Leaning / step climbing?

[aaronw]

Hi all:

I fly underneath a Class B airspace (Washington). My question is that
while I am leaving the area on a flight, I will often end up climbing
up higher as I get further from my departure airport as I get under
the shelves that are higher up. When I am entirely free of the Class
B, I pick a VFR cruising altitude that is appropriate, and at that
point I lean the engine out on the 172. My question is, knowing that
I will have frequent full power applications to climb out to higher
altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
altitude, or is it better to just let it go until I have stabilized at
my cruising altitude and then lean accordingly?

aw

[Flynn]

For the SR22, there's a specific fuel flow setting (mix adjustment) for
every 4000' to generate max power. So, leaning at various altitudes.

I used a similar though not nearly so precise approach to climb settings in
my Grumman Tiger. Just mind the EGT/CHTs.

--
Patrick Flynn
Sammamish, WA
Cirrus SR22 N6099Z KRNT

"aaronw" > wrote in message
...
> Hi all:
>
> I fly underneath a Class B airspace (Washington). My question is that
> while I am leaving the area on a flight, I will often end up climbing
> up higher as I get further from my departure airport as I get under
> the shelves that are higher up. When I am entirely free of the Class
> B, I pick a VFR cruising altitude that is appropriate, and at that
> point I lean the engine out on the 172. My question is, knowing that
> I will have frequent full power applications to climb out to higher
> altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?
>
> aw

[Steve Robertson]

My engine is notorious for spark plug fouling (200hp Lycoming IO-360), so
I lean whenever I (1) level off or (2) exceed 5000' MSL in climb. This is
as per Lycoming's recommednations. If I level off and lean below 5000' and
then climb again, I go full rich until I level off again or climb above
5000'. This procedure can be a pain, but it keeps things running smooth
and keeps the plugs clean.

Best regards,

Steve Robertson
N4732J 1967 Beechcraft Musketeer Super III

aaronw wrote:

> Hi all:
>
> I fly underneath a Class B airspace (Washington). My question is that
> while I am leaving the area on a flight, I will often end up climbing
> up higher as I get further from my departure airport as I get under
> the shelves that are higher up. When I am entirely free of the Class
> B, I pick a VFR cruising altitude that is appropriate, and at that
> point I lean the engine out on the 172. My question is, knowing that
> I will have frequent full power applications to climb out to higher
> altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?
>
> aw

[Thomas Borchert]

Aaronw,

You might take note of the EGT indication during your initial climb.
Then, when you climb further and leave the power setting as it is, the
EGT will drop. It would be safe to lean so much that the EGT setting
will climb back to the take-off value. Howeever, you should probably
select a climb speed higher than Vy in order to cool the engine better.

--
Thomas Borchert (EDDH)

[James M. Knox]

aaronw > wrote in
:

> I fly underneath a Class B airspace (Washington). My question is that
> while I am leaving the area on a flight, I will often end up climbing
> up higher as I get further from my departure airport as I get under
> the shelves that are higher up. ... should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?

Most Class-B's have that little trick. They never "quite" let you in...
just step you up right below the floor.

The answer to your question in part depends upon how long you are going
to be in cruise at each altitude, and how big the step climb is. If the
steps are small, and far apart, then you can lean some and probably
still climb without going back to a richer setting. [Remember, it will
be getting richer automatically as you climb.] With something like a
1000 foot climb, if I am at reduced RPM, I will probably just leave it
there for the climb - whereas if I am climbing 10K feet I will certainly
want to go back to max RPM.

