Favorite parachute knots?

[DocSeuss]

I had an ASP 15" parachute I was working on the other day, tied my knot, followed the directions, but my knot slipped and tore right through the parachute and the stiffening ring. Not eager to make the same mistake twice, I figured I'd ask what all ya'll tend to use for knots for LPR parachute assembly. I appear to have forgotten the knots I used to use when I used to fly rockets 20 years ago.

Anyone have any favorites they like?

 

[bjphoenix]

I learned the bowline long ago for fishing. For some reason it is the only knot I can remember. I've tried to learn new knots but I don't use them enough to remember them. The bowline works well enough for building parachutes but is a little tedious to tie with small line, it helps if I use a pair of tweezers.
If your knot is ripping through the parachute and stiffening ring then it seems that you need a stronger stiffening ring. Some people here have suggested various reinforced rings. I use a long thin piece of duck tape. Half of it goes on top of the parachute, angled slightly off of the radius of the parachute, the other half folds under the parachute so together they form a V. The string loops through the V and gets strength from the duck tape, and the strips of duck tape anchor to a good amount of parachute material.

 

[Azamiryou]

Perfection Loop
It's a little trickier to tie when you have to pass the loop through a hole in the chute, but it can be done. (From that page: "Alternative: It can also be tied through a fly or lure by passing the free end along the path shown in Frame 7 of the animation.")

For best results, use tweezers.

 

[SolarYellow]

https://www.rocketryforum.com/threads/perfection-loop-knot-another-way-to-tie-it.177792/

 

[bjphoenix]

Perfection Loop
It's a little trickier to tie when you have to pass the loop through a hole in the chute, but it can be done. (From that page: "Alternative: It can also be tied through a fly or lure by passing the free end along the path shown in Frame 7 of the animation.")

For best results, use tweezers.

https://www.rocketryforum.com/threads/perfection-loop-knot-another-way-to-tie-it.177792/

The perfection knot is one that I was going to try. I have been getting by with just a few parachutes but I feel like I need to build a couple more for spares. I put snap swivels on my parachutes so I can launch a lot of rockets with only 2 parachutes (LPR).

 

[bjphoenix]

https://www.rocketryforum.com/threads/perfection-loop-knot-another-way-to-tie-it.177792/

I'm going to grit my teeth and assemble a few more parachutes, giving this a try.

 

[crossfire]

When I owned TFR we repaired many cutes where the shroud lines were knotted on. The knot would just tear out of the fabric.

 

[SolarYellow]

I'm going to grit my teeth and assemble a few more parachutes, giving this a try.

In the beginning, I wanted to make my own chutes. Bought mylar table cloths and everything. Then I tried making one. With the time I spent doing it and the results I got, I decided that going to work and buying parachutes is a better use of my time.

 

[bjphoenix]

In the beginning, I wanted to make my own chutes. Bought mylar table cloths and everything. Then I tried making one. With the time I spent doing it and the results I got, I decided that going to work and buying parachutes is a better use of my time.

I use the basic Estes parachutes but usually the shroud lines are not strong enough so I cut those off and replace them. I also use a long thin strip of duck tape to reinforce the attachment points then tie the lines on with knots.

 

[Blast it Tom!]

In the beginning, I wanted to make my own chutes. Bought mylar table cloths and everything. Then I tried making one. With the time I spent doing it and the results I got, I decided that going to work and buying parachutes is a better use of my time.

That I understand, but for some reason, nutty me decided to make life tough. I modeled a semi-elliptical parachute in Solidworks (parametrically) and generated a set of patterns from 12" up to 18" (inflated diameter), with a 20% spill hole. I got a bunch of pretty 1.1 oz ripstop nylon from Ripstop by the Roll, and my beloved sews them up. Nylon works better, especially in the cold, and you don't need to powder them, and the shroud lines are sewn right into the canopy. Plus they are actually round, they don't lay flat. I wish I had a good picture to show it. Maybe next launch.

Sorry for the slight derail. I reinforce the plastic character-themed parachutes on the grandkid's Looney Tunes rockets with clear packing tape. So far, so good!

 

[SolarYellow]

I think I probably sew more and better than my beloved, but that’s a moot point in the question about is a DIY chute worth it. Apogee printed nylon chutes are really nice for flat ones and reasonably affordable. I can pack their 18in with the shroud lines inside it to fit in 1.14 ID x ~2.5 inches. And they are super easy to open. If I needed maximum performance/size, I’d probably go with Spherachutes.

 

[bjphoenix]

Today I finished a couple for LPR. This one is cut down from an 18" Estes chute to 15". You can see in the photo how I reinforce the attachment point with a thin strip of duck tape. I don't cut this strip across the roll, I pull off a 3" strip of tape and then cut 3/16" strips lengthwise so the strips are going in the strong direction of the tape. I bought some nylon string at hobby lobby, I haven't had any problems with it burning or melting. I used the perfection knot, the tweezers help a lot but it's still a bit fiddly although for me not as bad as the bowline that I used to use. For some reason tieing a bowline you can occasionally get the loops oriented wrong and when you pull to tighten it the end of the string just slides out.

 

[kuririn]

Saw this FB reel today.

Maybe could be used for attaching shroud lines to chute corners?
Thoughts?
Pros and cons?

 

[Rocket-Fan]

https://www.rocketryforum.com/threads/plastic-parachute-reinforcing.175877/post-2344417

 

[Azamiryou]

https://www.rocketryforum.com/threads/plastic-parachute-reinforcing.175877/post-2344417

This seems like a good way to go. Perfection loops are easy to tie if you don't have to pass it through something. With those jewelry tags, you can tie the loop first, then pass the tag through and attach it. Seems much quicker than my current method (attach reinforcement, punch hole, tie perfection loop through hole).

 

[SolarYellow]

My link in post #4 above makes it much easier to tie a Perfection Loop passing it through something.

 

[Azamiryou]

My link in post #4 above makes it much easier to tie a Perfection Loop passing it through something.

That's how I do it. It's still much more fiddly and time consuming than tying it without passing through something.

 

[bjphoenix]

My link in post #4 above makes it much easier to tie a Perfection Loop passing it through something.

The tweezers are real helpful. If you are making a couple of parachutes you get plenty of practice and you figure it out pretty quickly. My problem is that I forget how to do it before I need to do parachutes again. I saved some photos on my computer so I can look at them and refresh my memory.

 

[ReynoldsSlumber]

The Grog Knots site has excellent directions with photo animations, including for the Perfection Loop. They also have a smartphone app.