Report discussing the A.B.C. Motors Robin, a single-seat monoplane that was built for pilot comfort, speed, and fuel efficiency. Information about the structural design, dimensions, weight, performance, and rough blueprints is included.

Report issued by the U.S. Bureau of Mines covering accidents that happened in metal mines located in the United States including statistics for injuries, fatalities, kinds and causes of accidents, and operational data, such as number of mine workers and shifts worked.

Report published by the U.S. Bureau of Mines which is a compilation of accidents in quarries located in the United States with data regarding the number and kinds of accidents as well as information about the mining operations (e.g., number of men employed, kinds of quarries, amount of work performed, etc.).

"The investigation described in this report is concerned with the changes in the aerodynamic characteristics of an airfoil which are produced by a gauze-covered suction slot, located near the leading edge, and connected by an air passage to a split flap at the trailing edge. The tests were conducted at the Langley Memorial Aeronautical Laboratory. At the larger values of lift coefficient where the action of the slot might be expected to be most effective, the pressure differences were such that the air flowed out of the slot rather than in through it, and in consequence, the maximum lift coefficient was decreased" (p. 1).

Technical paper issued by the Bureau of Mines over formula corrections to make up for gravity gradients. The new formulas are presented and discussed in detail. This paper includes tables, and illustrations.

"Among the numerous thermodynamic and kinetic problems that have arisen in the application of the gaseous explosive reaction as a source of power in the internal combustion engine, the problem of the mode or way by which the transformation proceeds and the rate at which the heat energy is delivered to the working fluid became very early in the engine's development a problem of prime importance. The work of Becker here given is a notable extension of earlier investigations, because it covers the entire range of the explosive reaction in gases - normal detonation and burning" (p. i).

A continuation of a previous technical memorandum regarding impact waves and detonation. This particular report focuses on the applications to detonation under several different conditions, including variations in pressure.

"In an attempt to treat theoretically the effect of ailerons, difficulty arises because an aileron may begin at any point of the wing. Hence the question arises as to how the transition of the lift distribution proceeds at such a point, since the effect of the aileron (i.e., the moment generated about the longitudinal axis) depends largely on this distribution. In order to answer this question regarding the lift distribution during irregular variations in the angle of attack at first independently of other influences, especially those of the wing tips, we have taken as the basis of the following theoretical discussion a wing of infinite span and constant chord which exhibits at one point an irregular variation in the angle of attack" (p. 1).

Technical paper issued by the Bureau of Mines over the salvage of necessary equipment for the oil industry. The types of materials that can be salvaged are presented and discussed. This paper includes photographs, and illustrations.

Annual report submitted by the Boy Scouts of America to Congress describing highlights from 1928, activities, finance, foreign relations, organizational leadership, and other information about scouting programs.

"Before undertaking a detailed description of an automatic-control mechanism, I will state briefly the fundamental conditions for such devices. These are: 1) it must be sensitive at one or more reference values; 2) it must stop the angular motions of the airplane not produced by the pilot; and 3) it must be possible to switch it off and on by a simple hand lever" (p. 1).

In the numerical examples, we have considered an airplane landing in calm air in a fixed direction after crossing the border (with its obstacles) at a height of 30 m. Its stopping point is at a distance D from the obstacle, comprising: a distance D(sub 1) in regular gliding flight; a distance D(sub 2) in levelling off; a distance D(sub 3) in taxying on the ground. The calculations enable us to make out the following table, which gives an idea of the improvements to be expected in the use of various possible methods of braking in the air and on the ground.

Lautal is a refinable aluminum alloy which, unlike duralumin, contains no magnesium. According to the statements of the Lauta Works, lautal contains: aluminum, 94%; copper, 4%; silicon, 2%. The use of lautal as a construction material is discussed in relation to specific weight, production methods, and riveting tests.

From Introduction: "This bulletin is the seventh in this series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, 216, and 220 being complications for the years 1915, 1916, 1917, 1918, 1919-20, and 1921, respectively. In this bulletin the same general plan of classification of references has been followed, but several additions have been made."

Note presenting tests using a multicylinder engine to determine the effect that atmospheric humidity has on some phases of engine performance. Three test series with different types of fuel were carried out. The results indicate that failure to allow for the effect of differences in atmospheric humidity may introduce errors as great as would be occasioned by failure to allow for changes in barometric pressure.

"It would appear that welds in some stainless steels, heat-treated in some practicable way, will probably be found to have all the resistance to corrosion that is required for aircraft. Certainly these structures are not subjected to the severe conditions that are found in chemical plants. This article should be considered as an outline of what can be done, not necessarily as instructions, which will enable anyone to obtain satisfactory results in commercial work" (p. 1).

" The writer discusses the phenomena of expansion and compression which alternately take place in the cylinders of four-stroke engines during the induction process at a high mean piston speed due to the inertia and elasticity of the mixture in the intake pipe. The present paper is intended to demonstrate theoretically the existence of a most favorable pipe length for charging" (p. 1).

The results of tests to determine the effect of wheel brakes on the landing run of an airplane under conditions of load and at various wind velocities are presented.

This report describes the atmospheric conditions under which ice is formed upon the exposed parts of airplanes in flight. It identifies the formation found under different conditions, and describes some studies of preventative means.

"The flight path followed by an airplane which was being flown by a blindfolded pilot was observed and recorded. When the pilot attempted to make a straight-away flight there was a tendency to deviate from the straight path and to take up a spiral one" (p. 1).

From introduction: The discovery of oil near Kevin, Mont., in March, 1922, gave prominence to the Sweetgrass arch, which is a large structural uplift somewhat similar in size and degree of folding to the Cincinnati arch. Most of the development so far attempted on this fold has been on the Kevin-Sunburst dome, a bulge upon the crest of the arch just south of the Canadian boundary. The dome covers about 16 townships, is nearly circular in outline, and has very low dips away from its highest point in all directions. Within the last five years (1923-1927) about 1,500 wells have been drilled upon it, over 880 of which are rated as productive. Since May, 1925, the field has stood second in production in the Rocky Mountain States being exceeded only by Salt Creek.

From Introduction: "The mining methods described and discussed in this report have been considered historically-that is, from early to present practice. The data for this report were collected during 1927."

From Introduction: "The effect of rock pressure may be general and continuous disintegration and reduction in size of pillars of ore and rock left for the support of the workings, resulting in the collapse of hanging wall and the closing of stopes, drifts, and shafts, or the action may be sudden and violent and aside from seriously affecting the workings may present a real hazard to the operation of mines. The object in the preparation of this report is to add to the accumulated information and from the facts presented to make suggestions for protective measures to be taken when possible."

Report issued by the Bureau of Mines over studies conducted on the ground movement and support failure of Michigan mines. Factors involved in surface subsidence in the mines are discussed. This report includes tables, maps, illustrations, and photographs.