My wife getting scared

On Sat, 06 Oct 2007 11:40:55 GMT, Matt Whiting
wrote in :

I'm not aware of any real data on the subject




http://www.lycoming.textron.com/supp...ces/SSP400.pdf
Descent

Plan ahead to make a smooth temperature transition between cruise
and descent. Start descent early and allow airspeed to increase
within aircraft limits. Maintain power as required and mixture
setting. Cylinder head temperature change rate should not exceed
50 degree F per minute to avoid rapid shock cooling.




http://www.lycoming.com/support/tips...Operations.pdf
And finally, power-off letdowns should be avoided. This
is especially applicable to cold-weather operations when
shock-cooling of the cylinder heads is likely. It is recommended
that cylinder head temperature change not exceed 50° F. per
minute. Plan ahead, reduce power gradually and maintain some
power throughout the descent. Also keep the fuel/air mixture
leaned out during the descent. If an exhaust gas temperature gage
is installed with a normally aspirated engine, keep it peaked to
ensure the greatest possible engine heat for the power setting
selected; for a turbocharged installation, lean to peak during
descent unless otherwise specified in the Pilot’s Operating
Handbook, or under conditions where the limiting turbine inlet
temperature would be exceeded.



http://whitts.alioth.net/Pageb31%20E...ystems.htm#SC_
Shock Cooling

An aircraft engine spends much more time developing near full
power than does an automobile engine. The wear on an aircraft
engine is made shorter through negligent operation, non-operation,
corrosion, and the shocking effect of hot and cold cycles. Shock
heating cycles the metals of an engine just as much as does shock
cooling.

Heat shock can be reduced by starting the engine at idle leaning
to reduce oil dilution by excess fuel and then allowing the oil
pressure to rise before aggressive leaning. The start of an engine
its most damaging cycle of operation.

A sudden reduction of engine power after a period of increased
power causes a rapid reduction of engine heat being generated.
This heat change inside the cylinders is reflected in the heat
released by the cooling fins and increased cooling airflow through
the engine plenum. The result is called shock cooling. Lycoming
says that shock cooling results in worn piston grooves, broken
rings, warped exhaust valves, bent pushrods, and plug fouling.
Recommended cooling rate is no greater than 50-degrees per minute.

Shock cooling occurs when the pilot reduces power to off and goes
into a descent. The effect of this is to suddenly reduce the
internal heat of the engine and greatly increasing the cooling
effect of the air over the cooling fins of the engine. This may be
a damaging shock to the bimetallic cylinder blocks. The principal
effects of shock cooling are cylinder-head cracking, valve seat to
valve seat, plug to plug. Anywhere inside the engine where tool
marks, sharp edges and other stress points are liable to damage.
Any engine operation that makes it possible for the valve guide to
shrink faster than the valve will cause sticking. Valves stick
open and the pushrod bends. A raised valve hits the piston dome,
breaks and is redistributed throughout the engine and turbo if
any. This situation often occurs when poor navigational planning
causes the pilot to arrive over his destination at several
thousand feet too high. Never make descents that will shock cool
the engine. It may not fail on your but it will on some pilot down
the road.

To prevent all these bad things from happening to your engine keep
some power on the engine, re-lean during altitude changes to keep
the EGT near cruise values. If you have CHT on all cylinders
maintain a controlled (slow) decrease rate. Use of factory CHT on
one cylinder is a very poor second. Regardless, always reduce
power in increments so that engine temperature changes will be
gradual. Retard the throttle during descents. Do not enter a
descent that will both give a throttle reduction and an increase
in engine cooling air. Use landing gear and flaps to keep the
speed down. control the thermal changes of the engine to limit
temperature and cooling related damage.

When on the ground, take advantage of any cooling wind, lean the
mixture, open cowl flaps on the ground and during climb. All
engines should be run for at least two or three minutes on the
ground after a long flight to allow the oil to carry heat away
from the engine. In hot weather or with a turbo engine allow more
time. Before killing the engine run it up to 1200 and lean to but
not into roughness for 20 seconds. This will clean the plugs from
any residue of lead or carbon.

Borchert would argue that black-eyed beans are really black-eyed peas,
just for the sake of arguing. His arguing a point has little to do
with anything, real or imagined, other than that he enjoys the sound
of his own voice.

Nice. Very nice. Why are you doing this?

Short attention span, eh? Here's why: (From your post):

No offense, but you're making very bold, sweepingly general statements from
your personal little world view again, a trap you so often like to fall
into.

I've tried for years to ignore your rude posts. I've tried to humor
you. I've tried to engage you. All to no avail. Therefore, when you
respond with your typically inappropriate, arrogant remarks, you may
expect a mild (too mild, I might add) rebuke from me.

I don't know why you can't keep a civil tongue in your head while
holding a discussion, but to whine about this as if you've been
"zinged" unexpectedly only reinforces my opinion of you.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On Oct 6, 7:43 am, Thomas Borchert
wrote:
I don't think Jay has intentionally insulted anyone in the process of
stating his belief about engine operation.

I would think the following does count:

"Borchert would argue that black-eyed beans are really black-eyed peas,
just for the sake of arguing. His arguing a point has little to do
with anything, real or imagined, other than that he enjoys the sound
of his own voice."

