You are in IMC, when *everything* fails! Now what?

Tom, The battery I have is a Gel and bought it from Batteries plus. They
have many sizes etc. It is cheap insurance.Chris

--
http://irish5string.homestead.com/chrisG.html
http://home.kc.rr.com/grotewohl/CFI.html

"Roy Smith" wrote in message
...

The other advantage to using rudder is that the rudder is more effective
in a stall or spin. In a fully developed spin, the ailerons are
probably useless. When I teach stall recovery, I stress use of the
rudder to pick up a dropping wing.
....
I've done another exercise with people who insist on trying to use
aileron to pick up a wing drop in a stall. I take control of the yoke
and they get the rudders. The game is for them to keep the plane on a
constant heading while I try to turn us. The rudder wins every time!

There's a great deal of debate in this part of the world at least on the
issue of which control to use to pick up a dropped wing.

http://www.pprune.org/forums/showthr...threadid=75116

is one such thread. I've not really thought fully through the arguments.
Is yours simply about control authority or is there more to it than that?
Perhaps we should take this one out of .ifr?

Julian Scarfe

"Julian Scarfe" wrote:
There's a great deal of debate in this part of the world at least on the
issue of which control to use to pick up a dropped wing.

http://www.pprune.org/forums/showthr...threadid=75116

To be honest, I don't see much debate in that thread. Sounds like
pretty much everybody is saying the same thing I am -- that rudder is
the right thing to use to recover from a wing drop during a stall.

I've not really thought fully through the arguments.
Is yours simply about control authority or is there more to it than that?
Perhaps we should take this one out of .ifr?

Yup, control authority. That's pretty much it. The rudder has control
authority over a much wider range of conditions than the ailerons do.
When things are happening fast, you want to have a plan that always
works, without having to put any thought into it. Hence, my
recommendation to use the rudder to maintain heading.

This started in .ifr because we were talking about how to control the
plane in IMC with no gyros. The basic assumption is that you've got
*some* heading reference, be it the wet compass, the ADF pointing at a
distant station, or a GPS course line. Even with the GPS (which is by
far the most useful of the three), you've got limited information, so
your best plan is to stick with something which always works, even if it
doesn't work very elegantly. That's the rudder.

Julian Scarfe wrote:

Well yes, but solving the roll problem and getting the wings level will
solve the pitch problem. Solving the pitch problem doesn't solve the roll
problem.

I'll have to try this again next time I'm out playing, but I guess I'm
trying to say (at least in my plane) I don't think they're separable.
That is to say it's not enough to *get* the wings level, if the pitch
is oscillating a wing will drop. (this is a practical observation)

I can't speak for the others but the Mooney doesn't feel lighter in roll
than anything else.

I defer to your experience, but I thought the Mooneys I had a chance
to fly were quite a bit more positive in roll control and also lighter
and faster in roll than a small Cessna or Piper. Once banked, it seemed
happy to stay banked, just like Tigger.

I'm not sure I'd agree that an IR pilot, lacking major portions of the
normal feedback from gyro instruments, would be better able to separate
pitch and roll input. I guess we'd have to do the experiment.

Cheers,
Sydney

Julian Scarfe wrote:
"Roy Smith" wrote in message
...

Is yours simply about control authority or is there more to it than that?

In the airplanes that I've tried using ailerons to recover from a
incipent spin (Decathlon, YAK52, Pitts) the adverse yaw accelerates the
spin. If I've got either wing stalled I always use the rudder first.

In the case described in this thread I would use rudder only.

Roy Smith writes:

The biggest key is to make very small power and
trim changes and then be patient and wait for the fugoids to damp out
before deciding if you got the descent rate you were looking for.
Go-arounds can be kind of exciting too!

It's been a few months since I've flown a Cessna, but in my Cherokee,
with the big trim wheel on the floor between the seats, it is actually
possible to damp out phugoids actively with a light touch and a bit of
anticipation.


All the best,


David

--
David Megginson, , http://www.megginson.com/

Roy Smith writes:

The biggest key is to make very small power and
trim changes and then be patient and wait for the fugoids to damp out
before deciding if you got the descent rate you were looking for.
Go-arounds can be kind of exciting too!

It's been a few months since I've flown a Cessna, but in my Cherokee,
with the big trim wheel on the floor between the seats, it is actually
possible to damp out phugoids actively with a light touch and a bit of
anticipation.


All the best,


David

--
David Megginson, , http://www.megginson.com/

"Julian Scarfe" writes:

There's a great deal of debate in this part of the world at least on the
issue of which control to use to pick up a dropped wing.

There shouldn't be. Using ailerons to pick up a wing in a stall and
actually cause the wing to drop further (by increasing its angle of
attack). It's ugly stuff.


All the best,


David

--
David Megginson, , http://www.megginson.com/

"Gary L. Drescher" writes:

I've often wondered if a pendulum, in lieu of a GPS or compass,
would provide sufficient yaw information to keep the wings. But
I've never tried the experiment.

Here's an easier experiment: take a carpenter's level and duct-tape it
to your bicycle's handlebars. Now, go around a few turns fairly fast
(i.e. the bicycle is at a good bank). Does the level show that the
handlebars are tilted during the turn, or is the bubble still in the
centre?

The answer will help show why you need gyroscopic instruments (or
newer expensive equivalents) to fly in IMC.


All the best,


David

--
David Megginson, , http://www.megginson.com/

"Julian Scarfe" wrote:
There's a great deal of debate in this part of the world at least on the
issue of which control to use to pick up a dropped wing.

http://www.pprune.org/forums/showthr...threadid=75116

"Roy Smith" wrote in message
...
To be honest, I don't see much debate in that thread. Sounds like
pretty much everybody is saying the same thing I am -- that rudder is
the right thing to use to recover from a wing drop during a stall.

Really?

"As for rudders - I teach - rudder to STOP yaw. Not to pick the wing up...."

"I taught stall recoveries as:
Centralise aileron
Rudder to stop *further* yaw (NOT raise the wing NOR prevent further wing
drop)
Reduce AoA eg to ~ glide attitude
...."

"I have found that teaching the stude to use rudder at the stall to 'limit
further wingdrop' can actually lead to 'EXCESSIVE AND OVER ENTHUSIASTIC'
opposite rudder.......leading to SPIN!"

All three of those correspondents seem to oppose the idea of the use of
rudder for roll control.

I've not really thought fully through the arguments.
Is yours simply about control authority or is there more to it than
that?
Perhaps we should take this one out of .ifr?

Yup, control authority. That's pretty much it. The rudder has control
authority over a much wider range of conditions than the ailerons do.
When things are happening fast, you want to have a plan that always
works, without having to put any thought into it. Hence, my
recommendation to use the rudder to maintain heading.

I'm not convinced by that. I can see two arguments against it:

1) The use of rudder for roll control works as a secondary effect of yaw.
At speeds approaching stall, that yaw can make the difference between
spinning or not. (Of course, so can an abrupt aileron input :-))

2) In any control loop the timing of the effect of control inputs has a
significant impact and an unhelpful lag can lead to divergence. Thomas wrote
in his original post:

"Now using the rudder to turn, the airplane takes a while
to respond. With the constant upsetting influence of the thermals, the
plane is always wanting to turn. You see it on the GPS, and by the time
you get some rudder pressure on, you are maybe 10 to the right. Now
you hold the rudder and wait for the plane to respond, and slowly you
come back on course, but overshoot. I try to adjust my inputs to smooth
things out but the TB makes it pointless. I resign myself to the fact that
at best we will make constant small s-turns all the way."

That wouldn't happen with the ailerons.

Julian Scarfe