Interview Q

[Happydays]

If a brand new engine is producing 60,000 lbs of thrust and indicating 1.8EPR and ten years down the road, it is still indicating 1.8EPR will it still produce 60600lbs of thrust?

Need some help with this? EPR is diff in pressure of PT2 compared to PT7 probe. Will it be correct to say that trust will be the same? But due to the fact than after 10 years the engine will have some damage you will have a higher N1 and fuel burn...and possible a different thrust lever position?

Is this the reason why RR uses EPR for take-off and not N1. If this is the case why do some manufacturers use N1 then to set thrust.

I might be wrong; any advice on this will be appreciated thanks!
:)

[GlueBall]

It's exhaust pressure compared to the intake pressure, so 1.8 EPR "10 years later" will give you the same thrust level. But the EGT, N1, N2 and N3 could be slightly higher due to wear and tear. There are maintenance parameters, for example, of how deep the leading edges of fan blades can be filed off for nicks and cracks. So, N1 [fan] speed alone is not as an accurate measure of thrust as is EPR, . . . as the blades will move less air when its leading edges are filed.