First on page 6 Mr. Hensley claims a Honda engine has a BSFC 29%
less than an aircraft engine so that would put it in the
the .28 BSFC category. Is he in for a rude surprise or what?

Classic "Lycosaur" wives' tale.  Obviously, this was the point of my

starting the BSFC morass.  I hate seeing prejudice spouted as fact with
unquestioned acceptance by a lot of people.  Engineering decisions (i.e.,
engine selections) need to be based upon empirical data, not unsupported
opinion.  One piece of empirical data that should be obtainable by most are
engine dynanometer curves.  Evaluating these would probably show that a
Honda does not have much advantage (if any) over an aircraft engine when it
comes to BSFC.

A subjective evaluation taking into account real world usage could be

added to the empirica data.  This is where the advantages of the EFI and
liquid cooling of the Honda come into play.  In typical weekend flyer mode,
involving lots of throttle transients and low altitude operation, you could
end up with a real world BSFC advantage for the Honda.  However, on a long
cross country trip at altitude, the BSFC advantage would disappear.

Of course, this does not even begin to take into account all the other

variables affecting engine selection, such as reliability (where the rotary
shines), ease of installation, maintainability, etc.

I digress . . . I just hate it when people are so loose with numbers.

Damn salesmen.

Rick Price

Yeah, I laughed out load and read that one to my wife.  Few of these
folks know the basics.  Perhaps I should dust off my article and
submit it.

Bill Freeman
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

 
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