Compass

On Feb 23, 9:19 am, John Smith wrote:
Bill Daniels wrote:
If you get more than 15 - 20 degrees off a south heading, the trick
no longer works so turbulence is a real problem.

That's what I call theoretically perfect but unusable in real life.

The emergency procedure to escape a cloud without a gyro is to trim the
glider for slow straight flight, pull the airbrakes fully open, let go
of the stick and wait until you drop out of that cloud *somehow*. That's
why JAR requires the dive brakes to keep the dive speed under Vne for
dive angles up to 45 degrees.

That assumes the glider is stable in a benign spiral, not all are.
There is no requirement for the glider to be so. Try it out in
whatever particular glider(s) you fly before assuming it will work. I
happen to fly an ASH-26E and I can tell you my glider will not benign
spiral, other pilots have also come to the same conclusion with their
ASH-26E.

Darryl

On Feb 23, 7:40 am, "Bill Daniels" bildan@comcast-dot-net wrote:
"John Smith" wrote in message

. ..

wrote:

You can fly wings level in IMC using a standard compass. Not with GPS.

The eternal theory. Have you actually done it in a modern slippery glass
ship? I certainly couldn't, but maybe I'm just ham fisted.

Actually, you can maintain wings level with either, given a sufficient level
of skill. Garmin, I believe, sells a unit with an impressive "gyro panel"
based entirely on GPS data that works amazingly well.

With a wet compass, it's not extremely difficult to maintain heading and
wings level once the glider is stabilized on a magnetic south heading.
Getting it to that heading inside a turbulent cloud is a whole 'nuther
matter. If you get more than 15 - 20 degrees off a south heading, the trick
no longer works so turbulence is a real problem.

Yes, I've done both in a glider, under a "hood" with a safety pilot in the
other seat who held a CFII. This is the ONLY way to try this.

Bill D

Any of the current Garmin x96 series have the GPS derived "Instrument
Panel", as has been pointed out here before by Bumper and others the
danger with these devices is they use ground speed and change in
ground speed, not airspeed to calculate the panel display and in
extreme cases such as flying a glider in strong wind/wave conditions
the "instruments" may not work correctly, including possible reversal
of some instruments. Only worth mentioning as being enveloped in a
lennie or trapped on top in wave conditions may be one of the
unintended IMC situations worth worrying about.

Darryl

Darryl Ramm wrote:

That assumes the glider is stable in a benign spiral, not all are.

Correct. But it's the only method which *may* work. If it doesn't,
you're out of luck without a gyro. That "fly south and use the turn
error of the whisky compass to keep the wings level" just doesn't work
in real life. Of course it does't harm to try it first, but don't let it
fool you to think that you could rely on it.

"Darryl Ramm" wrote in message
...
On Feb 23, 7:40 am, "Bill Daniels" bildan@comcast-dot-net wrote:
"John Smith" wrote in message

. ..

wrote:

You can fly wings level in IMC using a standard compass. Not with GPS.

The eternal theory. Have you actually done it in a modern slippery
glass
ship? I certainly couldn't, but maybe I'm just ham fisted.

Actually, you can maintain wings level with either, given a sufficient
level
of skill. Garmin, I believe, sells a unit with an impressive "gyro
panel"
based entirely on GPS data that works amazingly well.

With a wet compass, it's not extremely difficult to maintain heading and
wings level once the glider is stabilized on a magnetic south heading.
Getting it to that heading inside a turbulent cloud is a whole 'nuther
matter. If you get more than 15 - 20 degrees off a south heading, the
trick
no longer works so turbulence is a real problem.

Yes, I've done both in a glider, under a "hood" with a safety pilot in
the
other seat who held a CFII. This is the ONLY way to try this.

Bill D

Any of the current Garmin x96 series have the GPS derived "Instrument
Panel", as has been pointed out here before by Bumper and others the
danger with these devices is they use ground speed and change in
ground speed, not airspeed to calculate the panel display and in
extreme cases such as flying a glider in strong wind/wave conditions
the "instruments" may not work correctly, including possible reversal
of some instruments. Only worth mentioning as being enveloped in a
lennie or trapped on top in wave conditions may be one of the
unintended IMC situations worth worrying about.

Darryl

All good points.

I guess, I'd set up the glider for a benign spiral with spoilers out and
trimmed for 55-60 and then attempt to hold a south heading with the wet
compass. If I lost it, I'd just let go and hope the benign spiral worked.
If I had a Germin with the "panel" and knew the winds were light, I'd try
using that too with a benign spiral as the backup.

