Forums: Skydiving Disciplines: Swooping and Canopy Control:
Full flight brake position

 


SethInMI  (A 47765)

Mar 20, 2012, 7:32 AM
Post #1 of 14 (1527 views)
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Full flight brake position Can't Post

I just put my first few jumps on a Sabre 2 135 I picked up used (~200 jumps, loading about 1.45). The brakes are set tight (<1" of play before the tail deflects) of so I want to let them out so the canopy will dive on fronts better.

Anyone have any advice for setting a "swoop friendly" full flight brake position? The trick is getting as little tail deflection as possible when on fronts and getting as much tail deflection as possible during full flare. There are points of diminishing returns on both ends, so you have to find a balance.

I have 24" risers and longer arms (6'3" tall) so I have about 4" inches of stroke over a typical jumper, my thought was I would end up with about 4-6" of play before deflection. I can't remember what my old setup had for free play (Sabre 2 150).

So if anyone has any tips or a method they like...

Seth


davelepka  (D 21448)

Mar 20, 2012, 8:14 AM
Post #2 of 14 (1504 views)
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Re: [SethInMI] Full flight brake position [In reply to] Can't Post

 
The amount of play isn't a set number, it's based on a variety of factors including the canopy, condition of the line set, the length of the risers and the lenght of the jumpers arms.

The 'standard' way to set your brake lines is via the stall point. You want it to be at full arms extension with your wrists rolled forward so your fists are pointing down as is you're 'punching' the ground. In that position, the canopy should continue flying for a couple seconds before rocking back into a stall. Setting them there will ensure that you can get 100% of the flare out of your canopy, but your odds of stalling it close to the ground are quite low. It would take a prolonged input of full arms extension including your wrists rolled forward to stall it, not likely something you'll do by accident on landing.

Once you have that established, you can then try some front riser manuvers while watching the tail for deflection. Be sure to clear traffic while doing this, but just do a front riser turn while watching the tail. Hold the turn through a full revolution or two, and see what happens. Some tail deflection is not that bad, but when it's enough that it causes the canopy to buffet or buck, that's too much. In that case, you'll can let your steering lines out some more, and do the test again.

The catch is that if you let them out more than the ideal 'stall' setting, that you lose some of your flare power on the bottom end. By making them longer, your stall point will be beyond your reach, and you won't be able to get to 100% of it.

A word of caution, only let the brake lines out 2" max at a time. Test the new setting and adjust as needed, repeating until it's right.

Another (bigger caution) letting your brake lines will significanty change the way the canopy flies and feels. With shorty brake lines, the canopy will dive less, and respond to input sooner. When you let them out, the canopy will dive longer, and the flare will be deeper in the stroke so it will take more input to get the canopy to react. Many jumpers have been caught off guard with a long dive and then a delayed flare when they went to dig out of it. Don't be one of those guys.


floormonkey  (D License)

Mar 20, 2012, 11:23 AM
Post #3 of 14 (1466 views)
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Re: [SethInMI] Full flight brake position [In reply to] Can't Post

The place to start is factory settings.

http://www.performancedesigns.com/products.asp?product=sa

Read the "How to measure line trims" doc (listed under "Line trim"). Then look at the appropriate trim chart. How does the existing length measure up? Are your brake lines twisted? Do they have a built in twist from poor maintenance?

Measure both bk-toggle length AND lower brake line length.

Always check your starting point...


beowulf  (C License)

Mar 20, 2012, 12:38 PM
Post #4 of 14 (1438 views)
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Re: [davelepka] Full flight brake position [In reply to] Can't Post

Just to reiterate. Knowing where the stall point is, is very important. It tells you how much range you have in your toggles for flaring. It should be a habit to always know where the stall point is on every canopy you fly. After any changes regarding risers or lines make sure to do practise flares up high to find the stall point. Stalling out your canopy during landing can cause serious injury.


Premier LouDiamond  (D 25931)
Moderator
Mar 20, 2012, 4:36 PM
Post #5 of 14 (1388 views)
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Re: [floormonkey] Full flight brake position [In reply to] Can't Post

In reply to:
The place to start is factory settings.

http://www.performancedesigns.com/products.asp?product=sa

Read the "How to measure line trims" doc (listed under "Line trim"). Then look at the appropriate trim chart. How does the existing length measure up? Are your brake lines twisted? Do they have a built in twist from poor maintenance?

Measure both bk-toggle length AND lower brake line length.

Always check your starting point...


This is the correct answer and the first step in addressing your issue.


d100965  (D 100965)

Mar 21, 2012, 4:22 AM
Post #6 of 14 (1310 views)
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Re: [SethInMI] Full flight brake position [In reply to] Can't Post

Bear in mind that standard riser lengths are usually 19" (or 21").
If you then increase the riser length by going any higher, say to 24" or 25", which are usually the top end for most jumpers and would be out of reach for us regular 5ft 8"ers. (I use 23"s, I could do 25"s but it's tight)
Then what you are doing is effectively moving the entire canopy away from you. The brake setting does not change as that's always in the same position from the top of the riser when manufactured and the loop is set in the brake line trim, but you have now effectively raised the stall point by moving the entire toggle range up.

eg. You have a rig with 19" risers. The brake lengths are in line with PD's trim chart and the stall point is exactly as DaveLepka describes. Happy days. You also get full flare and are not getting any tail deflection. Again, happy days.
You then decide to go to 24" risers. You have now increased riser length by 5". Therefore the stall position (the entire toggle range) has now moved 5" up without any change in brake line length.

