This report presents a description of an abacus with three scales: one for English measures, one for metric measures, and one with the "points of reduction", as well as construction details. There is also a detailed description on how to use the abacus.

Report discussing the problem to be solved, as presented to the pilot or observer of an aircraft, is as follows: The aircraft starting from A must land at B, the only data being the speed of the airplane, the altitude and the orientation D of the course. The above data would be amply sufficient, were it not for the fact that the airplane is constantly subjected to a wind of variable direction and strength.

Report discussing before proceeding to discuss the preparation of dope solutions, it will be necessary to consider some of the essential properties which should be possessed of a dope film, deposited in and on the surface of an aero fabric. The first is that it should tighten the material and second it should withstand weathering.

Ballistics is a science hundreds of years old and this report is an attempt to show how these older principles can be used in the newer science of aerodynamics.

For some time, the designers of airplanes have begun to occupy themselves with the question of longitudinal stability. In their quest to simplify calculation and data collection, the designers have attached the greatest importance to the coefficient of initial longitudinal stability. In this study a diagram was constructed from the data of the tunnel tests, which depends neither on the position of the center of gravity nor of the angle of deflection of the elevators. This diagram is constructed by means of straight lines drawn through the metacenters of the complete airplane, in a direction parallel to the tangents to the polar of the airplane relative to a system of axes fixed with reference to the airplane.

Circular presenting a description of the Amiot S.E.C.M. 110 C.1, which is a single-seat pursuit monoplane. Some of the design principles that the aircraft was built from are provided. A description of the design, components, dimensions, flight characteristics, and photographs are provided.

The following examples do not take up the discussion of viewpoints to be heeded in determining the design of a framework for given external conditions. Rather they are methods for determining the forces in airplane fuselages and wings, though similar considerations are applied to certain simple cases of a different kind. The object of this treatise is to summarize and amplify these considerations from definite viewpoints.

Autogenous welding is discussed and various methods of testing those welds are presented.

Report presenting a description of the autogiro, which is a flying machine built and designed in Spain. A history of the device and the reasons why it is safer and more stable than a typical aircraft are provided.

The establishment of air service in the Belgian Congo is detailed in this report. The airplanes, landing fields, and air routes are all discussed.

Circular describing the Avro Gosport 504 R, which is a new training airplane that is lighter than other Avro training airplanes but is strong enough to withstand rough handling that may be encountered in training. Details of the fuselage, construction, ailerons, tail, struts, landing gear, fuel tanks, performance, characteristics, and photographs are provided.

"The air is known to be charged with electricity (chiefly positive) with reference to the earth, so that its potential increases with the altitude and the difference in potential between two points in the same vertical line, divided by the distance between them, gives a value called the "potential gradient," which may vary greatly with the altitude, the nature of the ground and the atmospheric conditions" (p. 1).

A beacon light manufactured by the Julius Pintsch Company is described and the arrangement of these lights on a landing field is discussed.

Circular presenting a description of the Bernard 20 C.1, which is made of wood and has four main parts: a one-piece wing with a fuselage in the middle, a rear section with the tail surfaces, an engine mount, and a landing gear.

The Sprat is similar the Blackburn Swift and Dart models but is designed as a trainer. It is powered with a smaller 275 HP Rolls-Royce Falcon engine. It is a 2 seat biplane with equal sized upper and lower wings. It can quickly convert from a land to a seaplane.

The Caproni Company recently built a seaplane of unusual design. The main supporting surfaces consisted of three triplanes in tandem, the lower wings being attached to the hull, which was described as providing accommodation for a hundred passengers. On one of the first flights, the seaplane fell into a lake, nose down, and was destroyed. The authors wish to show that this failure could have been predicted.

The purpose of this treatise is, first of all, the determination of the effect of variously loaded spars on one another, since the neglect of this effect would present an economically very unfavorable computation method. The system of spars and cross-bars alone (whether solid or built-up) does not matter at first, the original assumption being that the spars are rigidly braced by the cross-bars.

The connections between the cockpit and the control surfaces are examined. An examination of the pros and cons of using stick control, the problems of control in giant aircraft, an effort to find a substitute for these controls, and a proposed concept for mechanically operated gear are provided.

The development of more efficient control surfaces requiring less force to operate are presented. Some of the control surfaces explored include the De Havilland gear, Flettner rudder, and some other possible control methods.

Memorandum presenting an overview of the development of light and small airplanes. Some of the characteristics explored include the development of airplanes of medium weight, development in countries other than Germany, development of light airplanes, general constructive fiducial lines, safety problems, the economy problem, and some special structural considerations are provided.

This note describes tests of the drag due to a Wright "Whirlwind" (J-5) radial air-cooled engine mounted on a cabin type airplane. The tests were made in the 20-foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics. The drag was obtained with three different types of exhaust stacks: Short individual stacks, a circular cross section collector ring, and a streamline cross section collector ring.

This report presents a discussion of how to determine the location of a line or surface from experimental data. What we desire to know practically is the number of ordinates required to obtain a certain probable precision in drawing a line or surface.

Various properties of duralumin as used in aircraft construction are discussed, including the effects of temperature, working, tempering, and strength.

The need for a device to measure flight resistance, engine and propeller power, and efficiency during flight grew in proportion to the demand for increased flying capacity in military types of aircraft. Here, a dynamometer hub was inserted between the engine and the propeller. Taken as a whole, the tests that were conducted show that though the dynamometer is a sensitive instrument liable to numerous derangements, it is undeniably useful even in its present form, when handled with care and skill.