Another suggestion - consider climbing at a cruise-climb rate. You will
get out from under the shelf faster and keep the engine cooler. Ideally
you will just sort of "continue" your climb from sector to sector.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

[Rick Durden]

Aaron,

The more reasonable question is "why not lean"? Leaning the mixture
in most airplanes to at least a ballpark location doesn't take long at
all and should be a part of setting the power every time one flies
level. Yes, when departing under circumstances where you have a
number of level flight periods and then short climbs, you are messing
with the power frequently. But, leaning produces good things, such as
avoiding fouled plugs and extending your range and endurance,
something you may be profoundly grateful for someday. If you are
running at 65% power or less, you absolutely cannot hurt the engine by
leaning it wrong, it will quit before it detonates. At 75% power
simply shoot for about 100 degrees rich of peak and you will get best
power while not getting the high temps and pressures you get at 50
degrees rich of peak. For most 172s you probably aren't going to
operate lean of peak as the engine usually runs roughly and is
uncomfortable. So, for each place where you level off, go ahead and
lean. Enrichen appropriately for the next climb. At cruise set the
mixture where you want it for the power setting you are using.
What's nice is that you can usually just leave the mixture knob in
that position for the rest of the flight, until you are on short final
at which time you may want to enrichen it in the event you make a go
around.

Go ahead and lean the mixture, why waste fuel?

All the best,
Rick

aaronw > wrote in message >...
> Hi all:
>
> I fly underneath a Class B airspace (Washington). My question is that
> while I am leaving the area on a flight, I will often end up climbing
> up higher as I get further from my departure airport as I get under
> the shelves that are higher up. When I am entirely free of the Class
> B, I pick a VFR cruising altitude that is appropriate, and at that
> point I lean the engine out on the 172. My question is, knowing that
> I will have frequent full power applications to climb out to higher
> altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?
>
> aw

[G.R. Patterson III]

aaronw wrote:
>
> My question is, knowing that
> I will have frequent full power applications to climb out to higher
> altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?

I have a Maule with a Lycoming O-320. I lean whenever I can and enrichen the
mixture for climb. If I know that I'll be climbing again in a few minutes, I
don't go through the entire procedure of leaning until it stumbles and then
enrichening until it's smooth, however. I just pull the red knob back using
the TLAR ("that looks about right") method.

George Patterson
If you're not part of the solution, you can make a lot of money prolonging
the problem.

[BTIZ]

always lean... during climbs..

we use a Pawnee with 235HP fixed pitch prop for towing gliders, we start at
2800MSL, and it is noticeable to lean above 4000MSL, (1200AGL), during the
climb I watch the RPM and lean for peak rpm in the full throttle climb and
then "bump" it rich, as we are always climbing.

Some will argue it is not needed to lean below 3000MSL.. for your area.. but
lean to peak RPM if the temp gauge is out.

BT
"aaronw" > wrote in message
...
> Hi all:
>
> I fly underneath a Class B airspace (Washington). My question is that
> while I am leaving the area on a flight, I will often end up climbing
> up higher as I get further from my departure airport as I get under
> the shelves that are higher up. When I am entirely free of the Class
> B, I pick a VFR cruising altitude that is appropriate, and at that
> point I lean the engine out on the 172. My question is, knowing that
> I will have frequent full power applications to climb out to higher
> altitudes, 1000 -> 2000 -> 2500 -> 3000, etc., should I lean at each
> altitude, or is it better to just let it go until I have stabilized at
> my cruising altitude and then lean accordingly?
>
> aw

[Thomas Borchert]

Btiz,

> Some will argue it is not needed to lean below 3000MSL..
>

Uh, only those clinging to one of the more stupid OWTs (Old Wive's
Tale).

--
Thomas Borchert (EDDH)

[Teacherjh]

> Some will argue it is not needed to lean below 3000MSL..

Fuel calculations are based on a properly leaned engine. You may come up short
if you don't lean.

Jose

--
(for Email, make the obvious changes in my address)

[John Galban]

Thomas Borchert > wrote in message >...
> Btiz,
>
> > Some will argue it is not needed to lean below 3000MSL..
> >
>
> Uh, only those clinging to one of the more stupid OWTs (Old Wive's
> Tale).

While it's true that leaning by altitude is somewhat of an OWT, it's
important to remember that, like most OWTs, it has some basis in fact.
Specifically, you should not be leaning if your engine in making 75%
power or better. Of course, in normally aspirated light singles, the
percentage of power available is greater at lower altitudes.

John Galban=====>N4BQ (PA28-180)

[Rick Durden]

John,

Specifically, you should not be leaning if your engine in making 75%
> power or better.

