Simulated Engine Outs

(Dan Thomas) wrote in message . com...
(Michael) wrote in message . com...
Big John wrote
Probably one rational behind keeping engine warm is that if you go to
idle and glide a long time the engine will cool down. You then slap on
full power and the cylinders are hit with a high temperature all of a
sudden.

That's probably the best rationale I've ever heard for 1500 RPM and
one notch of flaps. We all worry about shock cooling, but letting the
engine cool off and then pouring on the coals is a recipe for shock
heating. I might rethink the way I do this...

Of course idle engine will not duplicate aircraft performance with
dead engine.

No it won't. It's also a great recipe for icing up the carb. For
both those reasons, I usually pull the mixture to idle. That way you
get a true windmilling engine, and since no fuel is evaporating in the
carb there's no risk of ice.

Carb heat should be the first thing applied when the engine
"quits." Carb icing is the most common cause of engine failure, and if
the pilot is a bit slow in pulling it, there won't be any heat left to
remove the ice. As it is, he'll be lucky to regain power. Some folks
aren't aware of decreasing RPM or manifold pressure until things get
real quiet.
Pulling mix to idle cutoff has caused several accidents in
Canada, and it's no longer part of the simulated forced approach.

Dan

Do you have the details of these accidents, or where one might find
them? It would be interesting to know the exact cause of the accident.

I was taught that way. Full rich, carb heat, switch tanks, switch mags.
Unfortunately my only fully dead engine episode needed the
opposite solution. I didn't have time to figure it out, if I would have been
smart enough in the first place.

The carb float had sunk and the engine flooded on power to idle reduction. I
didn't know it. When I needed the power, no power. Full rich - wrong.
Switch mags - so what. Other tank - who cares. Carb heat -wrong.

If only I had pulled the mixture to lean and full throttle. Probably
wouldn't have helped - too low - the whole thing was under a minute
to touchdown.




In article ,
(Andrew Sarangan) wrote:
(Dan Thomas) wrote in message
. com...
(Michael) wrote in message
. com...
Big John wrote
Probably one rational behind keeping engine warm is that if you go to
idle and glide a long time the engine will cool down. You then slap on
full power and the cylinders are hit with a high temperature all of a
sudden.

That's probably the best rationale I've ever heard for 1500 RPM and
one notch of flaps. We all worry about shock cooling, but letting the
engine cool off and then pouring on the coals is a recipe for shock
heating. I might rethink the way I do this...

Of course idle engine will not duplicate aircraft performance with
dead engine.

No it won't. It's also a great recipe for icing up the carb. For
both those reasons, I usually pull the mixture to idle. That way you
get a true windmilling engine, and since no fuel is evaporating in the
carb there's no risk of ice.

Carb heat should be the first thing applied when the engine
"quits." Carb icing is the most common cause of engine failure, and if
the pilot is a bit slow in pulling it, there won't be any heat left to
remove the ice. As it is, he'll be lucky to regain power. Some folks
aren't aware of decreasing RPM or manifold pressure until things get
real quiet.
Pulling mix to idle cutoff has caused several accidents in
Canada, and it's no longer part of the simulated forced approach.

Dan

Do you have the details of these accidents, or where one might find
them? It would be interesting to know the exact cause of the accident.

Unfortunately my only fully dead engine episode needed the
opposite solution. [...] The carb float had sunk and the
engine flooded on power to idle reduction.


One size never fits all.


I didn't have time to figure it out, if I would have been
smart enough in the first place.


What would it have taken to figure it out in flight? (other than time to try
all the other combinations that are not in the first response?

Jose

--
(for Email, make the obvious changes in my address)

At that point in my experience, I would never have figured it out.
I had never heard of such an occurence. Dumb luck might have
saved the day, assuming I had plenty of time to remember
to do everything, like turn the fuel off. But if I had followed what
is the "proper" off field landing check, I wouldn't have turned
off the fuel early enough to have a positive effect. Since then
there have been multiple times that haven't fit any past learning
or knowledge. It's called the school of hard knocks. Fortunately
they haven't hurt anybody or any thing. Today's young
instructors have a long way to go (at least 20 years) before they
get good. Variety counts for a lot more than hours and ratings.


In article ,
(Teacherjh) wrote:

Unfortunately my only fully dead engine episode needed the
opposite solution. [...] The carb float had sunk and the
engine flooded on power to idle reduction.


One size never fits all.


I didn't have time to figure it out, if I would have been
smart enough in the first place.


What would it have taken to figure it out in flight? (other than time to try
all the other combinations that are not in the first response?

