Practicing SFLs with a constant speed prop - how?

I'm fairly new to GA after a 19 year break flying jets. I routinely
fly a single engine experimental with a constant speed prop mounted on
a Lycoming IO-360.

2 QUESTIONS:

1. What's the proper setup to simulate the way the plane would glide
in case of an engine failure? I'm looking for pitch and possibly a
manifold pressure number here.

2. It that motor quits, will it still rotate through the flying
airspeed envelope or can I expect it to stop rotation (assuming it's
not frozen due to a mechanical failure)?

In idle, with the prop at flat pitch, it feels too draggy and comes
down like a rock. With it at high pitch, it seems to have too
optimistic a glide ratio. What's the happy medium?

I don't live near a dry lake bed or I'd just shut it down and find
out. I have the proper airspeeds for max range and min sink out of
the POH but it does not quote any type of glide ratio.

Ed

"Ed" wrote in message
...
1. What's the proper setup to simulate the way the plane would glide
in case of an engine failure?

Generally, in a real engine failure with a constant speed prop, you'd pull
the RPM back to minimum. IMHO, your practice should match the *procedure*
you'll use in the real thing, even if the airplane performance doesn't,
since getting the procedure right is the most important thing.

Throttle to idle, to minimize the contribution of the engine to your glide,
of course.

2. It that motor quits, will it still rotate through the flying
airspeed envelope or can I expect it to stop rotation (assuming it's
not frozen due to a mechanical failure)?

It depends. But for most of the flight envelope, your prop will most likely
windmill. Each installation is different though. If you really want to
know, you either have to test it yourself, or talk to someone who has.

Pete

In article ,
Ed wrote:


1. What's the proper setup to simulate the way the plane would glide
in case of an engine failure? I'm looking for pitch and possibly a
manifold pressure number here.

IMO for practice you should leave the prop in the Hi RPM position so
that it provides plenty of drag. Regardless of how you simulate the
engine failure you will be getting some thrust from the engine which
does improve the glide performance. When the real thing happens you
could be caught short if expecting the performance you experienced when
practicing. Putting the prop to the Low RPM position should provide
less drag in an actual engine out situation.

The way I do deadstick landings is to put most of the drag out early and
stay very tight to the field. My thought is I can always get rid of
some drag if needed.

The way I've practiced and done them real life is to leave the prop at
Hi RPM. I also turn base abeam my intended landing point and put the
flaps down full. I fly an extremely tight pattern to prevent coming up
short. IF it appear I might be a little short I can reduce RPM on the
prop and/or reduce the flap setting some (Cessna 182/206) to reduce
drag. It's what I practiced and it's what has worked for me "real life".


2. It that motor quits, will it still rotate through the flying
airspeed envelope or can I expect it to stop rotation (assuming it's
not frozen due to a mechanical failure)?

The prop continued to turn until I was on the runway in all the engine
failures I've had.

--
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

In article , Dale
wrote:
IMO for practice you should leave the prop in the Hi RPM position so
that it provides plenty of drag. Regardless of how you simulate the
engine failure you will be getting some thrust from the engine which
does improve the glide performance. When the real thing happens you
could be caught short if expecting the performance you experienced when
practicing. Putting the prop to the Low RPM position should provide
less drag in an actual engine out situation.
The way I do deadstick landings is to put most of the drag out early and
stay very tight to the field. My thought is I can always get rid of
some drag if needed.
The way I've practiced and done them real life is to leave the prop at
Hi RPM. I also turn base abeam my intended landing point and put the
flaps down full. I fly an extremely tight pattern to prevent coming up
short. IF it appear I might be a little short I can reduce RPM on the
prop and/or reduce the flap setting some (Cessna 182/206) to reduce
drag. It's what I practiced and it's what has worked for me "real life".

The best way to simulate an engine failure without producing thrust is
to pull the mixture all the way out.
When you want to bring the power back, just push the mixture back in
and the engine will restart.

One caveat.. this works fine as long as the prop continues to windmill..
if it DOESNT... they you have just turned a training situation into what
may be a bonafide emergency.

