Gary:

** Since the
engine is "efficient" and the BSFC is relatively flat when running LOP there
have been people that say just to multiply fuel flow times a constant to get
horsepower.  That is probably accurate enough for our purposes.  Maybe
someone has some accurate friction horsepower numbers for these engines.**


Using FF LOP works accurately because it uses the BSFC for the engine as a starting point in the calculations.  The BSFC takes frictional loses into account.

Walter