Engine-Performance Data

This section describes typical engine outputs. The data are presented in nondimen­sional form. All power plants have prescribed power settings, as discussed herein. Power settings are decided by the engine rpm and/or by the exhaust-pressure ratio

(EPR) at the jet pipe temperature (JPT), which should remain lower than prescribed levels. An engine is identified at its sea-level STD day at takeoff in static conditions. For turbofans, it is denoted as TSLs. Typical power settings (i. e., ratings) of engines are given in the following subsections.

Takeoff Rating

This is the highest rating that produces the maximum power and is rated at 100% (i. e., at static run of turbofans, it is TSLs). At this rating, the engine runs the hottest and therefore has a time limit to ensure a longer life and less maintenance. For civil – aircraft engines, the limit is about 10 minutes; for military aircraft engines, it could extend somewhat longer. A situation may arise in which one engine is inoperative and the operative engine must supply more power at the augmented power rating (APR). Not all engines have an APR, which exceeds 100% power by «5% for a short duration (e. g., «5 minutes).