A last question
Something has been buggin me about my knowledge of turbine startups.
Basically, I understand that the TOT will rapidly rise to about 750°C then fall to 520°C by about N1 30% on ignition provided one keeps the starter depressed.
I also understand the basic concept that the starter is keep depressed to 58% N1 as that is the point at which the turbine is self-sustaining.
What I'm less clear about is what happens (not that you would do this) if you let up on the starter button in different ranges of N1, and why.
I would guess there is a low range like say under 30% where there is definately not enough suction to sustain the turbine and it will heat up to a certain level, but if left to spin down to zero, does it flame out? Would the TOT go through 1000°C or just go yellow?
Based on how turbines work, can anyone explain in theory what would happen at different points? Any difference at say 40% or 60% N1?
Thanks for your thoughts and helping me better understand turbines.
Helicopter pilots rock!