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The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

Date: January 1, 1943
Creator: Hildebrand, Francis B
Description: A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which further solutions can be readily obtained. The extension of the theory to cover certain cases of non-uniform cross section is indicated. Although the solutions are obtained in terms of infinite series, the present developments differ from those previously given in that, in practical cases, the series usually converge so rapidly that sufficient accuracy is afforded by a small number of terms. Comparisons are made in several cases between the present results and the corresponding solutions obtained by approximate procedures devised by Reissner and by Kuhn and Chiarito.
Contributing Partner: UNT Libraries Government Documents Department
Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Date: January 1, 1943
Creator: Pinkel, Benjamin; Turner, Richard; Voss, Fred & Humble, Leroy V
Description: This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.
Contributing Partner: UNT Libraries Government Documents Department
Experimental Investigation of Impact in Landing on Water

Experimental Investigation of Impact in Landing on Water

Date: January 1, 1943
Creator: Kreps, R. L.
Description: The extent of agreement of the theoretical impact computations with the actual phenomenon has not as yet been fully clarified. There is on the one hand a certain imperfection in the theory (simplifying assumptions made) and on the other an insufficiency in the experimental data available. The object of our present paper is to show how far test results agree with the available approximate computation methods, to investigate in greater detail the physical nature of impact on water, and to perfect the experimental method of studying the phenomenon.
Contributing Partner: UNT Libraries Government Documents Department
An experimental survey of flow across banks of elliptical and pointed tubes

An experimental survey of flow across banks of elliptical and pointed tubes

Date: January 1, 1943
Creator: Palmer, Carl B
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane I : high-inlet-velocity cowling with propeller cuffs tested in high-speed level flight

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane I : high-inlet-velocity cowling with propeller cuffs tested in high-speed level flight

Date: January 1, 1943
Creator: Johnston, J Ford
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane II : low-inlet-velocity cowling with axial-flow fan and propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane II : low-inlet-velocity cowling with axial-flow fan and propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane III : low-inlet-velocity cowling without fan or propeller cuffs, with axial-flow fan alone, and with two different sets of propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane III : low-inlet-velocity cowling without fan or propeller cuffs, with axial-flow fan alone, and with two different sets of propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane IV : high-inlet-velocity cowling tested in climb with and without propeller cuffs and in high-speed level flight without propeller cuffs

Flight investigation of NACA D(sub S) cowlings on the XP-42 airplane IV : high-inlet-velocity cowling tested in climb with and without propeller cuffs and in high-speed level flight without propeller cuffs

Date: January 1, 1943
Creator: Voglewede, T J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The flow of a compressible fluid past a curved surface

The flow of a compressible fluid past a curved surface

Date: January 1, 1943
Creator: Kaplan, Carl
Description: An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity but permits a transition from subsonic to supersonic conditions without the appearance of a compression shock. The limiting value at which potential flow no longer exits is indicated by the apparent divergence of the power series representing the velocity of the fluid at the surface of the solid boundary.
Contributing Partner: UNT Libraries Government Documents Department
Full-scale tunnel tests of a flying model of the Curtiss XP-55 airplane

Full-scale tunnel tests of a flying model of the Curtiss XP-55 airplane

Date: January 1, 1943
Creator: Biebel, William J
Description: None
Contributing Partner: UNT Libraries Government Documents Department
General free to trim tests in NACA tank no.2 of three 1/8-full-size models of flying-boat hulls at low speeds-NACA models 116E-3K, 120R, and 143

General free to trim tests in NACA tank no.2 of three 1/8-full-size models of flying-boat hulls at low speeds-NACA models 116E-3K, 120R, and 143

Date: January 1, 1943
Creator: Carter, Arthur W
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Generalized selection charts for bombers powered by two, four, and six 3000-horsepower engines I : capacity and economy

Generalized selection charts for bombers powered by two, four, and six 3000-horsepower engines I : capacity and economy

Date: January 1, 1943
Creator: Hill, Paul R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Hydrodynamic-stability tests of a model of a flying boat and of a planing surface having a small downward projection (hook) on the planing bottom near the step

Hydrodynamic-stability tests of a model of a flying boat and of a planing surface having a small downward projection (hook) on the planing bottom near the step

Date: January 1, 1943
Creator: Benson, James M
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Icing tests of aircraft-engine induction systems

Icing tests of aircraft-engine induction systems

Date: January 1, 1943
Creator: Kimball, Leo B
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Date: January 1, 1943
Creator: Miller, Cearcy D & Olsen, H Lowell
Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
Contributing Partner: UNT Libraries Government Documents Department
The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Date: January 1, 1943
Creator: Rothrock, Addison M; Krsek, Alois, Jr & Jones, Anthony W
Description: Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.
Contributing Partner: UNT Libraries Government Documents Department
Investigation of the effect of spray strips on the low-speed spray characteristics of a 1/8-size model of the Consolidated PB2Y-3 flying boat - NACA model 116E-3

