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On Rotational Conical Flow

Description: Some general properties of isoenergetic rotational conical fields are determined. For such fields, provided the physical parameters of the fluid flow are known on a conical reference surface, it being understood that they satisfy certain imposed conditions, it is shown how to construct the hodographs in the various meridional semiplanes, as the envelope of either the tangents to the hodographs or of the osculatory circles.
Date: February 1952
Creator: Ferrari, Carlo
Partner: UNT Libraries Government Documents Department

On the Actual Loads on Airplane Landing Gears

Description: This investigation was intended to throw light on a number of problems: 1) obtain a time history of the force acting on the gear wheels during take-off and landing runs; 2) obtain the time history of the direction of this force (magnitude of its three components along the coordinate axes); 3) derive conclusions as to the design load factors. In connection with the latter, of special interest was the solution of such problems as: a) the dynamic loads in the three main landing attitudes; b) the problem of the true direction of the forces for each of the three "pure" types of landing; c) combination of the above types; d) the comparison for each of the chassis members of the computed force (according to the design standards) with the actual force measured in the tests so as to determine the actual factors of safety.
Date: March 1937
Creator: Shiskin, S.
Partner: UNT Libraries Government Documents Department

Recent Results in Rocket Flight Technique

Description: "The concept of the effective ejection velocity of a rocket engine is explained and the magnitude of the attainable ejection velocity theoretically and experimentally investigated. Velocities above 3000 meters per second (6700 mph) are actually measured and the possibilities of further increases shown" (p. 1).
Date: April 1942
Creator: Sanger, Eugen
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 3

Description: The test equipment for studying the vaporization of heavy and medium oils is described as well as some of the experimental properties explored such as vaporization speed and diffusion coefficient. The experimental arrangement is also discussed.
Date: October 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department

The Electrodynamometric Balance of the Small Wind Tunnel of the French Service of Aeronautical Research

Description: This investigation shows the attempt to improve the electrodynamomoter designed by Mr. Villey. The force to be measured acts on a flexible steel plate which is placed in front of a fixed plate. The deformation varies the original thickness of the layer of air between the two plates, thus causing a more rapid variation in the coefficient of electrostatic attraction of the two plates than in the capacity of the condenser formed by the dynamometer.
Date: March 1930
Creator: Rebuffet, P.
Partner: UNT Libraries Government Documents Department

The Efficiency of Combustion Turbines With Constant-Pressure Combustion

Description: "Of the two fundamental cycles employed in combustion turbines, namely, the explosion (or constant-volume) cycle and the constant-pressure cycle, the latter is considered more in detail and its efficiency is derived with the aid of the cycle diagrams for the several cases with adiabatic and isothermal compression and expansion strokes and with and without utilization of the exhaust heat. Account is also taken of the separate efficiencies of the turbine and compressor and of the pressure losses and heat transfer in the piping. The results show that without the utilization of the exhaust heat the efficiencies for the two cases of adiabatic and isothermal compression is offset by the increase in the heat supplied" (p. 1).
Date: April 1941
Creator: Piening, Werner
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 1

Description: While little has been accomplished in obtaining an abundant supply of light oils from coal and heavy oils, progress has been made on engine design to make use of the heavier oils. Progress has been made in two different directions which are outlined in this paper: the group of engines with medium and high-pressure carburetion in the cylinder; and the group of engines with low-pressure carburetion of the heavy oils before reaching the cylinder.
Date: May 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department

Metal Airplane Construction

Description: It has long been thought that metal construction of airplanes would involve an increase in weight as compared with wood construction. Recent experience has shown that such is not the case. This report describes the materials used, treatment of, and characteristics of metal airplane construction.
Date: May 1926
Partner: UNT Libraries Government Documents Department

On Force-Deflection Diagrams of Airplane Shock Absorber Struts: First, Second, and Third Partial Reports

Description: This paper, which is presented in three parts, is an analytical study of the behavior of landing gear shock struts, with various types of assumptions for the shock-strut characteristics. The effects of tire springing are neglected. The first part compares the behavior of struts with linear and quadratic damping. The second part considers struts with nonlinear spring characteristics and linear or quadratic damping. The third part treats the oleo-pneumatic strut with air-compression springing without damping and with damping proportional to velocity.
Date: November 1954
Creator: Schlaefke, Karlhans
Partner: UNT Libraries Government Documents Department

Metal Covering of Airplanes

Description: This paper presents a relative determination of the wrinkling of a plate wall beam with variable number of supports and methods of attachment. The discussion is based entirely on tests with extensometer readings and number of wrinkles, with complete web and with cutout sections. The author notes that the number of corrugations increase with added stress, keeping constant edge spacing.
Date: November 1930
Creator: Mathar, J.
Partner: UNT Libraries Government Documents Department

The Mechanical Properties of Wood of Different Moisture Content Within -200 Degrees to +200 Degrees C Temperature Range

Description: Systematic experiments were undertaken with special reference to the effect of gross specific weight (specific weight inclusive of pores) and the moisture content of wood. It was found that the modules of elasticity of wood at room temperature and frozen at -8 degrees is practically the same. The effect of moisture on the compression strength of frozen wood was explored as well as the flexural and impact strength of frozen wood and frozen laminated wood.
Date: September 1941
Creator: Kollmann, Franz
Partner: UNT Libraries Government Documents Department

The Usefulness of Stunting

Description: Stunting is an important part of the training of a military pilot, and the knowledge gained in passing through the "acrobatic course" is put to constant use in service, especially with fighting aircraft.
Date: November 1922
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department

Variable Pitch Propeller

Description: The advantages of variable pitch propellers over constant pitch propellers is presented along with different methods of varying the pitch. The technique of varying the shape of the propeller is presented as the most efficient one.
Date: July 1923
Creator: Pistolesi, Enrico
Partner: UNT Libraries Government Documents Department

On the Three-Dimensional Instability of Laminar Boundary Layers on Concave Walls

Description: Memorandum presenting a study of the stability of laminar boundary layer profiles on slightly curved walls relative to small disturbances, in the shape of vortices, whose axes are parallel to the principal direction of flow. The result in an eigenvalue problem by which, for a given undisturbed flow at a prescribed wall, the amplification or decay is computed for each Reynolds number and each vortex thickness.
Date: June 1954
Creator: Göertler, H.
Partner: UNT Libraries Government Documents Department

Variable Pitch Propellers

Description: It is proposed in this report to explain the Gloster Hele-Shaw Beacham variable pitch propeller. It is a variable pitch propeller, which has been theorized to greatly improve the performance of an airplane or airship. An explanation of the way the propeller works and some of the physics behind propeller operation are provided.
Date: April 1928
Creator: Milner, H. L.
Partner: UNT Libraries Government Documents Department

Valve-Spring Surge

Description: Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.
Date: March 1937
Creator: Marti, Willy
Partner: UNT Libraries Government Documents Department

Variation in Velocity Profile with Change in Surface Roughness of Boundary

Description: "The present report deals with the variation of a turbulent velocity profile in flow from rough to smooth wall and vice versa. Expressions obtained for the shear-stress distribution with respect to the distance from the point of junction of the different roughnesses and from the wall distance, are utilized to ascertain the developing velocity distributions. Under simplified assumptions, the use of these formulas renders possible the integration of the motion equations for the shear stress. This calculation is carried out and compared with the experiments" (p. 1).
Date: September 1940
Creator: Jacobs, W.
Partner: UNT Libraries Government Documents Department