Leaning using the Deakin method
Corky Scott
It's not actually his method of course, it's an old method used by
many over the years but not so much with horizontally opposed engines,
until around 1998 when the Gami folks in Ada Oklahoma developed their
specialised fuel injection nozzles that allows leaning past peak
without roughness.
John Deakin is an oldtime radial engine guy and writes a column for
AVWeb. He found out about the Gami folks and visited them and was
convinced of the efficacy of their research and products, and wrote an
initial column about it called "Mixture Magic". That was several
years ago and he's branched out to the point where he and the Gami
folks now run regular workshops that include specific attention to
leaning techniques.
He's convinced that running lean of peak is absolutely the best way to
run the engine at cruise, but not every engine can do that and of
course, not every pilot can afford a set of Gami injectors, or even
have an injected engine.
So what method to you folks lean your engines? Do you lean on the
ground? How far do you go during cruise?
Thanks, Corky Scott
Bob Gardner
have. Use the "lean til it runs rough, enrich til it smooths out" method and
you won't go wrong. You won't be operating lean of peak, but then again you
are probably not operating a high-powered engine, either.
Bob Gardner
"Corky Scott" <charles...@deathtospammers.dartmouth.edu> wrote in
message news:3eb6b82f....@news.dartmouth.edu...
Peter Duniho
message news:3eb6b82f....@news.dartmouth.edu...
> ground? How far do you go during cruise?
I use the TIT gauge, and lean according to the AFM, 50 degrees rich of peak.
I cross-check my power setting by verifying expected fuel flow.
I lean while taxiing, to avoid fouled plugs. I don't enrichen the mixture
during descent, though of course when I bring the power back in as I level
off if returning to cruise, I then reset the mixture to 50 degrees rich of
peak. If after the descent I will be operating at reduced power (almost
always is the case), I just leave the mixture where it is. I would only
enrichen the mixture prior to shutdown if I had to go-around or otherwise
increase power. This is especially important at high-altitude airports, as
the engine will simply die on roll-out if the mixture is full-rich.
Engine is a Lycoming TIO-540. If I had an engine monitor *and* the matched
injectors, I might consider lean-of-peak settings, but only because this
particular installation is well below the usual Lycoming 540 cu.in. ratings,
at 270 horsepower, and even then only after researching the procedure more
carefully than I've done so far.
Wasn't there a high-performance turbocharged airplane (Piper Malibu?) that
called for lean-of-peak operation in the AFM, and which wound up having a
variety of engine problems as a result? If I recall, the results from that
weren't directly applicable to the procedures Deakin is talking about, but
it's still food for thought.
Pete
David Megginson
> How do people lean their engines? Do you lean by the Deakin method?
> It's not actually his method of course, it's an old method used by
> many over the years but not so much with horizontally opposed engines,
> until around 1998 when the Gami folks in Ada Oklahoma developed their
> specialised fuel injection nozzles that allows leaning past peak
> without roughness.
Actually, it's also the recommended method in the Piper Warrior II POH
from the early 1980's -- leave the throttle wide open and lean the
mixture until you have the right RPM for your power setting. It's no
problem running LOP with fixed-pitch propellers, because the tach
(combined with density altitude) gives a direct reading of your power
setting. Even Lycoming doesn't object in this case.
The reason some people (like Lycoming) object to LOP operation with
constant-speed props is that there is *no* direct reading of your
power setting when you go LOP, and it would be theoretically possible
to go well over 75% and into the detonation range.
> He's convinced that running lean of peak is absolutely the best way
> to run the engine at cruise, but not every engine can do that and of
> course, not every pilot can afford a set of Gami injectors, or even
> have an injected engine.
Mine O-320-D3G runs fine at 75% with wide-open throttle -- I guess
it's just hit or miss. If things get rough, you can always turn on
the carb heat to even out the distribution and/or cock the throttle
slightly.
The fuel savings are significant -- I cruise at under 8 gph at 75%
power vs. 10 gph ROP (POH number). For me, though, that's not the
most important point. I fly in the winter with the heater on, and the
leaner my engine is, the less CO it produces.
