Emergency

"Jay Honeck" wrote:

Glad you found the problem in time. Did your manifold pressure drop?

That was my first question, too. Dan?

I must have looked, but what I remember is being mystified at why I couldn't
hold altitude when the engine seemed fine. Perhaps I mis-read the gauge. I
was doing several things at once and rushing everything.

It was all over so quickly I didn't have much time to really examine the
data!

--
Dan
C172RG at BFM

In future I will be using carb heat as a matter of course when ambient
conditions are in the "severe" area of the chart. I definitely will not be
waiting for symptoms in such cases.

Dan, I have a couple hundred hours behind the normally aspirated 0-470
Continental in C182's.
Anytime there is significant moisture in the air, the carb will ice up.
The trick is to constantly monitor the manifold pressure. As soon as you
see a one-inch drop, you apply carb heat. When the pressure comes back
up, turn the carb heat off. Repeat as necessary.
I will not fly with carb heat on constantly.
I read somewhere in the past (years ago, don't recall where) that flying
with constant carb heat moves the ice farther down the throat where no
heat will be available to melt it.
SPORT AVIATION had an excellent article on carb ice back in the early
90's. The author had all the math and discussed latent heat of
vaporization and all the other technical stuff, but he made it
understandable by anyone with an eighth grade education.

"john smith" wrote:

In future I will be using carb heat as a matter of course when ambient
conditions are in the "severe" area of the chart. I definitely will not
be
waiting for symptoms in such cases.

Dan, I have a couple hundred hours behind the normally aspirated 0-470
Continental in C182's.
Anytime there is significant moisture in the air, the carb will ice up.

As I understand it, the carburetor arrangement on the TCM O-470 does not
provide for conduction of as much engine heat to the carburetor as the LYC
O-360s and O-540s, thus the O-470's notorious reputation for carb icing.

The trick is to constantly monitor the manifold pressure. As soon as you
see a one-inch drop, you apply carb heat. When the pressure comes back
up, turn the carb heat off. Repeat as necessary.

That's pretty much what my buddy Filipo told me about his 182. Carb ice is
a regular fact of life for him; it's a rare event for me (twice in six
years with this airplane).

--
Dan
C172RG at BFM

john smith wrote:



Dan, I have a couple hundred hours behind the normally aspirated 0-470
Continental in C182's.
Anytime there is significant moisture in the air, the carb will ice up.

Not true. I recently sold my 182 after having put 1000 hours on it.
Never had it ice up, even after trying. I would go out on those rare
days here when we had fog and fly just as it lifts, still 90 somethun'
percent humidity. Couldn't make it happen.


I will not fly with carb heat on constantly.
I read somewhere in the past (years ago, don't recall where) that flying
with constant carb heat moves the ice farther down the throat where no
heat will be available to melt it.

Old wives tale. Cessna Pilots Assoc reccomends whatever amount of carb
heat is necessary to keep the carb at about 45 degrees in cruise. Also
has the effect of evening out the fuel mixture so the engine ran smoother.

In article ,
Newps wrote:

john smith wrote:



Dan, I have a couple hundred hours behind the normally aspirated 0-470
Continental in C182's.
Anytime there is significant moisture in the air, the carb will ice up.

Not true. I recently sold my 182 after having put 1000 hours on it.
Never had it ice up, even after trying. I would go out on those rare
days here when we had fog and fly just as it lifts, still 90 somethun'
percent humidity. Couldn't make it happen.

Okay, I will rephrase my statement, temperature and humidity have to be
in the proper range. It can be too warm or too cold, but with
significant moisture in the proper range, the O-470 Continental in a
Cessna 182 will likely form carb ice.

On Mon, 27 Mar 2006 18:21:40 -0600, Dan Luke wrote:

vibration. The engine still sounded good and was still making 2500 rpm, but
the prop was probably in flat pitch to do it. I tried the electric fuel
pump: no joy. I glanced at the JPI engine analyzer and saw that all four
cylinders showed roughly even EGTs. All this took much less than a minute;
maybe only 30 seconds.

Finally, I pulled the carb heat. Within a few seconds I felt a surge of
power and we began to climb. I don't know for sure what a death row inmate
feels like when the governor calls at the last minute, but I'm guessing it
feels something like that.

I thought with a fixed speed prop, the clues for carb ice were reduced MP
and possibly decreased EGTs from a richer fuel burn? Where as on a fixed
pitch prop, rpm drop was the first clue.

Is this not correct?

Greg

On Tue, 28 Mar 2006 22:14:24 +0000, Alan wrote:

On Tue, 28 Mar 2006 17:00:58 -0500, T o d d P a t t i s t
wrote:


I've never quite figured out why carb heat is designed this
way. I've always got carb heat on during landing,

I'm curious as to why you keep your carb heat on during landing. I
usually pull it on during my GUMP check approaching an airport but
then shut it off. If you have to do a go around, you're not going to
get full power with it on.

For us, carb heat goes in (with my thumb) as the throttle is pushed
forward. Thus, you get full power in the same stroke you push the
throttle forward. Next, is reaching for the flaps...

Greg

vibration. The engine still sounded good and was still making 2500 rpm,
but
the prop was probably in flat pitch to do it. I tried the electric fuel
pump: no joy. I glanced at the JPI engine analyzer and saw that all four
cylinders showed roughly even EGTs. All this took much less than a minute;
maybe only 30 seconds.
Finally, I pulled the carb heat. Within a few seconds I felt a surge of
power and we began to climb. I don't know for sure what a death row inmate
feels like when the governor calls at the last minute, but I'm guessing it
feels something like that.

I thought with a fixed speed prop, the clues for carb ice were reduced MP
and possibly decreased EGTs from a richer fuel burn? Where as on a fixed
pitch prop, rpm drop was the first clue.
Is this not correct?

Yes.