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Lift Theory of Supporting Surfaces: Second Article

Description: Memorandum presenting a description of the hydrodynamic lift theory of supporting services. This report is mainly about the task of finding suitable wing sections for given lift conditions. Formulas are given for lift magnitude and moment, which make it possible to obtain solutions of great simplicity and clearness.
Date: September 1921
Creator: von Mises, R.
Partner: UNT Libraries Government Documents Department
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The critical velocity of a body towed by a cable from an airplane

Description: It is sufficient to consider only the equations of motion of the towed body whereas those of the cable may be left out of consideration. The result obtained makes it possible to determine which factors affect the critical velocity and what modifications of the instrument are necessary for extending the upper limit of that velocity.
Date: July 1937
Creator: Koning, C. & DeHaas, T. P.
Partner: UNT Libraries Government Documents Department
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The Transformation of Heat in an Engine

Description: This report presents a thermodynamic basis for rating heat engines. The production of work by a heat engine rests on the operation of supplying heat, under favorable conditions, to a working fluid and then taking it away.
Date: April 1929
Creator: Neumann, Kurt
Partner: UNT Libraries Government Documents Department
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Supplement to Comparison of Automatic Control Systems

Description: "This analysis deals with the indirect regulator, wherefrom the behavior of the direct regulator is deduced as a limiting case. The prime mover is looked upon as "independent of the load": a change in the adjusting power (to be applied) for the control link (as, for example, in relation to the adjusting path (eta) with pressure valves or the rudder of vessels) does not modify the actions of the prime mover. Mass forces and friction are discounted; "clearance" also is discounted in the transmission links of the regulator" (p. 1).
Date: August 1941
Creator: Oppelt, W.
Partner: UNT Libraries Government Documents Department
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The Boundary Layer as a Means of Controlling the Flow of Liquids and Gases

Description: According to one of the main propositions of the boundary layer theory the scarcely noticeable boundary layer may, under certain conditions, have a decisive influence on the form of the external flow by causing it to separate from the wing surface. These phenomena are known to be caused by a kind of stagnation of the boundary layer at the point of separation. The present report deals with similar phenomena. It is important to note that usually the cause (external interference) directly affects only the layer close to the wall, while its indirect effect extends to a large portion of the external flow.
Date: March 1930
Creator: Schrenk, Oskar
Partner: UNT Libraries Government Documents Department
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The Vortex Theory and Its Significance in Aviation

Description: This report will present ideas closely related to the vortex conception and illustrate them in the simplest possible terms. In addition to these general considerations, this report will attempt to show the application of the vortex theory in connection with the wing theory.
Date: July 1930
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
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Riveting in Metal Airplane Construction Part 1 : Riveting Methods and Equipment in German Metal Airplane Construction

Description: "Although all constructors in Germany use duralumin quite frequently, and prefer cold riveting exclusively for permanent (nondetachable) connections of individual structural components, their methods and equipment are very diversified. The differences are due to a great extent to the diversity of structural types and to the special shapes of the individual subassemblies. The results is that different manufacturers have developed totally different riveting methods, as well as entirely different working methods" (p. 1).
Date: December 1930
Creator: Pleines, Wilhelm
Partner: UNT Libraries Government Documents Department
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Problems Concerning the Stability and Maneuverability of Airplanes

Description: "The stability of an airplane can be easily determined by wind-tunnel tests, especially by simple tests with models mounted wind-vane fashion. However, each stability curve plotted by this method is valid only for a certain setting of the corresponding control surface, i.e., it characterizes the stability of the airplane with the control stick in a given position. The problems thus defined are studied from the point of view of longitudinal and transverse stability. Directional stability is not included in this study" (p. 1).
Date: March 1932
Creator: Biche, Jean
Partner: UNT Libraries Government Documents Department
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Combustion of Liquid Fuels in Diesel Engine

Description: Hitherto, definite specifications have always been made for fuel oils and they have been classified as more or less good or non-utilizable. The present aim, however, is to build Diesel engines capable of using even the poorest liquid fuels and especially the waste products of the oil industry, without special chemical or physical preparation.
Date: October 1924
Creator: Alt, Otto
Partner: UNT Libraries Government Documents Department
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Mathematical treatise on the recovery from a flat spin

