Breakcord

[d_goldsmith 1]

Anyone every use break cord other than the 80 lbs tape that paragear sells?

I recently cut a piece off and tied it around something to show a freind (that doesn't trust static lines) that it doesn't break easy, but that it breaks, and I couldn't get it to break. I was giving it atleast 100 lbs of force and it wasn't breaking. I ended up tying another peice around a table and sitting down bracing the table with my foot and then pulling on it. I'd say it broke around 150 lbs.

I'm also wondering what type of knot most people use to secure it. Regular overhand or figure eight or what?

P.S. I did some weight tests on cotton twine right after this, and a single strand could hold 20lbs in the air, but if you jerked it around it would break. Two strands held 50 lbs and broke when I jerked it around.

I'm considerring instead of using a big loop little loop 80 lbs break cord, maybe testing 5 ascending loops of double strand cotton twine at TF on video to see what happens.

[Mikeeey 0]

Shock force or constant pull force? big difference

[Tornolf 0]

All the tests I did with my breakcord showed it not breaking when 100lbs was suspended with it, but if you raised the weight about 2 inches and dropped it, it'd break on every attempt. It makes me believe that inertia is a nontrivial factor and I'm not worried since we have just a tiny bit of momentum on static lines.

A waddling elephant seal is the cutest thing in the entire world.
-TJ

[VincentVL. 0]

I have a "question" and would appreciate a response by anyone with experience.

When you do a solo static line, you use breakcord amirite? But this seems kinda dangerous for the following reason: the cord has to be strong enough to pull out PC (and canopy). But if it is too strong, doesn't it damage the point where the bridle is connected with the canopy?

Also, why would you do a SL without a pilot chute? Can't you use the PC in case somehing goes wrong? For instance if the static line doesn't get the canopy out, you're pretty much screwed right?

thx in advance.

[droquette 0]

from the teeny tiny bit i know... you ALWAYS use your PC when doing SL for the exact reason you mentioned. If it breaks early you still have something pulling your canopy out.

HISPA 72 ----- "Muff Brother" 3733

[Mikki_ZH 0]

same as droquette:
I would never ever do a static line jump without a pc as a back up.

And you don't use the static line to pull out the pc. You use the brake cord to tye the pc on it's connection point with the bridal (or closer to the pins if it is an ultra low jump) to the object. But you never dismount the pc (or at least I would not...) from the bridal.

Michi (#1068)
hsbc/gba/sba
www.swissbaseassociation.ch
www.michibase.ch

[980 0]

dude

your posts are starting to get annoying - do some research before asking the same question that has been discussed to death here before....

80lb break cord is fine

small primary loop with a big backup loop is the way to go

one night after a jump me and 3 other jumpers were having a cofffee at the local Tim Hortons and talking about static line technique and break cord

one of them did not see how a loop of 80lb breakcord will take 160lbs to break because it's a loop

so we got the strongest one of us (a firefighter who is something like 6'2" and 200lb+ all muscle) to try and pull a normal static-line setup till it breaks

we achored it to the table (one of those fixed to the floor jobbies) and he gave it hell

he couldn't break it, so we all agreed that it takes more than 80lbs to break the loop and probably more like 160lbs

so then some of us started getting paranoid about this being too much

so I (at 6'0" and 165lbs, certainly not the strongest person there) stepped up, took the 550 cord tie-off loop, moved it one side of the tie-off point and yanked it as fast and as I could past the tie-off point, the total travel was about one foot

the break cord snapped easily

this is a very informative little test you can do at home too

there is a VERY big difference between what kind of static load and what kind of dynamic load will break the cord


there is no need to re-invent the wheel here

80lb break cord is the bomb, just learn to use it properly

cya

PS - re-reading your post, it seems you tried to break a loop of break cord and expected it to happen at 80lbs, it happens at 160lbs, because a loop is two strands together! If you cannot get yourself to understand this, consider sticking to sports that do not require as much understanding as BASE does.

[crwper 7]

Dave: As 980 pointed out, there are two sides to the loop, so it breaks at about 160 lb. My understanding is thus: If you put 80 lb of tension on the cord, that's 80 lb per side, which means the total force between the anchor and the bridle is 160 lb.

