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Diatomites of the Pacific Northwest as Filter-Aids

Description: From Introduction Purpose of Investigation: "To determine some of the physical and chemical properties of known Pacific Northwest diatomites, the present investigation was started in 1938 by the Bureau of Mines in cooperation with the College of Mines, University of Washington.
Date: 1944
Creator: Skinner, Kenneth G.; Dammann, Arthur A.; Swift, Roy E.; Eyerly, George B. & Shuck, Gordon R., Jr.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Dynamics of the inlet system of a four-stroke engine

Description: Tests were run on a single-cylinder and a multicylinder four-stroke engine in order to determine the effect of the dynamics of the inlet system upon indicated mean effective pressure. Tests on the single-cylinder engine were made at various speeds, inlet valve timings, and inlet pipe lengths. These tests indicated that the indicated mean effective pressure could be raised considerably at any one speed by the use of a suitably long inlet pipe. Tests at other speeds with this length of pipe showed higher indicated mean effective pressure than with a very short pipe, although not so high as could be obtained with the pipe length adjusted for each speed. A general relation was discovered between optimum time of inlet valve closing and pipe length; namely, that longer pipes require later inlet valve closing in order to be fully effective. Tests were also made on three cylinders connected to a single pipe. With this arrangement, increased volumetric efficiency at low speed was obtainable by using a long pipe, but only with a sacrifice of volumetric efficiency at high speed. Volumetric efficiency at high speed was progressively lower as the pipe length was increased.
Date: January 1, 1944
Creator: Boden, R H & Schecter, Harry
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effect of hinge-moment parameters on elevator stick forces in rapid maneuvers

Description: The importance of the stick force per unit normal acceleration as a criterion of longitudinal stability and the critical dependence of this gradient on elevator hinge-moment parameters have been shown in previous reports. The present report continues the investigation with special reference to transient effects for maneuvers of short duration.
Date: January 1, 1944
Creator: Jones, Robert T & Greenberg, Harry
Item Type: Report
Partner: UNT Libraries Government Documents Department

The effect of increased cooling surface on performance of aircraft-engine cylinders as shown by tests of the NACA cylinder

Description: A method of constructing fins of nearly optimum proportions has been developed by the NACA to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences.
Date: January 1, 1944
Creator: Schey, Oscar W.; Rollin, Verne G. & Ellerbrock, Herman H., Jr.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effect of tilt of the propeller axis on the longitudinal-stability characteristics of single-engine airplanes

Description: Report presents the results of tests of a model of a single-engine airplane with two different tilts of the propeller axis. The results indicate that on a typical design a 5 degree downward tilt of the propeller axis will considerably reduce the destabilization effects of power. A comparison of the experimental results with those computed by use of existing theory is included. A comparison of the experimental results with those computed by use of existing theory is included. It is shown that the results can be predicted with an accuracy acceptable for preliminary design purposes, particularly at the higher powers where the effects are of significant magnitude.
Date: January 1, 1944
Creator: Goett, Harry J & Delaney, Noel K
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effects of small angles of sweep and moderate amounts of dihedral on stalling and lateral characteristics of a wing-fuselage combination equipped with partial- and full-span double slotted flaps

Description: Tests of a wing-fuselage combinations incorporating NACA 65-series airfoil sections were conducted in the NACA 19-foot pressure tunnel. The investigation included the tests with flaps neutral and with partial- and full-span double slotted flaps deflected to determine the effects of (1) variations of wing sweep between -4 degrees and 8 degrees on stalling and lateral stability and control characteristics and (2) variations of dihedral between 0 degree and 6.75 degrees on lateral stability characteristics.
Date: January 1, 1944
Creator: Teplitz, Jerome
Item Type: Report
Partner: UNT Libraries Government Documents Department

An Experimental Investigation of the Flow of Air in a Flat Broadening Channel

Description: The wide use of diffusers, in various fields of technology, has resulted in several experimental projects to study the action and design of diffusers. Most of the projects dealt with steam (steam turbine nozzles). But diffusers have other applications - that is, ventilators, smoke ducts, air coolers, refrigeration, drying, and so forth. At present there is another application for diffusers in wind-tunnel design. Because of higher requirements and increased power of such installations more attention must be paid to the correctness of work and the decrease in losses due to every section of the tunnel. A diffuser, being one of the component parts of a tunnel , can in the event of faulty construction introduce considerable losses. Therefore, in the design of the new CAHI wind tunnel, it was suggested that an experimental study of diffusers be made, with a view to applying the results to wind tunnels. The experiments conducted by K. K. Baulin in the laboratories of CAHI upon models of diffusers of different cross sections, lengths, and angles of divergence, were a valuable source of experimental data. They were of no help, however, in reaching any conclusion regarding the optimum shape because of the complexity and diversity of the factors which all appeared simultaneously, thereby precluding the.study of the effects of any one factor separately. On the suggestion of the director of the CAHI,Prof. B. N. Ureff, it was decided to experiment on a two-dimensional diffuser model and determine the effect, of the angle of divergence. The author is acquainted with two experimental projects of like nature: the first was conducted with water, the other with air. The first of these works, although containing a wealth of experimental data, does not indicate the nature of flow or its relation to the angle of divergence. The second work ...
Date: January 1, 1944
Creator: Vedernikoff, A. N.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Flight Studies of the Horizontal-Tail Loads Experienced by a Fighter Airplane in Abrupt Maneuvers

