Soaring Safety

On Feb 16, 8:00*pm, tommytoyz wrote:
Ok Kirk,
I concede it is a very dangerous and likely nutty idea. But when
you're roll authority is gone, is smacking into the mountain a better
alternative? Maybe the chances of coming out are not good, but isn't
it better than certain doom?

The problem is that in this situation you are already too close for
this "option" to have any chance of working. If you try to roll with
the upset, assuming you have any better roll authority in that
direction (not certain, the whole wing could be stalled), what will
happen is that you will end up hitting the ridge head on inverted
pointed almost straight down - which will probably not increase your
chance of surviving!

Again, if you haven't tried it - the half roll to inverted flight,
then turning inverted, is one of the hardest maneuvers to learn in a
glider (and may not even be possible in a normal 15 m racing/xc
glider). It's not just a matter of pushing the stick over! And
compared to an acro ship, takes forever. Time that you don't have on
the ridge during an upset.

When you're suddenly looking at the mountain slope and the mountain
side wing is going down, despite full input to the opposite, what is
the best alternative? We have discussed how to avoid getting into this
situation, my suggestion is what do you do when you encounter it
despite all efforts not to get into one.

My response (easy to come up with sitting here at my computer, of
course) would be to try to accellerate by unloading and diving towards
the ridge, and hope to regain roll control before hitting the rocks.
It that doesn't happen, then try to hit the softest thing in front of
me. But realistically, you may have put yourself in a non-recoverable
situation, and you just killed yourself. Pretty stupid, that!

Now, there is one situation where continueing the roll might work: if
the upset is next to a vertical cliff face, you could continue the
roll while pulling - to try a rolling split-s away from the mountain.
You would need lots of room underneath, and keep a lot of positive G
on the glider to avoid blasting through VNE, but it could work. I
doubt there are many areas of the US with the terrain that would allow
that option, though.

This may not even be an idea to pursue, but just maybe it's a chance
to NOT crash into a mountain in an emergency situation.

You are on the right track to what-if this kind of situation - but the
"Derry Roll" solution just won't work with most gliders. (A Derry
Roll is a 270 degree roll underneath to initiate a turn in the
opposite direction). Now if you were ridge soaring in a Swift or a
Fox, it might just work!

Like I said, it may not be a good idea nor am I advocating people do
this. But those who say it's nutty, of those I ask, what is the better
alternative is the exact same situation?

It sounds like a platitude, but the way to avoid this situation is to
not get into it in the first place - that means always having room to
get away from the ridge. Giving up that safety buffer means accepting
the risk of not being able to always avoid hitting the rocks if things
go wrong. We all make that decision when we get on the ridge and push
hard.

Kirk

I hate to drag up this topic again, because I know it is
controversial. But I can't stop thinking about it. This is an issue I
actively think about when flying in the mountains, which I mostly do.

Know let's simulate this for a second. Walk along any wall 1-2 feet
away or less - that's you flying along a mountain below ridge level.
Now something upsets you and start turning into the wall. What do you
do to not smack into it? What do you do if normal control inputs can
not correct in time?

Asking myself this, I simulated what it would take to make a quick
steep turn away from the mountain. Firstly, as we all know, making a
steep quick turn requires a steep bank angle, the more the better - so
long as we have the airspeed to do it.

So I figured that if my mountain side wing was pushed 45 degrees down
by the upset, I would only need another 46 degrees in the some
direction to be able to turn the other way, by pushing the stick. This
would only take maybe 2 seconds (maybe less if your being turned that
way anyway) in a 15 M ship with good airspeed, that should be carried
in close proximity to terrain anyway.

So the previous objections that it would take too long or be
disorienting, I find not a little overblown. However, once turned away
from the mountain, one would need to be careful in regaining a normal
flight position.

I'll be trying this with an aerobatic instructor and see what happens.
I just can't see any other way out of that situation when you are
asked - what do you do? when you're facing the mountain with a wing
down and probably tail high or rising.

Continuing the rotation another 46 degrees or more and pushing on the
stick to increase the angle of attack to turn, should turn the ship
away from the mountain quickest.

On Feb 28, 3:08*pm, tommytoyz wrote:
I hate to drag up this topic again, because I know it is
controversial. But I can't stop thinking about it. This is an issue I
actively think about when flying in the mountains, which I mostly do.

Know let's simulate this for a second. Walk along any wall 1-2 feet
away or less - that's you flying along a mountain below ridge level.
Now something upsets you and start turning into the wall. What do you
do to not smack into it? What do you do if normal control inputs can
not correct in time?

Asking myself this, I simulated what it would take to make a quick
steep turn away from the mountain. Firstly, as we all know, making a
steep quick turn requires a steep bank angle, the more the better - so
long as we have the airspeed to do it.

So I figured that if my mountain side wing was pushed 45 degrees down
by the upset, I would only need another 46 degrees in the some
direction to be able to turn the other way, by pushing the stick. This
would only take maybe 2 seconds (maybe less if your being turned that
way anyway) in a 15 M ship with good airspeed, that should be carried
in close proximity to terrain anyway.

