Posted for Walter Atkinson <walter@advancedpilot.com>:

 Having flown the TSOI-550 ROP, I can tell you that there is not one answer.
 His question is waaaay too open-ended.
 
 There are an unlimited number of FFs which result in 75% power.
 
 Give me the max MP and RPM for the engine and I can tell you the settings for
75% that have NOTHING to do with FF.  He asked for FF.  That's not part of the
equation ROP.  Since he asked for FFs, and that's not part of the answer,
there is no answer.
 
 I'm not trying to be difficult, I'm trying to be precise.
 
 Walter