Smokey, I tried to apply your 3.5 exponent to some approximate data for the Garrett 731 engine I had, generally called a medium bypass fan. Using N1 of 97.7% and 3700 lbs, I then produced the resulting Thrust vs N1 data. Unfortunately it was not all that close. An exponent of 2.4 seems the closest, however the middle values have the most discrepancies.
But then it occurred to me that the N2 section, a completely free spool from the N1, would for the same thrust have completely different speeds from the N1. Not having N2 data, I can’t take my calculations any further.
My interest is peaked in seeing how close a formula can come to predicting the thrust that an jet engine produces, based on rpm. Sea level and 15 deg C for starters.
Perhaps I should point out that my "data" I have for the 731 comes from the engineering pages off a level 2 simulator at Flight Safety
Do you have any representative data you could provide, for any engine at all?
Enicalyth?
Many thanks, Hawk
A= 0.062092802
exp= 2.4
N1 % EFN lbs Calculated Thrust
97.7 3705 3705
96.8 3658 3624
96 3614 3552
95.2 3575 3482
93.9 3475 3369
92.3 3347 3232
91.3 3255 3149
89 3059 2962
85.8 2748 2713
81.7 2350 2412
76.3 1937 2047
70.5 1554 1693
64.9 1293 1388
60.2 1084 1159
55.1 891 937
49.8 695 735
43.2 514 523
31.1 240 238