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The Lift Distribution of Swept-Back Wings

Description: "Two procedures for calculating the lift distribution along the span are given in which a better account is taken of the distribution of circulation over the area than in the Prandtl lifting-line theory. The methods are also applicable to wing sweepback. Calculated results for the two methods were in agreement" (p. 1).
Date: March 1947
Creator: Weissinger, J.
Partner: UNT Libraries Government Documents Department

Lame's Wave Functions of the Ellipsoid of Revolution

Description: "Lamé's wave functions result by separation of the wave equation in elliptic coordinates and by integration of the ordinary differential equations thus originating. They are a generalization of Lamé's potential functions which originate in the same manner from the potential equation. Lamé's wave functions are applied for boundary value problems of the wave equation for regions of space bounded by surfaces of a system of confocal ellipsoids and hyperboloids" (p. 1).
Date: April 1949
Creator: Meixner, J.
Partner: UNT Libraries Government Documents Department

Laboratory Report on the Investigation of the Flow Around Two Turbine-Blade Profiles Using the Interferometer Method

Description: "At the request of the Junkers Aircraft and Engine Construction Company, Engine Division, Dessau Main Plant, an investigation was made using the interferometer method on the two turbine-blade profiles submitted. The interferometer method enables making visible the differences in density and consequently the boundary layers that develop when a flow is directed on the profile. Recognition of the points on the profile at which separation of flow occurs is thus possible" (p. 1).
Date: July 1947
Creator: von Vietinghoff-Scheel, K.
Partner: UNT Libraries Government Documents Department

Lift Increase by Blowing Out Air, Tests on Airfoil of 12 Percent Thickness, Using Various Types of Flap

Description: "The NACA 23012-4 airfoil was investigated for the purpose of increasing lift by means of blowing out air from the wing, in conjunction with the effect of plain flap of variable contour and slotted flap of 25 percent chord length. The wing also was provided with a hinged nose, to be deflected at will. Air was blown out from the wing immediately in front of the flap; also at the opening between wing and hinged nose,tangentially to the surface of the wing" (p. 1).
Date: June 1947
Creator: Schwier, W.
Partner: UNT Libraries Government Documents Department

The Light Airplane

Description: T.M. 311 gave a short outline of modern theoretical aerodynamics as applied to light airplane design. This discussion may have been somewhat obscure to the nontechnical reader. A series of charts or curves should serve to clear up such obscurity as well as to more definitely emphasize those quantities most important for each flight characteristic.
Date: August 1925
Creator: Driggs, Ivan H.
Partner: UNT Libraries Government Documents Department

Investigation of an Afterburning Ramjet Using Gaseous Hydrogen as Fuel at Mach Number of 3.0

Description: Memorandum presenting an investigation conducted in the supersonic wind tunnel on a 16-inch ramjet that was equipped with an afterburner and used gaseous hydrogen for both the primary and afterburner fuels. The primary nozzle had a contraction ratio of 0.6 while the exit nozzle had a contraction ratio of 0.9. Data were obtained at a free-stream Mach number of 3.0 and zero angle of attack.
Date: June 17, 1957
Creator: Wasserbauer, Joseph F.
Partner: UNT Libraries Government Documents Department

Safeguards Against Flutter of Airplanes

Description: This report is a compilation of practical rules, derived at the same time from theory and from experience, intended to guide the aeronautical engineer in the design of flutter-free airplanes. Rules applicable to the wing, the ailerons, flaps, tabs,tail surfaces, and fuselage are discussed.
Date: August 1956
Creator: De Vries, Gerhard
Partner: UNT Libraries Government Documents Department

Self-Ignition and Combustion of Gases

Description: This paper attempts to state laws for the self-ignition and combustion of gases in a comprehensive manner. The primary focus is recent investigations in which new combustion phenomena or new methods of studying them experimentally are brought out and investigations that throw new light on already known phenomena.
Date: August 1942
Creator: Sokolik, A. S.
Partner: UNT Libraries Government Documents Department

Some New Problems on Shells and Thin Structures

Description: "Cylindrical shells of arbitrary section, reinforced by longitudinal and transverse members (stringers and ribs) are considered by us, for a sufficiently close spacing of the ribs, as in our previously published papers (references 1 end 2), as thin-walled orthotropic spatial systems at the cross-sections of which only axial (normal and shearing) forces can arise. The longitudinal bending and twisting moments, due to their weak effect on the stress state of the shell, are taken equal to zero. Along the longitudinal sections of the shell there may arise transverse forces in addition to the normal ~d shearing forces" (p. 1).
Date: March 1949
Creator: Vlasov, V. S.
Partner: UNT Libraries Government Documents Department

