Test Bed Calibration by Trend Analysis for Reliability of a Turboshaft Engine Performance

Abstract

Aero-engine test bed is the most vital test bench or test equipment for assessing the performance of any aero-engine after production, repair or overhaul as per the performance specification. Aero-engine test bed thus requires periodic calibration as a part of any quality control checks of engine passing out as per the acceptance test procedure laid down for the engine. Periodic aero-engine test bed calibration includes not only calibrating the various sensors used in the test bed system independently but also subjecting the test bed as a whole for calibration with a master engine. While calibration periodicity of the test bed sensors is generally one year or so, test bed calibration as a whole is carried out once in two years. Calibration of test bed using a master engine is very expensive and sometimes not feasible due to non-availability of such engines belonging to early generation of fighter aircrafts. This paper presents a novel concept for calibrating engine test bed using trend analysis. It is mainly based on the performance data of engine acceptance tests carried out over a considerable period of time. This concept completely avoids requirement of a master engine and thus saves enormous effort in terms of cost and man-hours. The concept evolved has been used for calibrating a typical vintage test bed as the proof for validation and found the results comparable with the present trending pattern followed by other engine houses.