Gosh darn it.
I am Going Back to Elastic. Kevlar is a tangled nightmare.
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goose_in_co
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Don't give up yet Brock!
I have that problem as well, and this is how I prep now that pretty much eliminates the tangles.
First place your wadding in the rocket, and make sure it is down far enough for the parachute and shock cord.
Then hold up two fingers, with about 1/2" in between
Then wrap the Kevlar around the two fingers in a figure 8 until you are really close to the parachute
Pull the Kevlar off of your fingers carefully and fold the loops in toward the center to form one loop
Carefully place that into the rocket with another sheet of wadding on top of it.
Place the parachute and whatever recovery harness on that and put the nose cone in place.
Once I started doing this, the tangles have largely disappeared.
Give it one more change before you swear off Kevlar.
One other thing I do is attach the snap swivel to the rocket harness, and then clip each of the parachute shroud lines to the swivel, which is backwards from what I have seen. It allows you to take off the parachute easily, even if it gets tangled. Of gourse you will need to make little loops at teh end of each of your shroud lines so the lines do not slide around once they are attached.
Later,
Goose
I have that problem as well, and this is how I prep now that pretty much eliminates the tangles.
First place your wadding in the rocket, and make sure it is down far enough for the parachute and shock cord.
Then hold up two fingers, with about 1/2" in between
Then wrap the Kevlar around the two fingers in a figure 8 until you are really close to the parachute
Pull the Kevlar off of your fingers carefully and fold the loops in toward the center to form one loop
Carefully place that into the rocket with another sheet of wadding on top of it.
Place the parachute and whatever recovery harness on that and put the nose cone in place.
Once I started doing this, the tangles have largely disappeared.
Give it one more change before you swear off Kevlar.
One other thing I do is attach the snap swivel to the rocket harness, and then clip each of the parachute shroud lines to the swivel, which is backwards from what I have seen. It allows you to take off the parachute easily, even if it gets tangled. Of gourse you will need to make little loops at teh end of each of your shroud lines so the lines do not slide around once they are attached.
Later,
Goose
Just take your new spool of thread, cut to length, tie a nut on one end, tie the other end to something tall and let it hang. It will untwist itself, and you are good to go.
I feel your pain, I have that problem sometimes despite what I do. I have other threads about my spool that I use and most of the time it works well but sometimes there is a tangle. Actually I still get some tangles after the rocket lands and before I get it and they get worse when I am carrying the rocket back to my car.
There are pros and cons to elastic. If it is new and the rocket is small it works well enough but I don't think the lengths included with most kits are enough, maybe combine 2 pieces and it would work. But someday the elastic will break and it will be hard to replace. I switched to kevlar to get away from the problems with elastic, then I had problems with kevlar that I've just about solved.
There are pros and cons to elastic. If it is new and the rocket is small it works well enough but I don't think the lengths included with most kits are enough, maybe combine 2 pieces and it would work. But someday the elastic will break and it will be hard to replace. I switched to kevlar to get away from the problems with elastic, then I had problems with kevlar that I've just about solved.
(red face) I looked, none of my spools are marked, not manufacturer, nor where or when I bought them. Hmmm...
I'm certain the thinnest thread came from a sailmaker shop. Several came from Apogee, they carry 4 or 5 model weights on their website. One spool of 500# ish was a thank you gift from the rocket club president. Heavier stuff for HPR came off spools in the vendor's trailer.
Emma Kites
Dude that happens with elastic too....Did it happen during transport or at the launch? I won't lie once in a while I untangle them, but its not bad. Are you using chute swivels too?
I buy Emma Kites stuff from Amazon. Kevlar and Elastic.
I buy Emma Kites stuff from Amazon. Kevlar and Elastic.
Try heavier Kevlar. I stopped using anything under #250 as it tangles like crazy. Only use I have for the thin 100# stuff is to make shroud lines for my chutes.
