The Aircraft Engine and Its Operation.  Part No. PWA 109702  PWA01. 100  Reprint with Revisions, February 1955. The first part of the book is devoted to a description of the basic engine sections and "systems" which together make up the powerplant and discusses them in relation to the different instruments and controls by means of which the pilot regulate   the performance of his engine.  The second part deals with the fundamental concepts of power and its measurement, bmep, and ratings with particular reference to the principles of engine operation.  The material in the book and its supplements relates principally to the radial, air-cooled engines manufactured by Pratt & Whitney Aircraft.