Dave

EDR wrote:
In article , Dale
wrote:

IMO for practice you should leave the prop in the Hi RPM position so
that it provides plenty of drag. Regardless of how you simulate the
engine failure you will be getting some thrust from the engine which
does improve the glide performance. When the real thing happens you
could be caught short if expecting the performance you experienced when
practicing. Putting the prop to the Low RPM position should provide
less drag in an actual engine out situation.
The way I do deadstick landings is to put most of the drag out early and
stay very tight to the field. My thought is I can always get rid of
some drag if needed.
The way I've practiced and done them real life is to leave the prop at
Hi RPM. I also turn base abeam my intended landing point and put the
flaps down full. I fly an extremely tight pattern to prevent coming up
short. IF it appear I might be a little short I can reduce RPM on the
prop and/or reduce the flap setting some (Cessna 182/206) to reduce
drag. It's what I practiced and it's what has worked for me "real life".


The best way to simulate an engine failure without producing thrust is
to pull the mixture all the way out.
When you want to bring the power back, just push the mixture back in
and the engine will restart.

In article . net, Dave S wrote:
One caveat.. this works fine as long as the prop continues to windmill..
if it DOESNT... they you have just turned a training situation into what
may be a bonafide emergency.

I believe Highflyer has a story about that in a Taylorcraft...which
lacked an electric starter, and the prop had stopped turning. Slope
soaring saved the day.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

I can't say that I have tried every prop and engine combination, but I have
never been able to stop a prop without pulling the nose up to an alarming
attitude...you can pretty much count on it windmilling.

You are experiencing "flat plate drag." In cruise and reduced power descent,
the prop is pulling the airplane through the air (duh). As manifold pressure
is reduced toward idle, the prop governor flattens the pitch in an attempt
to maintain RPM, but when it hits the low pitch stops, that's all there is.
If you go all the way to idle, the windmilling prop drives the engine...the
crankshaft is turning, the pistons are doing their thing, etc, but no motive
force is produced.What you do get is disturbed air over the horizontal
stabilizer, reducing its effectiveness. You goal is to set the MAP to where
the prop is essentially idling, neither pulling nor creating drag. That will
be at about 11 inches in most cases. If you set up a long glide to final,
just as a test, play with the manifold pressure and if you have a sensitive
butt you will almost feel it when you have pulled the throttle back too far.

Bob Gardner

"Ed" wrote in message
...
I'm fairly new to GA after a 19 year break flying jets. I routinely
fly a single engine experimental with a constant speed prop mounted on
a Lycoming IO-360.

2 QUESTIONS:

1. What's the proper setup to simulate the way the plane would glide
in case of an engine failure? I'm looking for pitch and possibly a
manifold pressure number here.

2. It that motor quits, will it still rotate through the flying
airspeed envelope or can I expect it to stop rotation (assuming it's
not frozen due to a mechanical failure)?

In idle, with the prop at flat pitch, it feels too draggy and comes
down like a rock. With it at high pitch, it seems to have too
optimistic a glide ratio. What's the happy medium?

I don't live near a dry lake bed or I'd just shut it down and find
out. I have the proper airspeeds for max range and min sink out of
the POH but it does not quote any type of glide ratio.

Ed

Bob Gardner wrote:

I can't say that I have tried every prop and engine combination, but I have
never been able to stop a prop without pulling the nose up to an alarming
attitude...you can pretty much count on it windmilling.

One of the aviation writers (Schiff, IIRC) did some experiments along those lines. He
came to the conclusion that stopping the prop was only productive in terms of
improving glide distance if you were more than 6,000' AGL at the time the rubber band
broke. You have to get very close to stall speed to get it stopped. He was working
with fixed pitch propellors, however.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".

On Mon, 12 Apr 2004 05:06:12 GMT, Ed wrote:

snip

In idle, with the prop at flat pitch, it feels too draggy and comes
down like a rock. With it at high pitch, it seems to have too
optimistic a glide ratio. What's the happy medium?

I'm a little confused by this portion of your question, and a couple
of the replies.

I have never actually messed around a bunch with airspeed/descent
rate/idle engine/prop rpm, but am pretty familiar with how a typical
pressure-to-increase pitch constant-speed prop/governor works.

Somewhere around 1600-1800 rpm, the prop governor ceases to output
enuff pressure to change/maintain the propeller pitch, and the
propeller goes to flat pitch. I've seen it on a gov bench, and on
approach-to-land.

Whether or not the engine is "running" if the rpm is below this range,
moving the prop control has no effect on the pitch of the prop.

TC

snip

In article ,
wrote:



Whether or not the engine is "running" if the rpm is below this range,
moving the prop control has no effect on the pitch of the prop.


That's what I thought until I tried it on my 182. Idle power, trimmed
stable 80 mph glide with the prop control all the way forward. Pulled
the blue knob back and watched the airspeed increase about 5MPH...pushed
the blue knob in and I slowed again.

--
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