So the previous objections that it would take too long or be
disorienting, I find not a little overblown. However, once turned away
from the mountain, one would need to be careful in regaining a normal
flight position.

I'll be trying this with an aerobatic instructor and see what happens.
I just can't see any other way out of that situation when you are
asked - what do you do? when you're facing the mountain with a wing
down and probably tail high or rising.

Continuing the rotation another 46 degrees or more and pushing on the
stick to increase the angle of attack to turn, should turn the ship
away from the mountain quickest.

Soaring safety... more than anyone thinks, is a function of the pilots
mental control and reaction when things go wrong.

I may be more familiar with the mountains near Crystalair than almost
anyone except Henry Combs. Mr. Combs is a thinker and very deliberate
pilot. He reviews plans for his flights and mentally stores a flight
plan in his lower concioness. When something in his flight plan
happens he is mentally prepared to deal with it.
He has tried to get me to teach his recovery tecnique but I either
didn't understand it well enough to teach it or in most cases most of
our students are taught to maintain extra control speed, to be aware
that at 9,000 on a hot day, the glider will not have the same turn
radius and end up without enough room.

The mountains have claimed more airplane pilots than glider pilots
around here. Mountain flying is very rewarding but also very
demanding.

The atmosphere flowing over mountains is somewhat like water flow over
rocks...except that it is compressible. The compression and heating,
along with expansion makes the air flowing over and between ridges
hard to predict. It is a facinating subject to spend a lifetime to
master.

My advice is to learn as much as you can from an old hand, study how
the air flows, understand density and forever mentally be prepared for
the unexpected and have a preplanned escape route. I've been in sudden
upsets but always had room to recover without aerobatic skills.
Fortunately the number of spins and rolls I have done makes me more
comfortable, but I doubt that any of that skill would have saved me
from a sudden upset near terrain. Do some ridge soaring, but leave
room for the unexpected.

Fred Robinson








t

On Feb 28, 5:08*pm, tommytoyz wrote:
I hate to drag up this topic again, because I know it is
controversial. But I can't stop thinking about it. This is an issue I
actively think about when flying in the mountains, which I mostly do.

Know let's simulate this for a second. Walk along any wall 1-2 feet
away or less - that's you flying along a mountain below ridge level.
Now something upsets you and start turning into the wall. What do you
do to not smack into it? What do you do if normal control inputs can
not correct in time?

Asking myself this, I simulated what it would take to make a quick
steep turn away from the mountain. Firstly, as we all know, making a
steep quick turn requires a steep bank angle, the more the better - so
long as we have the airspeed to do it.

So I figured that if my mountain side wing was pushed 45 degrees down
by the upset, I would only need another 46 degrees in the some
direction to be able to turn the other way, by pushing the stick. This
would only take maybe 2 seconds (maybe less if your being turned that
way anyway) in a 15 M ship with good airspeed, that should be carried
in close proximity to terrain anyway.

So the previous objections that it would take too long or be
disorienting, I find not a little overblown. However, once turned away
from the mountain, one would need to be careful in regaining a normal
flight position.

I'll be trying this with an aerobatic instructor and see what happens.
I just can't see any other way out of that situation when you are
asked - what do you do? when you're facing the mountain with a wing
down and probably tail high or rising.

Continuing the rotation another 46 degrees or more and pushing on the
stick to increase the angle of attack to turn, should turn the ship
away from the mountain quickest.

It's always good to think of possible accident scenarios before hand.

In the specific situation you are describing - upset next to a sheer
mountain face - the quickest way to get clear might be just to stuff
the stick forward to unload the wing and accelerate, then roll away
from the mountain as you regain roll authority, pulling hard g as soon
as your lift vector is paralles or away from the mountain. You might
exceed Vne, but not by much.

Trying to roll underneath will result in a vertical dive unless you
push hard from the beginning. Extemely uncomfortable and disorienting
without training and practice. And again, what kind of glider are you
in? A 1-26 (might work) or a Nimbus 3 (no way)?

If the upset is so severe that you end up pointing straight down, then
you don't want to push, since your negative g limit is a lot lower
(usually). So you are back to rolling the quickest way away from the
mountain, then pulling as hard as you can.

This assumes you are going slow to begin with. If you are fast, you
will probably have enough control authority to stop the upset.

Acro training is great! Let us know what you think of it - I think
you will be surprised at what you can (and can't) do in a glider.

Cheers,

Kirk
66

On Feb 28, 8:09*pm, fredsez wrote:
On Feb 28, 3:08*pm, tommytoyz wrote:





I hate to drag up this topic again, because I know it is
controversial. But I can't stop thinking about it. This is an issue I
actively think about when flying in the mountains, which I mostly do.

Know let's simulate this for a second. Walk along any wall 1-2 feet
away or less - that's you flying along a mountain below ridge level.
Now something upsets you and start turning into the wall. What do you
do to not smack into it? What do you do if normal control inputs can
not correct in time?

Asking myself this, I simulated what it would take to make a quick
steep turn away from the mountain. Firstly, as we all know, making a
steep quick turn requires a steep bank angle, the more the better - so
long as we have the airspeed to do it.

