Message-ID: <000a01c0d3df$93972da0$831aecce@cardellnet.com>
From: "Ed de Chazal" <edechazal@mindspring.com>
To: <lancair.list@olsusa.com>
References: <20010503055228.AAA8781@pop3.olsusa.com>
Subject: Re: LOP/ROP debate
Date: Thu, 3 May 2001 10:44:35 -0400
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Reply-To: lancair.list@olsusa.com

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>>
George, thanks for your contributions here!  Regarding your recommendation
to run normally aspirated engines at WOT for takeoff, climb and cruise,
could you elaborate a little more on why you recommend this.  I think all of
us were taught to pull back to 25 or 26 square shortly after takeoff.  While
I now understand that running over square is not the concern that we were
led to believe, I understand that Lycomings have an enrichment circuit that
richens the mixture at WOT.  Can you confirm this for IO-360-B1F engines and
if so, maybe explain how that really works.  Would this circuit interfere
with the leaning process?

I recall when I was working on engine calibrations at Chrysler that dyno
engines were most likely to detonate under WOT (high manifold pressure) and
at low rpm because this led to the highest cylinder pressure.  We made sure
that engines leaving the factory would not detonate under any driver induced
circumstances.  Has Lycoming not done the same thing?  Also, how are you
measuring/detecting detonation - by in-cylinder pressure probes or some
other means?

Also, can I boil down your advice to simply: run your N.A. engine as lean as
it will smoothly go and add manifold pressure to get power back.  If we run
out of manifold pressure, richen it to get power back subject to CHT and
fuel burn tradeoffs.  When stated this way, peak EGT becomes irrelevant
except as a proxy for other things.

Thanks,
Ed de Chazal


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