Hello.
This had been thrashed to death no doubt many times so sorry for inducing nausea in those who couldn't care less. But I just don't get it...!
I can repeat it parrot fashion all day but when asked to explain the detail my description ends up describing the opposite. By the way please look away now if, like me, you get a reasonable grasp of something only for some numpty to come along and chuck a spanner in the works!
I'm thinking like this. Our engine is factory rated under ISA+15c conditions to, say, 20,000lbs so that under ISA+15c it will produce 20,000 when asked to deliver 100% - all it's got.
Then I muse about the same setup (a/c, runway, pax, wind, etc..) but 5deg cooler. Here our engine(s) will still develop the 20,000lbs (same as before - that's the factory limit) so theoretically same wear and tear forces beacause the work done is the same in both cases. So far so good? If we go for 5deg warmer then under full throttle the engine will deliver its all but the output or product of all this will be less, say 18,500lbs, and therefore less wear and tear as the work done is less. All above assuming commanded full throttle.
Why then would we want an engine to "think" that it's got its work cut out by
fooling it to believe that the temperature is hotter and that it'd "better work its little legs off for us" - so presumably will be giving all its got in preparation for these adverse conditions. Surely
only in the case of a genuinely hot day would the engine develop less thrust because of external factors. But in the case of the temperature being less and the engine giving all it's got (beacuse it thinks we're under inferior conditions) then this defeats the principle and we end up with the limiting arbitrary output for the actual (real) temperature....?
Excuse me whilst I puke....