Description: In this mathematical investigation, made in collaboration with Dr. Wilhelm Schmidt, we interpret the temporary change (due to some disturbance) in the quantities which define the position of the airplane while in a flat spin. We further examine the effect of this change, of the means resorted to to produce the disturbance, and thus reveal the expedients available for recovering from a flat spin.
Date: November 1930
Creator: Fuchs, R.
Partner: UNT Libraries Government Documents Department
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Development of Light and Small Airplanes

Description: Memorandum presenting an overview of the development of light and small airplanes. Some of the characteristics explored include the development of airplanes of medium weight, development in countries other than Germany, development of light airplanes, general constructive fiducial lines, safety problems, the economy problem, and some special structural considerations are provided.
Date: July 1926
Creator: Lachmann, G.
Partner: UNT Libraries Government Documents Department
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Accurate Calculation of Multispar Cantilever and Semicantilever Wings With Parallel Webs Under Direct and Indirect Loading

Description: In the present report the computation is actually carried through for the case of parallel spars of equal resistance in bending without direct loading, including plotting of the influence lines; for other cases the method of calculation is explained. The development of large size airplanes can be speeded up by accurate methods of calculation such as this.
Date: March 1932
Creator: Sänger, Eugen
Partner: UNT Libraries Government Documents Department
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Measuring Vibration and Torque With the Oscillograph

Description: "The recent development of technical science demands maximum reliability of functioning, together with maximum utilization of construction materials. For this purpose we must know what stresses are produced during functioning. One cause of great stresses are mechanical vibrations and this report describes a method of using an oscilloscope to measure the stresses of rapidly changing phenomena" (p. 1).
Date: December 1924
Creator: Elsässer, R.
Partner: UNT Libraries Government Documents Department
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Contribution to the Systematic Investigation on Joukowsky Profiles

Description: "This article resulted from the need of showing, in a simple way, how the aerodynamic properties of airfoils are affected by the shape of their profiles. No general solution of this problem could be found, since the profile shapes cannot ordinarily be expressed by simple mathematical formulas. This advantage is possessed only by the Joukowsky profiles and this discussion of the problem is therefore limited to them" (p. 1).
Date: April 1928
Creator: Loew, Gottfried
Partner: UNT Libraries Government Documents Department
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A Few More Mechanical-Flight Formulas Without the Aid of Polar Diagrams

Description: The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The present report deals only with the relations of the airfoils. The mutual action of the airfoils, engine and propeller will be treated in a subsequent report.
Date: March 1928
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department
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Atomization of Liquid Fuels Part 3: Critical Discussion of Experimental Reesults, Mixing the Atomized Fuel with Air

Description: This report provides a critical discussion of the results of the experiments conducted in the previous NACA-TM's 329 and 330. The main object of this investigation was to determine the size of the drops in mechanical atomization.
Date: September 1925
Creator: Kuehn, R.
Partner: UNT Libraries Government Documents Department
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Kinetographic Determination of Airplane Flight Characteristics

Description: The author's first experiments with a glider on flight characteristics demonstrated that an accurate flight-path measurement would enable determination of the polar diagram from a gliding flight. Since then he has endeavored to obtain accurate flight measurements by means of kinetograph (motion-picture camera). Different methods of accomplishing this are presented.
Date: April 1927
Creator: Raethjen, P.
Partner: UNT Libraries Government Documents Department
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The Mutual Action of Airplane Body and Power Plant

Description: The present report concerns the development of general propeller performance and r.p.m. curves which, combined with the general curve of the power required for level flight, presents a complete picture of the performance. The curve of power required for level flight in this paper is only an approximation for constant profile drag coefficient, meaning that it is not suitable to unconventional wing sections.
Date: April 1932
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department
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Rules and Regulations for Endurance Contest of Aviation Engines: Under the Auspices of the Aero Club of France

Description: Memorandum presenting the rules and regulations of the Endurance Contest of Aviation Engines, which was put on by the Aero Club of France. A description of the rules regarding the aircraft in competition, the characteristics of the tests that were conducted, and information regarding classification of the aircraft is provided.
Date: November 1923
Partner: UNT Libraries Government Documents Department
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Wind Tunnel Tests of Correction Formula for Wings of Large Span

Description: The theory (wing experiments in an artificial air stream are subject to error, due to the fact that the wing is not situated in an unlimited body of air) by means of which the given drag correction was obtained, was based on various assumptions (e.g., elliptical distribution of lift) which do not always hold true. For this reason it was desirable to test the equation for the additional drag in regard to its reliability and range of application.
Date: May 1924
Creator: Wieselsberger, C.
Partner: UNT Libraries Government Documents Department
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