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Discussion of a simple hand calculation method for determining wave or pressure drag of a nonuniform body at supersonic speed. In the past, even the simplest calculation proved to be a tedious process -- prone to errors. The author introduces the use of two-dimensional methods to solve these three-dimensional problems and justifies the use of this method by demonstrative calculations.

THE 2-cyl “compound” engine on which the data reported in this paper were obtained is provided with a high-pressure cylinder, and a low-pressure cylinder which serves as a compressor as well as a working cylinder. The primary consideration in this work was the extracting of additional work from the already partially expanded gases from the high-pressure cylinder; a secondary consideration was the use of the same low-pressure cylinder as a second-stage compressor to aid in supercharging the high-pressure cylinder. In reporting test results covering the development and testing program on the 2-cyl test unit, indicator diagrams showing the power developed in both high-pressure and low-pressure cylinders are presented. The method of summarizing the test results is by tabulating the representative runs and plotting the final runs. Some results and conclusions follow: 1.

OPTICAL, balanced-pressure, electrical and sampling-valve indicators are discussed with particular reference to their shortcomings. Sampling-valve indicators possess the advantage of simplicity, as compared with the balanced-pressure type, and make a permanent record on ordinary indicator paper. The sampling or averaging type and the electric or instantaneous type each has fields of usefulness not covered by the other. The electric indicator is claimed to be the most satisfactory device for transient and qualitative work such as combustion study, but the sampling type is said to be better suited for engine development, valve-timing studies, supercharging and similar work.

FOR the rapid calculation of bearing loads in aircraft engines the authors have developed an analytical method that is described for the first time in the paper. This was derived from the long tedious graphical method that was formerly used and its accuracy is asserted to be sufficient for all purposes of engine design. Results of an analysis of the bearing loads in the Curtiss V-1570 Conqueror engine which were obtained by the graphical method are first presented in considerable detail. The Wright R-1750 Cyclone is next analyzed, the method that was employed not being as precise as that used for the other engine. An application of the analytical method using empirical constants derived from a graphical analysis of various engines is also presented. Numerous illustrations and tables supplement the text.