I did a little investigative reporting on this subject
and came up with some untruths and exaggerations.

I obtained a printed version on this chart and even
though it is supposed to be from the Continental IO-550 Operators
Manual there is a 1997 copyright claim by one George W. Braly
below the lower left corner. Obviously the chart is not from the
Continental IO-550 Operators Manual but is in fact a fabrication
by  one George W. Braly whom I suspect is the owner of GAMI.
Otherwise why would he copyright it under his own name.


Although it is unreadable on the GAMI web site version it clearly
states on the 8.5 by 11 printed version that this chart is
for 79% and 70% peak power. Continental dis allows leaning the
engine over 65% peak power. Therefore any BSFC calculations
made with the aid of this chart and assuming 50 degrees lean of
peak are invalid.  

More on this later.

Paul Lamar
 
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