I just did my first oil change, plug gapping, etc., with a mechanic
helping me through. He pronounced the colour of my plugs to be very
healthy after my first 50 hours LOP.
> So what method to you folks lean your engines? Do you lean on the
> ground?
Yes, lean like a maniac. If you don't lean, you'll have fouled plugs
all the time; if you lean only a little, you could have a
bad-checklist day and take off with a lean mixture.
If you lean almost to the point of shutdown, and you do advance the
throttle for a takeoff roll, the engine will just sputter and stop
instead of letting you take off with diminished power or detonation.
You'll be embarrassed, but otherwise safe.
> How far do you go during cruise?
As far as I can. Always back to 75% with wide-open throttle, and
often back to 65% or further (with a little carb heat). I have less
fuel burn, cleaner plugs, healthier cylinders, virtually no risk
of CO poisoning, *and* I'm following the recommended procedure from
the POH -- what's not to love?
All the best,
David
--
David Megginson, da...@megginson.com, http://www.megginson.com/
Craig Prouse
> Wasn't there a high-performance turbocharged airplane (Piper Malibu?) that
> called for lean-of-peak operation in the AFM, and which wound up having a
> variety of engine problems as a result? If I recall, the results from that
> weren't directly applicable to the procedures Deakin is talking about, but
> it's still food for thought.
Deakin has something to say about that. He says that pilots were so
indoctrinated to never ever run lean of peak that they routinely/habitually
ran at a more "acceptable" 50 ROP, which results in the hottest possible
CHTs, and THAT is why the Malibus had engine problems.
The circumspect way to interpret Deakin's writings is not that everyone
ought to run LOP. It is that most pilots ought to run a lot leaner or a lot
richer than they do. Leaning to 50 ROP is bad, the man says, and he
provides fancy graphs to prove it. He happens to prefer leaner, but richer
is OK too, for those who would rather spend money on fuel than on fancy fuel
injectors and engine instrumentation.
FWIW, I lean to peak because that's what my book says. Sometimes I may end
up running a little leaner, and the main thing I notice is a cooler engine.
My stock injectors seem to be pretty well balanced. I think it would be
pretty hard to hurt an IO-540 that only makes 230 HP.
Kyler Laird
>This is especially important at high-altitude airports, as
>the engine will simply die on roll-out if the mixture is full-rich.
Nothing says "Hi, I'm from Indiana" like taxiing around Denver
on one engine... (I did it the first time I landed there and
again the last time I was there. I even leaned it last time.)
>Engine is a Lycoming TIO-540. If I had an engine monitor *and* the matched
>injectors, I might consider lean-of-peak settings, but only because this
>particular installation is well below the usual Lycoming 540 cu.in. ratings,
>at 270 horsepower, and even then only after researching the procedure more
>carefully than I've done so far.
I have monitors on my turbocharged IO-540 (not TIO-540) engines
and would love to lean some more. I've read Deakin's articles
and have considered getting Gemijectors, but it's still hard
for me to believe I can lean enough to make a difference while
keeping the turbos cool.
--kyler
Peter Duniho
news:ngejo-...@news.lairds.org...
> Nothing says "Hi, I'm from Indiana" like taxiing around Denver
> on one engine
When I first got my plane, it took me two times to figure it out. Once at
Fort Collins, then a day later at Aspen. The tower controller at Aspen was
very accomodating. "Turn off next exit, contact ground. Whenever you get
your engine restarted is fine". :) I'm guessing I wasn't the first person
he saw do that.
To my credit, I haven't drowned the engine since. Some lessons take longer
than others, but I do okay learning them most of the time.
At least with a twin, you can claim that you were just trying to save gas.
:)
Pete
G.R. Patterson III
Corky Scott wrote:
>
> So what method to you folks lean your engines? Do you lean on the
> ground? How far do you go during cruise?
Mine's carbureted with a fixed pitch prop, so I believe I can't use any
of the fancy methods. I lean to maximum rpm in cruise. I do not lean on
the ground.
George Patterson
"Cuius testiculos habes, habeas cardia et cerebellum." - When you have
their full attention in your grip, their hearts and minds will follow.
