Nasa Icing courses

In rec.aviation.owning Stan Prevost wrote:
: If the mixture is set to spec, it is not necessary to lean for ground ops,
: since it is already lean enough to prevent plug fouling. Ground leaning is
: effective only if leaned back to the edge of idle cutoff, anyway.

: The Lycoming manual doesn't seem to have any tables for adjusting RPM rise
: for density altitude. If it is leaned to the 5RPM rise spec at a high
: altitude airport, I wonder if it might be too lean at a low-altitude
: airport, with no way to enrichen it.

Not to mention seasonal variation. With temperatures in Virginia in the 60s
(!) the past weeks it's difficult to even do it for winter/summer... not to mention
density altitude.

I ground lean mine... typically right on the edge of idle cutoff. It's enough
so that anything over 1200 RPM will cause the engine to stumble. That way it will be
periodically run extra-lean during the taxi and help reduce plug fouling. Can't hurt
the engine with leaning at such low power and it's impossible to runup or takeoff
without enrichening.

-Cory


--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

With regard to severe leaning on the ground, does hot summertime temps make
a difference? Long taxis or long hold shorts? I made the "lean the sh!t out
of it on the ground" comment at a flying club meeting once, & one of the
guys flipped.


wrote in message
...
In rec.aviation.owning Stan Prevost wrote:
: If the mixture is set to spec, it is not necessary to lean for ground
ops,
: since it is already lean enough to prevent plug fouling. Ground leaning
is
: effective only if leaned back to the edge of idle cutoff, anyway.

: The Lycoming manual doesn't seem to have any tables for adjusting RPM
rise
: for density altitude. If it is leaned to the 5RPM rise spec at a high
: altitude airport, I wonder if it might be too lean at a low-altitude
: airport, with no way to enrichen it.

Not to mention seasonal variation. With temperatures in Virginia in the
60s
(!) the past weeks it's difficult to even do it for winter/summer... not
to mention
density altitude.

I ground lean mine... typically right on the edge of idle cutoff. It's
enough
so that anything over 1200 RPM will cause the engine to stumble. That way
it will be
periodically run extra-lean during the taxi and help reduce plug fouling.
Can't hurt
the engine with leaning at such low power and it's impossible to runup or
takeoff
without enrichening.

-Cory


--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Steven Barnes wrote:

With regard to severe leaning on the ground, does hot summertime temps make
a difference? Long taxis or long hold shorts? I made the "lean the sh!t out
of it on the ground" comment at a flying club meeting once, & one of the
guys flipped.

Leaning during high ground temperatures should not cause excessive cylinder
temperatures since you are taxiing at very low RPMS.

The C172SPs (fuel-injected engines) at my former flight school always
experienced fouled plugs if the students/renters failed to lean for ground
operations.

--
Peter