Not necessarily so. It is perfectly okay to lean at 75% power, the
manual for your airplane has a fuel burn for 75% with lean mixture.
In fact, if you don't lean when operating at 75% with that Lycoming,
you will significantly reduce your range and endurance and possibly
foul the plugs. www.gami.com has a good discussion of leaning and
what's going on during combustion. It may be perfectly okay to lean
at power settings above 75%.

While cliches may have some basis in fact, few of the OWTs do. Some
are erroneous carryovers from radial engine days (such as a power
reduction after takeoff on most horizontally opposed engines) and
some, such as not leaning below some arbitrary altitude come from a
very simple misreading of the Owner's Manuals/POHs where the manual
said to lean in the climb above some altitude and some folks
misinterpreted that as meaning not to lean in level flight below that
altitude and didn't notice that the cruise performance charts for
those altitudes stated clearly "with lean mixture".

All the best,
Rick

[David Megginson]

(Rick Durden) writes:

> Not necessarily so. It is perfectly okay to lean at 75% power, the
> manual for your airplane has a fuel burn for 75% with lean mixture.

Quite right. That one surprised me as well.


All the best,


David

[Neal]

On Sat, 08 Nov 2003 13:21:32 GMT, David Megginson
> wrote:

(Rick Durden) writes:
>
>> Not necessarily so. It is perfectly okay to lean at 75% power, the
>> manual for your airplane has a fuel burn for 75% with lean mixture.
>
>Quite right. That one surprised me as well.

I always simply just lean for peak RPM whenever climbing... or even
taking off, anymore. I don't think I can hurt my low compression
O-320 this way. Three years and well over 300 hours later since I
bought the plane and this leaning style seems to suit this engine
perfectly since I have no EGT/CHT guages. I do lean as agressively as
I can to keep the engine smooth once I've reached level cruise
altitude. My plugs stay clean, my fuel burn is spot-on what a 150hp
Cherokee ought to get too. If I don't lean to peak RPM in climbs, of
course the climb rate is lethargic, and it seems like all I'm doing is
wasting gas and loading up my plugs and crankcase oil with extra lead
ash.

[BTIZ]

true

"Thomas Borchert" > wrote in message
...
> Btiz,
>
> > Some will argue it is not needed to lean below 3000MSL..
> >
>
> Uh, only those clinging to one of the more stupid OWTs (Old Wive's
> Tale).
>
> --
> Thomas Borchert (EDDH)
>

[Thomas Borchert]

David,

> Quite right. That one surprised me as well.
>

Why?

--
Thomas Borchert (EDDH)

[David Megginson]

Thomas Borchert > writes:

> David,
>
>> Quite right. That one surprised me as well.
>>
>
> Why?

Note the original statement:

Specifically, you should not be leaning if your engine in making 75%
power or better.

There may be planes where it's not OK to lean at 75%, but all of the
POH's I've looked at so far *require* leaning at 75% power to get the
performance numbers (fuel burn and range) that they list.


All the best,


David

[Tom S.]

"David Megginson" > wrote in message
...
> Note the original statement:
>
> Specifically, you should not be leaning if your engine in making 75%
> power or better.
>
> There may be planes where it's not OK to lean at 75%, but all of the
> POH's I've looked at so far *require* leaning at 75% power to get the
> performance numbers (fuel burn and range) that they list.

http://www.avweb.com/news/columns/182152-1.html (Article 57, but read 58 &
59 as well).

[Tom S.]

"David Megginson" > wrote in message
...


Three part series - often contradicts the contradictions in the POH.

http://www.avweb.com/news/columns/182583-1.html
http://www.avweb.com/news/columns/182176-1.html
http://www.avweb.com/news/columns/182179-1.html

[Thomas Borchert]

David,

got it. Thanks.

--
Thomas Borchert (EDDH)

[David Megginson]

"Tom S." > writes:

>> There may be planes where it's not OK to lean at 75%, but all of the
>> POH's I've looked at so far *require* leaning at 75% power to get the
>> performance numbers (fuel burn and range) that they list.
>
> http://www.avweb.com/news/columns/182152-1.html (Article 57, but read 58 &
> 59 as well).

