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Date: Sat, 12 Oct 2013 19:00:46 -0400
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From: jeffrey liegner <liegner@ptd.net>
Subject: Discussed engine management with the team from Continental Motors
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LML PIlots,

At LOBO Greenville, I discussed engine management with the team from Contin=
ental Motors.  They provided their slides from their presentations (which I=
 have reviewed) and I asked them many questions.  I communicated to Jeff Ed=
wards that the group would definitely benefit from a group open forum discu=
ssing engine management settings commonly used, with opportunity for others=
 to listen and others to explain why they do what they do, perhaps moderate=
d by a Continental guy or GAMI people and/or an exemplary Lancair authority=
.  Old wives tales would be debunked, poor techniques would be scolded, and=
 new settings could be integrated into all phases of flight for each indivi=
dual.

One thing that was clearly stated by TCM: we should cruise at power setting=
 no more than our Maximum Recommended Cruise.  If you don't have access to =
the TCM engine manual for turbocharged TSIO550 series engines, here's the l=
ink:

http://www.tcmlink.com/pdf2/MaintenanceManuals/OI-18/OI-18.pdf
CONTINENTAL=AE AIRCRAFT ENGINE PERMOLD SERIES ENGINE=20
ENGINE INSTALLATION AND OPERATION MANUAL=20

In my TSIO-550E, the maximum recommended cruise is 262 BHP @ 2500 RPM, whic=
h is 75% of 350HP.  Elsewhere in the manual, this Rich of Peak (ROP) operat=
ion (75%) is listed to be at 29GPH fuel flow (ROP).

Based on prior LML discussions with help from GAMI experts, and engine comp=
ression calculations, the Lean of Peak (LOP) fuel flow (GPH) to horsepower =
(HP) conversion ration for my TSIO550E is 13.73 HP/GPH (for 7.5:1 compressi=
on ratio).  So LOP operations at 75% cruise (263HP) would be 19.15 GPH.

I will occassionally cruise at 2500/34.0"/19GPH, when the flight is three h=
ours or less, which some at LOBO felt is TOO MUCH cruise power (not that th=
is is still below 75% power).

I also occassionally cruise at 2500/31.5"/18 GPH, which is an OK setting fo=
r speed and economy.

For long flights (and super economy), I will cruise at 2350/31.5"/16.3GPH (=
64%).  If facing a headwind, I'll give it more gas to 17.1GPH (67%).

I have noticed through a detailed study of indicated airspeed (IAS) at diff=
erent prop RPM settins (2500-2540-2400-2350-2300) that the Hartzell Simitar=
 3-Blade prop's highest efficiency seems to be at 2350 RPM.  That is, IAS i=
s best at same LOP fuel flows when the prop is turning 2350 RPM, independen=
t of MAP.

I'm sharing these engine settings in case anyone has comments.

Interestingly, the TCM guy said that LOP operations is not correlated to HP=
, and that the fuel conversion HP/GPH is not a value measure of HP output. =
 His advice: best to use the graph provided in the manual (which is limited=
 in RPM and not depicting LOP operations with precision).  He was saying th=
at 19 GPH fuel flow at 34"/2500/19GPH is not the same HP engine output as 3=
1.5"/2500/19GPH (still LOP at 19 GPH but closer to peak); this is different=
 from what our friends at GAMI have said.

Comments welcomed.

Jeff L