Data Acquisition and Processing in the NGTE Altitude Test Facility Free

The Engine Test Facility of the National Gas Turbine Establishment has used computer-controlled instrumentation systems for on-line data acquisition and processing for over 15 yr. The development of the system is outlined and the current system described. To illustrate its present use typical results obtained during tests on a large turbofan engine are presented and discussed. The emphasis of this paper is on the use of the system to assess the accuracy and reliability of the test measurements before commencing qualification tests on the engine. The probable sources of error are described and placed into three categories, to assist handling and propagation through the calculation processes. The resultant uncertainty in measurement of Thrust and sfc at cruise (M = 0.85, 35,000 ft), is estimated to be 0.50 percent (one standard deviation) for a single performance curve.