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Annual Report of Research and Technologic Work on Coal: Fiscal Year 1942

Description: Report issued by the U.S. Bureau of Mines discussing studies over the research and technology of coal during 1942. As stated in the introduction, "the annual reports of the research and technologic investigations conducted by the Bureau of Mines on the occurrence, properties, mining, preparation, and uses of coal, of which the present report is the seventh, are intended to be brief summaries of progress" (p. 4). This report includes tables, illustrations, and photographs.
Date: May 1943
Creator: Fieldner, Arno Carl & Rice, W. E.

Effect of powered propellers on the aerodynamic characteristics and the porpoising stability of a dynamic model of a long-range flying boat

Description: Report discusses the results of two tests: "1) aerodynamic tests to determine the effect of the slipstream and thrust from the powered propellers on the lift and trimming-moment characteristics, and 2) hydrodynamic tests to determine the effect of the powered propellers on the range of stable locations of the center of gravity (from Introduction)." Large differences in the stable range between half-thrust and full-thrust conditions were observed. Three effects of power were also involved in the location of the stable range of the center of gravity.
Date: May 1943
Creator: Land, Norman S.

Emergency measures for increasing the range of fighter airplanes

Description: From Summary: "An analysis was made to show the relative effectiveness of streamline external fuel tanks, a fuel tank in the form of a wing mounted in a biplane position, and auxiliary wing panels attached at the wing tips to increase the span as temporary means for increasing the range of a fighter-type airplane. Figures and charts for the various devices considered show the results of calculations of range, duration of flight, and take-off distance for both land-base and carrier operation. The results indicated that the wing-tip extensions were the most promising of the devices considered."
Date: May 1943
Creator: Jones, Robert T. & Wetmore, Joseph W.

The Heat Transfer to a Plate in Flow at High Speed

Description: The heat transfer in the laminar boundary layer of a heated plate in flow at high speed can be obtained by integration of the conventional differential equations of the boundary layer, so long as the material values can be regarded as constant. This premise is fairly well satisfied at speeds up to about twice the sonic speed and at not excessive temperature rise of the heated plate. The general solution of the equation includes Pohlhausen's specific cases of heat transfer to a plate at low speeds and of the plate thermometer. The solution shows that the heat transfer coefficient at high speed must be computed with the same equation as at low speed, when it is referred to the difference of the wall temperature of the heated plate in respect to its "natural temperature." Since this fact follows from the linear structure of the differential equation describing the temperature field, it is equally applicable to the heat transfer in the turbulent boundary layer.
Date: May 1, 1943
Creator: Eckert, E. & Drewitz, O.

Large-deflection theory of curved sheet

Description: Equations are given for the elastic behavior of initially curved sheets in which the deflections are not small in comparison with the thickness, but at the same time small enough to justify the use of simplified formulas for curvature. These equations are solved for the case of a sheet with circular cylindrical shape simply supported along two edges parallel to the axis of the generating cylinder. Numerical results are given for three values of the curvature and for three ratios of buckle length to buckle width. The computations are carried to buckle deflections of about twice the sheet thickness. It was concluded that initial curvature may cause an appreciable increase in the buckling load but that, for edge strains which are several times the buckling strain, the initial curvature causes a negligibly small change in the effective width.
Date: May 1, 1943
Creator: Levy, Samuel

The longitudinal shear strength required in double-angle columns of 24S-T aluminum alloy

Description: From Summary: "Tests were made of riveted double-angle columns to determine the total rivet strength that is required to make these built-up columns develop the strength predicted by the standard column formulas. Results of the tests led to the conclusion that the required rivet strength may be calculated by the beam method of design."
Date: May 1943
Creator: Kuhn, Paul & Moggio, Edwin M.

Shear tests on DuPont explosive rivets with the countersunk head milled flush after expansion

Description: Report discusses the results of shear testing in which the heads of Du Pont explosive countersunk rivets were allowed to protrude above the skin surface before expansion and the protruding portions were removed after expansion. As the height of the rivet head above the skin increases, the tightness of the rivet was found to increase. The report concludes that it may be desirable to investigating filling an entire shank with an explosive charge in order to permit greater tolerances in the drilled hole diameter and still have consistently tight rivets.
Date: May 1943
Creator: Gottieb, Robert & Bartone, Leonard M.

Tests of exhaust propulsion nozzles

Description: From Summary: "The thrust produced by a variety of exhaust stacks and nozzles, and the effect of these stacks and nozzles on the power of a single-cylinder R-2800 engine were investigated over a wide range of engine speeds and manifold pressures in a series of tests in the Pratt & Whitney experimental test department. From the data obtained it is possible to estimate the optimum form of nozzles and the available thrust for airplanes fitted with R-2800 engines under sea-level conditions."
Date: May 1943
Creator: Campbell, Paul J.

The use of a retractable planing flap instead of a fixed step on a seaplane

Description: Report presents and discusses the improvements in hydrodynamic and aerodynamic performance of a seaplane with a retractable planing flap instead of a conventional main step. A type of flap that could be used is described and tested for hydrodynamic stability. Results regarding the trim limits of stability, limiting positions of the center of gravity, and skipping are provided.
Date: May 1943
Creator: Benson, James M. & Lina, Lindsay J.