JerryK
What John D points out makes sense and thus far I have not seen any ill
effects. BTW I am running a couple TSIO-520-NBs with GamiInjectors and a
EDM-760 engine analyzer.
jerry
"Corky Scott" <charles...@deathtospammers.dartmouth.edu> wrote in
message news:3eb6b82f....@news.dartmouth.edu...
Corky Scott
George, in one of John's recent columns he wrote about a friend who
had a carburated engine and experimented with his carb heat to see if
that helped fuel distribution, it did. This guy was using the engine
analysers and could see the EGT's even out when he pulled his carb
heat on. So Deakin suggested people might try it to see how this
affected their cruise fuel distribution.
Without any sort of engine analyser though, it's probably difficult to
see what is going on.
In addition, the engine(s) were radials as this was a Beech 18.
Corky Scott
Rick Durden
I recently spent about ten days flying a Cessna 206 in Central America
where the afternoon temps were 95 degrees F. The airplane had GAMIs
and an engine analyzer. Running LOP was a huge help because fuel down
there is very expensive and it is the most effective way to get
cylinder head temperatures down, especially when it's so gawd-awful
hot outside and the flying called for staying around 1,000 ft MSL.
Being curious, I did try 50 degrees rich of peak, the absolutely worst
spot to run an engine, and found that CHTs were some 70 degrees hotter
than running 50-75 degrees LOP.
The airplane has had GAMIs for about two years now and the engine is
in the best shape its ever been. Running cooler is a good thing for a
ContinentalIO-520.
All the best,
Rick
charles...@deathtospammers.dartmouth.edu (Corky Scott) wrote in message news:<3eb6b82f....@news.dartmouth.edu>...
Thomas Borchert
> Wasn't there a high-performance turbocharged airplane (Piper Malibu?) that
> called for lean-of-peak operation in the AFM, and which wound up having a
> variety of engine problems as a result?
>
Dead wrong. It required LOP, but pilots wouldn't do it since they weren't
used to it. That's where the problems came from.
--
Thomas Borchert (EDDH)
James M. Knox
news:vbdseqd...@corp.supernews.com:
> "Corky Scott" <charles...@deathtospammers.dartmouth.edu> wrote in
> message news:3eb6b82f....@news.dartmouth.edu...
>> So what method to you folks lean your engines? Do you lean on the
>> ground? How far do you go during cruise?
> I lean while taxiing, to avoid fouled plugs.
Very good procedure.
> Wasn't there a high-performance turbocharged airplane (Piper Malibu?)
> that called for lean-of-peak operation in the AFM, and which wound up
> having a variety of engine problems as a result?
Correct. However, many of the problems people had were (at least in Piper's
view) caused by people NOT running LOP. The engine installation really needs
LOP operation to operate within temperatures - it's the only way to get
anywhere near the performance and range Piper specs. But so many pilots were
reluctant to do it and ran ROP instead... Burned valves and cylinders all
over the place. Pretty marginal installation, regardless of how it is
operated.
-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721 jk...@trisoft.com
-----------------------------------------------
Viperdoc
After reading Deakin's articles they make sense to me. All of the cylinders
peak within 0.5 gph, and subjectively they run smoother as well. CHT's in
cruise are always less than 350, even on hot days, and the cost in cruise
speed is less than five knots when running at 50 degrees LOP. This also
saves around 2GPH in fuel burn.
I think the difference would be more apparent in a larger engine, since my
are only IO 470's.
James M. Knox
> I have monitors on my turbocharged IO-540 (not TIO-540) engines
> and would love to lean some more. I've read Deakin's articles
> and have considered getting Gemijectors, but it's still hard
> for me to believe I can lean enough to make a difference while
> keeping the turbos cool.
Easy enough to tell, since you have all cylinder monitoring. There are
two savings points on GAMI's:
1. Balanced fuel flow - you get this saving even if you keep running the
engine like you always have, ROP.
2. LOP operation
Go to the GAMI site and get the little test procedure. Run it on each
engine and look at the spread between the first and last cylinder to
peak. Could be anywhere from zero to 4 gph. Whatever it is, add the two
together and this is your savings with GAMI's (maybe less a couple of
tenths) -- if you contine to run ROP, just like you always have.
