Soaring Safety

Very good post and links. I consider myself a novice ridge flyer and,
despite having done a fair amount of reading on the subject, have
never seen this phenomenon addressed. Being low on ridge experience, I
tend to give the mountain a pretty wide berth but, as my confidence
level goes up and I start flying closer, the chances of encountering
this will increase. It has happened to me only a couple times at
altitude (once while still on tow) and, initially, scared me pretty
good each time. Being at what seems to be a 90 degree bank with full
opposite control inputs is a little disconcerting. A few seconds of
"What the*#!%?" followed by "Wow! Let me get back to that thermal!"
Great food for thought as the ridge season in the northeast
approaches.

Mike

One thing I've wondered is whether some of these "wing lift" incidents
are actually *wing drop* incidents. I don't have much ridge-time in
full-scale gliders, but I have already experienced some good amounts
of turbulence.

There's nothing that says a turbulent parcel of air couldn't hit the
wing that's closer to the ridge. After all, the wing closer to the
ridge is also closer to the ground. Accordingly, that wing is
possibly more exposed to turbulence caused by ground features - these
can extend downwind (i.e. up-slope) to a distance of 10 or 20 times
the height of the original object. For example, a 100-foot-tall tree
can create turbulence over 1000 feet downwind of it. When I did slope-
soaring with R/C gliders, we used to have to be VERY cautious of this
- so its always in my mind when I visually scan the ridge ahead of me
when in my cockpit.

So imagine a situation where you're getting rocked by lift and
turbulence, and all of a sudden the ridge-facing wing drops. Could
you confidently distinguish that from a wing-lift on the opposite side
if you're going through pulses of lift and sink, or turbulent roiling
air?

Of course, there's a BIG difference in what might be the best way to
recover from those two different situations. With a wing-drop, you
have a stalled condition - giving the aircraft full aileron to lower
the upwind wing just increases the angle of attack on the stalled wing
and doesn't make the situation any better. And if we're close to
terrain we might subconsciously be pulling on the stick, too (again,
not helpful to a stalled wing).

....Just some food for thought that a relative newbie like me wonders
about at midnight (being a night-owl I tend to be obsessing over
gliders at that time quite frequently *grin*).

Take care,

--Noel

Noel,
You do make in interesting point in making that distinction. In that
situation , rolling inverted so as not to stall the mountain side wing
would seem the best way out alive without stalling or more probably
spinning in.

The main hindrance I think is most pilot's reluctance to actually
deliberately go inverted and steer from that position and without
stalling while inverted.

I'm interested in thoughts on this issue, am I nuts?

On Feb 15, 11:43 pm, tommytoyz wrote:
The main hindrance I think is most pilot's reluctance to actually
deliberately go inverted and steer from that position and without
stalling while inverted.

I'm interested in thoughts on this issue, am I nuts?

Its been proven how much lower the survival rate is for people who
haven't had spin training and get into a spin.

Do you really want to advocate that people should go into an unusual
attitude that they are neither used to nor is their glider rated for,
in a moment of confusion and stress? Can we expect them to stay
oriented? Can we expect their aircraft to perform well invertted?
Can we expect their aircraft to hold together under negative "G" loads
while invertted? (especially if this is a rough/strong day on a
mountain ridge)?

--Noel

On Feb 16, 12:43*am, tommytoyz wrote:
Noel,
You do make in interesting point in making that distinction. In that
situation , rolling inverted so as not to stall the mountain side wing
would seem the best way out alive without stalling or more probably
spinning in.

The main hindrance I think is most pilot's reluctance to actually
deliberately go inverted and steer from that position and without
stalling while inverted.

I'm interested in thoughts on this issue, am I nuts?

Have you ever had any aerobatic training in a glider? Or a power
plane?

I have. What you suggest is extremely dangerous, and unlikely to work
with a glider due to their extremely slow roll rate and extreme
negative angle of attack needed when inverted - combined with limited
elevator authority. As well as being extremely disorienting.

In addition, while most gliders are extremely spin resistant right
side up, they will spin in a heartbeat inverted (think anhedral and
wash-in).

So yes, in this case, you are nuts! ;)

But please, if you get a chance, get some glider acro training and see
for yourself, at a safe altitude, in a proper acro glider (which most
XC ships are definitely not).

Cheers,

Kirk
66

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?

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.

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.

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?
Tom

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.

I actually saw Tom Madigan hit the Whites just east of Bishop. Most
of us thought he had experienced heat prostration, but after re-
reading Henry Combs explanation I can see that Tom might have placed
his sailplane in exactly the wrong position relative to the mountain.
It was the second day of the 1985 regionals and hotter than hell, like
105! About 12:30 we started towing to the Whites which weren't working
very well because the sun hadn't been hitting the western slopes very
long. Several of us were slope-soaring back and forth without much
success. Then I saw a ship circling and immediately headed for his
location, figuring he had finally snagged a thermal. Just before
getting there I saw the ship CRASH on a small plateau! The terrain was
about 30 degrees up slope with a small plateau of maybe 100 feet
across, then the mountain continued on up the 30 degree slope. Tom
obviously turned because he had hit lift, lets say 300 fpm. Using
Henry's explanation, that thermal would have been kicked off when
rising hot air hit the edge of the plateau. When Tom's ship got
between the thermal and the air coming down the mountain feeding his
thermal, he may have been in exactly the wrong place at the wrong
time. Let's say he had 300 fpm UP air under his LEFT wing and 200 fpm
DOWN air on top of his RIGHT wing. Old Tom might not have had the
aileron AUTHORITY to make the ship do his bidding?

Food for thought, this would explain how a relatively weak 'first
thermal' could have overpowered Tom's ship and also the Phoebus
example in Henry's article which crashed about 10:45 in the morning
JJ






On Feb 15, 9:29*pm, "noel.wade" wrote:
One thing I've wondered is whether some of these "wing lift" incidents
are actually *wing drop* incidents. *I don't have much ridge-time in
full-scale gliders, but I have already experienced some good amounts
of turbulence.

There's nothing that says a turbulent parcel of air couldn't hit the
wing that's closer to the ridge. *After all, the wing closer to the
ridge is also closer to the ground. *Accordingly, that wing is
possibly more exposed to turbulence caused by ground features - these
can extend downwind (i.e. up-slope) to a distance of 10 or 20 times
the height of the original object. *For example, a 100-foot-tall tree
can create turbulence over 1000 feet downwind of it. *When I did slope-
soaring with R/C gliders, we used to have to be VERY cautious of this
- so its always in my mind when I visually scan the ridge ahead of me
when in my cockpit.

So imagine a situation where you're getting rocked by lift and
turbulence, and all of a sudden the ridge-facing wing drops. *Could
you confidently distinguish that from a wing-lift on the opposite side
if you're going through pulses of lift and sink, or turbulent roiling
air?

Of course, there's a BIG difference in what might be the best way to
recover from those two different situations. *With a wing-drop, you
have a stalled condition - giving the aircraft full aileron to lower
the upwind wing just increases the angle of attack on the stalled wing
and doesn't make the situation any better. *And if we're close to
terrain we might subconsciously be pulling on the stick, too (again,
not helpful to a stalled wing).

...Just some food for thought that a relative newbie like me wonders
about at midnight (being a night-owl I tend to be obsessing over
gliders at that time quite frequently *grin*).

Take care,

--Noel