National Advisory Committee for Aeronautics (NACA) - 41 Matching Results

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Tests of Lead-Bronze Bearings in the DVL Bearing-Testing Machine

Description: "The lead-bronze bearings tested in the DVL machine have proven themselves very sensitive to load changes as in comparison with bearings of light metal. In order to prevent surface injuries and consequently running interruptions, the increase of the load has to be made in small steps with sufficient run-in time between steps. The absence of lead in the running surface, impurities in the alloy (especially iron) and surface irregularities (pores) decreases the load-carrying capacity of the bearin… more
Date: June 1940
Creator: Fischer, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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On the Theory of Unsteady Planing and the Motion of a Wing With Vortex Separation

Description: The disturbance imparted to water by a planing body give rise to a wave form of motion on the free surface, the length of the waves increasing indefinitely with increase in the Froude number and being directly proportional to the latter in the case of the plane or two-dimensional problem. At large Froude numbers the effect of the weight shows up to any appreciable extent only at some distance from the body, so that the flow near the body can be considered as part of a flow of an infinitely exte… more
Date: May 1940
Creator: Sedov, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Lead Susceptibility of Fuels and Its Dependence on the Chemical Composition

Description: The fact that by the use of tetraethyl lead a number of otherwise unsuitable fuels could be made to meet engine requirements was not sufficiently appreciated. While use of tetraethyl lead is limited, the addition of special leaded fuels that increase the octane number is a requirement for many fuels. In this connection, the extent to which the action of tetraethyl lead through the addition of knock-resistant hydrocarbons to the base gasoline is influenced, is quite important. To the elucidation… more
Date: April 1940
Creator: Widmaier, O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Some Data on the Static Longitudinal Stability and Control of Airplanes: Design of Control Surfaces

Description: In the solution of a number of problems on the stability and controllability of airplanes, there arises the necessity for knowing the characteristics of the tail surfaces of the types in common use today. Of those characteristics, the most important are the effectiveness and hinge moments of the tail surfaces. As has been shown in the present paper, there exists the possibility of determining these characteristics by the formulas obtained with a degree of accuracy sufficient for the purposes of… more
Date: May 1940
Creator: Martinov, A. & Kolosov, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Torsion of Box Beams With One Side Lacking

Description: "The torsion of box beams of rectangular section, the edges of which are strengthened by flanges, and of which one side is lacking, is analyzed by the energy method. The torsional stresses are generally taken up by the bending of the two parallel walls, the rigidity of which is augmented by the third wall. The result was checked experimentally on duralumin and plywood boxes. The torsion recorded was 10 to 30 percent less than that given by the calculation, owing to self-stiffening" (p. 1).
Date: April 1940
Creator: Cambilargiu, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Shock-Absorbed System of the Airplane Landing Gear

Description: "A discussion is given of the behavior of the shock-absorbing system, consisting of elastic struts and tires, under landing, take-off, and taxying conditions, and a general formula derived for obtaining the minimum stroke required to satisfy the conditions imposed on the landing gear. Finally, the operation of some typical shock-absorbing systems are examined and the necessity brought out for taking into account, in dynamic landing-gear tests, the effect of the wing lift at the instant of conta… more
Date: March 1940
Creator: Callerio, Pietro
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stresses in Single-Spar Wing Constructions With Incompletely Built-Up Ribs

Description: It is shown that the force distribution resulting from incomplete ribs in single spar wing structures may be determined with the aid of the shear field method by a statistically indeterminate computation. A numerical computation is given of the force distribution of a wing structure whose two neighboring incomplete ribs with web missing in half the section are torsionally loaded.
Date: March 1940
Creator: Reinitzhuber, F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Measurement of Knock Characteristics in Spark-Ignition Engines

Description: This paper presents a discussion of three potential sources of error in recording engine knocking which are: the natural oscillation of the membrane, the shock process between test contacts, and the danger of burned contacts. Following this discussion, the paper calls attention to various results which make the bouncing-pin indicator appear fundamentally unsuitable for recording knock phenomena.
Date: March 1940
Creator: Schütz, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of the Methods of Gas Dynamics to Water Flows With Free Surface 2: Flows With Momentum Discontinuities (Hydraulic Jumps)

Description: In this paper an introduction to shock polar diagrams is given which then leads into an examination of water depths in hydraulic jumps. Energy loss during these jumps is considered along with an extended look at elementary solutions of flow. An experimental test set-up is described and the results presented.
Date: March 1940
Creator: Preiswerk, Ernst
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of the Methods of Gas Dynamics to Water Flows With Free Surface 1: Flows With No Energy Dissipation

Description: The application is treated in sufficient detail to facilitate as much as possible its application by the engineer who is less familiar with the subject. The present work was undertaken with two objects in view. In the first place, it is considered as a contribution to the water analogy of gas flows, and secondly, a large portion is devoted to the general theory of the two-dimensional supersonic flows.
Date: March 1940
Creator: Preiswerk, Ernst
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Rectangular Shell Plating Under Uniformly Distributed Hydrostatic Pressure

Description: "A check of the calculation methods used by Foppl and Henky for investigating the reliability of shell plating under hydrostatic pressure has proved that the formulas yield practical results within the elastic range of the material. Foppl's approximate calculation leaves one on the safe side. It further was found on the basis of the marked ductility of the shell plating under tensile stress that the strength is from 50 to 100 percent higher in the elastic range than expected by either method" (… more
Date: December 1940
Creator: Neubert, M. & Sommer, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Materials for Slack Diaphragms