Simple... and will only cost you a trip for a $100 hamburger.
Want to know what your LOP burn would be? Even easier... Take your
desired cruise power and multiply by the appropriate factor for your
engine compression ratio. [Numbers should be available on the site.]
For my little turbocharged TSIO-360 it comes out to 10.5 gph at 75%.
Ron Rosenfeld
>Keep in mind that John uses an engine analyzer that you probably do not
>have. Use the "lean til it runs rough, enrich til it smooths out" method and
>you won't go wrong. You won't be operating lean of peak, but then again you
>are probably not operating a high-powered engine, either.
>
>Bob Gardner
On my Lycoming IO360, the "lean til it runs rough, enrich til it smooths
out" method generally results in running more than 25°F lean of peak,
according to my Insight GEM.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)
C Yank
but one of my good friends is a pilot who is about two days from his IA
checkride. We've actually flown into Ada OK (home base is Tulsa). I
believe he wanted to check out Gami, but it was closed (Sunday). The
airport isn't real big, but it is a nice place to visit. Awesome barbeque
place just south of the airport. Maybe next time we go, we'll check out
Gami.
I do know watching him fly the 172P, he just uses the "lean until rough,
enrich until smooth" method. Of course, these planes are late 70s early 80s
model rentals.
He wants to buy a Stationair...I'm sure he'll try and get all the
aftermarket stuff on that as well.
We've also been to the Cessna Assembly Plant in Independence KS...that was a
fascinating tour.
"Peter Duniho" <NpOeS...@NnOwSlPiAnMk.com> wrote in message
news:vbe63ps...@corp.supernews.com...
MT
>
> Actually, it's also the recommended method in the Piper Warrior II POH
> from the early 1980's -- leave the throttle wide open and lean the
> mixture until you have the right RPM for your power setting. It's no
> problem running LOP with fixed-pitch propellers, because the tach
> (combined with density altitude) gives a direct reading of your power
> setting. Even Lycoming doesn't object in this case.
>
> The reason some people (like Lycoming) object to LOP operation with
> constant-speed props is that there is *no* direct reading of your
> power setting when you go LOP, and it would be theoretically possible
> to go well over 75% and into the detonation range.
Can you reference the page # in the Warrior II POH thats states this?
I am looking at page 4-13 (Normal Procedures) & it says to "lean until
rough, then enrich until smooth, only at 75% power or less" 75% power
is the normal max cruise power, however the book says "if in doubt as
to amount of power being used, use full rich mixture"
On page 5-5 (Performance) it says "refer to Avco Lycoming Operators
Manual when selecting power settings" This section also mentions
"best power" and "best economy" and "lean per Lycoming leaning
instructions" on the various perforance charts.
The Lycoming 0-320 Operators Manual, page 3-7 (Operating Instructions)
says:
"Maximum Power Cruise" (approx 75% power). Never lean beyond 150 deg
F on rich side of peak EGT unless aircraft operator's manual shows
otherwise. Monitor CHT's"
"Best Economy Cruise" (approx 75% power and below). Operate at peak
EGT, or if desired, drop 50 deg F on rich side of peak EGT"
Richard Kaplan
> The reason some people (like Lycoming) object to LOP operation with
> constant-speed props is that there is *no* direct reading of your
> power setting when you go LOP, and it would be theoretically possible
> to go well over 75% and into the detonation range.
This is true for a stock airplane.
If you install a digital fuel totalizer, then fuel flow becomes a
direct reading of your power setting when operating LOP.
An all-cylinder engine monitor and digital fuel totalizer would seem
to be the minimum requirements to run LOP.
For what it is worth, I have been quite skeptical for a while of LOP
operation but I am reconsidering that given the quality of the data
posted on the GAMI website (www.gami.com). If nothing else, having
GAMIs and a knowledge of LOP operation is nice to have as a tool in
the toolbox in case you need maximum range some day due to unforecast
weather.
There was a really good discussion of LOP/ROP operation recently on
the Cessna Pilot Association Forums which would be worthwhile for any
CPA member to read.
--
Richard Kaplan, CFII
rka...@flyimc.com
www.flyimc.com