"Jay Honeck" wrote in message
oups.com...
Maybe you can have him explain how he's doing such a great business in
when
maybe 5% of the aircraft are being run LOP?

Maybe you can have him explain how that happens when the EGT is
symetrical
on either side of peak EGT, and the CHT is actually cooler...much cooler?

I believe Dawley's exhaust business is benefiting from people running
INCORRECTLY lean of peak.

Considering that most engines will shake themselves to death before they're
much leaner than peak, that's a bit of a stretch.

If someone is leaning incorrectly, attemping LOP will give warnings before
they get there. Blaming it BLINDLY on LOP is stupid. If he wants to say
"Incorrect leaning procedures", that's what he should say. Again, for YEARS
the standard procedure was right at peak EGT, as in the standard dogma, "I
lean to peak then enrich a bit". Well, that kept the engine shops busy doing
jugs and heads. It kept the maintenance people busy doing fouled plugs and
valves.

Think of someone you drove with who was driving a stick shift, but who
didn't give it enough gas before engaging the clutch, or who rode the
clutch; does that mean stick shifts are bad because they'd wear out the
clutch really soon?


The problem isn't necessarily running lean
of peak, which most people know should produce cooler (not hotter) EGTs
and CHTs.

Most people DON'T know that LOP is cooler. AAMOF, on the A&P tests, the
correct answer to "What will too lean a mixture produce" define the problem
just the opposite (ie, higher CHT temps).


The trouble comes with everyone TRYING to run LOP (or, just plain
leanER) to save gas, without the proper instrumentation, technique, or
knowledge.

SInce most people are flying rentals/club aircraft which are rented WET, I
really wonder how many are trying ot overlean without the proper equipment
and instrumentation. Even so, having the right "stuff", LOP procedures is
different (ie, going from full rich to LOP in 2-3 seconds, not the several
seconds up to a minute that some people use in adjusting the mixture.


Heat kills exhaust systems. Dawley has noticed a spike in their sales
since gas prices went through the roof, and they believe it is due to
everyone trying to run LOP. I have no reason to doubt them.

Well, when people were running in the "Red Zone", that would have been a
boon to his business since ROP is hotter. Much hotter.


People are saving a few bucks on gas, but are spending a few hundred on
more frequent exhaust system replacement costs. I would imagine this
may translate into other repair costs as well. It's the nature of the
beast.

As above...but no doubt, many have changed from 200ROP over to peak to
20LOP, still in the "Red Zone". But again, if he doesn't know the difference
between LOP and merely bad leaning technique, he should qualify his
statement or else he comes off a fool.

Just to show how stupid the FAA exams are and the naiveté of many of they
people they "spawned", see what Mike Busch has to say:
http://www.avweb.com/news/columns/182135-1.html

Now, you can take that stuff as an "Internet Legend" because we all know
that what comes out of the engine manufacturers Legal or Sales & Marketing
departments is GOSPEL (everybody say "Amen"!!).


--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO