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A big AMEN!!
The GAMI guys are direct, knowledgeable and have the data to back up what
they say. TCM has too many lawyers behind them.
If you do the GAMI APS you will understand what your engine is doing and how
to operate it.
Available online or in person. A good investment.
Gordon
-----Original Message-----
From: Colyn Case [mailto:colyncase@earthlink.net]
Sent: Sunday, October 13, 2013 3:01 PM
To: Lancair Mailing List
Subject: Re: [LML] Discussed engine management with the team from
Continental Motors
Jeff,
I've been to Continental's presentation and I've been through APS.
I will only make this comment: In 3 days of APS I was not able to ask a
single question for which the answer was not backed up by data displayed at
time of question, from actual tests performed by GAMI. I would suggest
attending and then put the Continental remarks in context.
Colyn
On Oct 12, 2013, at 7:00 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
CONTINENTALR AIRCRAFT ENGINE PERMOLD SERIES ENGINE ENGINE INSTALLATION AND
OPERATION MANUAL
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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