UNT Libraries Government Documents Department - 176 Matching Results

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Propeller charts for the determination of the rotational speed for the maximum ratio of the propulsive efficiency to the specific fuel consumption

Description: A set of propeller operating efficiency charts, based on a coefficient from which the propeller rotational speed has been eliminated, is presented. These charts were prepared with data obtained from tests of full-size metal propellers in the NACA propeller-research tunnel. Working charts for nine propeller-body combinations are presented, including results from tests of dual-rotating propellers. These charts are to be used in the calculation of the range and the endurance of airplanes equipped … more
Date: December 11, 1940
Creator: Biermann, David & Conway, Robert N.
Item Type: Refine your search to only Report
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An Approximate Method of Calculation of Relative Humidity Required to Prevent Frosting on Inside of Aircraft Pressure Cabin Windows, Special Report

Description: This report has been prepare in response to a request for information from an aircraft company. A typical example was selected for the presentation of an approximate method of calculation of the relative humidity required to prevent frosting on the inside of a plastic window in a pressure type cabin on a high speed airplane. The results of the study are reviewed.
Date: December 5, 1940
Creator: Jones, Alun R.
Item Type: Refine your search to only Report
open access

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
open access

Cyclic stress-strain studies of metals in torsion

Description: Report presenting cyclic torsion tests made to determine the effects of varying amounts of torsional overstrain on the shape of the shearing stress-strain diagrams of aluminum alloy 17ST, mild steel, wrought iron, copper, brass, and magnesium alloy AX57S. Results regarding the tensile, compressive, and shear properties are provided.
Date: December 1940
Creator: Paul, D. A. & Moore, R. L.
Item Type: Refine your search to only Report
open access

The Design of Cooling Ducts With Special Reference to the Boundary Layer at the Inlet

Description: "A study has been made of underslung cooling ducts with special references to the problems presented by the boundary layer on the fuselage skin. It was found that good flow can be obtained in such ducts by (1) making the inlet opening of such size that the mean inlet velocity is about 0.6 the free-stream velocity and (2) providing vanes behind as well as ahead of the radiator. Tables to facilitate design are included, together with an example " (p. 1).
Date: December 1940
Creator: Katzoff, S.
Item Type: Refine your search to only Report
open access

Drag and propulsive characteristics of air-cooled engine-nacelle installations for two-engine airplanes

Description: Report presenting a study on wing-nacelle propeller arrangements using a two-engine airplane with nacelles varying in diameter. Results regarding the power-off characteristics, propulsive and overall efficiencies, power-on characteristics, and pressure distributions are provided.
Date: December 1940
Creator: Wilson, Herbert A., Jr. & Lehr, Robert R.
Item Type: Refine your search to only Report
open access

Drag Determinations of the Forward Component of a Tricycle Landing Gear

Description: "Wind-tunnel tests were performed to determine the drag of the front-wheel arrangements of several types of tricycle landing gear. One wheel was tested in arrangements to simulate both nonretracted and partially retracted types. The landing gears were tested in conjunction with a fuselage, and the effects of wheel extension and longitudinal location were determined" (p. 1).
Date: December 1940
Creator: Harmon, Hubert N.
Item Type: Refine your search to only Report
open access

Extension of Pack Method for Compressive Tests

Description: "The pack method for determining compressive stress-strain graphs described in NACA Report No. 649 has been modified to extend it's application to thinner gages and stronger materials. The principal modifications consisted in the provision of additional support against instability cementing the specimens of the pack together with fused shellac and the provision of special clamps to hold the specimens together while the test is in progress. The shellac was found to increase the buckling load of … more
Date: December 1940
Creator: Aitchison, C. S.
Item Type: Refine your search to only Report
open access

Factors Affecting Heat Transfer in the Internal-Combustion Engine

Description: Note presenting a method developed for the direct measurement of the average heat-transfer coefficient from the gases in the cylinder during the cycle of operation of an internal-combustion engine. Experimental measurmeents were made with a heat collector projecting through a spark-plug hole into the combustion chamber of the test engine in order to examine the effects of several engine-operating and design parameters on the mean heat transfer to the collector.
Date: December 1940
Creator: Ku, P. M.
Item Type: Refine your search to only Report
open access

