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."