Description: This report deals with systematic experiments carried out on five diaphragm materials with different pretreatment, for the purpose of ascertaining the suitability of such materials for slack diaphragms. The relationship of deflection and load, temperature and moisture, was recorded. Of the explored materials, synthetic leather, balloon cloth, goldbeaters skin, Igelit and Buna, synthetic leather treated with castor oil is the most suitable material for the small pressure range required.
Date: December 1940
Creator: Puschmann, Traute
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chordwise Load Distribution of a Simple Rectangular Wing

Description: The chordwise distribution theory was taken over from the theory of the infinite wing. Since in this work a series expansion in b/t was used, the computation converges only for large aspect ratios. In this paper a useful approximate solution will be found also for wings with large chord - i.e., small aspect ratio.
Date: December 1940
Creator: Wieghardt, Karl
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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DFS Dive-Control Brakes for Gliders and Airplanes and Analytical Study of the Drag of the DFS Dive-Control Brake

Description: These two reports are surveys on the progress and present state of development of dive-control flaps for gliders and airplanes. The second article describes how on the basis of wind tunnel and free-flight tests, the drag increase on brake flaps of the type DFS, can be predicted. Pressure records confirm a two-dimensional load distribution along the brake-flap surface.
Date: January 1940
Creator: Jacobs, Hans & Wanner, Adolf
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recent Work on Airfoil Theory

Description: The basic ideas of a new method for treating the problem of the airfoil are presented, and a review is given of the problems thus far computed for incompressible and supersonic flows. Test results are reported for the airfoil of circular plan form and the results are shown to agree well with the theory. As a supplement, a theory based on the older methods is presented for the rectangular of small aspect ratio.
Date: December 1940
Creator: Prandtl, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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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 ed… more
Date: December 1940
Creator: Schmieden, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Creep Strength of Stabilized Wrought-Aluminum Alloys

Description: Rohn-type equipment has been mounted on rubber blocks, for the purpose of damping the vibrations of the ground and of rendering the plastic yielding of the test bars less subject to outside interferences. New equipment also included three shockproof creep-testing machines with the Martens mirror instruments for recording the strain curve of the fatigue-tested specimens.
Date: November 1940
Creator: Müller, W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Note on the Calculation of Boundary Layers

Description: The properties of the solutions of the hydrodynamic equations of viscous fluid by "boundary-layer omission" are discussed. A method is indicated for the numerical determination of the solution for a known initial profile u(x(sub o),y) and pressure distribution p(x) within the region.
Date: November 1940
Creator: Prandtl, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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General Relationships Between the Various Systems of Reference Axes Employed in Flight Mechanics

Description: "The different possibilities of orientation of the systems of axes currently employed in flight mechanics are compiled and described. Of the three possible couplings between the wind and aircraft axes, the most suitable coupling is that in which the y axis is made the principal axis of rotation for one of the two coupling angles (angles of attack). In connection with this coupling, an experimental system of axes is introduced, whose axes x(sub e) and z(sub e) are situated in the plane of symmet… more
Date: November 1940
Creator: Rautenberg, H. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Resonance Vibrations in Intake and Exhaust Pipes of in-Line Engines 3: The Inlet Process of a Four-Stroke-Cycle Engine

Description: Using a previously developed method, the boundary process of four-stroke-cycle engines are set up. The results deviate considerably from those obtained under the assumption that the velocity fluctuation is proportional to the cylinder piston motion. The deviation is less at the position of resonance frequencies. By the method developed, the effect of the resonance vibrations on the volumetric efficiency can be demonstrated.
Date: October 1940
Creator: Lutz, O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Corrections on the Thermometer Reading in an Air Stream

Description: A method is described for checking a correction formula, based partly on theoretical considerations, for adiabatic compression and friction in flight tests and determining the value of the constant. It is necessary to apply a threefold correction to each thermometer reading. They are a correction for adiabatic compression, friction and for time lag.
Date: October 1940
Creator: Van der Maas, H. J. & Wynia, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Cause of Welding Cracks in Aircraft Steels

Description: The discussion in this article refers to gas welding of thin-walled parts of up to about 3 mm thickness. It was proven that by restricting the sulphur, carbon, and phosphorous content, and by electric-furnace production of the steel, it was possible in a short time to remove this defect. Weld hardness - i.e., martensite formation and hardness of the overheated zone - has no connection with the tendency to weld-crack development. Si, Cr, Mo, or V content has no appreciable effect, while increase… more
Date: October 1940
Creator: Müller, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Limits of Single-Stage Compression in Centrifugal Superchargers for Aircraft

Description: The limits of the single-stage compression in superchargers at the present state of development are determined by five factors. 1) by the rotor material; 2) by the formation of the flow; 3) by the manufacture of double shrouded rotors; 4) by the bearing problem; 5) by the drive method.
Date: September 1940
Creator: Kollmann, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Pressure and Temperature Measurement in Supercharger Investigations

Description: "With the further development of the supercharger, requirements with regard to measuring accuracy increase while at the same time the conditions under which the measurements must be carried out become more difficult. The present paper is a contribution toward the improvement and refinement of the measuring methods. For pressure measurements some suggestions are made with regard to design and location of the measuring stations" (p. 1).
Date: September 1940
Creator: Franz, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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