Leaning / step climbing?

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)

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

(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

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.

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)

David,

Quite right. That one surprised me as well.


Why?

--
Thomas Borchert (EDDH)

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

"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).

"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

David,

got it. Thanks.

--
Thomas Borchert (EDDH)