Measurement of turbofan/turbojet thrust from tailpipe statistic pressure

Abstract

The most accurate method for measuring turbojet/turbofan thrust is mechanical. A more practical method is often desired , however, since a mechanical device is costly and non-portable. An investigation was conducted to determine whether inferring thrust indirectly from pressure provides sufficient accuracy to justify its use as an alternate technique for determining uninstalled thrust. TF41 engine data were provided by the Naval Air Rework

Facility at Jacksonville, Florida. The data consisted of a

The most accurate method for measuring turbojet/turbofan thrust is mechanical. A more practical method is often desired , however, since a mechanical device is costly and non-portable. An investigation was conducted to determine whether inferring thrust indirectly from pressure provides sufficient accuracy to justify its use as an alternate technique for determining uninstalled thrust. TF41 engine data were provided by the Naval Air Rework Facility at Jacksonville, Florida. The data consisted of a variety of engine parameters which had been recorded during routine post-maintenance performance tests plus an additional set of tailpipe static pressure readings that had been obtained from a "slave" tailpipe used for this project. It was decided to approach the data evaluation empirically. The engine data were combined and an ensemble plot of tailpipe static pressure versus thrust was produced for analysis. A curve fitting technique was then employed to determine how well the parameter correlated with thrust. The results were tested statistically and found to be reasonable. Correlation between thrust and tailpipe static pressure was excellent.