Originally Posted by
orion1210
Mods: please move to techlog, apologies.
Orion, it may well be that compressor degredation due to caccrued grunge is accounted for in the Measured to Gross performance factors applied to performance charts and further accounted for in Gross to Net as part of the safety factors applied. It is logical that a contaminated/dirty compressor will provide less total thrust for a given N1 than one fresh out of the shop. How much, i guess only the manufacturer will know through in service life. May have the same issue with EPR controlled engines which use the pressure ratio at the front of the fan to the hot efflux as a ratio, rather cold fan input/output.