[As far as I understand, you're saying that people should run engines
full rich at 75% power. If that's not your point, apologies in
advance for the misunderstand.]

I'm a big fan of Deakin, and it's worth reading this article more
closely -- he's *not* recommending flying full rich at 75% power, but
rather, not leaning to 50 degF ROP. Here's the part that I'm guessing
you were looking at:

Take an engine set up at 50 ROP (rich of peak). Is it "too rich" or
"too lean"? We cannot say, without knowing what else is going on. At
any power setting above about 60 or 65%, 50 ROP is BOTH "too rich,"
and "too lean," in that it is the worst possible mixture setting for
the engine, and moving the mixture EITHER way will improve
things. On the other hand, at about 9,000 feet and above, with no
turbo, 50 to 80 ROP is an EXCELLENT mixture setting, for it will
produce just about the maximum possible power, and it won't overheat
anything at and above that altitude. You NEED 50 to 80 ROP up there!
But 50 to 80 ROP and full power at sea level will destroy your
engine.

To understand Deakin's point, you have to read this part as well:

The more accurate statement is, "Mixtures that are not rich enough,
or mixtures that are not lean enough may be harmful to your engine."
This is NOT a contradiction! The "harmful point" is a CENTER
POINT. Again, look back at the graph.

If you lean to best power or peak EGT at 75% (especially at lower
altitudes), you're going to be very close to that zone (on one side or
the other) -- in fact, some of your cylinders may be in it. That's
his point.

If you lean to 75% and enrich until you see a slight RPM drop (and
adjust throttle, etc. until you're back at 75%), you should be running
rich enough to be clear of the danger zone. If your engine runs rough
LOP, this is probably your best choice.

If you leave your throttle wide-open and lean until power settles at
75%, you should be running lean enough to be clear of the danger zone.
If your engine runs smoothly LOP, this is the absolute best choice.

If you leave the mixture full rich at 75%, you'll also be well clear
of the danger zone, but you'll burn lots of extra gas and are more
likely to have to deal with annoyances like fouled plugs and stuck
valves at some point down the road. More importantly, you're ensuring
that your engine is producing as much CO as it possibly can, so if
you're flying in the winter or at cold altitudes, you'll want to be
particularly careful that that heater shroud doesn't have any leaks.


All the best,


David

[John Galban]

(Rick Durden) wrote in message >...
> John,
>
> Specifically, you should not be leaning if your engine in making 75%
> > power or better.
>
> Not necessarily so. It is perfectly okay to lean at 75% power, the
> manual for your airplane has a fuel burn for 75% with lean mixture.
> In fact, if you don't lean when operating at 75% with that Lycoming,
> you will significantly reduce your range and endurance and possibly
> foul the plugs. www.gami.com has a good discussion of leaning and
> what's going on during combustion. It may be perfectly okay to lean
> at power settings above 75%.
>

[John Galban]

(Rick Durden) wrote in message >...
> John,
>
> Specifically, you should not be leaning if your engine in making 75%
> > power or better.
>
> Not necessarily so. It is perfectly okay to lean at 75% power, the
> manual for your airplane has a fuel burn for 75% with lean mixture.
> In fact, if you don't lean when operating at 75% with that Lycoming,
> you will significantly reduce your range and endurance and possibly
> foul the plugs. www.gami.com has a good discussion of leaning and
> what's going on during combustion. It may be perfectly okay to lean
> at power settings above 75%.
>

OK, perhaps I didn't include enough information. For the Lycoming
engines found in most common Cessnas & Pipers, Lycoming manuals
usually have caution against leaning above 75% power. Perhaps I
should have reworded my comment above to read "76%" or "75.5%".

I've seen exhaust valves from engines that were run at high power
settings while leaned to just below peak. They were not pretty (and
would not hold compression).

John Galban=====>N4BQ (PA28-180)

[Tom S.]

