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By davisstraub
#311729
CAUTION : "Pitch angle" (cradles setting) >20° : that means a basebar in front of you and NOT below !
Yes. You want the base bar in front of you when you let go of it and just hang on the cart to see where you hang. You can have the back cradle quite low if you are more than willing to pull in immediately (and be sure that the cart is rolling) to get to a proper gliding angle. The problem with doing is that you are already at too high an angle and it would be better at the start to have a lower angle just before you begin to roll.
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By davisstraub
#311730
Deltaman wrote:
Let the tension pull you forward (..)
..is not the same that "pull in"
Well, it is the same to me. Yes, let the tug pull you until your chest is over the control bar. It is nice to let the line help you pull in.
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By Hangskier
#311737
Are these statements correct or incorrect?

1) One should get away from the cart asap.

2) Getting pulled through the control frame will require more speed and a longer time on the cart.
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By Ttsjeff
#311739
I have a questions about pro tow vs the bridle. Viewing that tragic picture of the man who went over the front coming off the cart. It seems to me that a pro tow might be the better of the two options. I dont really like the idea of a rope attached to my glider. Given this, is it not normal for newer pilots to only use the brdle to help control pitch?
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By Hangskier
#311740
davisstraub wrote:
In the case illustrated above there were two problems. First, the bad design of the cart made it so it stopped in mid roll and I kept going.

.
So there where others that had blown launches on that cart? I hope that cart has been fixed.
By ksykes
#311742
Hangskier wrote:Are these statements correct or incorrect?

1) One should get away from the cart asap.

2) Getting pulled through the control frame will require more speed and a longer time on the cart.
1. You should release the cart when you have sufficient speed to fly. Too slow and you mush the launch and risk a lockout or other bad stuff. Stay on too long and you rocket off the cart and likely hit the prop wash.

2. You shouldn't "get pulled through", you should be flying the glider as you expect it to come off the cart by your position relative to the bar. That might mean you let yourself go forward a bit which seems like being pulled through, but you need to fly the glider, not let the tow or the glider fly you.
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By peanuts
#311744
I've probably missed where someone explained this, and if so, just to reiterate and possibly simplify, angle of attack is relative to the direction of travel. in normal flight, our wings be traveling downward at a few degrees below level or so. under AT, we start out traveling horizontally and then change to more of a climbing path. when we become unhooked from the towline as in a broken weak link, our path changes back to the downward normal line, but our wings are still tilted like the climbing line, which is what makes us to be instantly in a very deep stall. the trick is to immediately recognize this and to lower our AofA before we lose our forward momentum and get back to a proper "speed".
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By Hangskier
#311748
ksykes wrote:
Hangskier wrote:Are these statements correct or incorrect?

1) One should get away from the cart asap.

2) Getting pulled through the control frame will require more speed and a longer time on the cart.
1. You should release the cart when you have sufficient speed to fly. Too slow and you mush the launch and risk a lockout or other bad stuff. Stay on too long and you rocket off the cart and likely hit the prop wash.

2. You shouldn't "get pulled through", you should be flying the glider as you expect it to come off the cart by your position relative to the bar. That might mean you let yourself go forward a bit which seems like being pulled through, but you need to fly the glider, not let the tow or the glider fly you.
That's my point. One should resist the pull and not get pulled forward. I was taught pro-tow at one tow park and was taught to let the line pull me forward. Many times I was on the cart too long and had to push out. This year while at Wallaby I was instructed to resist being pulled forward. I did not stay on the cart as long. THE MORE A PILOT IS PULLED FORWARD, THE FASTER THE LIFT OFF MUST BE, AND OR THE PILOT BEING PINNED TO THE CART. That is elementary. This is seen over and over again when pilots get use to not resisting the pull and at some point push out too soon as Davis did it the pics above. I myself had a dip after launch where my legs hit the cart. Regardless of the pro-tow or V bridle, if one is pulled forward the possibility of a face plant is more likely. However, too far back and not ready to fly there is a possibility of straight up launch and weak link failure.
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By davisstraub
#311751
So there where others that had blown launches on that cart? I hope that cart has been fixed.
That would be carts, plural and yes and as I recall they were recalled the next day and re done.
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By davisstraub
#311753
Are these statements correct or incorrect?

1) One should get away from the cart asap.

2) Getting pulled through the control frame will require more speed and a longer time on the cart.
1) One should leave the cart behind after you have obtained flying speed so that if the weaklink were to break right then you could rock up and land safely.

