We are undertaking the task of computing the air forces on a slightly cambered airfoil in the absence of friction and with an infinite aspect ratio. We also assume in advance that the leading edge is very sharp and that its tangent lies in the direction of motion.

This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).

"Every strength calculation, including those on airplanes, must be preceded by a determination of the forces to be taken into account. In the following discussion, it will be assumed that the magnitudes of these forces are known and that it is only a question of how, on the basis of these known forces, to meet the prescribed conditions on the one hand and the practical requirements on the other" (p. 1).

The phenomenon of the Magnus effect consists in the fact that a revolving body moving relatively to the surrounding fluid (air) is subjected not only to drag (i.e., a force acting in a direction opposite to that of the direction of motion), but also to a lift.

In order that the method may be more easily understood, we will first consider the simpler case when there is no lift, but only drag, and when the streamlines at the measuring point behind the obstacle are nearly parallel. Moreover, the flow is assumed not to deviate much from the two-dimensional flow.

The economic costs and benefits of speed on airship traffic are calculated and different factors are considered.

In the first article, in connection with a lecture on the hydrodynamic basis of flight and the potential flow about a Joukowski wing, the pressure distribution on several wings is computed and plotted. The diagrams of the pressure distributions are presented accompanied with a qualitative discussion of the pressure distribution. In the second article, the the cross-sectional outline (or profile) a Joukowski wing are plotted.

The hydrodynamics and mathematical models as applied to the potential flow about a Joukowski wing are presented.

Memorandum describing the results of the Royal Aero Club light airplane competition and some of the history surrounding the event. A list of the planes that participated and an analysis of the performance of the various aircraft are provided.

This report begins with a review and analysis of the work being done to develop light airplanes in the U.S. and abroad. A technical discussion of the construction and innovations in light airplanes is then presented.

T.M. 311 gave a short outline of modern theoretical aerodynamics as applied to light airplane design. This discussion may have been somewhat obscure to the nontechnical reader. A series of charts or curves should serve to clear up such obscurity as well as to more definitely emphasize those quantities most important for each flight characteristic.

"The extensive applicability of the hydrodynamic theory to the problems of engine construction is clearly shown in the following attempt to determine by exact methods the nature of the flow in valves under variously restricted conditions. Observation shows that two principal kinds of flow occur in simple flat-seated valves. For small valve lifts, the flow is along the horizontal wall and is therefore deflected 90 degrees, but for greater valve lifts the flow separates and forms a free stream, whose angle of deflection naturally increases with increasing lift" (p. 1).

"It has frequently been stated and written that in order to popularize light aircraft the first essential is the production of a reliable engine capable of being easily maintained and having a long life, at the same time selling at a low figure. It is desired to point out the difficulties in the way of realizing this ideal before remarking on the claims of the various types for adoption" (p. 1).

"In this article, the phenomena of the upward component in the case of flat surfaces will be referred to as the "Lilienthal effect." The Lilienthal effect will be distinguished from the Knoller-Betz effect which is explained by means of vertical wind oscillations, at the basis of which, however, there lie air motions which the Lilienthal effect could not produce. It will be shown that the same cause, which can produce the Lilienthal effect on flat airfoils, considerably strengthens the thrust due to the Knoller-Betz effect" (p. 1).

This report details the contest to design and build concrete airship hangers. The difficulty lies in the magnitude of the absolute dimensions. An airship shed must withstand two principal types of stresses: those resulting from its own weight and those due to the wind. This report discusses both problems in detail.

This report deals mainly with the methods of construction employed when after the plan had been approved. The foundation, side walls, doors and roof are all discussed and the economic savings resulting from this method of construction.

The proof of the validity of the Reynolds law of similitude for the surface resistance of planes has been developed with an accuracy hitherto unattained and for a large range of lengths and speeds. It has been shown that, in addition to the form resistance, the resistance of the longitudinal edges must be taken into account.

"This article is based on the experience of the Schute-Lanz Airship Company in light construction. The object is to stimulate the employment of these methods in other fields of industry" (p. 1).

Memorandum presenting a description of the Hesselman heavy-oil high-compression engine, which is meant to solve many of the problems associated with standard diesel engines. Specific details of the fuel pump, fuel valve, spraying, and process by which the engine functions are provided.

"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 elimination of the rigid supports for models and their replacement by wires constitute a great improvement by rendering negligible the interactions of support. There are disadvantages to wire, namely, the aerodynamic resistance is very large and their use is rather difficult because the whole suspension lacks rigidity and easily becomes distorted. We will here investigate the nature of these distortions, evaluate the errors they entail and describe the methods for taking account of or avoiding them.

"The calculation of wing spars of constant cross-section and load has been thoroughly treated by a large number of authors. Such is not the case,however, regarding the calculation of wing spars whose section and linear load diminish toward the ends, as in wings of trapezoidal contour and decreasing section" (p. 1).

It is the object of this report to review briefly the aerodynamic and construction data already available regarding helicopters and to set forth the difficulties which must be met.

In the present treatise we will consider chiefly the problem of solid injection in comparison with air injection. On leaving the valve or nozzle through one or more small openings, the fuel is split up into innumerable fine drops, which penetrate the combustion chamber in divergent directions in the form of a conical jet. The efficiency of this jet is judged from the following three viewpoints: 1) with respect to the fineness of atomization; 2) with respect to the direction or distribution of sprayed particles; 3) with respect to the penetration of the particles.