Run up for plug clearing

In article ,
Larry Dighera wrote:


That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

A difference between a runup and the takeoff roll is the cooling air
flowing thru the cowling when moving. There is very little airflow when
stationary, even with high power settings. I'm not saying you shouldn't
do a high power runup, but you should be cautious and aware of the
possibity of heat problems.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

--

Roger Long



"Larry Dighera" wrote in message
...
On Sat, 09 Oct 2004 10:54:44 GMT, "Roger Long"
wrote in ::

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me.

That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

--

Roger Long



"Larry Dighera" wrote in message
...
On Sat, 09 Oct 2004 10:54:44 GMT, "Roger Long"
wrote in ::

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me.

That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

#&*(^%$#!)+=- Microsoft.

With the budgets that world domination provides, you would think someone
would have figured out that putting the Send button under the Reply button
would lead to inadvertent blank replies.

With Windows 98, you could move the buttons around so that didn't happen
when you accidentally double clicked. Eliminating that option seems to have
been one of those "Innovations that users demand."

--

Roger Long



"Roger Long" wrote in message
. ..


--

Roger Long



"Larry Dighera" wrote in message
...
On Sat, 09 Oct 2004 10:54:44 GMT, "Roger Long"
wrote in ::

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me.

That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

#&*(^%$#!)+=- Microsoft.

With the budgets that world domination provides, you would think someone
would have figured out that putting the Send button under the Reply button
would lead to inadvertent blank replies.

With Windows 98, you could move the buttons around so that didn't happen
when you accidentally double clicked. Eliminating that option seems to have
been one of those "Innovations that users demand."

--

Roger Long



"Roger Long" wrote in message
. ..


--

Roger Long



"Larry Dighera" wrote in message
...
On Sat, 09 Oct 2004 10:54:44 GMT, "Roger Long"
wrote in ::

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me.

That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

On Sat, 09 Oct 2004 07:30:28 -0800, Dale wrote in
::

In article ,
Larry Dighera wrote:


That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

A difference between a runup and the takeoff roll is the cooling air
flowing thru the cowling when moving.

True.

There is very little airflow when stationary, even with high power settings.

Are you able to cite a credible source that supports that assertion?
I'm not saying it isn't true, but I'd like to hear the input of an
A&P.

I'm not saying you shouldn't do a high power runup, but you should be
cautious and aware of the possibity of heat problems.

A pilot should always be aware of that possibility.

As the plugs tend to foul more easily when the engine is cold, the
admonition for caution in this instance is mitigated by the fact that
the engine temperature usually hasn't reached a point where it is a
factor at run up time. At least here in California that is what I've
found. In colder climates plug fouling may occur more frequently, but
I would expect the ambient temperature to also mitigate the cautionary
advice.

On Sat, 09 Oct 2004 07:30:28 -0800, Dale wrote in
::

In article ,
Larry Dighera wrote:


That's what I was taught. Often it only takes 10 - 15 seconds to
clear/burn the carbon deposit without the necessity of leaning. I
don't see anything abusive or abnormal about this procedure, as the
engine sees full throttle on each takeoff.

A difference between a runup and the takeoff roll is the cooling air
flowing thru the cowling when moving.

True.

There is very little airflow when stationary, even with high power settings.

Are you able to cite a credible source that supports that assertion?
I'm not saying it isn't true, but I'd like to hear the input of an
A&P.

I'm not saying you shouldn't do a high power runup, but you should be
cautious and aware of the possibity of heat problems.

A pilot should always be aware of that possibility.

As the plugs tend to foul more easily when the engine is cold, the
admonition for caution in this instance is mitigated by the fact that
the engine temperature usually hasn't reached a point where it is a
factor at run up time. At least here in California that is what I've
found. In colder climates plug fouling may occur more frequently, but
I would expect the ambient temperature to also mitigate the cautionary
advice.

"Daniel L. Lieberman" wrote in message
...

The answer to questions such as this can be found in the POH from the
manufacturer who supposedly knows more than the average flight
instructor.

I just love posts like this one!!

A good flight instructor would know that the answer to this question is
not a general answer that works for all aircraft and would therefore not
deal with it on a newgroup forum or in person before checking it out for
engine manufacturer recommendations and POH remarks as the answer
relates to the SPECIFIC aircraft/engine combination involved with the
question.
Although your answer is correct, unless you are one of these "pilots" on
"piloting" who think CFI's are morons, I see no reason to assume that
the "average" flight instructor wouldn't be intelligent enough to do
this.
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

"Daniel L. Lieberman" wrote in message
...

The answer to questions such as this can be found in the POH from the
manufacturer who supposedly knows more than the average flight
instructor.

I just love posts like this one!!

A good flight instructor would know that the answer to this question is
not a general answer that works for all aircraft and would therefore not
deal with it on a newgroup forum or in person before checking it out for
engine manufacturer recommendations and POH remarks as the answer
relates to the SPECIFIC aircraft/engine combination involved with the
question.
Although your answer is correct, unless you are one of these "pilots" on
"piloting" who think CFI's are morons, I see no reason to assume that
the "average" flight instructor wouldn't be intelligent enough to do
this.
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

"Roger Long" wrote

I can't remember where I "learned" it but I always thought 1800 RPM was the
limit for ground running leaned to clear plugs. I had a really bad one
yesterday with 250 RPM drop. I taxied back to the shop and they said to try
full throttle before pulling the plugs.

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me. Maybe you can get away with it because the
CHT's have not yet risen to max.

Any thoughts? What were you taught?

I was tought the full-power tactic. But what I found out empirically
was that leaning like crazy for all ground ops (to the point the
engine will barely run) has so far prevented the mag drop problem from
occurring again. I posted about this within the past few months and
found that others use similar procedures.

Jim Rosinski