Description: Field measurements were made on a fighter airplane to determine the approximate magnitude of the horizontal tail loads in accelerated flight. In these flight measurements, pressures at a few points were used as an index of the tail loads by correlating these pressures with complete pressure-distribution data obtained in the NACA full-scale tunnel. In addition, strain gages and motion pictures of tail deflections were used to explore the general nature and order of magnitude of fluctuating tail loads in accelerated stalls.
Date: January 1, 1944
Item Type: Report
Partner: UNT Libraries Government Documents Department

Flight studies of the horizontal-tail loads experienced by a fighter airplane in abrupt maneuvers

Description: Field measurements were made on a fighter airplane to determine the approximate magnitude of the horizontal tail loads in accelerated flight. In these flight measurements, pressures at a few points were used as an index of the tail loads by correlating these pressures with complete pressure-distribution data obtained in the NACA full-scale tunnel. In addition, strain gages and motion pictures of tail deflections were used to explore the general nature and order of magnitude of fluctuating tail loads in accelerated stalls.
Date: January 1, 1944
Item Type: Report
Partner: UNT Libraries Government Documents Department

The flow of a compressible fluid past a circular arc profile

Description: The Ackeret iteration process is utilized to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient. The first two terms of the development correspond to the Prandtl-Glauert approximation and yield the well-known correction to the circulation about the profile. The second approximation, involving the square of the camber coefficient, improves the velocity and pressure fields but yields no new results with regard to the circulation, since the circulation about the profile is an odd function of the camber coefficient. The third approximation, involving the cube of the camber coefficient, permits the use of higher values of the camber coefficient and furthermore yields an improvement to the Prandtl-Glauert rule with regard to the effect of compressibility on the circulation of the circular arc profile. Numerical examples with tables and graphs illustrate the results of the analysis.
Date: January 1, 1944
Creator: Kaplan, Carl
Item Type: Report
Partner: UNT Libraries Government Documents Department

Fundamentals of Coal Sampling

Description: From Forward: "The intent has been rather to furnish another contribution to the growing list of studies on the principles governing the establishment of specifications for the sampling of coal."
Date: 1944
Creator: Landry, Bertrand A.
Item Type: Report
Partner: UNT Libraries Government Documents Department

The influence of the aerodynamic span effect on the magnitude of the torsional-divergence velocity and on the shape of the corresponding deflection mode

Description: A procedure which takes into account the aerodynamic span effect is given for the determination of the torsional-divergence velocities of monoplanes. The explicit solutions obtained in several cases indicate that the aerodynamic span effect may increase the divergence velocities found by means of the section-force theory by as much as 17 to 40 percent. It is found that the magnitude of the effect increases with increasing degree of stiffness taper and decreases with increasing degree of chord taper. By a slight extension of the present method it is possible to analyze the elastic deformations of wings, and the resultant lift distributions, before torsional divergence occurs.
Date: January 1, 1944
Creator: Hildebrand, Francis B & Reissner, Eric
Item Type: Report
Partner: UNT Libraries Government Documents Department

Intercooler cooling-air weight flow and pressure drop for minimum drag loss

Description: An analysis has been made of the drag losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give a minimum drag loss for any given cooling effectiveness and, thus, a maximum power-plant net gain due to charge-air cooling. The drag losses considered in this analysis are those due to (1) the extra drag imposed on the airplane by the weight of the intercooler, its duct, and its supports and (2) the drag sustained by the cooling air in flowing through the intercooler and its duct. The investigation covers a range of conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and supercharger adiabatic efficiency. The optimum values of cooling air pressure drop and weight flow ratio are tabulated. Curves are presented to illustrate the results of the analysis.
Date: January 1, 1944
Creator: Reuter, J George & Valerino, Michael F
Item Type: Report
Partner: UNT Libraries Government Documents Department

The inward bulge type buckling of monocoque cylinders I : calculation of the effect upon the buckling stress of a compressive force, a nonlinear direct stress distribution, and a shear force

Description: In the present part I of a series of reports on the inward bulge type buckling of monocoque cylinders the buckling load in combined bending and compression is first derived. Next the reduction in the buckling load because of a nonlinear direct stress distribution is determined. In experiments nonlinearity may result from an inadequate stiffness of the end attachments in actual airplanes from the existence of concentrated loads or cut-outs. The effect of a shearing force upon the critical load is investigated through an analysis of the results of tests carried out at GALCIT with 55 reinforced monocoque cylinders. Finally, a simple criterion of general instability is presented in the form of a buckling inequality which should be helpful to the designer of a monocoque in determining the sizes of the rings required for excluding the possibility of inward bulge type buckling.
Date: January 1, 1944
Creator: Hoff, N J & Klein, Bertram
Item Type: Report
Partner: UNT Libraries Government Documents Department