INTRODUCTION

Data Items in the group ESDU PERF RP 1/0, RP 1/1, RP 1/2 and RP 1/3 (Reference 1, 3, 4 and 5) give the standard British methods of performance reduction for piston-engined aircraft with constant-speed propellers (see also Reference 6). Besides ignoring compressibility effects these methods imply certain other assumptions, for example, average values are assumed for the variation of propeller efficiency with speed and the relations assumed for the engine performance do not apply to turbo-blown or compounded engines or to engines with charge temperature control. Because of these limitations there are some cases in which it is necessary to use a more general form of the performance reduction equation, and the present Data Item suggests a method of doing this.