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
open access

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
open access

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
open access

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
open access

A graphical method of determining pressure distribution in two-dimensional flow

Description: By a generalization of the Joukowski method, a procedure is developed for effecting localized modifications of airfoil shapes and for determining graphically the resultant changes in the pressure distribution. The application of the procedure to the determination of the pressure distribution over airfoils of original design is demonstrated. Formulas for the lift, the moment, and the aerodynamic center are also given.
Date: November 12, 1940
Creator: Jones, Robert T. & Cohen, Doris
Item Type: Refine your search to only Report
open access

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
open access

The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous Over Three Supports

Description: Report presenting an investigation of a long column continuous over three supports to determine its critical load when the center support was given varying amounts of initial displacement. During each test, the middle support was hinged so as to be free to move parallel to the column axis during buckling. The critical loads predicted from load-deflection readings were different for the upper and lower spans.
Date: November 1940
Creator: Lundquist, Eugene E. & Kotanchik, Joseph N.
Item Type: Refine your search to only Report
open access

The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous Over Three Supports

Description: Report presenting a test of a long column continuous over three supports to determine its critical load when the center support was given varying amounts of initial displacement. During each test, the middle support was hinged so as to be free to move parallel to the column axis during buckling.
Date: November 1940
Creator: Lunquist, Eugene E. & Kotanchik, Joseph N.
Item Type: Refine your search to only Report
open access

A Flight Investigation of Exhaust-Heat De-Icing

Description: The National Advisory Committee for Aeronautics conducted exhaust-heat de-icing tests in flight to provide data needed in the application of this method. The capacity to extract heat from the exhaust gas for de-icing purposes, the quantity of heat required, and other factors were examined. The results indicate that a wing-heating system employing a spanwise exhaust tube within the leading edge of the wing removed 30 to 35 percent of the heat from exhaust gas entering the wing. Data are given fr… more
Date: November 1940
Creator: Rodert, Lewis A. & Jones, Alun R.
Item Type: Refine your search to only Report
open access

Flight Tests of Exhaust-Gas Jet Propulsion

Description: "Flight tests were conducted on the XP-41 airplane, equipped with a Pratt & Whitney R1830-19, 14-cylinder, air-cooled engine, to determine the increase in flight speed obtainable by the use of individual exhaust stacks directly rearwardly to obtain exhaust-gas thrust. Speed increases up to 13 miles per hour at 20,000 feet altitude were obtained using stacks having an exit area of 3.42 square inches for each cylinder. A slight increase in engine power and decrease in cylinder temperature at a gi… more
Date: November 1940
Creator: Pinkel, Benjamin & Turner, L. Richard
Item Type: Refine your search to only Report
open access

Flight Tests of Exhaust Gas Jet Propulsion, Special Report

Description: "Flight tests were conducted on the XP-41 airplane, equipped with a Pratt & Whitney R1830-19, 14-cylinder, air-cooled engine, to determine the increase in flight speed obtainable by the use of individual exhaust stacks directed rearwardly to obtain exhaust-gas thrust. Speed increases up to 18 miles per hour at 20,000 feet altitude were obtained using stacks having an exit area of 3.42 square inches for each cylinder. A slight increase in engine power and decrease in cylinder temperature at a gi… more
Date: November 1940
Creator: Pinkel, Benjamin & Turner, L. Richard
Item Type: Refine your search to only Report
open access

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
open access

Heat-Transfer Tests of a Steel Cylinder Barrel With Aluminum Fins of Optimum Proportions

Description: Report presenting testing of a steel cylinder barrel with aluminum fins of the optimum spacing of 0.090 inch. The primary purpose is to determine the excellence of the thermal bonds between the aluminum fins and the aluminum base and between the aluminum base and the steel and to compare the heat transfer of the barrel with that of barrels with a fin space of 0.052 inch.
Date: November 1940
Creator: Ellerbrock, Herman H., Jr. & Mann, Alvin H.
Item Type: Refine your search to only Report
open access

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
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