Nasa Icing courses

Low rpm does save the prop, it also keeps the load on the
bearings a little less, throttle jockeying is worst, cold
oil doesn't flow quickly in response to throttle changes.
Also, if you have a constant speed prop, the governor uses
engine oil, so avoid taxing the oil pressure with rpm and /
or prop changes until the oil has had a chance to warm up a
little.

It also came to mind, that a sticking valve will cause more
wear on that cam/lifter assembly, so that can be a problem
to check.

Most engines have the oil pump at one end and oil pressure
is measured from a point on the other end, probably a cam
shaft gallery so that you can tell that oil passages are not
blocked. That is one reason for the "shutdown in 30
seconds" if you don't have oil pressure on starting note.

I like to idle an engine for a minute (4-5 minutes with
turbocharged engine) to allow it to cool before shutdown
while still having oil cooling. This would be at
1,000-1,200 rpm so the prop would be blowing some air
through the cowl. I then think it is a good idea to
throttle back to minimum rpm, to see that the idle is smooth
at 500-700 rpm range and I do a mag grounding check at that
point and then pull the mixture to shut it down. That
should show a slight 25-50 rpm increase just as it shuts
down since idle should be a little rich.

I start the engine at minimum throttle and using as little
priming as possible [wait after priming a few seconds to a
minute in cold weather to allow the fuel to vaporize, liquid
doesn't burn and it washes the oil off the cylinder walls]
then after it starts, advance the throttle smoothly to 1000
rpm to get some prop wash cooling and generator output.

Change to oil often, it is a lot cheaper to change the oil
than to tear down the engine. Use the best oil you can find
and the multi-weight oils do start working/ pumping faster.
Oil changes can be done by the pilot/owner as preventative
maintenance. A logbook entry is required and you must
follow the service manual procedures. Be sure to check for
leaks after the change and be sure to safety any drain
plugs. A quick drain system makes it a lot easier to do,
and an extension hose on the drain will keep the cowl clean.
Filters may not need to be changed every time if the oil
change is due to calendar time and condensation draining.
The oil filter does work on engine time in service since it
only functions when the oil is flowing and being filtered.
But follow the manual, if it says change the filter with
every oil change, you should do so.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Jay Honeck" wrote in message
news:_J8wf.714011$xm3.343650@attbi_s21...
| Start with the throttle 1/2 open, zero rpm to 1800 with
no
| oil pressure. Etc.
|
| I aim to keep RPMs at 1000 (or less) from start-up to
run-up. (My A&P
| showed me that 1000 RPM is too low to kick up stones, so
being patient and
| taxiing slowly really saves your prop.)
|
| What do you think causes a problem like Ray's, Jim? It
just seems to, I
| don't know -- random.
| --
| Jay Honeck
| Iowa City, IA
| Pathfinder N56993
| www.AlexisParkInn.com
| "Your Aviation Destination"
|
|

"Jim Macklin" wrote in message
news:Wgcwf.40975$QW2.5751@dukeread08...
point and then pull the mixture to shut it down. That
should show a slight 25-50 rpm increase just as it shuts
down since idle should be a little rich.


For my TIO540-S1AD, Lycoming says five rpm, not more than ten.

Stan

I'll buy that, always best to use specific data rather than
a generic answer. It takes a pretty good eye and tach to
see 5 rpm.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Stan Prevost" wrote in message
...
|
| "Jim Macklin" wrote
in message
| news:Wgcwf.40975$QW2.5751@dukeread08...
| point and then pull the mixture to shut it down. That
| should show a slight 25-50 rpm increase just as it shuts
| down since idle should be a little rich.
|
|
| For my TIO540-S1AD, Lycoming says five rpm, not more than
ten.
|
| Stan
|
|

"Jim Macklin" wrote in message
news:7ilwf.41026$QW2.13106@dukeread08...
I'll buy that, always best to use specific data rather than
a generic answer. It takes a pretty good eye and tach to
see 5 rpm.



Sure does. And a digital tach may flicker that much. Sometimes it is
called a "barely perceptible rise".

Some say it is easier to observe a rise in MP than such a small RPM rise,
and that is borne out by my observation.
The MP will rise one to two inches, and the MP gauge seems to be more stable
than the tach.

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.

Stan

I flew a demo in a BE 58P Baron into a high altitude
private strip in the Wyoming mountains,


A-A Ranch Airport is an airport in Carbon County,
Wyoming. It has an elevation of 7,880 feet.

With the Continental fuel injection, being the
mechanical constant displacement type, the engines died when
they were set to idle during the landing because they were
too rich and then turbos had spun down. This was a problem
because the runway looked like a ski-jump and I was half way
up the hill. I was able to hold the brakes and get it
started again and manually leaned the mixture to about 1/2
travel on the lever and taxi up the hill to the level ramp
area. Of course you have to keep it full rich in case of a
go-around, so I learned a lesson that was not in the manual,
as soon as touching down, mixture reduce, throttle reduce.
For take-off run up to 2000 RPM then full rich.
I much preferred the Bendix injection because it is
metered by ambient fuel and air pressure, so the mixture is
more stable and self-leaning. I love the PT6 even better.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their
rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and
duties.







"Stan Prevost" wrote in message
...
|
| "Jim Macklin" wrote
in message
| news:7ilwf.41026$QW2.13106@dukeread08...
| I'll buy that, always best to use specific data rather
than
| a generic answer. It takes a pretty good eye and tach
to
| see 5 rpm.
|
|
|
| Sure does. And a digital tach may flicker that much.
Sometimes it is
| called a "barely perceptible rise".
|
| Some say it is easier to observe a rise in MP than such a
small RPM rise,
| and that is borne out by my observation.
| The MP will rise one to two inches, and the MP gauge seems
to be more stable
| than the tach.
|
| 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.
|
| Stan
|
|

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

Stan Prevost wrote:
"Jim Macklin" wrote in message
news:Wgcwf.40975$QW2.5751@dukeread08...

point and then pull the mixture to shut it down. That
should show a slight 25-50 rpm increase just as it shuts
down since idle should be a little rich.

For my TIO540-S1AD, Lycoming says five rpm, not more than ten.

The mixture on injected engines typically is not as rich at idle as carburetted
engines, so the rpm increase should not be as great.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

With the low rpm, air flow in the manifold is not smooth or
steady. A carb meters fuel based on volume and the engine
burns fuel by mass. Getting balanced and safe fuel mixture
in each cylinder with a carb is not easy, they tend to meter
a little extra at all power settings. Aircraft injection is
usually constant flow port injection, but it is more precise
and the fuel is dumped into the intake manifold just at the
intake valve. The automotive and newer aircraft systems
have controlled injectors which only squirt fuel as needed,
making even more accurate distribution.
Diesel and the big radial engines late in WWII/until the
1950's had direct injection into the combustion chamber.
[Most radials used a pressure carb [fuel injection with the
nozzle in the throttle body] or port injection.]


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.




"George Patterson" wrote in message
news:Volwf.18567$em5.10846@trnddc05...
| Stan Prevost wrote:
| "Jim Macklin"
wrote in message
| news:Wgcwf.40975$QW2.5751@dukeread08...
|
| point and then pull the mixture to shut it down. That
| should show a slight 25-50 rpm increase just as it shuts
| down since idle should be a little rich.
|
| For my TIO540-S1AD, Lycoming says five rpm, not more
than ten.
|
| The mixture on injected engines typically is not as rich
at idle as carburetted
| engines, so the rpm increase should not be as great.
|
| George Patterson
| Coffee is only a way of stealing time that should by
rights belong to
| your slightly older self.