Bill D

The emergency procedure to escape a cloud without a gyro is to trim the
glider for slow straight flight, pull the airbrakes fully open, let go
of the stick and wait until you drop out of that cloud *somehow*. That's
why JAR requires the dive brakes to keep the dive speed under Vne for
dive angles up to 45 degrees.[/quote]

so, let me get this right-

your actually already in the cloud (blinded, conditions turbulent)
and THEN you trim for slow, straight flight?!

Who wrote that bit of emergency procedure?

Bagger

bagmaker wrote:

your actually already in the cloud (blinded, conditions turbulent)
and THEN you trim for slow, straight flight?!

Who wrote that bit of emergency procedure?

I did. I don't know about you, but *I* do know the approximate trim
positions of the gliders which I fly. Approximate is good enough in that
situation.

your actually already in the cloud (blinded, conditions turbulent)
and THEN you trim for slow, straight flight?!

Who wrote that bit of emergency procedure?

Bagger

Good point there Bagger, one should trim for 60ish speed before going
IFR. I did this in a 301 Libelle for a good 45 minutes, trimmed her up
for 60 knots and then released the stick and took my feet off the
rudder pedals. I was not in the clouds, just checking the idea out.
The nose would slowly drop, but as speed increased, the nose came back
up. Then the speed would get real slow, but not stall, just mush over
and start the next vertical maneuver. As this was going on, one wing
would slowly drop, but never more than 45 degrees, then slowly come
back up. My heading was all over the sky. Worked well in a H-301
Libelle, best to give it a try in your bird before you really need it.
JJ

Boy oh boy . . . I'm not sure if some of you have your head in the clouds or
your head in the sand (g).

If everything is nice and smooth, like in stable air trying to descend
through a socked-in cloud deck below . . . probably okay, maybe. Spinning
down works in some aircraft too, as long as your really sure about ceiling
height and terrain.

But in moderate to severe turbulence while in the soup, good luck and
hopefully you'll have good hull insurance and a even better parachute.

If you even remotely contemplate the possibility of going IMC in your
glider, accidentally or otherwise, then at least get a gyro instrument (or
electronic equivalent - - I have a TruTrak) and some under the hood or
better, actual instrument training. If you don't go for the full power and
instrument rating, then ask the instructor to concentrate on partial panel
unusual attitude recovery. Even though you won't be looking outside, it
should be a real eye opener for those benign spiral / follow the compass
south believers.

Disclaimer . . . not saying spiral, spin, compass aren't options, just that
they're not so good in some of the stuff gliders can get into.

fly safe,

bumper

"John Smith" wrote in message
...
bagmaker wrote:

your actually already in the cloud (blinded, conditions turbulent)
and THEN you trim for slow, straight flight?!

Who wrote that bit of emergency procedure?

I did. I don't know about you, but *I* do know the approximate trim
positions of the gliders which I fly. Approximate is good enough in that
situation.

JJ Sinclair wrote:
your actually already in the cloud (blinded, conditions turbulent)
and THEN you trim for slow, straight flight?!

Who wrote that bit of emergency procedure?

Bagger

Good point there Bagger, one should trim for 60ish speed before going
IFR. I did this in a 301 Libelle for a good 45 minutes, trimmed her up
for 60 knots and then released the stick and took my feet off the
rudder pedals. I was not in the clouds, just checking the idea out.
The nose would slowly drop, but as speed increased, the nose came back
up. Then the speed would get real slow, but not stall, just mush over
and start the next vertical maneuver. As this was going on, one wing
would slowly drop, but never more than 45 degrees, then slowly come
back up. My heading was all over the sky. Worked well in a H-301
Libelle, best to give it a try in your bird before you really need it.

I've tried that in my H.201, but not for so long.

Full forward trim on mine gives between 50 and 55 kts (last W&B in
flying trim with parachute on showed the CG to be a bit behind the
middle of the allowed range). It built up to a stable +/- 5 kt speed
swing as the phugoid appeared. I kept my feet on the pedals - she just
stayed pretty straight with little if any footwork being necessary. Must
try it again, though I do have a T&B installed in case I might need it
some day.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

bumper wrote:

Boy oh boy . . . I'm not sure if some of you have your head in the clouds or
your head in the sand (g).

Boy oh boy... do you really read a post before you're answering to it
(g)? If you had followed this thread, then you'd know that this is
exactly what I wrote.

This discussion started when I wrote that "the whisky compass method
doesn't work in real life". I added that if you ever manage to be in a
situation where you need an emergency descent through IMC, then the only
procedure which may work is the one I mentioned. I repeat: *emergency
procedure* and *may*. BTW, many modern gliders will go from a spin into
a spiral dive after a couple of turns, so that old "spin it down"
emergenca procedure is a no-no in modern ships, and is actually
explicitely forbidden in some POHs for that very reason.