Today's Message Index:
----------------------
1. 05:05 AM - Re: Lycoming POH (Art Zemon)
2. 02:39 PM - Re: Bent EGT Probe Acceptable? (jdubner)
3. 03:00 PM - Re: Lycoming POH (Peter Pengilly)
4. 05:00 PM - Re: Lycoming POH (Kelly McMullen)
Message 1
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| Subject: | Re: Lycoming POH |
Thanks for correcting my scrambled interpretation, Paul. Yet another reason
why I am sticking to the simple method at 65% of leaning until I experience
a loss of power and then enrichening until the engine runs smoothly again.
I may not get the absolutely perfectly most optimal fuel flow but my engine
seems healthy and I am happy with the gallons per hour (if not the $$$ per
gallon).
-- Art Z.
On Sun, Aug 18, 2019 at 10:27 PM Paul Millner <millner@me.com> wrote:
> Art Zemon wrflyote:
>
> Executive summary:
>
> =C2=B7 75% power or greater, run at peak EGT
>
> =C2=B7 less than 75% power, run up to 150 degrees F lean of peak
>
>
> I think that's kind of scrambled, Art... the engine won't run 150 F lean
> of peak. What the Lycoming POH refers to is 150 ROP as best power...
>
> Beyond that, running at peak EGT above 65% is not going to have good
> results...
>
>
> The wording of the POH is misleading, unfortunately. For instance,
> Lycoming wrote: Maximum Power Cruise (approximately 75% power) =93
Never lean
> beyond 150=C2=B0F on rich side of peak EGT unless aircraft operator's man
ual
> shows otherwise.
>
> So, which way is beyond, leaner or richer? What they mean is do not run
> leaner than 150 ROP at 75% power or greater. But they do their best to
> conceal that information.
>
>
> If you refer to Lycoming SP700, "There are Experts Everywhere" Lycoming
> explains that their engines can run just fine lean of peak. It's just tha
t
> Lycoming believes most pilots are too stupid to do so correctly, and so
> they'll damage their engines... at least , that's what it says in SP700.
>
>
> So the guidance intended, if we can puzzle our way through the byzantine
> wording, is that 65% power or less, run anywhere you want, peak is a good
> place.
>
> Above 65% power, run RICH enough or LEAN enough to keep CHTs below 380 F.
>
>
> Paul, Talmudic service publication reader mode
>
--
https://CheerfulCurmudgeon.com/
*Love the stranger for you yourselves were strangers in Egypt. *Deut. 10:19
Message 2
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| Subject: | Re: Bent EGT Probe Acceptable? |
Thanks, Jerry. That's what I was thinking too although I have not heard of it
being done.
--------
RV-8A
Independence, OR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=490959#490959
Message 3
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I found the articles written by John Deakin in the
=9CPelican=99s Perch=9D very informative, they used to
be on AvWeb but I don=99t know if they are still there. They are
written for large Continentals, but the concepts are valid on other
engines. As Paul has said, above 75% power lean with care as it is
possible to get into detonation which can be very poor for the health of
your engine and you/your wallet. But above 6000ft most normally
aspirated engines won=99t pull more than 75%.
Below 75% I lean aggressively to reduce fuel burn =93 as I live in
a land where gas is expensive ($8.50 a gallon =93 I really wish I
hadn=99t done that sum) if I can save a gallon an hour it
is attractive. I have found a fuel flow /rpm number where I am happy to
leave the engine. It does take some experience with your particular
installation to get to know what the numbers are. CHTs are cooler than
running ROP for the same airspeed. It does take some care to run LOP
safely, start up high in a low workload cruise so it is possible to
monitor temperatures closely. Once you have some experience it is
possible to run LOP nearly all the time once the initial climbing is
done.
Peter
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Art Zemon
Sent: 19 August 2019 13:03
Subject: Re: AeroElectric-List: Lycoming POH
Thanks for correcting my scrambled interpretation, Paul. Yet another
reason why I am sticking to the simple method at 65% of leaning until I
experience a loss of power and then enrichening until the engine runs
smoothly again. I may not get the absolutely perfectly most optimal fuel
flow but my engine seems healthy and I am happy with the gallons per
hour (if not the $$$ per gallon).
-- Art Z.
On Sun, Aug 18, 2019 at 10:27 PM Paul Millner <millner@me.com
<mailto:millner@me.com> > wrote:
Art Zemon wrflyote:
Executive summary:
* 75% power or greater, run at peak EGT
* less than 75% power, run up to 150 degrees F lean of peak
I think that's kind of scrambled, Art... the engine won't run 150 F lean
of peak. What the Lycoming POH refers to is 150 ROP as best power...
Beyond that, running at peak EGT above 65% is not going to have good
results...
