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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Year: 1942
 Month: January
 Collection: Technical Report Archive and Image Library
Annual report of the National Advisory Committee for Aeronautics (27th).administrative report including Technical Report nos. 704 to 726

Annual report of the National Advisory Committee for Aeronautics (27th).administrative report including Technical Report nos. 704 to 726

Date: January 1, 1942
Creator: unknown
Description: Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
Contributing Partner: UNT Libraries Government Documents Department
Bending of rectangular plates with large deflections

Bending of rectangular plates with large deflections

Date: January 1, 1942
Creator: Levy, Samuel
Description: The solution of Von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to Von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, Mcpherson, and Levy. The deflections of a square plate under lateral pressure are compared with experimental and theoretical results by Kaiser. It is found that the effective widths agree closely with Marguerre's formula and with the experimentally observed values and that the deflections agree with the experimental results and with Kaiser's work.
Contributing Partner: UNT Libraries Government Documents Department
Bending tests of a monocoque box

Bending tests of a monocoque box

Date: January 1, 1942
Creator: Mcpherson, Albert E; Ramberg, Walter & Levy, Samuel
Description: A monocoque box beam consisting of a 24S-T aluminum-alloy sheet reinforced by four bulkheads and by longitudinal stringers and corner posts was subjected to bending loads as follows: pure bending about the lift axis, cantilever bending about the lift axis, and pure bending about both lift and drag axis. Longitudinal strains were measured for loads up to a load at which permanent set became measurable. The loads were sufficient to produce buckling of the sheet between stringers on the compression side of the box. The only noticeable effect of this buckling was a small increase in extreme-fiber strain on the compression side. The measured strains and measured deflections differed less than 10 percent from those computed from the simple beam theory after taking account of the effective width of the buckled sheet. The effect of the bulkheads on the distribution of stringer strain was negligible.
Contributing Partner: UNT Libraries Government Documents Department
Contribution to the ideal efficiency of screw propellers

Contribution to the ideal efficiency of screw propellers

Date: January 1, 1942
Creator: Hoff, Wilhelm
Description: The stipulation of best thrust distribution is applied to the annular elements of the screw propeller with infinitely many blades in frictionless, incompressible flow and an ideal jet propulsion system derived possessing hyperbolic angular velocity distribution along the blade radius and combining the advantage of uniform thrust distribution over the section with minimum slipstream and rotation losses. This system is then compared with a propeller possessing the same angular velocity at all blade elements and the best possible thrust distribution secured by means of an induced efficiency varying uniformly over the radius. Lastly, the case of the lightly loaded propeller also is discussed.
Contributing Partner: UNT Libraries Government Documents Department
Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges

Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges

Date: January 1, 1942
Creator: Lundquist, Eugene E & Stowell, Elbridge Z
Description: A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.
Contributing Partner: UNT Libraries Government Documents Department
Critical Compressive Stress for Outstanding Flanges

Critical Compressive Stress for Outstanding Flanges

Date: January 1, 1942
Creator: Lundquist, Eugene E & Stowell, Elbridge Z
Description: A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given.
Contributing Partner: UNT Libraries Government Documents Department
The design of propeller blade roots

The design of propeller blade roots

Date: January 1, 1942
Creator: Cordes, G
Description: Predicated on the assumption of certain normal conditions for engine and propeller, simple expressions for the static and dynamic stresses of propeller blade roots are evolved. They, in combination with the fatigue strength diagram of the employed material, afford for each engine power one certain operating point by which the state of stress serving as a basis for the design of the root is defined. Different stress cases must be analyzed, depending on the vibration tendency of engine and use of propeller. The solution affords an insight into the possible introduction of different size classes of propeller.
Contributing Partner: UNT Libraries Government Documents Department
Determination of optimum plan forms for control surfaces

Determination of optimum plan forms for control surfaces

Date: January 1, 1942
Creator: Jones, Robert T & Cohen, Doris
Description: Solutions found for a range of airfoil plan forms indicate that, regardless of the characteristics of the tail surface, the chord of the rudder or of the elevator should be very nearly constant over its span. The optimum ailerons are also of a characteristic shape, varying little with the plan form of the wing.
Contributing Partner: UNT Libraries Government Documents Department
Drag and Propulsive Characteristics of Air-Cooled Engine-Nacelle Installations for Large Airplane

Drag and Propulsive Characteristics of Air-Cooled Engine-Nacelle Installations for Large Airplane

Date: January 1, 1942
Creator: Silverstein, Abe & Wilson, Herbert A , Jr
Description: An investigation was conducted in the NACA full-scale wind tunnel to determine the drag and the propulsive efficiency of nacelle-propeller arrangements for a large range of nacelle sizes. In contrast with usual tests with a single nacelle, these tests were conducted with nacelle-propeller installations on a large model of a four-engine airplane. Data are presented on the first part of the investigation, covering seven nacelle arrangements with nacelle diameters from 0.53 to 1.5 times the wing thickness. These ratios are similar to those occurring on airplanes weighing from about 20 to 100 tons. The results show the drag, the propulsive efficiency, and the over-all efficiency of the various nacelle arrangements as functions of the nacelle size, the propeller position, and the airplane lift coefficient. The effect of the nacelles on the aerodynamic characteristics of the model is shown for both propeller-removed and propeller-operating conditions.
Contributing Partner: UNT Libraries Government Documents Department
Flutter calculations in three degrees of freedom

Flutter calculations in three degrees of freedom

Date: January 1, 1942
Creator: Theodorsen, Theodore & Garrick, I E
Description: The present paper is a continuation of the general study of flutter published in NACA reports nos. 496 and 685. The paper is mainly devoted to flutter in three degrees of freedom (bending, torsion, and aileron) for which a number of selected cases have been calculated and presented in graphical form. The results are analyzed and discussed with regard to the effects of structural damping, of fractional-span ailerons, and of mass-balancing. The analysis shows that more emphasis should be put on the effect of structural damping and less on mass-balancing. The conclusion is drawn that a definite minimum amount of structural damping, which is usually found to be present, is essential in the calculations for an adequate description of the flutter case. Theoretical flutter predictions are thus brought into closer agreement with the facts of experience. A brief discussion is included of a particular biplane that had experienced flutter at about 200 miles per hour. Some simplifications have been achieved in the method of calculation. (author).
Contributing Partner: UNT Libraries Government Documents Department
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