2) I don't understand this statement.
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By davisstraub
#311754
I have questions about pro tow vs the bridle. Viewing that tragic picture of the man who went over the front coming off the cart. It seems to me that a pro tow might be the better of the two options. I don't really like the idea of a rope attached to my glider. Given this, is it not normal for newer pilots to only use the bridle to help control pitch?
That was me.

Yes, the protow would have helped in that situation.

Yes, it it normal to have newer pilots on 2(or 3) point tow setups. It reduces the bar pressure, makes it easier to control the glider up in the air behind the tug, and puts the base tube in a more comfortable position.
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By davisstraub
#311756
That's my point. One should resist the pull and not get pulled forward. I was taught pro-tow at one tow park and was taught to let the line pull me forward. Many times I was on the cart too long and had to push out. This year while at Wallaby I was instructed to resist being pulled forward. I did not stay on the cart as long. THE MORE A PILOT IS PULLED FORWARD, THE FASTER THE LIFT OFF MUST BE, AND OR THE PILOT BEING PINNED TO THE CART. That is elementary. This is seen over and over again when pilots get use to not resisting the pull and at some point push out too soon as Davis did it the pics above. I myself had a dip after launch where my legs hit the cart. Regardless of the pro-tow or V bridle, if one is pulled forward the possibility of a face plant is more likely. However, too far back and not ready to fly there is a possibility of straight up launch and weak link failure.
Well, this is a subtle point and discussion. Of course, you should make sure that the cart is rolling along with you. You might want to push a bit to get it rolling, but most of the time you don't want to do that. You want to hold on tight to the rubber handles to make sure that the cart is rolling with you or have someone push it a little from behind. This is overcoming the static friction which would be higher than rolling friction.

Essentially you don't have to worry about this. Let the line pull you to where your chest is over the base tube and make sure that the cart is moving by holding on tight. If this is not working then in that situation (holes in the ground, bad wheels, perhaps something else), then you'll have to push the cart at first (or get someone to push you at the start) but then get yourself over the base tube.

You keel should come up off the back cradle. That is the back cradle isn't too high so that your nose is pushed down by the back cradle. You want to be flying on the cart with your keel free to float and you pulled it to a flying speed that is going to match the tug's.

If you are stuck on the cart and have to push out (this has happened to me) it means that you back cradle is too high.

I didn't push out in the pictures above.

Don't get pulled out of the cart, obviously. Hold on tight until you are ready to fly.

I just did 1,500 launches at the Worlds, and this is is what worked.
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By Hangskier
#311782
davisstraub wrote:
That's my point. One should resist the pull and not get pulled forward. I was taught pro-tow at one tow park and was taught to let the line pull me forward. Many times I was on the cart too long and had to push out. This year while at Wallaby I was instructed to resist being pulled forward. I did not stay on the cart as long. THE MORE A PILOT IS PULLED FORWARD, THE FASTER THE LIFT OFF MUST BE, AND OR THE PILOT BEING PINNED TO THE CART. That is elementary. This is seen over and over again when pilots get use to not resisting the pull and at some point push out too soon as Davis did it the pics above. I myself had a dip after launch where my legs hit the cart. Regardless of the pro-tow or V bridle, if one is pulled forward the possibility of a face plant is more likely. However, too far back and not ready to fly there is a possibility of straight up launch and weak link failure.
Well, this is a subtle point and discussion. Of course, you should make sure that the cart is rolling along with you. You might want to push a bit to get it rolling, but most of the time you don't want to do that. You want to hold on tight to the rubber handles to make sure that the cart is rolling with you or have someone push it a little from behind. This is overcoming the static friction which would be higher than rolling friction.

Essentially you don't have to worry about this. Let the line pull you to where your chest is over the base tube and make sure that the cart is moving by holding on tight. If this is not working then in that situation (holes in the ground, bad wheels, perhaps something else), then you'll have to push the cart at first (or get someone to push you at the start) but then get yourself over the base tube. This statement is where I and I think others get confused. I was taught at Quest to let myself be pulled forward. And last month Malcolm informed me that I should resist more and not be pulled forward as much. Prior to be corrected, this summer at another tow park my legs hit the cart as my glider dipped. Thank god that I now know not to be pulled forward.

You keel should come up off the back cradle. That is the back cradle isn't too high so that your nose is pushed down by the back cradle. You want to be flying on the cart with your keel free to float and you pulled it to a flying speed that is going to match the tug's. I agree.