Investigation of the effect of spray strips on the low-speed spray characteristics of a 1/8-size model of the Consolidated PB2Y-3 flying boat - NACA model 116E-3

Date: January 1, 1943
Creator: Olson, Roland E
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Date: January 1, 1943
Creator: Swanson, Robert S & Toll, Thomas A
Description: A detailed method for determining the jet-boundary corrections for reflection-plane models in rectangular wind tunnels is presented. The method includes the determination of the tunnel span local distribution and the derivation of equations for the corrections to the angle of attack, the lift and drag coefficients, and the pitching-, rolling-, yawing-, and hinge-moment coefficients. The principle effects of aerodynamic induction and of the boundary-induced curvature of the streamlines have been considered. An example is included to illustrate the method. Numerical values of the more important corrections for reflection-plane models in 7 by 10-foot closed wind tunnels are presented.
Contributing Partner: UNT Libraries Government Documents Department
Large-deflection theory for end compression of long rectangular plates rigidly clamped along two edges

Large-deflection theory for end compression of long rectangular plates rigidly clamped along two edges

Date: January 1, 1943
Creator: Levy, Samuel & Krupen, Philip
Description: The von Karman equations for flat plates are solved beyond the buckling load up to edge strains equal to eight time the buckling strain, for the extreme case of rigid clamping along the edges parallel to the load. Deflections, bending stresses, and membrane stresses are given as a function of end compressive load. The theoretical values of effective width are compared with the values derived for simple support along the edges parallel to the load. The increases in effective width due to rigid clamping drops from about 20 percent near the buckling strain to about 8 percent at an edge strain equal to eight times the buckling strain. Experimental values of effective width in the elastic range reported in NACA Technical Note No. 684 are between the theoretical curves for the extremes of simple support and rigid clamping.
Contributing Partner: UNT Libraries Government Documents Department
Least-work analysis of the problem of shear lag in box beams

Least-work analysis of the problem of shear lag in box beams

Date: January 1, 1943
Creator: Hildebrand, Francis B & Reissner, Eric
Description: The distribution of stress in the cover sheets of thin-wall box beams is analyzed, with regard to the effect of shear deformation in the cover sheets, by the method of least work. Explicit results are obtained for a number of representative cases that show the influence of the following factors on the stress patterns. (1) Variation of stress in spanwise direction as given by elementary beam theory. (2) Value of a parameter called shear-lag aspect ratio which designates the product of span-width ratio of the beam and of the square root of the ratio of effective shear modulus and tensing modulus of the cover sheets. (3) Value of ratio of cover-sheet stiffness to side-web stiffness. (4) Variation of beam height in span direction. (5) Variation of beam width in span direction. (6) Variation of cover-sheet thickness in span direction. General conclusions are drawn from the results obtained. Among them the most important one appears to be the fact that the shear-lag effect depends primarily on the following tow quantities: (1) the value of the shear-lag aspect ratio. (2) the shape of the curve representing the product of the stress of elementary beam theory and of the cover-sheet thickness.
Contributing Partner: UNT Libraries Government Documents Department
The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

Date: January 1, 1943
Creator: Gerrish, Harold C. & Meem, J. Lawrence, Jr.
Description: An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy fuel Specification No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs for the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124.
Contributing Partner: UNT Libraries Government Documents Department
A method for calculating heat transfer in the laminar flow region of bodies

A method for calculating heat transfer in the laminar flow region of bodies

Date: January 1, 1943
Creator: Allen, H Julian & Look, Bonne C
Description: This report has been prepared to provide a practical method for determining the chordwise distribution of the rate of heat transfer from the surface of a wing or body of revolution to air. The method is limited in use to the determination of heat transfer from the forward section of such bodies when the flow is laminar. A comparison of the calculated average heat-transfer coefficient for the nose section of the wing of a Lockheed 12-A airplane with that experimentally determined shows a satisfactory agreement. A sample calculation is appended.
Contributing Partner: UNT Libraries Government Documents Department
A method of estimating the knock rating of hydrocarbon fuel blend

A method of estimating the knock rating of hydrocarbon fuel blend

Date: January 1, 1943
Creator: Sanders, Newell D
Description: The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends.
Contributing Partner: UNT Libraries Government Documents Department
A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blends

A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blends

Date: January 1, 1943
Creator: Sanders, Newell D.
Description: The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends.
Contributing Partner: UNT Libraries Government Documents Department