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Date: Tue, 15 Oct 2013 18:28:25 -0400
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Subject: Re: [LML] Discussed engine management with the team from Continental Motors
From: Walter Atkinson <walter@advancedpilot.com>
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Neal:

***We set MAP and RPM per the charts to achieve the desired percent =
power. Then lean to achieve the recommended EGT (typically 75 deg F ROP =
or 50 deg F LOP). ***

Unfortunately, I see that you not one of the TCM reps who will be =
attending the APS class this weekend.  I had hoped to meet you.

If one sets the MAP and RPM per the charts for desired power, that will =
be the power produced ONLY when leaned to 75dF ROP--or essentially any =
useful ROP power setting.  That will NOT be the resulting power if one =
leans to a LOP setting (as you say is recommended at 50dF LOP).  MAP and =
RPM play no role in LOP power settings as power in a TCM TSIO engine is =
a function of fuel flow only--specifically 13.75 x FF =3D HP.

In addition, 50dF LOP is not the optimal mixture setting except at one =
power setting.  One flying a TSIO (at conventional high power settings =
might better choose 80dF LOP.  In these cases, one knows that setting to =
a specific FF does, in fact, get the desired mixture LOP.  For example, =
many choose to set MAP and RPM and simply pull to a conventionally known =
FF of, say 16.5 gph, where the known HP is 227 and that they are far =
enough LOP by reference to the appropriate CHTs having these as known, =
repeatable values.  If one does not have these known values (say, flying =
an airplane for the first time), then leaning by EGT will get one the FF =
values that can be used hence.  While using EGT and the slow leaning =
process does get you where you want to be, it is a sub-optimal practice =
since simply pulling quickly to a known FF by-passes the unhappy =
experience of spending a lot of time in the Red Box whilst ones heats up =
CHTs unnecessarily.

I hope to see you at an APS class soon.

Walter Atkinson
<walter@advancedpilot.com>
(225) 939-7508


On Oct 14, 2013, at 12:18 PM, Neal George wrote:

We set MAP and RPM per the charts to achieve the desired percent power. =
Then lean to achieve the recommended EGT (typically 75 deg F ROP or 50 =
deg F LOP).=20