"David Megginson" > wrote in message
...
> "Tom S." > writes:
>
> >> There may be planes where it's not OK to lean at 75%, but all of the
> >> POH's I've looked at so far *require* leaning at 75% power to get the
> >> performance numbers (fuel burn and range) that they list.
> >
> > http://www.avweb.com/news/columns/182152-1.html (Article 57, but read 58
&
> > 59 as well).
>
> [As far as I understand, you're saying that people should run engines
> full rich at 75% power. If that's not your point, apologies in
> advance for the misunderstand.]

No...you snipped the part I was responding to (note the >>>> mark
indentations).

>
> I'm a big fan of Deakin, and it's worth reading this article more
> closely -- he's *not* recommending flying full rich at 75% power, but
> rather, not leaning to 50 degF ROP. Here's the part that I'm guessing
> you were looking at:
>
> Take an engine set up at 50 ROP (rich of peak). Is it "too rich" or
> "too lean"? We cannot say, without knowing what else is going on. At
> any power setting above about 60 or 65%, 50 ROP is BOTH "too rich,"
> and "too lean," in that it is the worst possible mixture setting for
> the engine, and moving the mixture EITHER way will improve
> things. On the other hand, at about 9,000 feet and above, with no
> turbo, 50 to 80 ROP is an EXCELLENT mixture setting, for it will
> produce just about the maximum possible power, and it won't overheat
> anything at and above that altitude. You NEED 50 to 80 ROP up there!
> But 50 to 80 ROP and full power at sea level will destroy your
> engine.
>
> To understand Deakin's point, you have to read this part as well:
>
> The more accurate statement is, "Mixtures that are not rich enough,
> or mixtures that are not lean enough may be harmful to your engine."
> This is NOT a contradiction! The "harmful point" is a CENTER
> POINT. Again, look back at the graph.
>
> If you lean to best power or peak EGT at 75% (especially at lower
> altitudes), you're going to be very close to that zone (on one side or
> the other) -- in fact, some of your cylinders may be in it. That's
> his point.
>
> If you lean to 75% and enrich until you see a slight RPM drop (and
> adjust throttle, etc. until you're back at 75%), you should be running
> rich enough to be clear of the danger zone. If your engine runs rough
> LOP, this is probably your best choice.
>
> If you leave your throttle wide-open and lean until power settles at
> 75%, you should be running lean enough to be clear of the danger zone.
> If your engine runs smoothly LOP, this is the absolute best choice.
>
> If you leave the mixture full rich at 75%, you'll also be well clear
> of the danger zone, but you'll burn lots of extra gas and are more
> likely to have to deal with annoyances like fouled plugs and stuck
> valves at some point down the road. More importantly, you're ensuring
> that your engine is producing as much CO as it possibly can, so if
> you're flying in the winter or at cold altitudes, you'll want to be
> particularly careful that that heater shroud doesn't have any leaks.
>
David, what he's doing is reiterating, then dispelling, the conventional
wisdom.

Read the article in there where he does a 1100nm CC with the mixture set 250
degrees LOP.

[Tom S.]

"John Galban" > wrote in message
om...
> (Rick Durden) wrote in message
>...
> > John,
> >
> > Specifically, you should not be leaning if your engine in making 75%
> > > power or better.
> >
> > Not necessarily so. It is perfectly okay to lean at 75% power, the
> > manual for your airplane has a fuel burn for 75% with lean mixture.
> > In fact, if you don't lean when operating at 75% with that Lycoming,
> > you will significantly reduce your range and endurance and possibly
> > foul the plugs. www.gami.com has a good discussion of leaning and
> > what's going on during combustion. It may be perfectly okay to lean
> > at power settings above 75%.
> >
>
> OK, perhaps I didn't include enough information. For the Lycoming
> engines found in most common Cessnas & Pipers, Lycoming manuals
> usually have caution against leaning above 75% power. Perhaps I
> should have reworded my comment above to read "76%" or "75.5%".

http://www.avweb.com/news/columns/186015-1.html

November 9, 2003
Pelican's Perch #75:
Those Dreadful POHs (Part 1)

