The Analog Computer as an Operational Test Instrument for Jet Engine Testing

One of the most cumbersome features in present methods of wind tunnel testing is data taking and data reduction. This is mainly because of instrumentation methods which require step by step procedures from raw data to reduced data. In many tests it would greatly enhance the test value if immediate indication of reduced parameters such as combustor efficiency or calculated thrust were available. One method being studied at the Engine Test Facility, Arnold Engineering Development Center, for providing these indications is through use of electronic analog computer equipment. One of the most involved equations encountered and the method of computing the reduced value is presented in this paper. The instrumentation for transducing the fundamental measurements is discussed. Finally, some conclusions are drawn about the accuracy and usefulness of such an instrument.