Using ‘chute swivels. It happens on descent. Then gets worse on transport home, especially if I have to bug out in a hurry.
Ok! I will try the 250 pound stuff as shock cord. I thought the 250 pound kevlar was overkill for low power rockets, but as long as it is light and not bulky, it matters not. I will do overkill for no tangles.
I take mine and out them all in plastic bags them a tote. That way they don't get tangled. Best thing is right after flight. Wrao them up like your flying again but not, and then transport them home. Or like said use a bigger size like 250, it won't hurt. I mean do whats best for you, tossing mine in bags or wrapping them with bags and then elastic on the top so they stay together has been working well. And then after i get them home I take all the chutes out. Also prep the night before as much as possible but efficient and safe for transport. You can see in the picture some of the rockets have wal mart bags on them. I think...lol....this phone.
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It's overkill in terms of strength but it doesn't tangle anywhere near as much as it will have a much longer life as you will more than likely never need to replace it. I have yet to burn through a single piece of 250# Kevlar on any rocket.
Dang! The big spool of the 100 pound stuff will be shelved. Maybe I will get into kite flying?
Oops. Replied to my own post…
Two words: braided kevlar.
If it's much thicker and heavier than needed....who cares? Unless you're doing an altitude attempt.
I have a spool of twisted kevlar, 200 lb, over 200 feet. Free to anyone willing to pay postage. Ain't never using twisted kevlar again.
If it's much thicker and heavier than needed....who cares? Unless you're doing an altitude attempt.
I have a spool of twisted kevlar, 200 lb, over 200 feet. Free to anyone willing to pay postage. Ain't never using twisted kevlar again.
Yeah I use braided kevlar I should have mentioned that.
You could use the 100 pound for spare shroud lines or like Alpha III sized rockets.
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I'm surprised no one on this thread mentioned the use of tubular nylon. I have several 1" tubular nylon shock cords / harnesses. Any twisting that occurs during descent is easily corrected. They work fine every time. Vendors typically sell 1" tubular nylon shock cord for about $1.25/yard.
Use it for shroud lines on your chutes.
I am going to order a spool of the 250 pound or 300 pound braided kevlar and see if it tangles less. I launch mostly BT-50, BT-55, BT-56, and BT-60 sized rockets. The tangled kevlar cord was in a BT-60 sized rocket. I figure the 300 pound kevlar, even though it is over a millimeter in diameter, ought to fit in there fairly easily.
mh9162013
Well-Known Member
No one's mentioned it because most LPR rockets don't have the space or payload capacity to carry shock cord that's 1 inch in diameter.
Awesome. I use a mix of all, from 150, 250, 550, to 1800. Mostly from Amazon and Emma kites, they sell good elastic too. If I use that I make sure it can be easily replaced like below. And the rocket shops use Emma kites, your saving money by going right to the source. Im really picky about storage and transport, my one High-Flier XL has a shock cord about 10 feet long that gets tangled a lot, lol. I added a pc of kelvar strap in the middle to stop that. Anyways good luck!
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Hmm. This kevlar is from an old spool I bought many years ago. It may be the twisted stuff, not the braided stuff. I have a spool of 100 pound braided kevlar somewhere. Until now, I did not know that the braided stuff was better.
I've been using the cheap EmmaKites stuff, I think 150#. I don't think I have problems with tangling because it is twisted material, I have tangles because I use a 10' length of it. It's hard to stuff that much into the airframe and it not get tangled up when it starts unwinding. After some experience I think I could use 8' length for my LPR.
I've tried various ways to keep from getting tangles and I've written about it in past threads. I've done the figure-8 wrap and not gotten it to work. I've done the crochet thing and it works sometimes. I've done the crochet and folded it up in the parachute. This works but it is hard to do at the flying field inn a little bit of wind. My best luck has come from using my spool. It is fairly successful now that I have experience with it. I wrap up the cord on the spool then put a couple of small dabs of tape on it to hold it wrapped until it gets pulled pretty hard. Then I put the spool into the airframe on top of the wadding and put the parachute on top of that. I'm thinking that the pieces should be in the airframe in the order that they will be when the they deploy- with the chute coming out first connected to the nose cone and the shock cord coming out later and then unrolling.