This is why if you have a perfectly set up canopy and you increase the riser length, you should then also make the same change to increase the brake line length.

Also, a couple of other tips:-
1. Sabre2 brake lines are known for being a bit on the short side when new, perfect for regular jumpers but not really so for swoopers. That and the fact that shrinkage is also a bit on the heavy side with this canopy and lines, means that if you want to swoop you will usually need to increase the brake line length considerably.
DISCLAIMER= 2" at a time and with a rigger on side as well.
PD have a video showing how to do this http://www.youtube.com/...p;feature=plpp_video
My wife and I learnt to swoop on Sabre2's and with 4 canopies between us including the subsequent downsizes, (Sabre2 150, 135 and 120's) each one needed 5" added to the brakes and with only 19" risers. (This was done with Colin the Empuria rigger on side as well).
If you end up having to renew the entire brake lines then I would suggest in line with your rigger that you consider switching to HMA or Vectran. (Leave the canopy as Microline of course but keep a close eye on line shrinkage).

2. If after doing all of the above, including all the posts prior, you find that the setup is now perfect but when hard front risering you still get tail deflection, (and the subsequent bucking that happens when diving) you can also install another toggle guide ring onto the Slink.
Leave the original ring for brake setting only, which the brake line now does not pass through, and use the second ring on the Slink for which the line now passes through. This is a standard swooper modification. Get a swooper to show you and a rigger to check it.
DISCLAIMER= Some riggers are not advising putting the ring on the Slink but can sew it (correctly) to the riser instead. This was due to a previous Slink failure (and subsequent fatality) attributable mainly to poor Slink maintenance but ending up resulting in the ring situation be re-assessed.


(This post was edited by d100965 on Mar 21, 2012, 10:12 AM)


Pendragon  (D 104102)

Mar 21, 2012, 8:02 AM
Post #7 of 14 (1259 views)
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Re: [d100965] Full flight brake position [In reply to] Can't Post

In reply to:
...(Leave the canopy as Microline of course but keep a close eye on line shrinkage).

Note that microline shrinks with heat. Given that the control lines brush against the guide rings as you steer, shrinkage in the brake lines is always more acute - it's not just the action of the slider (which is worst for the control lines as they're more likely to be on the outside of the line bundle and in contact with the slider gromits). Consequently these may need to be replaced / toggle position changed to maintain the original settings even after only 150 jumps.

In reply to:
2. If after doing all of the above, including all the posts prior, you find that the setup is now perfect but when hard front risering you still get tail deflection, (and the subsequent bucking that happens when diving) you can also install another toggle guide ring onto the Slink.
Leave the first ring for brake setting only, which the brake line does not pass through, and the second ring on the Slink which the line now passes through. This is a standard swooper modification.

I would strongly advise against doing this; it will fundamentally alter the feel and action of your toggles on the canopy, which could be dangerous. You should be really experienced before experimenting with this kind of modification; personally I question whether it's really needed (you can certainly do without it). Regardless, if you wish to investigate doing this modification, get proper advice from someone on the DZ, preferably an advanced rigger, who knows what they're doing.


d100965  (D 100965)

Mar 21, 2012, 8:59 AM
Post #8 of 14 (1247 views)
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Re: [Pendragon] Full flight brake position [In reply to] Can't Post

Not sure if you meant to reply to me specifically but seeing as you did, please allow me to retort...Wink

Your quote:-
"I would strongly advise against doing this; it will fundamentally alter the feel and action of your toggles on the canopy, which could be dangerous. You should be really experienced before experimenting with this kind of modification"

It would certainly change the feel but not the action. And certainly not on any fundamental level.
The brakeline pully point when in flight moves up approx 4-6". Big whoop.

And although the feel would change I think you are overdramatising the actual change.
Dangerous? How?
It feels a little different but the action is exactly the same, pull down to flare. It would be no more change in feel than say when getting used to flying with your chest strap open, or when getting used to flying your canopy while sat in the harness more. Which are all valid steps on the road towards swooping.
Also, how do you need to be really experienced before experimenting with this type of mod as well?
Don't you just do it, jump it and see how it feels?
(No-ones forcing anyone to do anything by the way).

While I agree it is strictly not necessary, certainly at the OP's stage. It is simply information, as required to make a canopy's brake lines more swooper friendly and as was requested.

So to summarise, it will change the feel, but it's no big deal and once you taken a handful of jumps with it you'll wonder why it was ever like it was in the first place.

Can I just add that although you would strongly advise against doing the mod, I did actually say that only after doing all of the above, including all the posts prior, and only if you find that the setup is now perfect but when hard front risering you still get tail deflection.
Therefore meaning that by this point, this mod may in fact be your only remaining option.


