Silberfuchs;
Very helpful post. Wondering if you could clarify one point here:
When you say that EPR is not a linear indication of thrust; if a new engine is producing 60,600 # of thrust with an EPR of say, 1.9, if that engine is showing 1.9 EPR 5 years later is it still producing 60,600 # of thrust, or do we need to compare it to N1 to find the answer? Is this the reason that we need to "know the RPM of the fan" (to quote an earlier posting in this thread)?
Thanks