The performance of a jet power plant consisting of a compressor and a turbine is determined by the characteristic curves of these component parts and is controllable by the characteristics of the compressor and the turbine in relation to each other. The normal. output, overload, and throttled load of the Jet power plant are obtained on the basis of assumed straight-line characteristics.

This report describes the apparatus used to take air-flow photographs. The photographs show chiefly the spiral course of the lines of flow near the tip of the wing. They constitute therefore a visual presentation of the phenomena covered by airfoil theory.

The theory (wing experiments in an artificial air stream are subject to error, due to the fact that the wing is not situated in an unlimited body of air) by means of which the given drag correction was obtained, was based on various assumptions (e.g., elliptical distribution of lift) which do not always hold true. For this reason it was desirable to test the equation for the additional drag in regard to its reliability and range of application.

"Two fields are reserved for the application of rocket power plants. The first field is determined by the fact that the rocket power plant is the only type of power plant that can produce thrust without dependence upon environment. The second field is that in which the rocket power plant proves itself the most suitable as a high-power drive in free competition with other types of power plants" (p. 1).

"Completing the first paper dealing with charging methods and arrangements, the present paper discusses the design forms of two-stroke engines. Features which largely influence piston running are: (a) The shape and surface condition of the sliding parts. (b) The cylinder and piston materials. (c) Heat conditions in the piston, and lubrication. There is little essential difference between four-stroke and two-stroke engines with ordinary pistons" (p. 1).

This report treats the following problems: The beginning of the investigated motions is always a setting of the lateral controls, i.e., the rudder or the ailerons. Now, the first interesting question is how the motion would proceed if these settings were kept unchanged for some time; and particularly, what upward motion would set in, how soon, and for how long, since therein lie the dangers of yawing. Two different motions ensue with a high rate of turn and a steep down slope of flight path in both but a marked difference in angle of attack and consequently different character in the resultant aerodynamic forces: one, the "corkscrew" dive at normal angle, and the other, the "spin" at high angle.

"Many reports on various control systems are available, but the results cannot be generally applied since the effect of particular changes of surface-form and mounting are subject to variations depending upon airfoil section and influences of airplane layout. This report presents a simple analysis of several control systems in more general use. Elevators, ailerons, and rudders are all discussed" (p. 1).

This report details the rules and regulations for obtaining a British airworthiness certificate. Aircraft loading and construction are especially important.

This report describes the leading crankless engine types, which have appeared in recent years. These types include: the Mitchell crankless motor car engine and the German Michel engine.

"The purpose of this memorandum is to present in a concise form a description, with drawings, of the most practical light airplanes participating in the meet at Lympne, England, in October, 1923. Features, which are particularly suitable for this type of aircraft, are described and a special reference is made to achievements which indicate progress and possibilities both from a commercial and a military point of view" (p. 1).

It has long been thought that metal construction of airplanes would involve an increase in weight as compared with wood construction. Recent experience has shown that such is not the case. This report describes the materials used, treatment of, and characteristics of metal airplane construction.

Memorandum describing the rules and regulations of the 1923 Rhön Soaring-Flight Contest. The requirements of the aircraft, pilot and competitor requirements, and prizes are provided.