It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil.

The authors argue that the center of gravity has a preponderating influence on the longitudinal stability of an airplane in flight, but that manufacturers, although aware of this influence, are still content to apply empirical rules to the balancing of their airplanes instead of conducting wind tunnel tests. The author examines the following points: 1) longitudinal stability, in flight, of a glider with coinciding centers; 2) the influence exercised on the stability of flight by the position of the axis of thrust with respect to the center of gravity and the whole of the glider; 3) the stability on the ground before taking off, and the influence of the position of the landing gear. 4) the influence of the elements of the glider on the balance, the possibility of sometimes correcting defective balance, and the valuable information given on this point by wind tunnel tests; 5) and a brief examination of the equilibrium of power in horizontal flight, where the conditions of stability peculiar to this kind of flight are added to previously existing conditions of the stability of the glider, and interfere in fixing the safety limits of certain evolutions.

From Summary: "The author, who was a captain of the Reserves in the Technical Department of the Aviation Division (Board of Airplane Experts) during the war, shows what means were taken for the creation of new airplane types and what tests were employed for trying out their flying properties, capacities and structural reliability. The principal representative types of each of the classes of airplanes are described and the characteristics of the important structural parts are discussed. Data regarding the number of airplanes at the front and the flying efficiency of the various classes of airplanes are given."

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.

Report presenting a description of the interaction between the dynamometer hub and the flywheel of the engine in aircraft. The negative rotary moments in propellers generally allow for the cessation of one cylinder without any lifting on the part of the propeller, and without depriving the engine of its flywheel.

Report presenting an investigation of the flexibility of bearing surfaces and stress on fabrics used in wings. Equations are given for calculating some of these loading factors.

To obtain the absolute velocity of an airship by knowing the speed at which two routes are covered, we have only to determine the geographical direction of the routes which we locate from a map, and the angles of routes as given by the compass, after correcting for the variation (the algebraical sum of the local magnetic declination and the deviation).

Report presenting a discussion of ways to save fuel on traffic flights, including some calculations that can be used for determining fuel efficiency. The primary ways of lessening fuel consumption include flying with a throttled engine and diminished speed.

Some advances in passenger comfort are discussed, namely, ventilated cabins, heating, seating arrangements, and doors.

Thin metal diaphragms form a satisfactory means for comparing maximum pressures in internal combustion engines. The diaphragm is clamped between two metal washers in a spark plug shell and its thickness is chosen such that, when subjected to explosion pressure, the exposed portion will be sheared from the rim in a short time.

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.

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.

"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 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.

From Summary: "This report contains the derivation of a series of relations between temperature, pressure, density, and altitude in a standard atmosphere which assumes a uniform decrease of temperature with altitude. The equations are collected and given with proper constants in both metric and English units for the temperature gradient adopted by the National Advisory Committee for Aeronautics. A table of values of temperature pressure and density at various altitudes in this standard atmosphere is included in the report."

"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).

The advantages of helicopters are listed along with a discussion of safety devices, the problems of control, and the need for horizontal flight.

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.

From Summary: "The aeronautical engineer often has occasion to estimate the absolute ceiling of an airplane for which a detailed performance calculation is out of the question. In such cases it is customary to use either empirical performance charts or formulae. The performance charts given in several of the recent works on aeronautics are satisfactory so long as the airplane under consideration does not depart too far from the average in its characteristics. The formulae, with one exception, are no better. Given here is that exception, with indications of which terms of the formula may be neglected without seriously affecting the results, thus simplifying the task."

Report presenting information regarding the use of slots in an airplane wing to considerably increase the lift and make it possible to operate the wing at higher angles of attack.

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.

Note presenting a number of instruments that can assist pilots with observing the position of the airplane. Some of the instruments include an inclinometer with stationary system of reference and an inclinometer with moving axes.

Report presenting an example of a heavily staggered biplane with a single rigid outer strut in order to help determine the influence of the initial tensions in the wing bracing on the stressing of airplane parts.

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