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Aerodynamic Characteristics of Anemometer Cups

Description: From Introduction: "The investigation was intended to cover the characteristics of individual cups and of similar cups mounted on complete cup wheals. This report treats the static tests run on the individual cups."
Date: February 1934
Creator: Brevoort, M. J. & Joyner, U. T.
Partner: UNT Libraries Government Documents Department

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

The Behavior of Conventional Airplanes in Situations Thought to Lead to Most Crashes

Description: Simple flight tests were made on ten conventional airplanes for the purpose of determining their action in two situations, which are generally thought to precede and lead to a large proportion of airplane crashes. These situations are when in an attempt to stretch the glide in a forced landing, the airplane is stalled, and when while taking off, particularly if taking off steeply, the engine fails at a low altitude.
Date: February 1931
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

The charging process in a high-speed, single-cylinder, four-stroke engine

Description: From Summary: "Experimental measurements and theoretical calculations were made on an aircraft-type, single cylinder engine, in order to determine the physical nature of the inlet process, especially at high piston speeds. The engine was run at speeds from 1,500 to 2,600 r.p.m. (mean piston speeds of 1,370 to 2,380 feet per minute). Measurements were made of the cylinder pressure during the inlet stroke and of the power output and volumetric efficiency. Measurements were also made, with the engine not running, to determine the resistance and mass of air in the inlet valve port at various crank angles. Results of analysis indicate that mass has an appreciable effect, but friction plays the major part in restricting flow. The observed fact that the volumetric efficiency is considerably less than 100 percent is attributed to thermal effects. An estimate was made of the magnitude of these effects in the present case, and their general nature is discussed."
Date: February 1939
Creator: Reynolds, Blake; Schecter, Harry & Taylor, E. S.
Partner: UNT Libraries Government Documents Department

Circular Motion of Bodies of Revolution

Description: The circular motion for airship-like bodies has thus far been calculated only for a prolate ellipsoid of revolution (reference 1, p.133 and reference 2). In this paper, however, the circular motion of elongated bodies of revolution more nearly resembling airships will be investigated. The results will give the effect of rotation on the pressure distribution and thus yield some information as to the stresses set up in an airship in circular flight.
Date: February 1936
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department

Circulation Measurements About the Tip of an Airfoil During Flight Through a Gust

Description: "Measurements were made of the circulation about the rectangular tip of a short-span airfoil passing through an artificial gust of known velocity gradient. A Clark Y airfoil of 30-centimeter chord was mounted on a whirling arm and moved at a velocity of 29 meters per second over a vertical gust with a velocity of nearly 7 meters per second. Flow angles were measured with a hot-wire apparatus" (p. 1).
Date: February 1939
Creator: Kuethe, Arnold M.
Partner: UNT Libraries Government Documents Department

Comparative Performance Obtained With XF7C-1 Airplane Using Several Different Engine Cowlings

Description: Discussed here are problems with the use of cowlings with radial air cooled engines. An XF7C-1 airplane, equipped with service cowling and with narrow ring, wide ring, and exhaust collector ring cowlings over the service cowling, was used. For these four cowling conditions, the rate of climb and high speed performance were determined, the cylinder conditions were measured, and pictures to show visibility were taken. The level flight performance obtained with an engine speed of 1900 r.p.m. for the service type, the narrow ring, the wide ring, and the exhaust collector ring was 144.4, 146.6, 152.8, and 155 mph, respectively.
Date: February 1930
Creator: Schey, Oscar W.; Johnson, Ernest & Gough, Melvin N.
Partner: UNT Libraries Government Documents Department

Comparative Performance of Engines Using a Carburetor, Manifold Injection, and Cylinder Injection

Description: "The comparative performance was determined of engines using three methods of mixing the fuel and the air: the use of a carburetor, manifold injection, and cylinder injection. The tests were made of a single-cylinder engine with a Wright 1820-G air-cooled cylinder. Each method of mixing the fuel and the air was investigated over a range of fuel-air ratios from 0.10 to the limit of stable operation and at engine speeds of 1,500 and 1,900 r.p.m." (p. 1).
Date: February 1939
Creator: Schey, Oscar W. & Clark, J. Denny
Partner: UNT Libraries Government Documents Department

