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The Comparative Performance of Superchargers

Description: "This report presents a comparison of superchargers on the basis of the power required to compress the air at a definite rate, and on the basis of the net engine power developed at altitudes from 0 to 40,000 feet. The investigation included geared centrifugal, turbine-driven centrifugal, roots, and vane-type superchargers. It also includes a brief discussion of the mechanical limitations of each supercharger and explains how the method of control affects the power requirements" (p. 425).
Date: January 13, 1931
Creator: Schey, Oscar W.
Partner: UNT Libraries Government Documents Department
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Wind-Tunnel Tests on Airfoil Boundary Layer Control Using a Backward-Opening Slot (1931)

Description: "This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil. Boundary layer control was accomplished by means of a backward-opening slot in the upper surface of the hollow airfoil. Air was caused to flow through this slot by a pressure which was maintained inside the airfoil by a blower. Various slot locations, slot openings, and wing pressures were used" (p. 3).
Date: 1931
Creator: Bamber, Millard J.
Partner: UNT Libraries Government Documents Department
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On the Theory of Wing Sections With Particular Reference to the Lift Distribution

Description: This report gives a simple and exact method of calculating the lift distribution on thin wing sections. The most essential feature of the new theory is the introduction of an "ideal angle of attack," this angle being defined as that at which the flow enters the leading edge smoothly or, more precisely, as the angle of attack at which the lift at the leading edge equals zero. The lift distribution at this particular angle is shown to be a characteristic property of the section and has been terme… more
Date: 1931
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department
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Investigation of the Diaphragm-Type Pressure Cell

Description: "This report relates to various improvements in the process of manufacture of the NACA standard pressure cell. Like most pressure recording devices employing thin diaphragms, they would in general show considerable change in calibration with temperature and also some change of calibration with time or aging effect. The required diaphragm thickness and the desirable rate of mechanical magnification have been determined on the basis of several hundred tests" (p. 507).
Date: February 3, 1931
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department
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The effect of small angles of yaw and pitch on the characteristics of airplane propellers

Description: This report presents the results of wind tunnel tests to determine the effect on the characteristics of a propeller of inclining the propeller axis at small angles to the relative wind. Tests were made of a full-scale propeller and fuselage combination at four angles of yaw (0 degree, +5 degrees, +10 degrees, +15 degrees), and of a model propeller, nacelle, and wing combination of five angles of pitch (-5 degrees, 0 degree, +5 degrees, +10 degrees and +15 degrees). The results of the full-scale… more
Date: January 20, 1931
Creator: Freeman, Hugh B.
Partner: UNT Libraries Government Documents Department
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The effect of valve timing upon the performance of a supercharged engine at altitude and an unsupercharged engine at sea level

Description: This investigation was conducted to determine the comparative effects of valve timing on the performance of an unsupercharged engine at sea level and a supercharged engine at altitude. The tests were conducted on the NACA universal test engine. The timing of the four valve events was varied over a wide range; the engine speeds were varied between 1,050 and 1,500 r.p.m.; the compression ratios were varied between 4.35:1 and 7.35:1. The conditions of exhaust pressure and carburetor pressure of a … more
Date: February 4, 1931
Creator: Schey, Oscar W. & Biermann, Arnold E.
Partner: UNT Libraries Government Documents Department
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Span-load distribution as a factor in stability in roll

Description: "This report gives the results of pressure-distribution tests made to study the effects on lateral stability of changing the span-load distribution on a rectangular monoplane wing model of fairly thick section. Three methods of changing the distribution were employed: variation in profile along the span to a thin symmetrical section at the tip, twist from +5 degrees to -15 degrees at the tip, and sweepback from +20 degrees to -20 degrees. The tests were conducted in a 5-foot closed-throat atmos… more
Date: March 4, 1931
Creator: Knight, Montgomery & Noyes, Richard W.
Partner: UNT Libraries Government Documents Department
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Airship Model Tests in the Variable Density Wind Tunnel

Description: This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of airship models. Eight Goodyear-Zeppelin airship models were tested in the original closed-throat tunnel. After the tunnel was rebuilt with an open throat a new model was tested, and one of the Goodyear-Zeppelin models was retested. The results indicate that much may be done to determine the drag of airships from evaluations of the pressure and skin-frictional drags on models tested at… more
Date: January 27, 1931
Creator: Abbott, Ira H.
Partner: UNT Libraries Government Documents Department
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A New Principle of Sound Frequency Analysis

Description: "In connection with the study of aircraft and propeller noises, the National Advisory Committee for Aeronautics has developed an instrument for sound-frequency analysis which differs fundamentally from previous types, and which, owing to its simplicity of principle, construction, and operation, has proved to be of value in this investigation. The method is based on the well-known fact that the Ohmic loss in an electrical resistance is equal to the sum of the losses of the harmonic components of… more
Date: March 23, 1931
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department
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Hydraulics of Fuel-Injection Pumps for Compression-Ignition Engines

Description: "Formulas are derived for computing the instantaneous pressures delivered by a fuel pump. The first derivation considers the compressibility of the fuel and the second, the compressibility, elasticity, and inertia of the fuel. The second derivation follows that given by Sass; it is shown to be the more accurate of the two. Additional formulas are given for determining the resistance losses in the injection tube" (p. 621).
Date: March 6, 1931
Creator: Rothrock, A. M.
Partner: UNT Libraries Government Documents Department
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The drag characteristics of several airships determined by deceleration tests

