Kevlar shock cord packing suggestions?

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Dave S.

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Looking for suggested methods for packing a long Kevlar shock cord into the body tube so it won’t get tangled.

The Kevlar is like a long piece of twine, so I’m thinking you can’t really fan fold it or roll it like flat nylon strapping.

I searched the forums and found lots of suggestions for mounting a Kevlar shock cord but not for how to pack it so it won’t get tangled.
 
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Tim VanMilligan has a series of videos on YouTube with all kinds of helpful tips and tricks regarding rocket construction and recovery device installation techniques.

Go to 2:10 here...

 
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Looking for suggested methods for packing a long Kevlar shock cord into the body tube so it won’t get tangled.

The Kevlar is like a long piece of twine, so I’m thinking you can’t really fan fold it or roll it like flat nylon strapping.

I searched the forums and found lots of suggestions for mounting a Kevlar shock cord but not for how to pack it so it won’t get tangled.
I spread out one hand as far as I can and wrap the cord around my thumb and pinky finger. When completed, the bundle is a fairly tight oval shape that slips inside your airframe. I also use swivels at each connection point to help avoid tangling.
 
I use both methods. On smaller tubes and limited space I do the taped bundles, typically 3 bundles of three wraps each. These then lay next to each other in the tube and pack into a small space.
Have found that minimum tape is needed so the bundle does pull apart.
For larger tubes and cords, both Kevlar and nylon, I do the braiding. This does take up more space so may not fit into a smaller, shorter tube along with the chute.

Both methods do absorb energy during the deployment. This slows down the Nose or Main bay so there is not a Shock to the recovery system when cord becomes fully extended.

I also braid thin kevlar cords for small, 13mm, rockets for the reasons Tim mentions in the video. This thin cords and small diameter makes it difficult to get the cord into the tube. Also to prevent tangling.
 
For larger bridles, I like the Z-fold method because it not only keeps things neat, but helps to ensure an orderly deployment.

The third segment of this video shows the packing process for an HPR rocket.
 
For smaller airframes (<3") I z-fold my line and then tape across the middle with some 1/4" blue painter's tape - just one wrap. This keeps everything together and ensures nothing tangles inside the airframe. There's always enough tug at deployment to break the tape. For larger airframes (>3") with larger tubular kevlar or flat strap kevlar, I really like the harness winder from Allen Hall. Really keeps the space required for your shock cord minimal.
 
This is for LPR with 10' length of very thin kevlar.

I had an idea to create a spool to wind the cord on. I start from the middle and wind both sides, that way when the rocket pulls on one end and the parachute pulls on the other end, both strings come off of the spool. I've since built a new spool with 2 sides so the 2 strings don't get twisted together. Most of the time this works well but not every time so I'm still experimenting with it. My early experiment is shown here:
https://www.rocketryforum.com/threads/shock-cord-control.167471
Some people in my club wind the cord into a figure 8 around their fingers and they have good luck with it, but I haven't gotten it to work yet.

I've watched the Apogee video of doing crochet with the cord. I've done a similar, maybe simplified, method myself and it seemed to work when I did it right but doing it right in the field is hard for me. I've seen people do this same type crochet for long electric extension cords so they don't get tangled in the back of the truck and can be extended easily. That's the crochet method I use. I'll crochet my 10' cord and maybe end up with 3" diameter loops and the whole thing is maybe 14" long. I lay the parachute out folded in half, lay half of the crochet on it and fold 1/3 of the parachute over it, fold the crochet over on the parachute and fold a little more parachute over it, then lay the shroud lines on the remaining part of the chute and fold it again. Now everything is contained and somewhat compartmentalized so I can stuff it in the airframe. If I do a good job of this it works well but it is hard to do at the launch field with a little bit of wind blowing.
 
Small stuff: Figure 8 between my fingers. The crossover reduces tangles and knots.

Large stuff: Z fold and inside out tape.
 
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