How did you solve your line-twists problem?

[gunsmokex 1]

  Pat007

Got this tip from Brian Germain during a recent canopy course he put on at Kapowsin Skydiving: At opening push outward on your front and rear risers at the same time. This spreads out the risers and makes it more difficult for the canopy to start turning in the first place. This has greatly reduced my off-heading openings and line twists.

I'll give this a shot. By "at opening" I assume you mean when you are firmly in the saddle?

[Pat007 0]

Not quite. As soon as you're stood upright and your canopy is opening, reach up and push the risers out away from your shoulders. Don't wait for the canopy to be fully open to do this as that will probably be too late. Good luck. I'd be interested to hear if this works for you.

My Dad used to ask me if someone jumped off a bridge would I do that too? No, but if they jumped out of an airplane, that's a different question...

[mathrick 2]

  AlanS

#1) Don't pack a line twist. Be very careful that you don't twist the bag while putting it into the tray. (Thanks, Chase for catching when I was learning)

I packed myself half a twist recently when learning psycho pack. It won't give you twists by itself, but it will spin you violently as it deploys, since the twist is all the way up at the canopy and it will pull on the lines vigorously during inflation.

"Skydivers are highly emotional people. They get all excited about their magical black box full of mysterious life saving forces."

[pchapman 279]

  Pat007

At opening push outward on your front and rear risers at the same time. This spreads out the risers and makes it more difficult for the canopy to start turning in the first place.

Brian may be right, since he knows a lot of stuff. But I'm still a little skeptical that it really can do all that much to stop the canopy from turning, but I dunno.

I think it is more a case of preventing oneself from twisting under the canopy after the canopy does its thing, by simply bracing against the risers.

If the canopy really wants to turn, how much does pushing out a little on the risers really affect the opening canopy up above? So if your rings on either shoulder are normally 12" apart and the snivelling canopy's base is kept say 32" apart by the slider up at the stops, will the canopy really open better if you manage to shove the lines apart a few inches? Who knows, maybe getting them 20" apart, how will that really improve the canopy opening? And how much can you really spread them when under elevated G force during the opening?

Well the canopy shouldn't be affected much, but your weight at the end of separated lines will create resistance to turning. (Eg., if you went the other way, and tightened the chest strap so much that your 3-rings were 6" apart, line twists would likely increase). I'm not sure how much you will be able to spread the risers during opening, if that's enough to really increase the resistance to twisting much.

Although I suppose one is also reducing the length of the lines that can twist: While one can't realistically stop all twisting, if one were infinitely strong when reaching up and would never have one's arms pushed around by the risers and lines, one might be reducing the line length that can twist from say 11' down to 9'. Which leads to increased resistance to twisting. An improvement of some sort, but just in an idealized case.


What I believe, is that bracing against the risers just helps the jumper reduce the chance of himself not being able to follow the canopy if the canopy does start to twist the lines. The canopy is largely gonna do what it's gonna do, but the jumper can help resist that first quarter to half twist from happening, where resistance to further twisting goes to zero as the lines or risers from opposite sides get close and then touch.

So let's say the canopy snivels and then snaps 120 degrees left. By bracing, the jumper may be able to keep himself following the canopy instead of having the lines turn 120 degrees which would put them very close to touching -- and thus leaving zero resistance to further twisting up between canopy and jumper. In this case it would likely be the jumper that turns more, not the canopy. The jumper gets whipped about, the lines touch each other as the canopy darts off on another heading, and then the jumper has been thrown into twists as he rotates under the canopy with almost no resistance. The canopy is flying straight, 120 degrees off the original heading, but the jumper has rotated into 2-4 twists as is common.

Bracing on the risers may help one follow the canopy if the change in direction isn't too severe.

(araglider pilots, although working with risers that are spread more, will indeed brace off their risers when doing advanced maneuvers that might throw them into twists. Note they aren't stopping the canopy from twisting, but preventing their own bodies from being thrown into twists below the canopy.

(One also has to be careful of twitchy canopies -- If one presses on the risers unevenly during opening that can cause the canopy to try to rotate. Which is why some manuals, eg for the PD Katana, say to keep hands off the risers on opening -- even if a particular experienced jumper in tune with their canopy might be able to do better by working the risers.)

[Pat007 0]

You may very well be right. Doesn't really matter to me, though, as long as my openings are more consistently on heading.

My Dad used to ask me if someone jumped off a bridge would I do that too? No, but if they jumped out of an airplane, that's a different question...

[BigL 4]

My canopy is a 150 Sabre2 loaded at about 1.2 and I was fighting considerable linetwists on about half of my jumps. Never had a chop though.

Had the brake lines replaced as they were due shortly after the line twists began and my rigger said one brake line was heavily out of trim. Fixed the problem straight away.

[Joellercoaster 6]

  kallend

I retired my Stiletto.

I realise that the plural of "anecdote" is not "evidence", but my twists stopped when I bought mine! I'm not saying it opens on heading very often either, but it has never wound up.

(My only chop was massive twists from a Pilot 132. True story )

--
"I'll tell you how all skydivers are judged, . They are judged by the laws of physics." - kkeenan

"You jump out, pull the string and either live or die. What's there to be good at?