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PostPosted: Mon Sep 19, 2011 5:58 am    Post subject: Reply with quote #21   
FMAN wrote:

I remember seeing someone on a single surface staying low on the ridge and hill side if he got too high above the ridge he would have gone over the back.



I agree with what Red said above.... however....

Ive been in that scenario. Was flying a Mark IV (aka Pulse), was benching up from a low launch. When I got over the mountain, realized I was in a super strong headwind and going backwards. (Down low there was not enough wind to ridge soar, I had to thermal up.)

I stuffed the bar and got below the mountain top and then could penetrate forward.


So yes, sometimes the airflow lower is a lot slower lower, than higher, so diving down to get into slower air can allow you to penetrate forward.

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PostPosted: Mon Sep 19, 2011 6:31 am    Post subject: Re: Headwind > Crosswind Reply with quote #22   
red wrote:
Hoping for wind shadows or wind gradient to help you is just hoping for disaster. Expect massive turbulence, in such a case. Avoid this, or be ready with your reserve parachute. It won't be fun.


As a general rule I agree with you Red.

However, those emergency strategies are almost standard at Ellenville due to the site's topography. If you are using them, you probably launched in questionable conditions, or drifted too far back on a strong day for the glider you are flying.

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PostPosted: Mon Sep 19, 2011 10:02 am    Post subject: Headwind > Crosswind Reply with quote #23   
jwiebe wrote:
Mavi Gogun wrote:
theayeinthesky wrote:
If the crab angle was small enough, you may be able to tack like a sailboat and gain ground. This is beyond my pay grade.

No- sailboats tack upwind by being squeezed between apposing forces - the wind and the water; it works like shooting a watermelon seeds from between two fingers. Flying, we lack the second finger.

Flying, our second finger is gravity, no?
Jason

Jason,

No.

Tacking needs two different "wings" in two different mediums, which on a sailboat is one sail (in air) and one keel (in water).
In flight, we lack the keel. On a land-sailer, wheels act as the "keel" needed, for tacking.

Mr. Green

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PostPosted: Mon Sep 19, 2011 1:02 pm    Post subject: Reply with quote #24   
OK, do-over.
Just like the barometric pressure thread, I throw out conjecture, recieve feedback, and modify my thoughts on the origional question.

Some tangential issues have been brought up such as terrain effects,
and perhaps some incorrect terms get used so the question becomes
unclear.

Is Fred really asking: In a strong headwind, is it possible to YAW (not really
crabbing) the wing into the wind, thus presenting less surface area and
make some headway?
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PostPosted: Mon Sep 19, 2011 1:10 pm    Post subject: Reply with quote #25   
theayeinthesky wrote:
is it possible to YAW (not really
crabbing) the wing into the wind, thus presenting less surface area and
make some headway?



no. remember how you get best L/D, and it ain't sideways.
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PostPosted: Mon Sep 19, 2011 1:55 pm    Post subject: Reply with quote #26   
theayeinthesky wrote:
OK, do-over.
Just like the barometric pressure thread, I throw out conjecture, recieve feedback, and modify my thoughts on the origional question.

Some tangential issues have been brought up such as terrain effects,
and perhaps some incorrect terms get used so the question becomes
unclear.

Is Fred really asking: In a strong headwind, is it possible to YAW (not really
crabbing) the wing into the wind, thus presenting less surface area and
make some headway?


Yes, that's the best explanation of my question to me.

When you experience yaw on glide that doesn't make sink rate increase or glide decrease, that is because of atmosphere conditions not the glider taking the path of least resistance.

The path of least resistance is forward.
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PostPosted: Mon Sep 19, 2011 2:49 pm    Post subject: Reply with quote #27   
Yes, Perhaps the best solution may be to try to decend and take some advantage of the gradient. Of course this may mean even further limiting
your landing options.
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PostPosted: Mon Sep 19, 2011 9:14 pm    Post subject: Reply with quote #28   
FMAN wrote:
When you experience yaw on glide that doesn't make sink rate increase or glide decrease, that is because of atmosphere conditions not the glider taking the path of least resistance.

The path of least resistance is forward.


I think not, on all points. Is the contention now that allowing the glider to perform yaw osculations will be more efficient, because the glider will seek the path of least resistance? Here's a sad bit of news: the glider doesn't have your agenda- the path of least resistance is not upwind. The wind is not akin to a crowd of people that you are walking against and make better time by occasionally side stepping and leading with the shoulder when an opportune vacancy presents itself. Some pilots are able to exploit micro-lift and surge to milk out tiny altitude gains on glide by allowing the glider to pitch and yaw in response- a far different proposal than what we consider here.
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PostPosted: Mon Sep 19, 2011 9:23 pm    Post subject: Reply with quote #29   
theayeinthesky wrote:
Yes, Perhaps the best solution may be to try to decend and take some advantage of the gradient. Of course this may mean even further limiting
your landing options.


