Report presenting a description of fluid compasses that are being used in aircraft, including why magnetic compasses are not usable. Details of the distant compass are provided, which is an improved form of the compass that has a practical application in seaplanes.

Memorandum describing a device, constructed according to the system of Gati, with which it is possible to measure the sound of an engine and test the effect of a silencer.

This report gives a general method for drawing airplane profiles. This method is useful, but it leads to a somewhat laborious drawing which becomes quite complicated when we take a transformation function having terms of a high degree.

Memorandum presenting the rules and regulations of the Fokker Soaring Flight Contest, which occurred over the water and over level land.

This report presents the results of tests on two-stroke-cycle Diesel engines to determine the efficiency of the crank case scavenging pump. It was determined that efficiencies were between 95 and 100%.

The following pages present a review of the air transportation activities of England, France, Germany and Holland, based on an inspection trip during the summer of 1924. The different components described include operating companies, nature of transportation services, air traffic, flying equipment, government relations, and general remarks.

The aim of this article is to present, in broad outline, a scientific method for solving the problem, "Wood or Metal." It will be shown that structural methods have by no means reached their final perfection. The strength of the different materials is discussed as well as different construction methods.

The most essential phenomena of aircraft should be classified according to their origin and then measured. Information can thus be obtained in a quicker, cheaper, and more reliable way than otherwise would be possible.

The causes of error in experiments conducted in wind tunnel tests are given and the value of in-flight tests are promoted. The four main causes explored include neglect of the laws of dynamic similitude, interference between the support and the model, nature of the air stream, and the influence of the walls of the tunnel.

The "Turkey Buzzard" is a semi-internally braced monoplane (Fig. 1). The wing is placed above the fuselage for two important aerodynamical reasons: first, because this position minimizes the mutual interference between the wing and the fuselage, and, second, useful lifting surface is utilized with the wing passing over the fuselage instead of through it.

"The object of this article is to set forth the particular properties of swiftly-moving air, how these affect the installation of a wind tunnel, the experimental results already obtained, the possible applications of such a tunnel, and what can be easily accomplished at the present time" (p. 1).

The Schneebeli silencer is made entirely of soft sheet steel. It is connected with the engine for receiving the exhaust gases, and consists of two parts: the silencer proper and a conical exit. The Birger silencer, made by the Ad Astra Company in Switzerland, is based on the principle of rapid cooling of the exhaust gases.

Economic and safety factors are discussed in relation to a switch from hydrogen to helium in airships.

This report concerns, first, the determination of the lift of a wing which is situated in a curvilinear flow; and second, to calculate the curvature which one wing of a biplane produces in the vicinity of the other.

Two methods to replace the weight of gas lost on long airship flights are discussed: condensing the water of combustion and thermic sustentation. In the present article we will discuss the first method, leaving the second to be examined in a subsequent article.

The aim of this article is to present, in broad outline, a scientific method for solving the problem, "Wood or Metal." It will be shown that structural methods have by no means reached their final perfection. The strength of the different materials is discussed as well as different construction methods.

The control of an airplane is discussed beginning with sideways motion and following up with control by weight shifting and by swinging wing tips.

This report presents detailed descriptions, statistics, and graphs on European and American air transport. The European countries listed are Belgium, Czecho-Slovakia, Denmark, France, Germany, Great Britain, Holland, and Italy.

This article presents a recounting of the Rhon soaring competition with emphasis on new designs, results, and prizes awarded. A round-robin discussion is also included at the end of the report.

"In designing the Fakir fuel pump, the fundamental idea was to obtain a simple and reliable method of conveying the fuel from a low tank to the carburetor, with the avoidance of the faults of all former methods and the simultaneous warming of the fuel by means of the heat of compression generated. The principle of the Fakir fuel pump rests on the well-known principle of the diaphragm pump, which must be suitably adapted to the present purpose" (p. 1).

This report presents the results of testing 32 sets of light metal pistons from 16 different aluminum and magnesium alloys, 2 sets of cast iron pistons, and one piston of pure electrolytic copper. The many-fold mutual relations between material properties, shape, thermic and dynamic processes in the engine were clarified by comprehensive technical, thermic, chemical, physical and metallographic investigations of pistons and piston materials.

The experiments herein described were made for the purpose of finding whether removing a larger portion of the wing to improve the pilot's view would be possible, without too great detriment to the aerodynamic properties of the airplane. The experiments were conducted on a wing similar to the Fokker F III.

"It is to be expected that the advantageous properties, hitherto discovered in many slotted wing sections, depend very largely on the contour of the slot and the structural details of the wing. It is therefore of interest, aside from measurements on wings of constant cross-section along the span, to measure also wing models in which the structural details have already been given practical consideration" (p. 1).

An airship frame may be regarded as a rigid girder subjected to a number of forces which, according to their nature, may be classified as follows: weight or loads (force of gravity); lifting forces (aero-static); accelerations (dynamic). These forces must be in equilibrium in the three most important cases during flight: 1) when the airship is floating (aerostatic problem); 2) when flying without acceleration (aerodynamic problem). 3) When under the influence of any accelerating force (dynamic problem). This report will briefly discuss each of these cases in regard to the R-38 airship accident.