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Abstracts of Current Decisions on Mines and Mining: May to August, 1919

Description: Bulletin issued by the U.S. Bureau of Mines: "This publication is devoted exclusively to a review and abstracts of decisions based on the laws governing the rights and duties of mine owners, operators, miners, and persons trafficking in all kinds of mining properties. It includes abstracts of current decisions of all the Federal and State courts of last resort on questions relating to the mining industries" (Bulletin 61, p. 9).
Date: 1920
Creator: Thompson, J. W.

The aerodynamic properties of thick aerofoils suitable for internal bracing

Description: From Introduction: "The object of this investigation was to determine the characteristics of various types of wings having sufficient depth to entirely inclose the wing bracing, and also to provide data for the further design of such sections. Results of the investigation of the following subjects are given: (1) effect of changing the upper and lower camber of thick aerofoils of uniform section; (2) effect of thickening the center and thinning the tips of a thin aerofoil; (3) effect of adding a convex lower surface to a tapered section; (4) effect of changing the mean thickness with constant center and tip sections; and (5) effect of varying the chord along the span."
Date: 1920
Creator: Norton, F. H.

Airplane performance as influenced by the use of a supercharged engine

Description: The question of the influence of a supercharged engine on airplane performance is treated here in a first approximation, but one that gives an exact idea of the advantage of supercharging. Considered here is an airplane that climbs first with an ordinary engine, not supercharged, and afterwards climbs with a supercharged engine. The aim is to find the difference of the ceilings reached in the two cases. In the case of our figure, the ceiling from 25,000 feet is increased to 37,000 feet, the supercharging maintaining the power only up to 20,000 feet. This makes, in comparison with an engine without supercharging, an increase of about 50 percent.
Date: May 1920
Creator: De Bothezat, George

Carbureting conditions characteristics of aircraft engines

Description: Tests were conducted at the altitude laboratory erected at the Bureau of Standards for the National Advisory Committee for Aeronautics to determine the changes in engine performance with changes in atmospheric temperature and pressure at various levels above the earth's surface, with special reference to (a) the variables affecting the functioning of the carburetor and (b) the changes in performance resulting from variables in the carburetor itself. This report constitutes a concise statement of the difficulties to be encountered in this branch of carburetion.
Date: January 1, 1920
Creator: Tice, Percival S

Coal-Mine Fatalities in the United States, 1919: and Coal-Mine Statistics Supplementing Those Published in Bulletin 115

Description: Supplementary report published by the U.S. Bureau of Mines regarding fatalities in coal mines located in the United States: "In addition to giving monthly fatality tables for 1919, this report includes several tables that were published in various monthly statements since 1914, thus making available in one publication all of the data compiled since that time" (p. 9).
Date: 1920
Creator: Fay, Albert H.

Design of recording wind tunnel balances

Description: Given here is a description of the design of a scientific recording wind tunnel balance. It was decided that the most satisfactory arrangement would be a rigid ring completely surrounding the tunnel or wind stream, so that the model could be supported from it by wires or any arrangement of spindles. The forces and moments acting on this ring can then be recorded by suitable weighing apparatus. The methods available for recording forces on the arms are explained. The proposed type of balance will support the model rigidly in a variety of ways, will make a complete test without attention, and will plot the results so that all computations are avoided.
Date: December 1, 1920
Creator: Norton, F. H.

Development of air speed nozzles

Description: Report describes the development of a suitable speed nozzle for the first few thousand airplanes made by the United States during the recent war in Europe, and to furnish a basis for more mature instruments in the future. Requirements for the project were to provide a suitable pressure collector for aircraft speed meters and to develop a speed nozzle which would be waterproof, powerful, unaffected by slight pitch and yaw, rugged and easy to manufacture, and uniform in structure and reading, so as not to require individual calibration.
Date: January 1, 1920
Creator: Zahm, A F

Drag or negative traction of geared-down supporting propellers in the downward vertical glide of a helicopter

Description: Discussed here are computations of drag or negative traction of geared down supporting propellers in the downward vertical glide of a helicopter. By means of Frounde's Theory, the maximum value of the drag of a windmill is calculated. For wooden propellers, the author finds that the difference between the drag and the weight is proportional to the number of blades and is larger for propellers of small diameter; thus it is 25 kg. for a six blade propeller with a diameter of 2 m. 50. The author notes that if we are to adopt large propellers, we must have recourse to a different method of construction, resulting in large dimension propellers much lighter than those made of wood. In discussing insufficient drag, the author notes that the question of the drag of geared down supporting propellers can only be decided by experiment.
Date: September 1, 1920
Creator: Toussaint, A

Duralumin

Description: The use of duralumin in the construction of aircraft makes an account of the properties of this material desirable especially with reference to its working qualities as developed by experience.
Date: July 1, 1920
Creator: Unger, E & Schmidt, E