If you are loosing ground at altitude, if you have no options down wind, if you aren't up slope and won't encounter compression acceleration, if you have cause to believe a gust front is incipient. A lot of 'ifs'. I'd take what Red wrote to hart.
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PostPosted: Mon Sep 19, 2011 9:24 pm    Post subject: Reply with quote #30   
Or start the motor, gain some height and fly tailwind to a better landing or high enough to reach wind blowing in a different direction.

Oh, hang on, not everyone has a motor...

=:)

(sorry I couldn't resist)

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PostPosted: Mon Sep 19, 2011 9:35 pm    Post subject: Reply with quote #31   
theayeinthesky wrote:
Now if someone would discuss getting away from a gust front (T-cell outflow)
away from terrain effects, with no downwind options, that would be great, as
it is beyond my experience.


There is no choice but to go down wind- even if you are pointed up wind. I've known pilots to land looking backward/down wind because that was their direction of travel, despite being pointed upwind. Of course, what you do once on the ground is it's own mess.

Remember too, that a cell collapse isn't just the gust front- there is a HUGE dropping air mass; even if you are able to maintain a heading, the glider may well still plummet.

Downwind into dinosaur country may be the lesser of two evils.
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PostPosted: Mon Sep 19, 2011 9:45 pm    Post subject: Reply with quote #32   
Mavi Gogun wrote:
theayeinthesky wrote:
Now if someone would discuss getting away from a gust front (T-cell outflow)
away from terrain effects, with no downwind options, that would be great, as
it is beyond my experience.


There is no choice but to go down wind- even if you are pointed up wind. I've known pilots to land looking backward/down wind because that was their direction of travel, despite being pointed upwind. Of course, what you do once on the ground is it's own mess.

Remember too, that a cell collapse isn't just the gust front- there is a HUGE dropping air mass; even if you are able to maintain a heading, the glider may well still plummet.

Downwind into dinosaur country may be the lesser of two evils.


Lot of ifs in any scenario. I do value Reds input, and these are the type
of things to be considered in an unforseeable situation.

Contrary to Airthugs not wanting to believe the statement "It came up out
of nowhere", the weather is a fickle thing.

Unfortunatly, my bother Tim that I never knew got got in such a situation,
and did everything right from what I have read.

I respect Reds advice, but I would like to know which particular statment
I should take to heart. I don't agree 100% with anyone I know, and some
of Reds advice in this thread leaves me wondering.

Thing is the more we learn about, the more arrows we have in our
quiver, when the Sh*t hits the fan.
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PostPosted: Mon Sep 19, 2011 10:39 pm    Post subject: Reply with quote #33   
theayeinthesky wrote:
I respect Reds advice, but I would like to know which particular statment I should take to heart. I don't agree 100% with anyone I know, and some of Reds advice in this thread leaves me wondering.


The above missive was meant to complement, not rebut, the quoted text; I was unclear. What was in mind was Red's caution not to bank on a tactic negating circumstance.

theayeinthesky wrote:
Thing is the more we learn about, the more arrows we have in our quiver, when the Sh*t hits the fan.


Amen to that, brother!
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PostPosted: Mon Sep 19, 2011 10:44 pm    Post subject: Reply with quote #34   
theayeinthesky wrote:

I respect Reds advice, but I would like to know which particular statment
I should take to heart. I don't agree 100% with anyone I know, and some
of Reds advice in this thread leaves me wondering.


From a physics/aero point of view Red's posts in this thread have been dead on the money. From a "what can you expect here?" point of view, I can't really say. There are a lot of people with a lot of experience at different sites and in different conditions. I know that I have used the "get low and then get forward" approach in certain specific situations (with and without motor). But that's a matter of winds and topography.

What advice of Red's has you wondering?
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PostPosted: Mon Sep 19, 2011 10:57 pm    Post subject: Reply with quote #35   
gasdive wrote:
Or start the motor, gain some height and fly tailwind to a better landing or high enough to reach wind blowing in a different direction.

Oh, hang on, not everyone has a motor...

=Smile

(sorry I couldn't resist)


Well, the motorized harness isn't going to help that much, those are sweet little engines though. Shocked

I'll make an attempt at not using words that I don't really understand, that might help. I've always had difficulty with english grammar and I'm American.

Back on topic, I don't know where to continue for now.

This is part of an understanding for me, and hopefully others, to be able to have good judgement about different flying conditions.

Like theeyeinthesky said, "more arrows in the quiver"

Declared records, when you say you can make it to a specific place, and do, is it for me. That's cool.