Everything your POH says is correct, and anything it doesn't say you can do,
you can't, right? Did you really think John Deakin -- AVweb's favorite
contrarian -- could let that kind of gross generality continue unquestioned?
> I've seen exhaust valves from engines that were run at high power
> settings while leaned to just below peak. They were not pretty (and
> would not hold compression).
>
http://www.avweb.com/news/columns/183094-1.html
March 2, 2003
Pelican's Perch #66
Where Should I Run My Engine?
(Part 4 -- Descent)

After a short discussion about whether running engines the factory way or
the skydiving way will hurt or help engines, AVweb's John Deakin settles in
for the descent. And, yes, there are more old wives tales to be debunked,
and better control settings to use.
-----------------------------------------
http://www.avweb.com/news/columns/182583-1.html
February 2, 2003
Pelican's Perch #65
Where Should I Run My Engine?
(Part 3 -- Cruise)

Cruise -- Time to sit back and enjoy the flight. But wait ... did you leave
the mixture set where it was during the climb? Or do you just set it where
it
------------------------------------------------

Picture, charts, loads of data... Deakin makes some very strong points that
much of what has been presented in POH's over the last several (read: 30 or
more) years has been downright BOGUS.

Tom
--
"What's our vector, Victor?"

[Tom S.]

"David Megginson" > wrote in message
...
> "Tom S." > writes:
>
> >> There may be planes where it's not OK to lean at 75%, but all of the
> >> POH's I've looked at so far *require* leaning at 75% power to get the
> >> performance numbers (fuel burn and range) that they list.
> >
> > http://www.avweb.com/news/columns/182152-1.html (Article 57, but read 58
&
> > 59 as well).
>
> [As far as I understand, you're saying that people should run engines
> full rich at 75% power. If that's not your point, apologies in
> advance for the misunderstand.]
>
> I'm a big fan of Deakin, and it's worth reading this article more
> closely -- he's *not* recommending flying full rich at 75% power, but
> rather, not leaning to 50 degF ROP. Here's the part that I'm guessing
> you were looking at:

Nope, he's recommending 40 LOP or even more lean than that. After peak,
CHT's AND EGT drop.

Read the article again (closely, as you mentioned) and read the four part
series. Hell, read his entire series of engine management articles (in the
sidebar).

[David Megginson]

(John Galban) writes:

> I've seen exhaust valves from engines that were run at high power
> settings while leaned to just below peak. They were not pretty (and
> would not hold compression).

Was it heat damage? I'd imagine that they'd be even worse if they
were leaned to just above peak.


All the best,


David

[David Megginson]

"Tom S." > writes:

> Read the article in there where he does a 1100nm CC with the mixture
> set 250 degrees LOP.

It sounds like we're in very noisy agreement here, after all.


All the best,


David

[David Megginson]

"Tom S." > writes:

> Nope, he's recommending 40 LOP or even more lean than that. After peak,
> CHT's AND EGT drop.
>
> Read the article again (closely, as you mentioned) and read the four part
> series. Hell, read his entire series of engine management articles (in the
> sidebar).

I've read them all several times -- they're great. When I wrote "he
recommends not leaning to 50 degF ROP", I meant that he recommends
leaning more, not less. I think that the thread became confused, and
that you and I each ended up thinking that the other was arguing
against LOP operations rather than of in favour of them.


All the best,


David

[John Galban]

David Megginson > wrote in message >...
> (John Galban) writes:
>
> > I've seen exhaust valves from engines that were run at high power
> > settings while leaned to just below peak. They were not pretty (and
> > would not hold compression).
>
> Was it heat damage? I'd imagine that they'd be even worse if they
> were leaned to just above peak.
>

Yes, it was heat damage. The plane in routinely ran leaned at about
85% power for about 150 hrs. Two of the 4 exhaust valves were
toasted.

On a well instrumented engine you could probably get away with
leaning at higher power settings. I think the reason Lyc. puts the
limit at 75% is that the average spam can does not have enough
instrumentation to keep all cylinders in the green during all types of
operation.

John Galban=====>N4BQ (PA28-180)

[Paul Sengupta]

Just above peak?

Paul

"David Megginson" > wrote in message
...
> Was it heat damage? I'd imagine that they'd be even worse if they
> were leaned to just above peak.