Turbofan Engine (BPR > 4)
Larger engines have a higher BPR. Current large operational turbofans have a BPR around 5 or 6 (new-generation turbofans have achieved a BPR > 8). These engines have performance characteristics slightly different than smaller engines – specifically, the maximum climb rating has no break in thrust with altitude gain. Using Figures 10.48 through 10.50, the installed thrust and fuel-flow rates can be worked out as in previous sections.
13.3.2 Military Turbofan (Advanced Jet Trainer/CAS Role – Very Low BPR) – STD Day
This extended section of the book can be found on the Web at www. cambridge .org/Kundu and presents a typical military turbofan-engine installed performance (with and without reheat) at maximum rating suited to the classroom example of an AJT and a derivative in a CAS role. The installed performance is computed from the graph given in Subsection 10.11.4.
Table 13.2. 30,000-ft altitude (p = 0.00088 slug/ft3, a = 0.37) maximum climb