Originally Posted by
Connedrod
Once again you need to read and understand what is going on.
The limiting factor is the egt. The power lever is reduced to maintain a maximum of 750lbs per hour. The compressor speed would be at its maximum hence the higher egt. In this state the engine is not in idle. Its no where near idle. Only the flow fuel is near idle. The fcu will maintain compressor speed to the set figque. The engine has no more fuel to give due to the air ratio to continue to climb or maintain operation above this flight level. Idle speed is a factor of compressor speed and not wf. Wf on the ground and prefromance runs is a factor of compressor speed and must be within it graph for compressor speed to wf.
The engine is not in an idle condition due to the speed of the compressor. The engine would not be consided as in idle.
Connedrod, it seems like people keep trying to explain it to you, and you keep trying not to understand. N1 is back at idle rpm, not at its maximum, at that point, which is what the flight manual says. In flight, at high altitude, the maximum allowable N1 reduces, not increases, for those engines. Again, from the manual, at 50,000ft, max allowable N1 is 90%. At 60,000ft, max allowable N1 is 88%. Above those altitudes other limits are more restrictive so maximum N1 figures aren't published, but the N1 achieved will be reducing.
The n1 at 70000 feet would be at or near max n1 and not at sl n1 speed.
The engine will not work at sl n1 at 70000feet. My i suggest you go do basic gas
No, no it won't, the flight manual states this clearly. At the maximum cruising levels N1 is at idle RPM, fuel flow and power produced are all at their lowest levels, and the power lever is on or near the idle stop. I don't know how else this can be described as other than at idle power.
Have a look through the manual if you like, here's the link I found to it:
https://www.scribd.com/document/1194...-Hb-1-Mar-1959 the engine limitations are on around page 244. Takeoff is done at around 94-96% N1, idle N1 is 55-57% N1, which will be close to the N1 achieved at maximum cruising altitudes; all this is in the flight manual which is freely available to read.