Test Procedures for Establishing the Altitude Performance of Turbofan Engines to Validate Contractual Guarantees
The facilities at The National Gas Turbine Establishment for direct-connect tests on turbofans and turbojets at conditions simulating flight at altitude are briefly described. The measurements that have to be made to establish performance within the prescribed limits required for contractual guarantees are derived. Techniques are discussed for eliminating the effect of small, but significant, time-variant changes which occur in the quantities being measured due to unsteadiness in instrumentation, engine and test conditions. Methods evolved for ensuring continuing operation of the instrumentation and data gathering system at the required high level of accuracy are outlined. A standardized test procedure (Test Code) for establishing contract guarantee performance at NGTE is discussed with illustrative examples.