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Old 1st Dec 2012, 19:51
  #54 (permalink)  
barit1
 
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boofhead:

Full thrust takeoffs and max power climbs, max cruise settings at the highest altitudes will save on fuel. With fuel costs so high, it might be necessary to scale back on reduced thrust takeoffs.
True, when you consider only that one flight..

But the legacy of that one flight, and a few dozen more of the same, is an engine with reduced efficiency and it perhaps burns a percent more fuel as long it remains on wing. So long-term fuel conservation does not follow from your suggested protocol.

But the worst element of deterioration is definitely takeoff. The transient from idle EGT to takeoff - several hundred degrees in a few seconds - carries with it the risk of rubs, etc. Anything which reduces the rate and magnitude of the EGT transient helps mitigate engine deterioration.

But after TO power (derate or reduced) has been set, and run stably for a minute or two, then using max climb is a (by comparison) small EGT transient. Most engine folks would say "be my guest" re max climb thrust.
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