If you are stuck on the cart and have to push out (this has happened to me) it means that you back cradle is too high. Not necessarily. If the pilot is pulled to far forward through the control frame the glider there will be more weight forward requiring a higher speed launch.

I didn't push out in the pictures above. But too much weight forward.

Don't get pulled out of the cart, obviously. Hold on tight until you are ready to fly.

I just did 1,500 launches at the Worlds, and this is is what worked.
This is obviously something that needs more attention if the worlds best pilots needed instruction at the 2013 worlds.
By Zack
#311797
peanuts wrote:the trick is to immediately recognize this and to lower our AofA before we lose our forward momentum and get back to a proper "speed".
There are situations when a stall is unavoidable following a tow termination no matter what the pilot does. If this happens near the ground the results could be catastrophic.

Here's part of a fatal accident report by Doug Hildreth from twenty two years ago (the pilot was Eric Aasletten):
Immediately after launch, the glider pitched up sharply with nose very high. Apparently the angle caused an "auto release" of the tow line from the pilot, who completed a hammerhead stall and dove into the ground. Observer felt that a dust devil, invisible on the runway, contributed to or caused the relatively radical nose-up attitude. Also of concern was the presumed auto release which, if it had not occurred, might have prevented the accident.
His report was based on a report from Dave Broyles, who said:
I talked to a lot of pilots at Hobbs, and the consensus was that in the course of Eric Aasletten's accident, had a weak link break occurred instead of the manual or auto release that apparently did occur, the outcome would have been the same. Under the circumstances the one thing that would have given Eric a fighting chance to survive was to have remained on the towline.
Zack C
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By davisstraub
#311816
This is obviously something that needs more attention if the worlds best pilots needed instruction at the 2013 worlds.
Many of them were not the world's best pilots and many of the good pilots were new to aerotowing.
This statement is where I and I think others get confused. I was taught at Quest to let myself be pulled forward. And last month Malcolm informed me that I should resist more and not be pulled forward as much. Prior to be corrected, this summer at another tow park my legs hit the cart as my glider dipped. Thank god that I now know not to be pulled forward
.

Well this is why this is a subtle point. I don't want you to be "pulled through" I want you to let the tug's line pull you forward to the point where your chest is over the base bar. I don't want the tug's line to pull you so far that you are too far forward.

c--- your elbows. Think of keeping an orange in your arm pit. See where your hands are. This is about where you want to be. The base bar should be right behind your neck.
If the pilot is pulled to far forward through the control frame the glider there will be more weight forward requiring a higher speed launch.
Don't go that far forward.
Last edited by davisstraub on Mon Feb 11, 2013 10:18 pm, edited 1 time in total.
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By ChattaroyMan
#311817
This tragic accident shouldn’t happen again. I know very little about towing, having only seen it done by boat at a competition in Australia back in the late 70s and on videos linked to from this website (that I seldom watch). However, there are two characteristics of Zach’s accident that I feel apply to all pilots whether towing or not:

1) What to do if your glider whip stalls and/or tumbles at a low AGL.
2) Knowing your wind conditions on launch.

#1 The time involved from whip stall to ground contact may have occurred in the 15 – 5 second range. I have a feeling the episode wasn’t high enough for the glider to have been in the air for more than 15 seconds after weak link failure and may even have been in the air for only 5-10 seconds. I’m interested in the time frame to compare it to the time it takes an emergency parachute to open. I’ve seen an emergency chute fall out of a harness and fully open in around 4 seconds (not counting the time it takes the glider to rotate downward after the chute opens). If I use this time as an example (fully knowing that the time to full inflation of a chute varies widely even if it were able to obtain full deployment) it is my feeling that if a pilot experienced a similar situation as Zach’s accident that tossing a chute might at least slow down the impact speed - if the pilot had more than 5 seconds of air time left. More realistically, due to any radical glider behavior, I would think that 10 seconds might be closer to the minimum amount of time one might expect to get a chute out and deploy enough for speed to begin to be reduced. I personally feel that I’d throw my chute regardless of the time I had if I were within 300 feet of the ground. And, that that’s a bold statement for me to say (in all probability due to the fact that I’m firmly planted in an armchair at the moment). When poo hits the fan I hope that I’d at least remember that I had a chute!