For the knot, use a surgeon's knot. Back it up with as many overhand knots as you like.

Vincent: The bridle attachment point is much stronger than a loop of break cord. It's a good idea to check the attachment point regularly regardless of what kind of jumping you do, but unless something unusual is happening, there should be no problems.

I have done one static line jump with no pilot chute. We were jumping a 111-foot span and the canopy barely had time to fly. I thought if I removed the PC, it might help, and also thought it couldn't really be much of a backup from that height. There was no measurable difference in canopy flight between jumps with/without the pilot chute. DW later pointed out that the most likely time to get a premature break is actually fairly late in the deployment sequence, and there is a good chance that a 48" pilot chute would help even on very low jumps. So I don't think there's any reason to jump without one.

Michael

[TomAiello 25]

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But this seems kinda dangerous for the following reason: the cord has to be strong enough to pull out PC (and canopy). But if it is too strong, doesn't it damage the point where the bridle is connected with the canopy?

I don't think it will damage the bridle attachment point of your canopy. The forces just aren't there unless you've misrigged something.

However, if it did, it still wouldn't be dangerous. By the time that part of the system could take a big load, you'd already be at line stretch. Even if your attachment point was damaged then, you'd still have a functioning parachute over your head.

Gear maintenance issue? Maybe, but I doubt it. Safety issue? I don't think so.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[Faber 0]

hey you know more about sl than i thourght.. brig your gear end of feb as you visit Nikolaj
Ill take "a dance" whith you

looking forward but first another trip on pain and drugs..

Stay safe
Stefan Faber

[Faber 0]

Quote

the cord has to be strong enough to pull out PC (and canopy). But if it is too strong, doesn't it damage the point where the bridle is connected with the canopy?

if your attachment point on your bridel is going to break on a BASEjump there can be 2 faults..

#1 bad gear maintain,which means you jumped equipment that has been dammeged already

#2 your loops are so tight that you cant open your harness,if its that tigh you will die anyway(i dont know how that should happen,but i guess someone gonna prove it one day..)

I think its more likely that you gonna rip your topskin than ruin your bridel..

ALWAYS USE PC AT SL`S

Stay safe
Stefan Faber

[lifewithoutanet 0]

Canopy Strength

Credit: Martin Tilley- Asylum Designs / Adam Filippino- Consolidated Rigging

[gweeks 1]

A friend of mine had a bridle hang up on a static line jump. The opening and canopy flight were normal except in hindsight he said the line stretch shock was a little more than he was used to. He didn't even know it happened until the next day when he looked at his canopy and there was no bridle attachment point. Instead there was a very neat rectangular hole in the top skin of his BlackJack.

[Tornolf 0]

I've seen a canopy have the entire center cell topskin ripped out. It was a Lightning with a modified lineset on it, so non-reinforced BASE-style attachment point. Exit was a 120' bridge pylon. I had a solid 5 seconds under canopy with my vented Fox. The other guy had about the same amount of canopy time but flew 1/2 as far as I did and the canopy stalled and partially collapsed when he flared.

A waddling elephant seal is the cutest thing in the entire world.
-TJ

[TomAiello 25]

Wow. That's stunning.

Did he ever figure out what happened? Was there some kind of misrigging on the static line? Maybe the bridle snagged on the object?

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[gweeks 1]

Quote

Wow. That's stunning.

Did he ever figure out what happened? Was there some kind of misrigging on the static line? Maybe the bridle snagged on the object?

He went to the object the next day and couldn't find the bridle or pilot chute, so there's no way of knowing exactly what happened, but it's almost certain that the bridle and/or pilot chute snagged on the object. The tie off point was a rail recessed about 5 feet from the exit point. Between the tie off point and the exit point there is metal grating. Our best guess is the pilot chute got dragged along the grating and snagged something. The same exit point and tie off point had been used successfully in the past.

Marty said the bridle attachment point was designed to fail at 400 lbs and leave a small rectangular hole like that.

[maretus 0]

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Quote

Wow. That's stunning.

