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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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Jeff:

**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 that 19 GPH fuel flow at 34"/2500/19GPH is not the same HP =
engine output as 31.5"/2500/19GPH (still LOP at 19 GPH but closer to =
peak); this is different from what our friends at GAMI have said.**

His comment is simply not in harmony with the laws of physics with which =
all scientific sources agree.

He seems to be confused between HP production ROP in which RPM (mass =
airflow) is associated with HP production and LOP HP production in which =
only FF is a factor.  If you would be so kind as to provide me with his =
name in a PM to the email below, I will help Bill Ross (VP at TCM) =
improve his knowledge on the matter.=20

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


On Oct 12, 2013, at 6:00 PM, jeffrey liegner wrote:

LML PIlots,

At LOBO Greenville, I discussed engine management with the team from =
Continental Motors.  They provided their slides from their presentations =
(which I have reviewed) and I asked them many questions.  I communicated =
to Jeff Edwards that the group would definitely benefit from a group =
open forum discussing engine management settings commonly used, with =
opportunity for others to listen and others to explain why they do what =
they do, perhaps moderated 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 individual.

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 link:

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, =
which is 75% of 350HP.  Elsewhere in the manual, this Rich of Peak (ROP) =
operation (75%) is listed to be at 29GPH fuel flow (ROP).

Based on prior LML discussions with help from GAMI experts, and engine =
compression 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 compression 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 hours or less, which some at LOBO felt is TOO MUCH cruise power =
(not that this is still below 75% power).

I also occassionally cruise at 2500/31.5"/18 GPH, which is an OK setting =
for 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 =
different 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 is best at same LOP fuel flows when the prop is turning 2350 =
RPM, independent 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 that 19 GPH fuel flow at 34"/2500/19GPH is not the same HP =
engine output as 31.5"/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

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