The wording of the POH is misleading, unfortunately. For instance,
Lycoming wrote: Maximum Power Cruise (approximately 75% power) =93
Never lean beyond 150=C2=B0F on rich side of peak EGT unless aircraft
operator's manual shows otherwise.
So, which way is beyond, leaner or richer? What they mean is do not run
leaner than 150 ROP at 75% power or greater. But they do their best to
conceal that information.
If you refer to Lycoming SP700, "There are Experts Everywhere" Lycoming
explains that their engines can run just fine lean of peak. It's just
that Lycoming believes most pilots are too stupid to do so correctly,
and so they'll damage their engines... at least , that's what it says in
SP700.
So the guidance intended, if we can puzzle our way through the byzantine
wording, is that 65% power or less, run anywhere you want, peak is a
good place.
Above 65% power, run RICH enough or LEAN enough to keep CHTs below 380
F.
Paul, Talmudic service publication reader mode
--
https://CheerfulCurmudgeon.com/
Love the stranger for you yourselves were strangers in Egypt. Deut.
10:19
Message 4
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| Subject: | Re: Lycoming POH |
The articles have been moved a time or two. I believe this is still a
good link:
https://web.archive.org/web/20120119070724/http://www.avweb.com/news/pelican/list.html
On 8/19/2019 2:58 PM, Peter Pengilly wrote:
> I found the articles written by John Deakin in the Pelicans Perch
> very informative, they used to be on AvWeb but I dont know if they are
> still there. They are written for large Continentals, but the concepts
> are valid on other engines. As Paul has said, above 75% power lean with
> care as it is possible to get into detonation which can be very poor for
> the health of your engine and you/your wallet. But above 6000ft most
> normally aspirated engines wont pull more than 75%.
>
> Below 75% I lean aggressively to reduce fuel burn as I live in a land
> where gas is expensive ($8.50 a gallon I really wish I hadnt done
> that sum) if I can save a gallon an hour it is attractive. I have found
> a fuel flow /rpm number where I am happy to leave the engine. It does
> take some experience with your particular installation to get to know
> what the numbers are. CHTs are cooler than running ROP for the same
> airspeed. It does take some care to run LOP safely, start up high in a
> low workload cruise so it is possible to monitor temperatures closely.
> Once you have some experience it is possible to run LOP nearly all the
> time once the initial climbing is done.
>
> Peter
>
> *From:*owner-aeroelectric-list-server@matronics.com
> <owner-aeroelectric-list-server@matronics.com> *On Behalf Of *Art Zemon
> *Sent:* 19 August 2019 13:03
> *To:* aeroelectric-list@matronics.com
> *Subject:* Re: AeroElectric-List: Lycoming POH
>
> Thanks for correcting my scrambled interpretation, Paul. Yet another
> reason why I am sticking to the simple method at 65% of leaning until I
> experience a loss of power and then enrichening until the engine runs
> smoothly again. I may not get the absolutely perfectly most optimal fuel
> flow but my engine seems healthy and I am happy with the gallons per
> hour (if not the $$$ per gallon).
>
> -- Art Z.
>
> On Sun, Aug 18, 2019 at 10:27 PM Paul Millner <millner@me.com
> <mailto:millner@me.com>> wrote:
>
> Art Zemon wrflyote:
>
> Executive summary:
>
> 75% power or greater, run at peak EGT
>
> less than 75% power, run up to 150 degrees F lean of peak
>
> I think that's kind of scrambled, Art... the engine won't run 150 F
> lean of peak. What the Lycoming POH refers to is 150 ROP as best
> power...
>
> Beyond that, running at peak EGT above 65% is not going to have good
> results...
>
> The wording of the POH is misleading, unfortunately. For instance,
> Lycoming wrote: Maximum Power Cruise (approximately 75% power)
> Never lean beyond 150F on rich side of peak EGT unless aircraft
> operator's manual shows otherwise.
>
> So, which way is beyond, leaner or richer? What they mean is do not
> run leaner than 150 ROP at 75% power or greater. But they do their
> best to conceal that information.
>
> If you refer to Lycoming SP700, "There are Experts Everywhere"
> Lycoming explains that their engines can run just fine lean of peak.
> It's just that Lycoming believes most pilots are too stupid to do so
> correctly, and so they'll damage their engines... at least , that's
> what it says in SP700.
>
> So the guidance intended, if we can puzzle our way through the
> byzantine wording, is that 65% power or less, run anywhere you want,
> peak is a good place.
>
> Above 65% power, run RICH enough or LEAN enough to keep CHTs below
> 380 F.
>
> Paul, Talmudic service publication reader mode
>
>
> --
>
> https://CheerfulCurmudgeon.com/
>
> /Love the stranger for you yourselves were strangers in Egypt. /Deut. 10:19
>
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