So I figured that if my mountain side wing was pushed 45 degrees down
by the upset, I would only need another 46 degrees in the some
direction to be able to turn the other way, by pushing the stick. This
would only take maybe 2 seconds (maybe less if your being turned that
way anyway) in a 15 M ship with good airspeed, that should be carried
in close proximity to terrain anyway.

So the previous objections that it would take too long or be
disorienting, I find not a little overblown. However, once turned away
from the mountain, one would need to be careful in regaining a normal
flight position.

I'll be trying this with an aerobatic instructor and see what happens.
I just can't see any other way out of that situation when you are
asked - what do you do? when you're facing the mountain with a wing
down and probably tail high or rising.

Continuing the rotation another 46 degrees or more and pushing on the
stick to increase the angle of attack to turn, should turn the ship
away from the mountain quickest.

Soaring safety... more than anyone thinks, is a function of the pilots
mental control and reaction when things go wrong.

I may be more familiar with the mountains near Crystalair than almost
anyone except Henry Combs. Mr. Combs is a thinker and very deliberate
pilot. He reviews plans for his flights and mentally stores a flight
plan in his lower concioness. When something in his flight plan
happens he is mentally prepared to deal with it.
He has tried to get me to teach his recovery tecnique but I either
didn't understand it well enough to teach it or in most cases most of
our students are taught *to maintain extra control speed, to be aware
that at 9,000 on a hot day, the glider will not have the same turn
radius and end up without enough room.

The mountains have claimed more airplane pilots than glider pilots
around here. Mountain flying is very rewarding but also very
demanding.

The atmosphere flowing over mountains is somewhat like water flow over
rocks...except that it is compressible. The compression and heating,
along with expansion makes the air flowing over and between ridges
hard to predict. It is a facinating subject to spend a lifetime to
master.

My advice is to learn as much as you can from an old hand, study how
the air flows, understand density and forever mentally be prepared for
the unexpected and have a preplanned escape route. I've been in sudden
upsets but always had room to recover without aerobatic skills.
Fortunately the number of spins and rolls I have done makes me more
comfortable, but I doubt that any of that skill would have saved me
from a sudden upset near terrain. Do some ridge soaring, but leave
room for the unexpected.

Fred Robinson

t- Hide quoted text -

- Show quoted text -

I agree with everyting Fred said, but I think it's important that
students need to be made aware of the definition of "faster".
Each pilot must judge the situation and correctly understand that
going faster than what you need to maintain control authority reduces
the amount of reaction time that you have. You need to fly a little
further from the ridge as your speed increases over this "control
authority speed." Like my father once told me "When you are close to
the ground, add a little airspeed for the wife and kids".

Paul Gravance

I would like to know what Henry's recovery technique is. Anyway,
thinking this over some more, I'm thinking that so long as I have good
airspeed near terrain, vertical or horizontal (which I have always
practiced), and (here's the new part for me):

I don't fly into the corner of L shaped terrain

Flying close to vertical or horizontal terrain is OK with airspeed and
being prepared to recover from an upset. There is a place to go. But
flying into the corner of L shaped terrain is not recoverable in an
upset, not matter what. There is no room to the side nor bellow. I'm
boxed in.

Perhaps looking back at glider accidents in the mountains, we can look
if the accidents occurred close to the corner of L shaped terrain.

Kirk,
You made me realize that the recovery is even simpler and faster than
I thought, starting from the upset position putting me turning into
the mountain with the mountain wing low. The fastes way away from the
mountain is just to push the stick forward so the negative angle of
attack on the wings will instantly turn the glider away from the
mountain. Of course this is an inverted turn, but a very quick one,
the speed of which is dependent on elevator authority. So this could
work even with 26M wingspans. The wings never have to change their
bank angle at all. If the tail is lifted up, as Henry and others have
stated most likely would happen, the glider would move away from the
mountain even faster.

It's only in the recovery from the inverted turn that wings would have
to change their bank angle significantly.

Airspeed will increase but I think can be held in check by applying
rudder, like in any turn. Recovery after that depends on the terrain
but at that point, I'm upside down - without even having deflected the
ailerons and away from the mountain face.

This is a very unique situation, but I don't want to be caught with my
pants down should it ever happen. For now, I'm keeping a lookout for
the corners of L shaped terrain.

I know most of this sounds crazy, but the situation is a crazy one to
find oneself in.

I'm not advocating anything, just discussing possibilities here.

On Feb 16, 9:04*am, Jim White
wrote:

I dont think anyone has discussed airspeed in this
thread. My glider has crap airelon authority at 50kts
but at Va it is very good. Isn't safety near rocks
a factor of speed? If you are belting along at a Va
would you not be able to pull up / fly away from the
cliff if you needed to?

Combs' article says that your ailerons will not be able to overcome
the rolling tendency produced by 500 fpm differential lift on your
wings. He doesn't say at what speed that is, but even if it's at 60
kts and you're flying 80, there will be some differential lift you
cannot overcome. It pushes you further out on the bell shaped curve
(or whatever shape that curve takes), but it doesn't say it cannot
happen. It just happens less frequently.

If anyone has data for modern sailplanes at different speeds, please
chime in.

Martin