This is a multi-engine monoplane with a central hull and without external bracing. The trim of the seaplane on the water is assured by two wing floats, one on each side of the hull 9 m. from its axis. It has a total power of 2100 HP. from 5 air cooled Jupiter radial engines.

Circular presenting a description of the Vojenska-Smolik all-metal two-seater airplane. The design and flight characteristics are described and blueprints and photographs of the aircraft are provided.

The Calcutta is a large seaplane, with seating for 16 and a payload of 3,400 pounds. A description of the design, construction features, engine installation, specifications, performance, and photographs are provided.

The Nieuport Delage 640 is a single engine commercial high-wing monoplane of all wood construction, including the fuselage and tail. It's landing gear is hinged in two parts.

Report presenting a description of the Lioré-Olivier Type 12 night bomber, which can also be converted into the Type 20 commercial. A description of the cell of the wings, fuselage, power plant, landing gear, and flight characteristics is provided.

In soaring flight, ascending air currents are utilized and the interesting question is raised whether there are such currents which extend to any considerable distance and which can be utilized practically.

The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The present report deals only with the relations of the airfoils. The mutual action of the airfoils, engine and propeller will be treated in a subsequent report.

The S.55 is a two engine twin hull seaplane built by Societa Idrovolanti Alta Italia (Seaplane Company of Upper Italy). The S.55 (Santa Maria) is to be used for an around the world flight In 1927. It will have a useful load of 7,500 lbs. and a cruising speed of 100 MPH.

Circular describing the Morane-Saulnier 180 light airplane, which is a single-seat training monoplane. A description of the components, design, characteristics, theoretical performance, drawings, and photographs are provided.

Report issued by the U.S. Bureau of Mines on the air quality in metal-mines after using wet drills. Dust samples are collected and compared to samples collected from similar metal-mines in South Africa and Australia. This report includes tables.

List of reduction mills in Montana, compiled in the course of investigations of mineral resources of Montana. It includes information about each loaction including: the process, character of ore, when the mill was operated, and custom work; equipment and power used; and capacity in tons.

It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.

Different types of coatings to protect duralumin from corrosion are discussed. Plating, etching, brushing, coloring, painting and varnishing are all investigated.

The theory, structure and working of a vector slide rule is presented in this report. This instrument is used for determining a vector in magnitude and position when given its components and its moment about a point in their plane.

This paper relates some of the problems commercial aircraft companies have in attracting larger numbers of paying customers. The author discusses some remedies such as changing the public perception of flying as dangerous.

"In undertaking to analyze the functioning conditions of a reduction gear on an aviation engine, we will consider an ordinary twelve-cylinder V-engine. The reduction gear employed consists either of a pair of spur gears, one of which is integral with the engine shaft and the other with the propeller shaft, or of a planetary system of gears" (p. 1).

This report presents a method of calculating polar curves which is at least as precise as graphical methods, but it more rapid. Knowing the wind tunnel test of a wing and the performances of an airplane of the same profile, it is easy to verify the characteristic coefficients and, at the same time, the methods determining induced resistances.

This article presents the difficulties and triumphs of the airship Dixmude in its long distance flight over North Africa as described by one of the occupants.

This report presents an analysis of results of wind-tunnel tests conducted at the D.V.L. Values were determined for the effectiveness of all the controls at various angles of attack. The autorotation was studied by subjecting the rotating model to an air blast.

Suggestions are presented for the establishment of lecture courses on aviation. An outline of some courses that have previously been given is provided.

Different systems of navigations beacons are discussed with an emphasis on radiotelegraphy and radiotelephony.

"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).

Report presenting an investigation of problems related to helicopters. Also included are the history of the evolution of the helicopter and a series of propeller experiments.

Report issued by the Bureau of Mines covering petroleum laws of the U.S. and surrounding oil producing countries. As stated in the preface, "this bulletin includes the petroleum laws of (1) United States; (2) the several oil-producing States; (3) Canada; (4) Mexico; (5) the Republics of Central and South America" (p. iv).