Establish Engine Performance Data

The discussion in this section generates the available installed thrust and fuel-flow graphs matched for the worked-out, sized-aircraft examples (see Chapter 11): a Bizjet and an AJT. In addition, the performance data for a 1,140-shp turboprop engine are provided for readers to work out the associated aircraft performance.

Because the given sfc graphs are based on uninstalled thrust, the fuel-flow rates are computed using uninstalled thrust. Installation loss at cruise is approximately half the percentage loss at takeoff.

13.3.1 Turbofan Engine (BPR < 4)

Figures 10.45 through 10.47 provide the typical uninstalled turbofan thrust in nondi­mensional form in terms of TsLs, along with the corresponding sfc for the Bizjet aircraft class. Section 11.6 establishes the requirement of an uninstalled matched TsLs_UNINSTALLED = 3,560 lb per engine. Worked out herein and summarized in Table 13.1 are examples of installed thrust and fuel flows for the three engine rat­ings. The data are sufficient for the example used in this book; intermediate values may be interpolated linearly.

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