Mailing List lml@lancaironline.net Message #225
From: Gary Casey <glcasey@gte.net>
Subject: LOP
Date: Sat, 29 Dec 2001 07:51:09 -0800
To: <lancair.list@olsusa.com>
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Here is what the data shows.  At .75 X 350 Hp and  operating the engine 50
to 125F rich of peak, the peak internal cylinder pressures will be 10 to 15%
higher than the same engine operated at the same 0.75x350Hp with the engine
leaned and operating 60 to 90F  LOP.  AND, operating ROP, the CHTs will be
about 30-40F hotter than when LOP at the same horsepower.   I have a 100
dollar bill for anybody that can show me any data that is materially
inconsistent with what I just wrote.<<

I'm afraid I can't get your $100 as I think you are essentially right.  But,
you say the peak PRESSURES are 10% lower at LOP operation and at the same
power setting.  Are you taking into account that the manifold pressure will
be higher running LOP?  I would think that the peak pressure will be close
at the same power setting except for the fact that the timing is fixed and
the flame speed is slower LOP.  I don't think that would be enough to lower
the pressure by 10%.  As I recall, 50 LOP will be down at least 5% in power,
so the MAP will have to be more than 1" higher to get the same power.

Gary Casey



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