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