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 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.

This report presents methods by which it is possible to determine, in a simple manner, both pressure atomization and carburetor atomization.

Memorandum presenting the mutual action of wing and fuselage, which greatly affects the construction of airplanes. A description of systematic wind-tunnel tests that were made to answer that question is provided. Other tests deal with the transition from fuselage to wing root, which, if inadequate on low-wing monoplanes, may become dangerous by causing the air flow to separate at the wing root.

"The choice of the profile for the wings of an airplane is a problem which should be solved by a scientific method based on data obtained by systematic experimentation. The problem, in its present form, may be stated as follows: "To find a profile which has certain required aerodynamic characteristics and which encloses the spars, whose number, dimensions and separating distance are likewise determined by structural considerations." At present, the static test, corresponding to the case of accelerated flight at limited speed, requires the knowledge of the moment of the aerodynamic resultant at the angle of zero lift, and the possibility of controlling the magnitude of the corresponding absolute coefficient within more or less extensive limits" (p. 1).

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.

The thorough investigation of a Dorner four-cylinder, four-stroke-cycle Diesel engine with mechanical injection led me to investigate more thoroughly the operation of the Diesel as a vehicle engine. Aside from the obvious need of reliability of functioning, a high rotative speed, light weight and economy in heat consumption per horsepower are also indispensable requirements.

This report presents a description of the design of the Cuatro Vientes wind tunnel.

The object of this report was to indicate that we frequently only make use of 50 percent of the maximum brake horsepower of the engine in taking off the ground, that this loss is not inevitable, and that the effort to get engines of low weight per horsepower by boosting revolutions is of very little use to bombers and commercial airplanes.

It is stated that the index value 6000, as found in normal tests of wing sections with a 20 cm chord, falls in the same region where the transition of laminar to turbulent flow takes place on thin flat plates. It is to be expected that slightly cambered, thin wing sections will behave similarly. The following test of two such wing sections were made for the purpose of verifying this supposition.

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.

This report presents experiments in which two parts of the wing were arranged so as to form a biplane, which was subjected to normal three-component measurements, the two parts being placed in various relative positions with respect to the gap a and the stagger b.

Report presenting an explanation of the Flettner wind-driven rotor ship and how it functions using the "Magnus effect". The advantages of the construction of this type of ship and the development of flow around the cylinder used to power it are described.

This lecture concerns the combining effects in airplane wings so as to save some of the dead weight. Equations are provided in order to calculate some of the load characteristics and some of the effects to be considered.

Certain principles are common to all metal spars and the design of a particular metal spar is followed throughout the design process.

The researches at the Gottingen Institute are discussed especially in regards to the physical properties of fluids. The three main properties of fluids examined concern density, viscosity, and compressibility.

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.

"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).

"Commander Le Prieur, whose flight experience in a low-speed seaplane we related in our number of September 27, 1924, invented, four years ago, an instrument destined to render very great service to aviators, namely, the "navigraph", designed to correct errors of orientation due to the effect of the winds during flight" (p. 1).

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 question of behavior of a streamlined body with round or square cross-sections is of importance in determining the shape to give an airplane fuselage. It is our task here to show how the lift and drag are affected, with the object placed obliquely to the air stream" (p. 1).

The present article is a brief report on the development and testing of the Messerschmidt glider that set a duration record of 21 minutes. Its most conspicuous characteristic was the placing of the steering gear entirely inside the fuselage and wings.

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.

The laboratory instruments, which we often constructed with makeshift means, gave encouraging results and showed that they could satisfactorily meet the required conditions. By limiting ourselves to the employment of hot wires of 0.05 mm (0.002 in.) diameter, we obtained instruments which faithfully followed all the wind fluctuations of over 0.1 second and even much more rapid variations without any very great error.