Plastic parachute reinforcing

bjphoenix

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I had this idea some time ago for reinforcing plastic parachutes but never got around to it. A few weeks ago I rigged up a new parachute to use (not real new, printed on it is Cox and a date of 2012). I noticed that the thin shroud lines were very weak so I replaced with some nylon thread from Hobby Lobby. The parachute had paper reinforcing disks so I left it that way. The first time I used the parachute 2 of the shroud lines tore out through the paper disks. I've heard of people using fiber reinforced disks but I had an idea to use strips of duck tape for reinforcing so I used that to repair the parachute.
I had the idea to form a V with the tape which connects the shroud line to more of the plastic. The tape is cut so the thin strip is cut parallel to the long direction of the tape so it contains the reinforcing fibers. I cut a 3" long strip off of the roll, stuck it on the side of a slick surface cardboard milk carton, and cut it into 5mm wide strips with a sharp hobby knife. I like to do these little experiments to improve parts of my rocketry so next will be to see how this parachute performs when launched.
In the first photo you can see the failure. In the second photo you can see the thin strip of duck tape on top of the parachute and folded under to form a V.

IMG_4995r.JPG IMG_4996r.JPG
 
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I've used 3M clear tape successfully on parachutes. I imagine that mylar tape would also make a good reinforcement for plastic parachutes. It does reduce the ability to tightly fold up the chute, so use it strategically.
 

dhbarr

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If I'm going to really yank on them, I put the reinforcement on both sides before I punch the hole.
 

BEC

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Newway uses Tyvek jewelry tags, which are a really nice solution.
This!!

I bought a package of 1000 of them (https://smile.amazon.com/Jeweller-R...0pcs/dp/B00ANI5KQ8?ref_=ast_sto_dp&th=1&psc=1) seven years ago (and for half as much as they now cost) and still have many left.

I use these whenever I make up a new plastic 'chute (no more holes for me). They also can be used to repair existing 'chutes since the little strip between the circles has no adhesive on it. So when an Estes pre-made 'chute tears out a line, you can fish one of these Tyvek tabs through the existing loop in the shroud line and simply stick the circles on both sides of the place where it was and you're back in business. It's an easy field repair (unless it's too windy to hold on to things while you try to do it :) ). Even at the current price of 1.6¢ each, I'd buy them again if I needed 'em.

Here is one corner of the ‘chute from my Estes V-2 which has 15 flights on it. Five of the six corners are done this way now.0D5F0B6E-3E21-452B-BEAF-66AB7DA1C104.jpeg
 
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bjphoenix

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you can fish one of these Tyvek tabs through the existing loop in the shroud line and simply stick the circles on both sides of the place where it was
Those look fairly large compared to the size of the loop. I thought it was going to be difficult to fish a strip of tape through a loop considering how sticky it is but it wasn't quite that bad. At my desk with good light it could do it if I was careful, out in the field with wind it would be impossible. I one time thought I might need to stick the tape to something hard like a coffee stir stick, put that through the loop, then peel off the tape and continue. In the case of the tyvek things, I assume they come with a backing stuck onto the tape so you could feed them through the loop in the line and then when in position you could peel off the backing. This would make them pretty easy to install.

Years ago I had the idea to use tyvek to reinforce parts of rockets but I found that it didn't stick to wood glue. Before I had the chance to try it with epoxy I found out that it was sensitive to heat so I stopped. Using the pieces on a parachute, it is still sensitive to heat but not any more so than the rest of the parachute.

I used duck tape in my experiment because I already had it.
 

BEC

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Those look fairly large compared to the size of the loop. I thought it was going to be difficult to fish a strip of tape through a loop considering how sticky it is but it wasn't quite that bad. At my desk with good light it could do it if I was careful, out in the field with wind it would be impossible. I one time thought I might need to stick the tape to something hard like a coffee stir stick, put that through the loop, then peel off the tape and continue. In the case of the tyvek things, I assume they come with a backing stuck onto the tape so you could feed them through the loop in the line and then when in position you could peel off the backing. This would make them pretty easy to install.
The Tyvek jewelry tags come in various sizes and shapes (including the rectangular ones that Rick Randol @Bluegrass Rocket used in his kits). The ones I have (and linked to in the post above) are 12mm in diameter — just under half an inch — and have a straight section between the two circles that’s also 12mm. They come 24 to a sheet and the backing that they are on feels like stiff wax paper. The adhesive on the circles is quite tenacious. There is no adhesive on the straight section.F443C825-E129-4F3E-A749-3DC811DF26FC.jpeg

Here’s the process of fixing an almost-torn-out Estes ‘chute shroud line. Note that in this example I’m going to stick the jewelry tag over the hole in the ’chute just above the almost-failed attachment, to solve two problems at once. This particular ‘chute is much abused….

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First a view of the factory loop, pulled free, laid over one of the tags to show that it’s plenty big enough. Then the tag is fed through. It is laying on the table sticky side UP in that picture. Then, stuck to the back side of the ‘chute over that hole, then the tag folded over to meet on the top. This, even over the hole in the canopy, will be much stronger than the factory attachment through the punched hole and plastic reinforcement disc.

2018E0C1-9355-475C-B7DB-BAE09F56B6C0.jpeg 79569037-1590-4636-9656-C2C143422CBC.jpeg B000B264-A82C-436B-9896-D2CA6B754F79.jpeg 057C7785-881A-40B2-82E1-B5059BC41878.jpeg

At the field I will stick one end lightly to a X-acto knife I keep in my field kit to help hold things while doing this operation. I keep a sheet of these tags in the same box in my field bag. Burnishing them down with a thumbnail or the butt end of that knife will make sure they are well and truly stuck in place.

