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If N1 idle is 30%, will flying idle at very high speeds force the fan to go higher than 30%? (for example idle while descending fast)

And if no, why not?

Invariant
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1 Answers1

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Yes, N1 should increase as the plane reaches higher speeds. This means that the blade speed will increase, therefore, increasing N1. Now because the engine setting is constant (throttle), this means that only a slight increase in the amount of thrust will happen.

lectrician1
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  • Why does N1 increase with increasing airspeed? – Koyovis Sep 06 '17 at 21:42
  • N2 doesn't increase does it? – Invariant Sep 06 '17 at 21:57
  • @Koyovis you can refer to this to see what N1 is: https://aviation.stackexchange.com/questions/14690/what-are-n1-and-n2 It's basically self-explanatory because as the airspeed is greater, the fan will speed up. – lectrician1 Sep 10 '17 at 18:41
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    You can read the post above as well @Invariant . The N2 will increase as it is once again, the speed of the blades in the high-pressure shaft whereas N1 is the speed in the low-pressure. Either way, both should increase. – lectrician1 Sep 10 '17 at 18:46
  • @SethDeegan I know what N1 stands for, that wasn't my question. – Koyovis Sep 10 '17 at 19:30
  • Did I answer your question? Sorry for the extra explanation @Koyovis . – lectrician1 Sep 11 '17 at 19:03