A complete tank test of a flying-boat hull with a pointed step - N.A.C.A. Model No. 22

Description: "The results of a complete tank test of a model of a flying-boat hull of unconventional form, having a deep pointed step, are presented in this note. The advantage of the pointed-step type over the usual forms of flying-boat hulls with respect to resistance at high speeds is pointed out. A take-off example using the data from these tests is worked out, and the results are compared with those of an example in which the test data for a hull of the type in general use in the United States are applied to a flying boat having the same design specifications. A definite saving in take-off run is shown by the pointed-step type" (p. 1).
Date: February 1934
Creator: Shoemaker, James M.
Partner: UNT Libraries Government Documents Department

Considerations of the Take-Off Problem

Description: Many technical papers on the various phases of airplane take-off have been published. Frequently, however, there appear new ideas which affect only particular scattered phases of the subject and which do not receive individual publication. It is the purpose of this paper to present several ideas of this nature which may be of considerable aid in calculating take-off performance and one idea which should correct what appears to be a popular misconception of the importance of static propeller thrust.
Date: February 1936
Creator: Hartman, Edwin P.
Partner: UNT Libraries Government Documents Department

Effect of aging on taut rubber diaphragms

Description: As part of an investigation of special compositions of rubber suitable for use as diaphragms for aircraft instruments, six samples were used as taut diaphragms in instruments and allowed to age for five years. Two of the instruments were in operating condition after this period of time and one had remarkably little change in performance. In making the rubber tetraethyl thorium disulfide was employed as a vulcanizing agent.
Date: February 1932
Creator: Strother, D. H. & Henrickson, H. B.
Partner: UNT Libraries Government Documents Department

Effect of aileron displacement on wing characteristics

Description: The effect of aileron displacement on wing characteristics has been investigated for the Clark Y and the U.S.A. 27 wing sections equipped with rectangular ailerons. The airfoils, rectangular in plan, and having a 10 inch chord and 60 inch span, were mounted on a model fuselage.
Date: February 1933
Creator: Heald, R. H.
Partner: UNT Libraries Government Documents Department

Effect of the Reservoir Volume on the Discharge Pressures in the Injection System of the N.A.C.A. Spray Photography Equipment

Description: "Tests were made to determine the effect of the reservoir volume on the discharge pressures in the injection system of the N.A.C.A. spray photography equipment. The data obtained are applicable to the design of a common rail fuel-injection system. The data show that an injection system of the type described can be designed so that not more than full load fuel quantity can be injected into the engine cylinders, and so that the fuel spray characteristics remain constant over a large range of engine speeds" (p. 1).
Date: February 1932
Creator: Rothrock, A. M. & Lee, D. W.
Partner: UNT Libraries Government Documents Department

The estimation of the rate of change of yawing moment with sideslip

Description: "Wind-tunnel data are presented on the rate of change of yawing moment with sideslip for tests of 9 complete airplane models, 20 fuselage shapes, and 3 wing models with various combinations of dihedral, sweepback, and twist. The data were collected during a survey of existing information, which was made to find a reliable method of computing the yawing moment due to sideslip. Important errors common to methods of computation used at present appear to be due to large interference effects, the investigation of which will undoubtedly require an extensive program of systematic wind-tunnel tests. At present it is necessary to place considerable reliance on past design experience in proportioning an airplane so as to obtain a reasonable degree of directional stability" (p. 1).
Date: February 1938
Creator: Imlay, Frederick H.
Partner: UNT Libraries Government Documents Department

Experimental study of deformation and of effective width in axially loaded sheet-stringer panels

