Originally Posted by
Jimmy.
Definetly not linear. For example, I noted some NG/TGT valies in my last flight (GE CT7-8A):
Ng TGT
95.6 865 (cruise)
68.0 853 (idle, cooling down)
73.8 782 (cooling down, adjusted to keep NR outside the avoid range)
Obviously as in your wonderful example Ng and TOT are not linear as those ratios would be approximately 1:9, 1:12.5, and 1:10.5 but fuel flow and Ng would be wouldn’t they? I believe SLFMS is correct when he stated, “
I suspect part of your answer may come from the proportion of this ratio as it changes for different fuel flows and is not linear compared to compressor speed but that would be a guess.”