And yes, they can get cooked just like the ’chute, but I’ve never had one burn through. The V-2 ‘chute in the post last night has a couple of the five tags a little toasty. The Estes V-2 is a challenge to get adequate wadding in….
 
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bjphoenix

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At the field I will stick one end lightly to a X-acto knife I keep in my field kit to help hold things while doing this operation. I keep a sheet of these tags in the same box in my field bag. Burnishing them down with a thumbnail or the butt end of that knife will make sure they are well and truly stuck in place.
I thought you could cut around the shape of the tag with scissors and keep the wax paper stuck on, then feed it through the loop, then peel off the backing. If the loop was abnormally small you could even fold the circle in half so it would fit through the loop.

I repaired 2 parachutes yesterday, one had 2 torn lines, the other had one torn line. So I had to feed the tape strip through 9 loops that were still tied to the chute, those took a little more patience.

I'm thinking about how the jewelry tags are used- how does the customer get them off? They wouldn't easily tear off so the customer would have to very carefully cut them off. It would be tough for an unscrupulous person in a store to tear off a tag and put on a different one.
 

BEC

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I thought you could cut around the shape of the tag with scissors and keep the wax paper stuck on, then feed it through the loop, then peel off the backing. If the loop was abnormally small you could even fold the circle in half so it would fit through the loop.
Sure, you could do that. I’m just too lazy, especially at the field (though I do have a small pair of scissors in the same box with the knife and the Tyvek bits). I find that just using the knife as a handle with one disk lightly stuck to the blade generally makes it doable. Sometimes I do have to squeeze the circle a bit to get it through a small loop.
I repaired 2 parachutes yesterday, one had 2 torn lines, the other had one torn line. So I had to feed the tape strip through 9 loops that were still tied to the chute, those took a little more patience.
I don’t bother repairing them until they need it.

I do use these same devices to make up plastic ‘chutes, regardless of what the maker calls for. But there one puts the disks in place and then just ties the shroud to the little straight part, which by then forms a loop.
I'm thinking about how the jewelry tags are used- how does the customer get them off? They wouldn't easily tear off so the customer would have to very carefully cut them off. It would be tough for an unscrupulous person in a store to tear off a tag and put on a different one.
I expect one would cut them on the straight portion, with whatever care is needed. Like a Tyvek hospital bracelet, just tearing them is … difficult.
 

augendoc

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I've been using Tyvek or the generic equivalent for LPR shroud line anchors for some time now. The jewelry tags are the best for this application, and the Flanica USA brand seems to be the best. Definitely Tyvek and no adhesive on the bridge part, unlike a lot of other similar tags sold on Amazon. Yes, it will take me about 47 years to go through the 1,000 in the package.

Jewelers use them for labeling items because you can't remove the tag without destroying it. If the jeweler wants to remove the tag all it takes is a pair of scissors, which obviously destroys the tag, but the permanence deters those who would try to switch the price tag.

You can write on them with difficulty. Pencil and a fine-tip Sharpie work OK, though the Sharpie ink tends to bleed. Ball point pen is hit or miss, mostly the latter. The Tyvek is waterproof so if your rocket lands in wet grass or worse, the parachute at least will be OK.
 
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This!!

I bought a package of 1000 of them (https://smile.amazon.com/Jeweller-R...0pcs/dp/B00ANI5KQ8?ref_=ast_sto_dp&th=1&psc=1) seven years ago (and for half as much as they now cost) and still have many left.

I use these whenever I make up a new plastic 'chute (no more holes for me). They also can be used to repair existing 'chutes since the little strip between the circles has no adhesive on it. So when an Estes pre-made 'chute tears out a line, you can fish one of these Tyvek tabs through the existing loop in the shroud line and simply stick the circles on both sides of the place where it was and you're back in business. It's an easy field repair (unless it's too windy to hold on to things while you try to do it :) ). Even at the current price of 1.6¢ each, I'd buy them again if I needed 'em.

Here is one corner of the ‘chute from my Estes V-2 which has 15 flights on it. Five of the six corners are done this way now.View attachment 546100
Brilliant! 👍
 

bjphoenix

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The Tyvek is waterproof so if your rocket lands in wet grass or worse, the parachute at least will be OK.
At our last big launch I recovered 2 rockets that were floating out in a lake for a couple of hours. One of them lost its shock cord connection and one fin, I wondered if it was assembled with white glue. All of the pieces where floating there and were recovered. I think after it dried out it could have been reassembled.
I always thought tyvek was paper based with some fibers mixed in so I was surprised when Titebond II wouldn't stick to it. Then I researched what Tyvek is made of and I don't know what normal rocket construction glue would stick to it well. The adhesive used on envelopes (and jewelry tags I'm sure) sure sticks to it well.
If you have a box of 1000, you should pass them out to others in your club. One of our club officers brought a bale of dog barf and a box of ziplock bags to a launch and passed it out.
 

BEC

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I haven’t passed them out, but I have helped others at a launch repair their ’chutes from the ones I carry at the field, while explaining what they were and where I got them…..
 

bjphoenix

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I had 3 flights yesterday on one of the strengthened chutes. This one had the stock shroud lines and one of them broke on the last flight. So you strengthen one area and the next weakest link fails, but I have stronger string to replace the old lines with.
 
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