Description: From Summary: "The deformation of two sheet-stringer panels subjected to end compression under carefully controlled end conditions was measured at a number of points and at a number of loads, most of which were above the load at which the sheet had begun to buckle. The two panels were identical except for the sheet, which was 0.70-inch 24st alclad for specimen 1 and 0.025-inch 24st aluminum alloy for specimen 6. A technique was developed for attaching Tuckerman optical strain gauges to the sheet without disturbing the strain distribution in the sheet by the method of attachment. This technique was used to explore the strain distribution in the sheet at various loads. The twisting and the bending of the stringers was measured by means of pointers attached to the stringers. The shape of the buckles in the sheet of specimen 6 was recorded at two loads by means of plaster casts."
Date: February 1939
Creator: Ramberg, Walter; McPherson, Albert E. & Levy, Sam
Partner: UNT Libraries Government Documents Department

Full scale span load distribution on a tapered wing with split flaps of various spans

Description: Pressure-distribution tests were conducted in the full-scale wind tunnel on a 2:1 tapered U.S.A. 45 airfoil equipped with 20 percent chord split trailing-edge flaps of various spans. A special installation was employed in the tests utilizing a half-span airfoil mounted vertically above a reflection plane. The airfoil has a constant chord center section and rounded tips and is tapered in thickness from 18 percent c at the root to 9 percent c at the tip. The aerodynamic characteristics, given by the usual dimension less coefficients, are presented graphically as functions of flap span and angle of attack as well as by semispan load diagrams. The results indicate, in general, that only a relatively small increase in the normal-force coefficient is to be expected by extending the flap span of an airfoil-flap combination, similar to the one tested, beyond 70 percent of the wing span.
Date: February 1937
Creator: Parsons, John F. & Silverstein, Abe
Partner: UNT Libraries Government Documents Department

Further Measurements of Normal Accelerations on Racing Airplanes

Description: This report details the acceleration data collected from racing airplanes during actual races. The data was collected in order to make recommendations regarding the structural safety of racing airplanes and the methods of operating racing airplanes that reduces the probability of subjecting them to extreme air loads. The records do not lead to any conclusions regarding maximum air loads.
Date: February 1936
Creator: Kirschbaum, H. W. & Scudder, N. F.
Partner: UNT Libraries Government Documents Department

Injection Labs in a Common-Rail Fuel Injection System

Description: Note presenting injection lags determined for a common-rail fuel injection system for a compression-ignition engine. The system consisted of a high-pressure reservoir, a timing valve, an injection valve tube, and an automatic injection valve. Results regarding the variable injection valve tube length, variable tube diameter, variable valve opening pressure, variable injection pressure, and variable initial pressure are provided.
Date: February 1930
Creator: Rothrock, A. M.
Partner: UNT Libraries Government Documents Department

Interference effects and drag of struts on a monoplane wing

Description: "Tests were conducted in the Variable Density Wind Tunnel of the NACA to determine the importance of the interference effects and drag of struts on a monoplane. Inclined struts were placed upon a Gottingen 387 airfoil in the lower surface positions and in two upper surface positions. Tests were made at values of Reynolds Number comparable with those obtained in flight. It was found that the interference drag of struts may be as great as the drag of the struts alone" (p. 1).
Date: February 1931
Creator: Ward, Kenneth E.
Partner: UNT Libraries Government Documents Department

Loads Imposed on Intermediate Frames of Stiffened Shells

Description: "The loads imposed on intermediate frames by the curvature of the longitudinal and by the diagonal-tension effects are treated. A new empirical method is proposed for analyzing diagonal-tension effects. The basic formulas of the pure diagonal-tension theory are used, and the part of the total shear S carried by diagonal tension is assumed to be given the expression S (sub DT) = S (1-tau sub o/tau)(sup n) where tau (sub o) is the critical shear stress, tau the total (nominal shear stress), and n = 3 - sigma/tau where sigma is the stress in the intermediate frame. Numerical examples illustrate all cases treated" (p. 1).
Date: February 1939
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department

Local Instability of Symmetrical Rectangular Tubes Under Axial Compression

Description: "A chart is presented for the coefficient in the formula for the critical compressive stress at which cross sectional distortion begins in a thin-wall tube of rectangular section symmetrical about its two principal axes. The energy method of Timoshenko was used in the theoretical calculations required for the construction of the chart. The deflection equation used in this method was selected to give good accuracy" (p. 1).
Date: February 1939
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department