever wing, however, a wing with pointed tips may contain valuable aerodynamic advantages.
Date: October 1922
Creator: v. Prondzynski, Stephan
Partner: UNT Libraries Government Documents Department

Duralumin, Its Properties and Uses

Description: A historical sketch of duralumin is presented, especially in regards to its manufacture by various countries. The properties of duralumin are discussed and strength characteristics listed. Increasing the hardness of duralumin by tempering is discussed as well as the uses of the metal.
Date: October 1924
Creator: Beck, R.
Partner: UNT Libraries Government Documents Department

Results of Experiments With Slotted Wings

Description: This report recounts some of the successful experiments conducted in England and Germany on slotted wings and ailerons. Wind tunnel test results are given and examples of aircraft constructed with these new wing components are described.
Date: October 1924
Creator: Lachmann, G.
Partner: UNT Libraries Government Documents Department

Mooring Airships

Description: The purpose of this paper is to summarize the present status of the problem of mooring airships. Mooring with one, two and even three cables are all discussed.
Date: October 1924
Creator: Crocco, G. A.
Partner: UNT Libraries Government Documents Department

The Behavior Under Shearing Stress of Duralumin Strip With Round, Flanged Holes

Description: "This report presents the results of an investigation to determine the behavior of dural strip with flanged holes in the center when subjected to shear stresses. They buckle under a certain load just as a flat sheet. There is one optimum hole spacing and a corresponding buckling load in shear for each sheet width, sheet thickness, and flange form. Comparison with non-flanged sheets revealed a marked increase of buckling load in shear due to the flanging and a slightly greater displacement" (p. 1).
Date: October 1934
Creator: Schüssler, Karl
Partner: UNT Libraries Government Documents Department

The Behm Acoustic Sounder for Airplanes With Reference to Its Accuracy

Description: Relative altimetry is of great importance for increasing the safety in aerial transportation, because it makes possible safe flying at night, by poor visibility, and when landing. Among the instruments of this type is the Behm sounder, which operates on an acoustic principle. Acoustic altimetry in general and the Behn sounder, in particular, are covered in this report.
Date: October 1930
Creator: Schreiber, Ernest
Partner: UNT Libraries Government Documents Department

Torsion and Buckling of Open Sections

Description: In this paper is a discussion of the general principles for open sections of any shape. In what follows the torsion will be computed and on the basis of the results it will be possible to obtain a proper design of section in each case. The torsion of buckling members for the case where they are centrally loaded, leads to a problem in pure stability and is similar to that of stressed beams.
Date: October 1936
Creator: Wagner, Herbert
Partner: UNT Libraries Government Documents Department

Transmission of Heat From a Flat Plate to a Fluid Flowing at a High Velocity

Description: "The writer, starting with the consideration of the hydrodynamic and thermodynamic equations for the turbulent boundary layer of a flat plate when it is necessary to take into account the heat produced by friction, arrives at the conclusion that the transmission of the heat follows the same law that is valid when the frictional heat is negligible, provided the temperature of the fluid is considered to be that which the fluid would reach if arrested adiabatically. It is then shown how the same law holds good for faired bodies, and some applications of the law are made to the problems of flight at very high speeds" (p. 1).
Date: October 1932
Creator: Crocco, Luigi
Partner: UNT Libraries Government Documents Department

The Theories of Turbulence

Description: "The theory of turbulence reached its full growth at the end of the 19th century as a result of the work by Boussinesq and Reynolds. It then underwent a long period of stagnation which ended under the impulse given to it by the development of wind tunnels caused by the needs of aviation. Numerous researchers, attempted to put Reynolds' elementary statistical theory into a more precise form. During the war, some isolated scientists - von Weizsacker and Heisenberg in Germany, Kolmogoroff in Russia, Onsager in the U.S.A. - started a program of research. By a system of assumptions which make it possible to approach the structure of turbulence in well-defined limiting conditions quantitatively, they obtained a certain number of laws on the correlations and the spectrum. Since the late reports have improved the mathematical language of turbulence, it was deemed advisable to start with a detailed account of the mathematical methods applicable to turbulence, inspired at first by the work of the French school, above all for the basic principles, then the work of the foreigners, above all for the theory of the spectrum" (p. 1).
Date: October 1955
Creator: Agostini, L. & Bass, J.
Partner: UNT Libraries Government Documents Department

Load Assumptions for the Landing Impact of Seaplanes

Description: The formula for the impact of floats must include the enlargement factor itself as well as the type of enlargement. The latter is preferably characterized by the change in surface loading. It is shown that the enlargement of a small seaplane generally results in a changed float (or boat) loading as well as wing loading. The conditions of starting stipulate the retention of the float loading when changing from single-float (boat) to twin-float arrangement. This contingency is followed by an increased impact factor in the twin-float type against the otherwise equivalent single-float type.
Date: October 1931
Creator: Taub, Josef
Partner: UNT Libraries Government Documents Department