But also when the rocket lands it can get tangled laying in the grass, or it can get tangled when I pick it up and walk back to the car. I know that if I take time out in the field to roll everything up and repack it then walk back to the car there is less chance of tangles but I'm usually in a hurry and don't do that.
I've tried various ways to keep from getting tangles and I've written about it in past threads. I've done the figure-8 wrap and not gotten it to work. I've done the crochet thing and it works sometimes. I've done the crochet and folded it up in the parachute. This works but it is hard to do at the flying field inn a little bit of wind. My best luck has come from using my spool. It is fairly successful now that I have experience with it. I wrap up the cord on the spool then put a couple of small dabs of tape on it to hold it wrapped until it gets pulled pretty hard. Then I put the spool into the airframe on top of the wadding and put the parachute on top of that. I'm thinking that the pieces should be in the airframe in the order that they will be when the they deploy- with the chute coming out first connected to the nose cone and the shock cord coming out later and then unrolling.
But also when the rocket lands it can get tangled laying in the grass, or it can get tangled when I pick it up and walk back to the car. I know that if I take time out in the field to roll everything up and repack it then walk back to the car there is less chance of tangles but I'm usually in a hurry and don't do that.
Hmm. Is this braided or twisted?
Maybe I will try using my spool of braided 100 pound kevlar (labeled as braided) before I buy the 250 pound stuff for $15.
Of course, $15 is the cost of an up-sized meal from McDonald’s these days. Sigh.
Maybe I will try using my spool of braided 100 pound kevlar (labeled as braided) before I buy the 250 pound stuff for $15.
Of course, $15 is the cost of an up-sized meal from McDonald’s these days. Sigh.
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I can't really tell from the image. Small twisted line usually has three threads. Try un-twisting with about an inch of line between thumb & finger of both hands. The threads of twisted line can partially or completely separate when un-twisting in one direction. Braided line is like braided hair---you can't undo it by trying to un-twist in either direction.
My experience and hypotheses: some twisted line can partially un-twist while packing the cord into the body tube, or during recovery (or maybe it happens at night when the rocket gremlins sneak in
). Heat of ejection seems to contribute to this to some degree, perhaps by breaking down some of the tiniest fibers in the cord that help to hold the three threads of the cord together.
As the threads separate, another part of the line can end up between the threads, jamming things up nicely. Individual fibers of two different parts of the cord can themselves tangle, making things even worse.
The braided cord I use is just over 1/16" diameter and is (theoretically) rated at 700 lb. I've used it in every rockets I've built over the last couple years except for my lightweight BT-50 model; "Long Wrong Silver" has the 200 lb twisted cord. And it's the only one for which tangling has been an issue. Almost. Every. Doggone. Time.
My experience and hypotheses: some twisted line can partially un-twist while packing the cord into the body tube, or during recovery (or maybe it happens at night when the rocket gremlins sneak in
). Heat of ejection seems to contribute to this to some degree, perhaps by breaking down some of the tiniest fibers in the cord that help to hold the three threads of the cord together.As the threads separate, another part of the line can end up between the threads, jamming things up nicely. Individual fibers of two different parts of the cord can themselves tangle, making things even worse.
The braided cord I use is just over 1/16" diameter and is (theoretically) rated at 700 lb. I've used it in every rockets I've built over the last couple years except for my lightweight BT-50 model; "Long Wrong Silver" has the 200 lb twisted cord. And it's the only one for which tangling has been an issue. Almost. Every. Doggone. Time.
Found the spool of braided kevlar cord. 100 pound. It is the Emma’s Kites brand some people like.
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