This report presents a method of calculating polar curves which is at least as precise as graphical methods, but it more rapid. Knowing the wind tunnel test of a wing and the performances of an airplane of the same profile, it is easy to verify the characteristic coefficients and, at the same time, the methods determining induced resistances.

Report issued by the Bureau of Mines covering petroleum laws of the U.S. and surrounding oil producing countries. As stated in the preface, "this bulletin includes the petroleum laws of (1) United States; (2) the several oil-producing States; (3) Canada; (4) Mexico; (5) the Republics of Central and South America" (p. iv).

As the purpose of the report is to transmit as smoothly and as easily as possible, certain facts and ideas, to the average person likely to read it, it should be written in a full and simple enough manner to be comprehended by the least tutored, and still not be boring to the more learned readers.

Different aircraft engines are categorized as being of interest to only the Army or Navy or to both armed services. A listing of the different engines is presented along with some statistics, namely, horsepower.

This report details the Rumpler Limousine which was a further development of the well known type 5 A 2. The fuselage, engine, cabin, wings, controls, and landing gear are all discussed.

In the subdivided wing section profile, the diagram of the current is entirely changed and the harmful formation of eddies is avoided through premature deflection. Pressure equalization does not occur between the upper and under sides. This report presents a discussion of the various laws relating to wing design with the conclusion being that lift increases with more acute angles of attack.

This report presents a table of specifications of the rotary engine and a very brief description of some of the notable features such as the exhaust valves controlled by means of a fixed cam gear.

Comparing the results of the calculations for computing the mean pressure of an aviation engine for any number of revolutions, with those of experiment, the writer, by numerous examples, shows the perfect agreement between them. This report will show that, by means of a special abacus, an engineer can instantly plot the characteristics of an engine.

The author argues that because of a general misunderstanding of the principles of flight at low speed, there are a large number of airplanes that could be made to fly several miles per hour slower than at present by making slight modifications. In order to show how greatly the wing section affects the minimum speed, curves are plotted against various loadings. The disposition of wings on the airplane slightly affects the lift coefficient, and a few such cases are discussed.

"It should be clear that in order to obtain a lift it is necessary that the air which flows past an aerofoil be given a downward acceleration; indeed the lift can be only the reaction produced by the downward acceleration of the flowing air. The motion of the air in the neighborhood of an aerofoil may be followed theoretically with great exactness. In the following, it will be undertaken to make understood, through the simplest possible considerations, the effect of span and loading on the air force on an aerofoil, and while these do not form a strong proof of the correctness of the formulae developed, yet they explain the essential features of the phenomena" (p. 1).

Much attention is given here to the design of the wind tunnel and the experimental set-up. In comparing their results on the wind resistance of spheres to the results of other researchers, the authors find wide discrepancies. They are unable to explain the cause of the discrepancies, concluding, as they do, that the differing results could not be explained by the action of the wind tunnel walls.

The aim was to bring attention to what might be the cause of some aircraft accidents for which there was no satisfactory explanation. The author notes that in testing aircraft accidents at the Bureau of Standards, it happened frequently that the engine performance became erratic when the temperature of the air entering the carburetor was between 0 C and 20 C. Investigation revealed the trouble to have been caused by the formation and collection of snow somewhere between the entrance to the carburetor and the manifold, probably at the throttle.