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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.
Date: August 1941
Creator: Oppelt, W
Partner: UNT Libraries Government Documents Department

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: De Haas, T P & Koning, C
Partner: UNT Libraries Government Documents Department

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

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 1, 1930
Creator: Schrenk, Oskar
Partner: UNT Libraries Government Documents Department

The 1929 Rhon soaring-flight contest

Description: The limitation of the 1929 contest to performance gliders necessitated the establishment of a formula which would make it possible to distinguish between performance gliders and school and training gliders. The sinking speed was therefore adopted as the basis for such a distinction, and the requirement was made that the sinking speed of a performance glider should not exceed 0.8 m/s. The rest of the report details the different entries with regard to design and performance.
Date: April 1930
Creator: Lippisch, Alexander
Partner: UNT Libraries Government Documents Department

Airfoil Theory at Supersonic Speed

Description: A theory is developed for the airfoil of finite span at supersonic speed analogous to the Prandtl airfoil theory of 1918-1919 for incompressible flow. In addition to the profile and induced drags, account must be taken at supersonic flow of still another drag, namely, the wave drag, which is independent of the wing aspect ratio. Both wave and induced drags are proportional to the square of the lift and depend on the Mach number, that is, the ratio of flight to sound speed. In general, in the case of supersonic flow, the drag-lift ratio is considerably less favorable than is the case for incompressible flow. Among others the following examples are considered: 1) lifting line with constant lift distribution (horseshoe vortex); 2) computation of wave and induced drag and the twist of a trapezoidal wing of constant lift density; 3) computation of the lift distribution and drag of an untwisted rectangular wing.
Date: June 1939
Creator: Schlichting, H
Partner: UNT Libraries Government Documents Department

"AM" gasoline cock.

Description: The "AM" cock was designed specially for gasoline pipes on vehicles using internal combustion engines (airplanes, airships, automobiles, tractors, battle "tanks", boats, etc.).
Date: February 1923
Partner: UNT Libraries Government Documents Department

Analysis of flight and wind-tunnel tests on Udet airplanes with reference to spinning characteristics

Description: This report presents an analysis of results of wind-tunnel tests conducted at the D.V.L. Values were determined for the effectiveness of all the controls at various angles of attack. The autorotation was studied by subjecting the rotating model to an air blast.
Date: March 1929
Creator: Herrmann, H
Partner: UNT Libraries Government Documents Department

Experimental investigation of the physical properties of medium and heavy oils, their vaporization and use in explosion engines. Part IV

Description: This report presents a theoretical treatment of the vaporization process of medium and heavy oils. The results of this investigation, which were mostly obtained from the lighter components of the heavy fuels, require a 10- or 16-fold vaporization in comparison with gasoline. We must attain a still finer degree of atomization, in order to include the heavier components.
Date: December 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department

Twelfth Rhon soaring contest, 1931

Description: The crew of the "Fafnir" was given an excellent opportunity for collecting first-hand data as to the usefulness of gliders in the Alps. It is necessary to recount the remarkable glider achievements ahead of the Rhon Soaring Contest, in order to understand the tension and expectation with which the Rhon contest was anticipated.
Date: May 1932
Creator: Georgii, Walter
Partner: UNT Libraries Government Documents Department

Magnan glider M-2

Description: The construction of the Magnan glider, M-2, is presented which is designed to fly in so-called horizontal winds.
Date: February 1924
Creator: Lesage, M Andre
Partner: UNT Libraries Government Documents Department

Airplane drag

Description: It has been less well understood that the induced drag (or, better said, the undesired increase in the induced drag as compared with the theoretical minimum calculated by Prandtl) plays a decisive role in the process of taking off and therefore in the requisite engine power. This paper seeks to clarify the induced drag.
Date: December 1929
Creator: Topfer, Carl
Partner: UNT Libraries Government Documents Department

Airplane flight in the stratosphere

Description: This brief survey of the problems encountered in high-altitude flight deals in particular with the need for high lift coefficient in the wings, large aspect ratios in the wings, and also the problem of hermetically sealing the cabin.
Date: February 1932
Creator: De Caria, Ugo
Partner: UNT Libraries Government Documents Department

Aeronautical education and research at the Swiss Institute of Technology in Zurich

Description: Progress in the scientific and practical fields of aviation has caused the Swiss Institute of Technology to organize lectures and practical training courses in all three branches of aeronautics and to found centers of scientific research, laboratories, etc., in order to supply the government and industries with scientifically and technically trained engineers.
Date: April 1931
Creator: Karner, L & Ackeret, J
Partner: UNT Libraries Government Documents Department

Aeronautical record : no. 1 (to June, 1923)

Description: "...considerations have prompted us to pay special attention to the development of aeronautical industries and aerial navigation as a commercial enterprise and to publish an analytical review of events in the aeronautical world and of the attendant problems.".
Date: December 1923
Partner: UNT Libraries Government Documents Department

The dangerous sideslip of a stalled airplane and its prevention

Description: This investigation covers only that phase of airplane accidents which are the result of sideslip. We examine the circumstances under which this occurs, study the behavior of present-day airplane types (monoplane, conventional and staggered biplane) therein and endeavor to find a solution whereby this danger may be avoided.
Date: September 1, 1931
Creator: Schmidt, Wilhelm & Fuchs, Richard
Partner: UNT Libraries Government Documents Department

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

Graetzin special carburetor

Description: Corresponding to practical requirements, this carburetor (especially the smaller sizes) may be regarded as the smallest form of a float carburetor and is adapted for use with all small engines, including auxiliary bicycle and similar engines.
Date: February 1923
Partner: UNT Libraries Government Documents Department