Jose

You are still talking to us, so it was a 'good' landing...
Mine was when a piston knocked a hole through the side of the jug and
proceeded to pump the oil overboard... Since then I prefer to fly twins...
denny
"d b" wrote in message
ink.net...
I was taught that way. Full rich, carb heat, switch tanks, switch mags.
Unfortunately my only fully dead engine episode needed the
opposite solution. I didn't have time to figure it out, if I would have
been
smart enough in the first place.

The carb float had sunk and the engine flooded on power to idle reduction.
I
didn't know it. When I needed the power, no power. Full rich - wrong.
Switch mags - so what. Other tank - who cares. Carb heat -wrong.

If only I had pulled the mixture to lean and full throttle. Probably
wouldn't have helped - too low - the whole thing was under a minute
to touchdown.




In article ,
(Andrew Sarangan) wrote:
(Dan Thomas) wrote in message
. com...
(Michael) wrote in message
. com...
Big John wrote
Probably one rational behind keeping engine warm is that if you go
to
idle and glide a long time the engine will cool down. You then slap
on
full power and the cylinders are hit with a high temperature all of
a
sudden.

That's probably the best rationale I've ever heard for 1500 RPM and
one notch of flaps. We all worry about shock cooling, but letting
the
engine cool off and then pouring on the coals is a recipe for shock
heating. I might rethink the way I do this...

Of course idle engine will not duplicate aircraft performance with
dead engine.

No it won't. It's also a great recipe for icing up the carb. For
both those reasons, I usually pull the mixture to idle. That way you
get a true windmilling engine, and since no fuel is evaporating in
the
carb there's no risk of ice.

Carb heat should be the first thing applied when the engine
"quits." Carb icing is the most common cause of engine failure, and if
the pilot is a bit slow in pulling it, there won't be any heat left to
remove the ice. As it is, he'll be lucky to regain power. Some folks
aren't aware of decreasing RPM or manifold pressure until things get
real quiet.
Pulling mix to idle cutoff has caused several accidents in
Canada, and it's no longer part of the simulated forced approach.

Dan

Do you have the details of these accidents, or where one might find
them? It would be interesting to know the exact cause of the accident.

"C J Campbell" wrote
Actually, no we do not all worry about shock cooling. Neither do we all
worry about shock heating. Many highly respected pilots and mechanics
believe that shock cooling and shock heating are myths, at least for modern
aircraft engines.

First - we do not fly behind modern aircraft engines, at least in
trainers. Those engines are warmed-over 1950's (at best) technology.

Second, maybe those who are not worried about it should be. I know a
Bonanza pilot who didn't worry about it. He would routinely cut the
power way back for a rapid descent. I attempted to get him to stop,
but he just wasn't worried about it. Then he lost a jug on takeoff.
He's more careful now.

The manufacturers have also said that shock cooling and
shock heating should not be a problem -- of course, maybe they like to sell
replacement engines. :-)

The manufacturers haven't had any engineering expertise worth
mentioning. And I bet what they like to sell are not replacement
engines (few people buy one) but replacement jugs. The bottom end
never really gets hot enough to be concerned, but the jugs sure do.

I seriously doubt that shock cooling is much of a problem on training
aircraft, at least. These airplanes are subjected to all kinds of supposed
mistreatment, but their engines almost always make it to TBO.

How many of them make it to TBO without replacing a jug here and
there? None that I know of.

Michael

Bad form, I know. Lousy proofreading.

I said:

The manufacturers haven't had any engineering expertise worth
mentioning.

I meant to say:

The manufacturers haven't had any engineering expertise worth
mentioning for years.

Michael

(Michael) wrote
How many of them make it to TBO without replacing a jug here and
there? None that I know of.

I and one other instructor flew a C-172N to overhaul (replacement)
twice with literally NO engine maintenance either time.
The secret to long engine life is daily operation and frequent oil
changes.

Bob Moore

In article ,
(Michael) wrote:


Second, maybe those who are not worried about it should be. I know a
Bonanza pilot who didn't worry about it. He would routinely cut the
power way back for a rapid descent. I attempted to get him to stop,
but he just wasn't worried about it. Then he lost a jug on takeoff.
He's more careful now.

But what indicates that his descent procedure led to the cylinder
failure? Maybe he didn't warm the engine enough for takeoff, maybe he
didn't change oil often, perhaps he over-boosted the engine routinely.

--
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

The only jug I ever lost was due to a leaky valve which lead to a cracked
cylinder.

Most engine maintenance seems to be caused by finding metal in the oil in
airplanes that do not fly much. Cylinder corrosion seems to be a much bigger
factor than shock cooling.