| Abstract | A brief test program was carried out to establish the effects of downtrimming on J85-CAN-15 engine operation and performance, under sea-level-static conditions. The engine was downtrimmed at different fuel flows to a maximum of 160 lbₘ/hr. As a result, the T5H limit temperature was decreased by 1°C per 4 lbₘ/hr fuel flow, which should increase the engine's hot end life.
The loss in static thrust was approximately 70 lbf per 100 lbₘ/hr fuel flow reduction at MIL power. In rapid transients from IDLE to MILITARY power, downtrimming had no apparent effect on the compressor operating line. In bursts from IDLE to MAX A/B, downtrimming the engine reduced the extent of compressor rollback during A/B development. Since rollbacks tend to decrease the stall margin, this change in operating mode is considered to be beneficial. |
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