Which, of course, was in response to your post:

No offense, but you're making very bold, sweepingly general statements from
your personal little world view again, a trap you so often like to fall
into.

A fact that you conveniently omit.

I am never rude here unless provoked. Keep a civil tongue in your
head, and you'll get nothing but sugar and honey from my keyboard...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Mxsmanic writes:
Larry Dighera writes:
Thomas Borchert writes:

Ah, this is truly a rare alignment of the stars, to have all three of
these guys present in one thread...

My work here is done. I can achieve no higher goal.

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Such a bias toward comrades is not unique to Usenet.

I see the bias you mention as the result of at least two factors: a
result of Mr. Honeck's "contribution" to GA, contrasted against Mr.
Atkielski's maligning of GA (and indeed most other aspects of
non-artificial aviation). Couple that with the social bonding that
occurs among drinking buddies and EAA members, and it's easy to see
how Mr. Honeck's frequent lack of insight and subjective opinion in
lieu of empirical fact are overlooked and tolerated by a certain
segment of the readership of the rec.aviation.piloting newsgroup.

Sorry, Larry, but the truth is that your Usenet persona is that of a
humorless drone who would rather die than laugh at himself. To those
of us who find humor everywhere, especially within ourselves, this
personality trait is the funniest thing of all.

THAT is why you (and Borchert, and MX) find little support here --
because you take yourself too danged seriously.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I do believe this thread proves the old Usenet adage that "anyone will
argue anything". For you to be questioning the rather obvious fact
that high-power/low-power engine operations are harder on an aircraft
than steady-state engine operations illustrates a remarkable, um,
quality.

Jay, this simply isn't an "obvious fact" and I'm not convinced it is a
fact at all. You have provided one mechanic who thinks your way and
several of us have provided mechanics who disagree. This is hardly the
scenario that would surround an "obvious" fact.

I am apparently speaking a foreign language here, because I'm having a
hard time comprehending how normally intelligent people can argue this
point. Let's see if I can 'splain myself.

1. High power operation of an engine puts increased strain on
EVERYTHING. Seals, rods, gears, accessories. You name it, high power
operation is harder on your engine than low power operation.

2. Going from low to high power abruptly (and that, remember, is the
crux of this issue; I don't think anyone is arguing that gradual/
gentle application is terrible for your engine -- although it WILL
wear it out faster) puts sudden, abrupt pressue on those
aforementioned seals, rods, gears, pistons, cylinders, accessories.
This is what is known as "BAD", in my world.

3. Your engine has a certain number of revolutions in it before it
reaches TBO. Might be a million, might be a billion -- I don't know.
Whatever that number, if you run at higher RPMs, you will reach that
finite limit sooner. Stuff run at high RPM wears out quicker.

And, most importantly to this thread, engines rammed from 900 RPM to
full power, and back, over and over, are going to wear out sooner.
Same with props, automobiles, lawn mowers, motorcycles, blenders,
chain saws, snow blowers, and virtually any other mechanical device
you can name.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On Sat, 06 Oct 2007 06:48:52 -0700, Jay Honeck
wrote in .com:

Such a bias toward comrades is not unique to Usenet.

I see the bias you mention as the result of at least two factors: a
result of Mr. Honeck's "contribution" to GA, contrasted against Mr.
Atkielski's maligning of GA (and indeed most other aspects of
non-artificial aviation). Couple that with the social bonding that
occurs among drinking buddies and EAA members, and it's easy to see
how Mr. Honeck's frequent lack of insight and subjective opinion in
lieu of empirical fact are overlooked and tolerated by a certain
segment of the readership of the rec.aviation.piloting newsgroup.

Sorry, Larry, but the truth is that your Usenet persona is that of a
humorless drone who would rather die than laugh at himself. To those
of us who find humor everywhere, especially within ourselves, this
personality trait is the funniest thing of all.

Of course, you are entitled to your opinion, but I haven't seen the
mention of humor in the newsgroup charter, have you?

THAT is why you (and Borchert, and MX) find little support here --
because you take yourself too danged seriously.

More groundless imaginings; that may be true in your little circle of
cronies, but as Bush is learning, there is a larger world beyond
cronyism.

In my opinion, it is the news, expertise, and information exchanged in
rec.aviation.piloting that is valuable, not the social prattle and ill
informed opinion. Should the newsgroup charter ever be amended to
value humor above information, you may see a change in my style.

Larry Dighera wrote:

Of course, you are entitled to your opinion, but I haven't seen the
mention of humor in the newsgroup charter, have you?


Concerning ANYTHING even remotely associated with getting something
across flight safety wise (or even in normal dialog between people )
that will be remembered by the most people either reading or hearing it,
humor is the catalyst in the communication equation that will be most
effective.

--
Dudley Henriques

Jay Honeck writes:

Ah, this is truly a rare alignment of the stars, to have all three of
these guys present in one thread...

My work here is done. I can achieve no higher goal.

A useful suggestion from a very experienced user of USENET: Never take
anything on USENET personally.

Thomas Borchert wrote:
Matt,

I don't think Jay has intentionally insulted anyone in the process of
stating his belief about engine operation.


I would think the following does count:

"Borchert would argue that black-eyed beans are really black-eyed peas,
just for the sake of arguing. His arguing a point has little to do
with anything, real or imagined, other than that he enjoys the sound
of his own voice."


Counts for what?

Matt