Description: This report presents the results of deceleration tests conducted for the purpose of determining the drag characteristics of six airships. The tests were made with airships of various shapes and sizes belonging to the Army, the Navy, and the Goodyear-Zeppelin Corporation. Drag coefficients for the following airships are shown: Army TC-6, TC-10, and TE-2; Navy Los Angeles and ZMC-2; Goodyear Puritan. The coefficients vary from about 0.045 for the small blunt airships to 0.023 for the relatively l… more
Date: March 2, 1931
Creator: Thompson, F. L. & Kirschbaum, H. W.
Partner: UNT Libraries Government Documents Department
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Investigation of damping liquids for aircraft instruments 2

Description: "Data are presented on the kinematic viscosity, in the temperature range -50 degrees to +30 degrees C. of pure liquids and of solutions of animal oils, vegetable oils, mineral oils, glycerine, and ethylene glycol in various low freezing point solvents. It is shown that the thermal coefficient of kinematic viscosity as a function of the kinematic viscosity of the solutions of glycerine and ethylene glycol in alcohols is practically independent of the temperature and the chemical composition of t… more
Date: March 28, 1931
Creator: Houseman, M. R. & Keulegan, G. H.
Partner: UNT Libraries Government Documents Department
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Flame Movement and Pressure Development in an Engine Cylinder

Description: "This investigation describes a visual method for making stroboscopic observations, through a large number of small windows, of the spread of flame throughout the combustion chamber of a gasoline engine. Data, secured by this method on a small engine burning gaseous fuels, are given to show the effects of mixture ratio, spark advance, engine speed, charge density, degree of dilution, compression ratio, and fuel composition on flame movement in the cylinder. Partial indicator diagrams showing pr… more
Date: May 1, 1931
Creator: Marvin, Charles F., Jr. & Best, Robert D.
Partner: UNT Libraries Government Documents Department
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The vertical wind tunnel of the National Advisory Committee for Aeronautics

Description: "The vertical open-throat wind tunnel of the National Advisory Committee for Aeronautics is described in this report. The tunnel was built mainly for studying the spinning characteristics of airplane models, but may be used as well for the usual types of wind-tunnel tests. A special spinning balance is being developed to measure the desired forces and moments with the model simulating the spin of an airplane. Satisfactory air flow has been attained with a velocity that is uniform over the jet t… more
Date: February 9, 1931
Creator: Wenzinger, Carl J. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
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Reduction of turbulence in wind tunnels

Description: From Summary: "A brief nonmathematical outline is given of modern views as to the nature of the effect of turbulence, and their bearing on the desirability of designing wind tunnels for small or large turbulence. Experiments made on a particular wind tunnel for the purpose of reducing the turbulence are described, to illustrate the influence of certain factors on the magnitude of the turbulence. Moderate changes in the size, shape, and wall thickness of cells of the honeycomb were found to have… more
Date: 1931
Creator: Dryden, Hugh L.
Partner: UNT Libraries Government Documents Department
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Physical Testing of Explosives at the Bureau of Mines Explosives Experiment Station, Brueceton, Pa.

Description: Report discussing methods of making physical tests of explosives. The methods are described in unusual detail to permit repetition that will duplicate as nearly as possible the precise manner in which they have been performed in the past and to reduce differences in technique to a minimum.
Date: 1931
Creator: Munroe, Charles E. & Tiffany, J. E.
Partner: UNT Libraries Government Documents Department
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Downwash Measurements Behind Wings With Detached Flow

Description: This investigation, which was made in the small wind tunnel having a diameter of 1.2 m (3.94 feet), embraced three wing models, behind which, at various angles of attack between 0 and 60 degrees, the static pressure and the total pressure along vertical lines (perpendicular to the direction of the undisturbed wind and to the wing span) were measured. The location of these vertical lines are indicated in Figure 1. Moreover, the wing polars were determined by the customary three-component measure… more
Date: August 1931
Creator: Petersohn, E.
Partner: UNT Libraries Government Documents Department
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The aerodynamic characteristics of three tapered airfoils tested in the variable density wind tunnel

Description: From Summary: "This report contains the lift, drag, and moment characteristics of tapered Clark Y, Gottingen 393, and USA 45 airfoils as obtained from tests made in the Variable Density Wind Tunnel of the NACA. The results are given at both low and high Reynolds Numbers to show scale effect and to provide data for use in airplane design."
Date: February 1931
Creator: Anderson, Raymond F.
Partner: UNT Libraries Government Documents Department
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The aerodynamic characteristics of six commonly used Airfoils over a large range of positive and negative angles of attack

Description: From Summary: "This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were foun… more
Date: November 1931
Creator: Anderson, Raymond F.
Partner: UNT Libraries Government Documents Department
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The Variation in Pressure in the Cabin of an Airplane in Flight

Description: From Summary: "The pressure in the cabin of a Fairchild cabin monoplane was surveyed in flight, and was found to decrease with increased air speed over the fuselage and to vary with the number and location of openings in the cabin. The maximum depression of 2.2 inches of water (equivalent pressure altitude at sea level of 152 feet) occurred at the high speed of the airplane in level flight with the cabin closed."
Date: March 1931
Creator: Gough, Melvin N.
Partner: UNT Libraries Government Documents Department
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