Engine mixture guidelines

Andrew Sarangan writes:

http://www.fsinsider.com/About/Learn...the-Engine.htm

Thanks! Is the stated rule that mixture should be adjusted to just
short of maximum EGT pretty reliable under all circumstances?

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic,

Thanks! Is the stated rule that mixture should be adjusted to just
short of maximum EGT pretty reliable under all circumstances?


No. It's a very bad rule, actually. Go find more info on leaning on the
net, and you'll see.

--
Thomas Borchert (EDDH)

On Tue, 2 Jan 2007 01:12:46 -0800, Thomas Borchert wrote
(in article ):

Mxsmanic,

Thanks! Is the stated rule that mixture should be adjusted to just
short of maximum EGT pretty reliable under all circumstances?


No. It's a very bad rule, actually. Go find more info on leaning on the
net, and you'll see.



The only things that start more arguments than flying "lean of peak" are
slips with flaps and a discussion of lift.

C,

The only things that start more arguments than flying "lean of peak" are
slips with flaps and a discussion of lift.


It's not only LOP, it's that 50 or 75 ROP is usually a bad place.

--
Thomas Borchert (EDDH)

The only things that start more arguments than flying "lean of peak" are
slips with flaps and a discussion of lift.

You forgot "running oversquare." I know two guys who have been flying
about as long as I have (50+ years) who are convinced they'll burn in
hell forever if the cruise "oversquare," even after I've shown them
Lycoming documents recommending it.

They know more about engines than the people who designed and built
them.

vince norris

Just do what is "reasonable and proper"

Ron Lee

In article ,
Mxsmanic wrote:
Up to now when flying in simulation, I've had the simulator take care
of engine mixture adjustments. However, since I'd have to do this
myself in real life, I've decided to make some modest attempts at
managing mixture myself. Unfortunately, the POH and the other sources
I've consulted are rather vague on how mixture should be adjusted.
Can anyone offer general guidelines on when to enrich or lean the
mixture? It seems that max rich is used when maximum power is
required (?), such as at take-off, but I'm not clear when the mixture
should be leaned in particular. And what are the potential
consequences of an incorrect mixture?


If you're simulating a rental just leave it full rich.

--
Scott Post

On Sat, 30 Dec 2006 13:56:30 -0800, Scott Post wrote
(in article ):

In article ,
Mxsmanic wrote:
Up to now when flying in simulation, I've had the simulator take care
of engine mixture adjustments. However, since I'd have to do this
myself in real life, I've decided to make some modest attempts at
managing mixture myself. Unfortunately, the POH and the other sources
I've consulted are rather vague on how mixture should be adjusted.
Can anyone offer general guidelines on when to enrich or lean the
mixture? It seems that max rich is used when maximum power is
required (?), such as at take-off, but I'm not clear when the mixture
should be leaned in particular. And what are the potential
consequences of an incorrect mixture?


If you're simulating a rental just leave it full rich.



Ouch!

But ain't it the truth?

Mxsmanic wrote:
Up to now when flying in simulation, I've had the simulator take care
of engine mixture adjustments. However, since I'd have to do this
myself in real life, I've decided to make some modest attempts at
managing mixture myself. Unfortunately, the POH and the other sources
I've consulted are rather vague on how mixture should be adjusted.
Can anyone offer general guidelines on when to enrich or lean the
mixture? It seems that max rich is used when maximum power is
required (?), such as at take-off, but I'm not clear when the mixture
should be leaned in particular. And what are the potential
consequences of an incorrect mixture?

--
Transpose mxsmanic and gmail to reach me by e-mail.

As altitude increases the air gets thinner so you need less fuel to
maintain the proper air to fuel ratio. Running too rich (too much fuel)
causes incomplete combustion resulting in spark plug fouling. Running
too lean (not enough fuel) causes overheating especially the exaust
valves.
The most efficient way to determine the correct mixture is with a EGT
(Exaust Gas Temperature) gauge. As you turn the mixture control out the
EGT will increase to a point and then begin to decrease as the mixture
gets too lean. Lean the mixture until it peaks and then enrichen it
(turn it back in) until it drops 50°C.
Though not as accurate, you can also note a increase in RPM's as you
lean it. Lean to peak RPM then turn it in a full turn.
Remember FULL rich for takeoffs and landings unless your flying at
Leadville, CO or some other really high altitude airport.
Steve

Running too rich (too much fuel)
causes incomplete combustion resulting in spark plug fouling. Running
too lean (not enough fuel) causes overheating especially the exaust
valves.

I suspect most MSFS simulated aircraft do not simulate engine damage
from improper leaning. They will simulate the fan quitting at idle
cutoff though.

The most efficient way to determine the correct mixture is with a EGT
(Exaust Gas Temperature) gauge. As you turn the mixture control out the
EGT will increase to a point and then begin to decrease as the mixture
gets too lean.

In real airplanes there is a lag. Lean it out slowly. A Cessna 182
manual I remember reading said that it should take about two minutes to
find the peak. This may also not be adequately simulated in
"entertainment level" simulators.

Lean to peak RPM then turn it in a full turn.

I've never heard "a full turn", though I have heard the less helpful
phrase "a bit". Not all airplanes have vernier controls, and I don't
think MSFS aircraft do either.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.