Pressure Recovery for Missiles with Reaction Propulsion at High Supersonic Speeds (The Efficiency of Shock Diffusers)

Description: "The problem of the intake of air is treated for a missile flying at supersonic speeds and of changing the kinetic energy of the air into pressure with the least possible losses. Calculations are carried out concerning the results which can be attained. After a discussion of several preliminary experiments, the practical solution of the problem at hand is indicated by model experiments. The results proved very satisfactory in view of the results which had been attained previously and the values which were anticipated theoretically" (p. 1).
Date: June 1947
Creator: Oswatitsch, K.
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

The Ground Effect on Lifting Propellers

Description: In what follows an estimate will be made of the magnitude of the ground effect. For the two cases where the distance a of the propeller from the ground is very small, and very large, respectively, in comparison with the propeller radius r(sub o) the relations may be simply expressed. We consider first the effect of the ground, assuming that the thrust is held constant, as may be done by a suitable change in the propeller speed.
Date: August 1937
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department

Flow Around Wings Accompanied by Separation of Vortices

Description: The flow around wings computed by the usual method leads in the case of a finite trailing edge to a stagnation point in the trailing edge due to the Kutta-Joukowsky condition of flow governing this region. As a result, the theoretical pressure distribution differs substantially from the experimental values in the vicinity of the trailing edge. The present report describes an alternative method of calculation in which the rear stagnation point no longer appears. The stream leaves the trailing edge tangentially on the pressure side and a similar tangential separation occurs on the suction side of the profile at a point slightly in front of the trailing edge.
Date: December 1940
Creator: Schmieden, C.
Partner: UNT Libraries Government Documents Department

Heat Transfer in Geometrically Similar Cylinders

Description: The power and heat-stress conditions of geometrically similar engines are discussed. The advantages accruing from smaller cylinder dimensions are higher specific horsepower, lower weight per horsepower, lower piston temperature, and less frontal area, with reduced detonation tendency.
Date: May 1941
Creator: Riekert, P. & Held, A.
Partner: UNT Libraries Government Documents Department

Inherent Stability of Helicopters

Description: The equilibrium, in still air, of a "stationary" helicopter (i.e., of one having neither vertical nor translational velocity, but a tendency to remain practically motionless within restricted limits of space) presents some difficulty in practice and justifies a theoretical investigation of its "inherent stability," i.e., independent of the pilot.
Date: October 1923
Creator: Crocco, G. Arturo
Partner: UNT Libraries Government Documents Department

Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Description: Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a form designed to be aerodynamically favorable, the ability to operate is at least questionable. This investigation will account for the important practical observation made by Paul Schmidt that the ratio of the effective valve cross-sectional area to the tube cross section may not be of any random magnitude and will explain why at too great flight speeds the jet tube ceases to operate. Chemical an thermodynamic processes (for example, constituents or mode of fuel-air-mixture formation or heat losses) are unimportant in this regard.
Date: February 1947
Creator: Schultz-Grunow, F.
Partner: UNT Libraries Government Documents Department

General Considerations on the Flow of Compressible Fluids

Description: This paper presents an introduction to the subject of the flow of compressible media. Information regarding steady potential flow, flows with "subsonic" velocities, higher approximations of subsonic velocities, flow with supersonic velocities, an approximate method for general two-dimensional supersonic flow, passage through the velocity of sound, and the application to airfoils is provided. Historical development and hydraulics are omitted.
Date: October 1936
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

General Characteristics of the Flow through Nozzles at Near Critical Speeds

Description: The characteristics of the position and form of the transition surface through the critical velocity are computed for flow through flat and round nozzles from subsonic to supersonic velocity. Corresponding considerations were carried out for the flow about profiles in the vicinity of sonic velocity.
Date: June 1947
Creator: Sauer, R.
Partner: UNT Libraries Government Documents Department

Interim Report on Fatigue Characteristics of a Typical Metal Wing

Description: Constant amplitude fatigue tests of seventy-two P-51D "Mustang" wings are reported. The tests were performed by a vibrational loading system and by an hydraulic loading device for conditions with and without varying amounts of pre-load. The results indicate that: (a) the frequency of occurrence of fatigue at any one location is related to the range of the loads applied, (b) the rate of propagation of visible cracks is more or less constant for a large portion of the life of the specimen, and (c) the fatigue strength of the structure is similar to that of notched material having a theoretical stress concentration factor of more than 3.0.
Date: March 1956
Creator: Kepert, J. L. & Payne, A. O.
Partner: UNT Libraries Government Documents Department

Researches on the Piston Ring

Description: "In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cylinder wall at any given point of the ring" (p. 1).
Date: February 1944
Creator: Ebihara, Keikiti
Partner: UNT Libraries Government Documents Department