Hexagon Chutes: How do you you arrange your shroud lines

[K'Tesh]

I don't know why Estes (and Quest) recommend that shroud lines be arranged in what I'd call a "Triangle" arrangement (back when you had to assemble your own). "Parallel" or "Crossing" lines seem to make more sense, and would keep the lines less tangled at the knot.



Personally, I use the "Parallel" arrangement, threading the centerpoint of each line through the eye of a swivel, one at a time, then securing it as a lark's head knot before adding a drop of white glue to secure the knot.

The "Crossing" arrangement requires a lot of care to make sure that the lines are threaded through the swivel, or attachment point, before both ends of each line are secured to the parachute, then carefully secured to prevent the lines from slipping off the center point.

So, what arrangement do you use?

Please excuse the crudity of these models. I didn't have time to build them to scale or paint them.

 

[Incongruent]

Preassembled Estes chutes use parallel. Apogee instructions say triangle. (Can we call it the Illuminati?) Estes PS II uses adjacent pairs (8 lines)

I'd use parallel for small chutes and adjacent for large ones. For many gored ones, I'd separate the bunches of lines into two, left half and right.

Just personal preference though.

 

[fyrwrxz]

Hold up a conventionally sewn 'chute-I'm talking about 90% of the ready made fabric chutes out there. See that built-in twist? That's the triangle. When we were making chutes in the 90's, i tasked my wife (head sewer and reluctant rocket widow) to rig chutes to be parallel. Look, Ma-no twist! I will admit the 10' chute she did was crossed, because it was easier to manage while sewing. Alex Boyce used a couple of my chutes and when he started Boyce Aerospace (the first time) he wanted those chutes. Unfortunately I left for Washington State (supposedly for 6 months-turned into two years) and when i returned the gang had gone and scattered. Wish i'd stayed home and grew a company. Mine and his. You can request Rocketchutes in Los Angeles to make yours (up to 36") sewn parallel and even get them to embroider your TRA/NAR# or name on 'em too! Tell 'em Dave sent ya!

 

[Coop]

I generally separate mine into L and R, and tend to work in multiples of 4, not 3, so rather than a six side (gore) parachute, I'd make an 8...


Later!

--Coop

 

[Lowpuller]

K Tesh,

I think you mean Larks Head versus Clove Hitch

 

[K'Tesh]

K Tesh,

I think you mean Larks Head versus Clove Hitch

Did I say Clove Hitch? Uhmmm... It's been corrected now.

 

[Bat-mite]

Wish I could answer, but I have never attached my own lines. I always buy TFR or military surplus, or use whatever came with the rocket. They are always in the "A" configuration from the manufacturer, it seems like.

 

[Cabernut]

If I'm building my own chute, which isn't that often, I'll go with option "B". Otherwise I'll use whatever it comes as. I would also be interested to hear about shroud lines for octagonal flat as well as hemispherical, etc.

 

[Bat-mite]

"B" would be my preferred, because it is the only way you can attach them to a link or swivel, etc., without crossing at least two of the lines. It has always baffled me why people make them in the "A" configuration. I don't think I have ever seen "C".

 

[NateLowrie]

"B" would be my preferred, because it is the only way you can attach them to a link or swivel, etc., without crossing at least two of the lines. It has always baffled me why people make them in the "A" configuration. I don't think I have ever seen "C".

"A" is solely an ease of construction thing. It's a lot easier to train people to always attach the end to the next point to the right.

 

[Bat-mite]

"A" is solely an ease of construction thing. It's a lot easier to train people to always attach the end to the next point to the right.

<sigh>

Why is life always dictated by the lowest common denominator?

 

[fyrwrxz]

<sigh>

Why is life always dictated by the lowest common denominator?

Hmm- I think Dr. Stephen Hawking said something to that effect, too.

 

[Lowpuller]

B requires different line lengths for a symmetrical canopy shape.

C has the best likely hood of success in the event that you break or blow one line out.

A well A is A, I've never found the twist to be an issue.

 

[new2hpr]

B requires different line lengths for a symmetrical canopy shape.

C has the best likely hood of success in the event that you break or blow one line out.

A well A is A, I've never found the twist to be an issue.

B does NOT require different line lengths. The measurement from the midpoint of each line (where the swivel would connect) to the attachment point is the same for all lines, so the lines must all be the same length.
-Ken

 

[Pat_B]

We provide our nylon parachutes with individual lines coming off the canopy so that the user can tie them into any arrangement they wish. Eliminates any hard feelings

 

[Incongruent]

We provide our nylon parachutes with individual lines coming off the canopy so that the user can tie them into any arrangement they wish. Eliminates any hard feelings

It would probably be better to just tie each line individually onto the snap swivel anyways.

Easy to ensure equal length.

 

[K'Tesh]

It would probably be better to just tie each line individually onto the snap swivel anyways.

Easy to ensure equal length.

But it's more work to do.

 

[Handeman]

I stopped using swivels on chutes a long time ago. The swivels go on the fin cans, that is what spins.

 

[GlenP]

This has been a really interesting THREAD!

 

[K'Tesh]

This has been a really interesting THREAD!

I see the LINE of puns has begun...

We'll keep stringing them on... one by one (knot!)

 

[Incongruent]

But it's more work to do.

Not if the lines are already individual.

 

[Incongruent]

the LINE of puns has begun...

They're taking over! Oh Chute!

 

[K'Tesh]

They're taking over! Oh Chute!

Deploy the troops! The Punishment begins now.

 

[Lowpuller]

Pat B,

Sorry but I have to disagree, it is simple geometry.

Yes you do need to attach the mid point of each line, but if the "middle" line that runs across the canopy is not longer than the other two lines, the inflated canopy will not be symmetrical. While it will be close enough to inflate the canopy it will be misshapen. Does this matter? Hard to say, probably not on a small canopy but would make a massive difference on a larger canopy.

I will throw in one caveat, if the diameter of the inflated canopy is the same as the distance between line attachment points the lines could be the same length but this would only be true for one specific canopy geometry. I am speaking in general regardless of inflated canopy shape.

 

[Incongruent]

Deploy the troops! The Punishment begins now.

Did you mean Punishment? :wink:

 

[K'Tesh]

Did you mean Punishment? :wink:

I will lift the Shroud of mystery and say "Yes"... and remember a good pun is its own reword.

 

[K'Tesh]

Pat B,

Sorry but I have to disagree, it is simple geometry.

Yes you do need to attach the mid point of each line, but if the "middle" line that runs across the canopy is not longer than the other two lines, the inflated canopy will not be symmetrical. While it will be close enough to inflate the canopy it will be misshapen. Does this matter? Hard to say, probably not on a small canopy but would make a massive difference on a larger canopy.

I will throw in one caveat, if the diameter of the inflated canopy is the same as the distance between line attachment points the lines could be the same length but this would only be true for one specific canopy geometry. I am speaking in general regardless of inflated canopy shape.

Just to be clear, this was intended as a conversation on the LPR/MPR sheet type parachutes, and not super performance parachutes used for other applications.

I'm pretty sure that if each line is the same length, the difference in shape between any of the three options given will be trivial. I was more concerned about keeping the lines from twisting up at the attachment point with the nosecone/swivel/shock cord.

 

[Incongruent]

Yes... and remember a good pun is its own reword.

What about a bad pun?

 

[K'Tesh]

What about a bad pun?

It should be punished (of course).

 

[Lowpuller]

K Tesh, understood and agreed.

A and C are less likely to cause twists in my opinion. If you use B the "middle" line can easily create an unsymmetrical canopy shape that will result in the canopy spinning or twisting up the lines, which is exasperated in a smaller size canopy.