does the thrust produced by the engines decrease over time? would a constant N1 or EPR setting over time equate to a reduction in total thrust of that engine??
Again one for the techs, not for pilots... but I'll give it a shot.
EPR is a fairly direct measure of thrust, thus assuming the pressure/temperature probes/gauges are working correctly, 1.72 EPR on a new engine should be equal thrust to 1.72 on an old one. What will change is how hard the engine has to work to produce that thrust: the older engine will probably show a higher EGT, fuel flow and indeed N1 to produce the same thrust.
N1 is a measure of engine rotation, so I would imagine an older engine turning at 111.4% N1 will not be producing as much thrust as a new one showing 111.4%... stand to be corrected though.
MD
PS When's a techie when you need one?