How's my grammar? Mr. Green
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PostPosted: Mon Sep 19, 2011 11:21 pm    Post subject: Reply with quote #36   
spork wrote:
theayeinthesky wrote:

I respect Reds advice, but I would like to know which particular statment
I should take to heart. I don't agree 100% with anyone I know, and some
of Reds advice in this thread leaves me wondering.


From a physics/aero point of view Red's posts in this thread have been dead on the money. From a "what can you expect here?" point of view, I can't really say. There are a lot of people with a lot of experience at different sites and in different conditions. I know that I have used the "get low and then get forward" approach in certain specific situations (with and without motor). But that's a matter of winds and topography.

What advice of Red's has you wondering?


Well in my Hull story, I had basically 2 options, head for the wind shadow of
the trees on shore, knowing it might be ratty, or go in the water with a heavy
pod harness. Lesser of two evils, it worked BUT I came pretty close to the trees
so Red is right. I might have been better off in the marsh.

And it really "came out of nowhere", since all I had was NOAA radio in the truck,
not much internet or cell phones or a radio in those days.

There is one thing on Red site, on another matter, that I take a small exception.
Best discussed with him. I will be heading to the point soon.

THESE ARE THE KIND OF DISCUSSIONS I'M HERE FOR! Haven't had to
think about this stuff for a long time, so I value being corrected in my thinking. thumbsup
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PostPosted: Mon Sep 19, 2011 11:23 pm    Post subject: Reply with quote #37   
FMAN wrote:

Declared records, when you say you can make it to a specific place, and do, is it for me.


As long as the declared goal is next to my cooler in the normal LZ I'm good to go. Mr. Green
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PostPosted: Mon Sep 19, 2011 11:28 pm    Post subject: Reply with quote #38   
theayeinthesky wrote:
THESE ARE THE KIND OF DISCUSSIONS I'M HERE FOR! Haven't had to think about this stuff for a long time, so I value being corrected in my thinking. thumbsup


When it comes to the types of decisions you have to make about gradient, wind shadow, rotors, etc. - it's often a matter of experience and calculated risk.

Where Red has talked about aerodynamics of crabbing, tacking, etc. he's spot on.

I was really interested in his thumbs down on the down-tubes approach. I'm curious to try that. Maybe I should wait until the very last minute when I really NEED it. Mr. Green
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PostPosted: Mon Sep 19, 2011 11:34 pm    Post subject: Reply with quote #39   
spork wrote:
theayeinthesky wrote:
THESE ARE THE KIND OF DISCUSSIONS I'M HERE FOR! Haven't had to think about this stuff for a long time, so I value being corrected in my thinking. thumbsup


When it comes to the types of decisions you have to make about gradient, wind shadow, rotors, etc. - it's often a matter of experience and calculated risk.

Where Red has talked about aerodynamics of crabbing, tacking, etc. he's spot on.

I was really interested in his thumbs down on the down-tubes approach. I'm curious to try that. Maybe I should wait until the very last minute when I really NEED it. Mr. Green


I would like to say that Fmans Uncle was a main mentor from my first
southwind soaring day at Sled, and sign-off most all my H4 stuff. So
I learned from a good source. The old pilots theories, I took with a grain of salt.
Night all! sleep
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PostPosted: Tue Sep 20, 2011 5:38 am    Post subject: Headwind > Crosswind Reply with quote #40   
theayeinthesky wrote:
spork wrote:
theayeinthesky wrote:

I respect Reds advice, but I would like to know which particular statment I should take to heart. I don't agree 100% with anyone I know, and some of Reds advice in this thread leaves me wondering.

From a physics/aero point of view Red's posts in this thread have been dead on the money. From a "what can you expect here?" point of view, I can't really say. There are a lot of people with a lot of experience at different sites and in different conditions. I know that I have used the "get low and then get forward" approach in certain specific situations (with and without motor). But that's a matter of winds and topography.
What advice of Red's has you wondering?
Well in my Hull story, I had basically 2 options, head for the wind shadow of the trees on shore, knowing it might be ratty, or go in the water with a heavy pod harness. Lesser of two evils, it worked BUT I came pretty close to the trees so Red is right. I might have been better off in the marsh.

theayeinthesky,

In this case, you may have found either a wind shadow behind the trees, or a severe rotor, when too low for a parachute. You took a calculated risk, and you won. It may not go so well, next time, even in the same location. Getting close to the trees is not an issue, except that the closer you get, the less likely you will find good air to land in.

In this case, you were lucky in several ways. You found no rotor. You found a blessed reduction of wind speed, but not so much that you stalled before you were close to the ground (extreme wind gradient). I am very glad you got good results, but it was a high-risk bet, and my advice would be, don't count on it, next time. It could go very bad.

Nobody has all the answers, though. I'm just another guy, and I was not flyin' there, that day. Talk with everybody you can.

Mr. Green

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