(This post was edited by d100965 on Mar 21, 2012, 10:48 AM)


SethInMI  (A 47765)

Mar 21, 2012, 7:32 PM
Post #9 of 14 (1174 views)
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Re: [floormonkey] Full flight brake position [In reply to] Can't Post

In reply to:
Always check your starting point...

Ok, so I did a few measurements, I will say accurate to +/- 0.5", not perfect, but close for this discussion.

A5 (outside A-line) is about 114 so about 3.5" short. A1 (center A-line) is 117.5" (no shrinkage) so there is some classic line shrinkage there.

The A5 to USTs are dead on, and LST is about 2.5" short.

Brk - Tog is about 1.5" short.

So the current setup has total toggle to ust of about 3.5 + 1.5 = 5" shorter than factory.

So a new question: When should I replace the line set? Or just the brake lines?

I will see how much I can let out the Brk - Tog, see if I can get it back to factory.

Seth


SethInMI  (A 47765)

Mar 21, 2012, 7:45 PM
Post #10 of 14 (1172 views)
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Re: [davelepka] Full flight brake position [In reply to] Can't Post

Couple other questions while my mind is on brake lines:

It makes sense to me that smaller canopies will have a higher stall point (shorter toggle stroke), as you need to deflect less tail to get the same proportional deflection of the wing, is that true?

I also remember hearing that elliptical canopies have a shorter toggle stroke than equivalently sized squares, is that true?

If either or both of these is true, it would allow HP pilots to do more with toggles in hand (front or rear riser pulling) without getting unwanted tail deflection. Not that this really applies to me, but I am curious.

Thanks,

Seth


Skydivesg  (D 10938)

Mar 21, 2012, 8:44 PM
Post #11 of 14 (1163 views)
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Re: [SethInMI] Full flight brake position [In reply to] Can't Post

So a new question: When should I replace the line set? Or just the brake lines?

*********************

I usually replace the lower steering lines at least once before a full re-line.

I'm not shy about doing line replacements.

Some people tell me I'm too quick to replace them.

I haven't had a malfunction in over 6,000 jumps.

I think I'll keep with my way of thinking.


Premier ianmdrennan  (D 25821)
Moderator
Mar 21, 2012, 8:48 PM
Post #12 of 14 (1160 views)
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Re: [Skydivesg] Full flight brake position [In reply to] Can't Post

I'm with you.


floormonkey  (D License)

Mar 22, 2012, 11:23 AM
Post #13 of 14 (1103 views)
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Re: [ianmdrennan] Full flight brake position [In reply to] Can't Post

Assuming a lineset every 500ish jumps, I budget in a set of lowers-tog every lineset. If jumping a Spectra/Dacron lined canopy, I would plan on measuring (just brake lines) every 100-150 jumps, and probably extending my bk-tog at that time. If you know you're going to be pulling toggles more than the average jumper (spirals, high pulls, etc), you might even have your rigger make bk-tog with more excess so you can get an extra lengthen per line set/replacement.

There is a way to make no sew replacements so you can have them ready, but immediate replacement is typically not as important on spectra/dacron lined canopies as it in on vectran/hma. Simply make the line and larkshead it on at the UCL cascade point. This does, however, add a small increase to the likelihood of a tension knot. Precision has been doing this for years and I've never heard of one happening there, so the increase is likely infinitesimal.

An easy reckless eyeball method of checking line trim is to walk your canopy up like you are packing and look at the difference between the length of outside A-lines and inside A-lines (a1 and a4/5). When that difference hits 2.5-3", it's time to consider a lineset or at least have it looked at by an experienced rigger.

Sabre 2's seem to get shrinkage a little earlier than others. If the other lines are still relatively close to factory and have worn consistently, you can just replace the outer. I have replaced the outer A/B's on many Sabre 2's to prevent slider hang up. This is NOT a substitute for a new lineset if needed, just a fix for one problem.

As a jumper with short arms, I prefer an extra 2"'s on most Semi-elliptical/elliptical canopies. My Velocity's factory setting, however, seemed spot-on so I did not adjust it.

If you are making a move towards high-performance flight, make sure your tools are maintained to the highest standards. Just like you wouldn't jump on a race track with spongy brakes, you shouldn't jump a canopy with shitty lines. There is at least one dead person and one paralyzed person who can (or could of) attest to this.


(This post was edited by floormonkey on Mar 22, 2012, 11:29 AM)


rwieder  (C 32349)

Mar 22, 2012, 3:11 PM
Post #14 of 14 (1076 views)
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Re: [SethInMI] Full flight brake position [In reply to] Can't Post

Quote:
Jumps: 350 / License: A: 47765 / In Sport: 9 Years @ Approx. 38 Jumps Per Year

Given your profile I don't think you should be worried about advanced canopy tricks just yet. maybe your a really fast learner? I've had close friends burn in at the same WL & the same canopy. Regardless of what you do, please contact a credible canopy pilot and take an advanced canopy course.


(This post was edited by rwieder on Mar 22, 2012, 3:53 PM)



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