Did he ever figure out what happened? Was there some kind of misrigging on the static line? Maybe the bridle snagged on the object?

He went to the object the next day and couldn't find the bridle or pilot chute, so there's no way of knowing exactly what happened, but it's almost certain that the bridle and/or pilot chute snagged on the object.

I'd be pretty sure that the bridle snagged the object. I had a PC snag on my last SL jump and resulted in torn PC but the topskin and bridle attachment point were fine. I'd guess that in case of PC snag the PC will be ripped to pieces but it will not affect the canopy.

http://sunmutsi.ufufreefly.com/tattivaurio.jpg

http://www.ufufreefly.com

[avenfoto 0]

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Marty said the bridle attachment point was designed to fail at 400 lbs and leave a small rectangular hole like that.

i had assumed something along those lines... nice

[HydroGuy 0]

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Quote

Wow. That's stunning.

Did he ever figure out what happened? Was there some kind of misrigging on the static line? Maybe the bridle snagged on the object?

He went to the object the next day and couldn't find the bridle or pilot chute, so there's no way of knowing exactly what happened, but it's almost certain that the bridle and/or pilot chute snagged on the object. The tie off point was a rail recessed about 5 feet from the exit point. Between the tie off point and the exit point there is metal grating. Our best guess is the pilot chute got dragged along the grating and snagged something. The same exit point and tie off point had been used successfully in the past.

Marty said the bridle attachment point was designed to fail at 400 lbs and leave a small rectangular hole like that.

Why not tie a runner of 900 Dacron or climbing rope or something to seperate the bridle from the object?

This also leads me to believe the breakcord/bridle attachment point was directly below the PC instead of down a couple feet...I've been taught (by Todd @ Apex)to attach the break cord to the bridle as close to the canopy as possible without the risking canopy hitting the object on extraction.

Get in - Get off - Get away....repeat as neccessary

[gweeks 1]

I was passing along what I heard from my friend. Correction from someone who would know:

"The Bridle attachemt is held on to a BlackJack with four bartacks, each one is in excess of 400 lbs."

[worldsocold 0]

i'll stick 2 freefallin'!!! staticlines R scary!!! i only done em' twice. once @ night and once in the day. i'm now convinced! thanks 4 the thread!! i'll pull it out myself ( the parachute that is ).

later

NPS SUX ASS

[Mikki_ZH 0]

Quote

hey you know more about sl than i thourght.. brig your gear end of feb as you visit Nikolaj
Ill take "a dance" whith you

looking forward but first another trip on pain and drugs..

That's because I static line stuff you would probably freefall... :-)

Michi (#1068)
hsbc/gba/sba
www.swissbaseassociation.ch
www.michibase.ch

[blitzkrieg 0]

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Why not tie a runner of 900 Dacron or climbing rope or something to seperate the bridle from the object?

unless i misunderstand what you mean, that would work, but you'd have to climb back up and get it to not "leave a trace".

[Faber 0]

that dosnt mean we cant have fun

pm in a min or two

Stay safe
Stefan Faber

[recovercrachead 0]

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Dave: As 980 pointed out, there are two sides to the loop, so it breaks at about 160 lb. My understanding is thus: If you put 80 lb of tension on the cord, that's 80 lb per side, which means the total force between the anchor and the bridle is 160 lb.

For the knot, use a surgeon's knot. Back it up with as many overhand knots as you like.

Vincent: The bridle attachment point is much stronger than a loop of break cord. It's a good idea to check the attachment point regularly regardless of what kind of jumping you do, but unless something unusual is happening, there should be no problems.

I have done one static line jump with no pilot chute. We were jumping a 111-foot span and the canopy barely had time to fly. I thought if I removed the PC, it might help, and also thought it couldn't really be much of a backup from that height. There was no measurable difference in canopy flight between jumps with/without the pilot chute. DW later pointed out that the most likely time to get a premature break is actually fairly late in the deployment sequence, and there is a good chance that a 48" pilot chute would help even on very low jumps. So I don't think there's any reason to jump without one.

Michael

would a direct bag be better in this case at 111'.

Track high, Pull LOW!!!