#2 “Dust devils”, whirlwinds, etc. can be avoided if one can ‘see’ them. I flag the areas I slope launch from extensively unless there are plenty of natural wind indicators in the vicinity of launch – and then I usually flag the heck out of the area anyway. I don’t know how many wind indicators towing sites use on flat ground. I’m guessing the number is minimal and spacing is wide due to launching and landing activities where they may get in the way. Even if flexible stakes could be put out with streamers tied to them I don’t know how well they could all be seen from level ground??? However, knowing if a dusty is present should not be guess work. I feel that some serious brainstorming is needed for this aspect of launching from level ground – better methods of identifying what micro-conditions you might encounter on a towing launch before you launch.
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By davisstraub
#311819
But too much weight forward.
Nope. That was the cart stopping and the 2 point V-bridle pulling me forward and down off the cart.
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By johhnn
#311887
I'm a newbie pilot or wannabee at this point with only 69 "flights" at the training hill all below the 150' level. I have been reading through the posts on the Quest accident and other topics, trying to learn everything I can from them.

Can anyone comment on whether or not a tail plane (not a fin) would have helped prevent the tumbling of the glider that occurred after the weak link broke? I know some manufacturers (e.g. Aeros) use a tail plane and say that it improves pitch stability in flight. Perhaps many do not use it because of the added drag it causes. Any comments or thoughts on this?
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By Hangskier
#311891
davisstraub wrote:
This is obviously something that needs more attention if the worlds best pilots needed instruction at the 2013 worlds.
Many of them were not the world's best pilots and many of the good pilots were new to aerotowing.
This statement is where I and I think others get confused. I was taught at Quest to let myself be pulled forward. And last month Malcolm informed me that I should resist more and not be pulled forward as much. Prior to be corrected, this summer at another tow park my legs hit the cart as my glider dipped. Thank god that I now know not to be pulled forward
.

Well this is why this is a subtle point. I don't want you to be "pulled through" I want you to let the tug's line pull you forward to the point where your chest is over the base bar. I don't want the tug's line to pull you so far that you are too far forward.

c*** your elbows. Think of keeping an orange in your arm pit. See where your hands are. This is about where you want to be. The base bar should be right behind your neck.
If the pilot is pulled to far forward through the control frame the glider there will be more weight forward requiring a higher speed launch.
Don't go that far forward.
I'm glad you clarified this. This is where I and others hear something different than what is originally intended. An experience pilot told me to let the line pull me and don't resist (something to that nature) and at some point I started letting the line pull me further forward. Yes, the pilot must not lock arms straight and should be pulled forward some. But I think there should be better wording. Chest over the base bar....is that the top of the chest, center of chest, ect. My correct position did not have my chest over the base bar but was closer than not pulling in at all. A better wording.... I don't know, maybe pulled forward just a couple inches, or pulled just into a normal flying position without being pulled to far forward. I have seen other pilots launch too far forward and stay on the cart way long and even pick the cart up with them before letting go of the cart handles. Also I have been on many different carts that have my AOA close but not exactly the same each time...in these cases, I don't think a reference of chest over base bar is accurate.

I don't want others reading this to shy away from aero-towing and I think the point is; do not lock arms resisting the line pull, but also do not let the line pull you through. It's not a relaxed posture but a flying posture of some resistance to the line pull.

I appreciate the conversation Davis.
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By dave hopkins
#311893
john wrote:I'm a newbie pilot or wannabee at this point with only 69 "flights" at the training hill all below the 150' level. I have been reading through the posts on the Quest accident and other topics, trying to learn everything I can from them.

Can anyone comment on whether or not a tail plane (not a fin) would have helped prevent the tumbling of the glider that occurred after the weak link broke? I know some manufacturers (e.g. Aeros) use a tail plane and say that it improves pitch stability in flight. Perhaps many do not use it because of the added drag it causes. Any comments or thoughts on this?


Yeah, a tail would have helped. I think most flex wings are reasonably pitch stable without a tail but it would add a great deal of tumble resistance in extreme situations like a hammer head stall.

Hang gliders have a low CENTER OF MASS. We the pilot hanging 4 or 5 feet below the glider creates this situation. This means the glider wants to rotate around the pilot in certain sever stall situations. Our pitching devices are designed to slow this process and allow the glider to get airspeed in a dive before they get upside down. Our vanity about not reinventing the airplane has prevented us from accepting tails on our high aspect ratio wings. It works for me on my Atos. We are catching on.


Dave
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