Hexagon Chutes: How do you you arrange your shroud lines

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

So, which arrangement do you use to attach your shroud lines?

  • Option A: the "Triangle" arrangement

  • Option B: the "Parallel" arrangement

  • Option C: the "Crossing" arrangement

  • Another method.


Results are only viewable after voting.
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.

Actually, if you make all three lines the same length, B will have all the same length shrouds, just like A & C. There will be no asymmetrical shape unless the canopy is cut out uneven. If you cut out a 12" hexagon that is a perfect hexagon and all three shroud lines are 24" long, all six shrouds will end up 12" long.
 
Actually, if you make all three lines the same length, B will have all the same length shrouds, just like A & C. There will be no asymmetrical shape unless the canopy is cut out uneven. If you cut out a 12" hexagon that is a perfect hexagon and all three shroud lines are 24" long, all six shrouds will end up 12" long.
Mathematical proof please!
Remember, shrouldines and barrel swivel loops have a thickness greater than 0. Thus the lengths will be less than 12, maybe a different amount less for the middle one, maybe not.
 
Mathematical proof please!
Remember, shrouldines and barrel swivel loops have a thickness greater than 0. Thus the lengths will be less than 12, maybe a different amount less for the middle one, maybe not.

Why would the middle one be any less then the others? You use the same length to attach each end and the same amount goes into the loop for the swivel. The final shrouds lengths from the swivel loop to the chute material will be the same for all six shrouds. If you use 24" long lines, of course they won't have a final length of 12", but they will all be the same.
 
B is the only consistant way to eliminate most of the inherent "built in twist" that occur with both A & C.
I've been building my own Flat, X and Hemi chutes for years. I found layout B in the early 1980's. Every Chute I've built since has had that arrangement for 3, 4, 6, & 8 Shroud chutes. Another thing is I always use either a ball bearing or Heavy duty swivel with all my competition, Sport and Hemi Nylon chutes.
All shroud lines are exactly the same length in every instance. I've also discovered that using very light 13lb to 50lb kevlar instead of Cotton, nylon or rayon as shroud lines completely eliminates burned off chute lines.

View attachment 6-Shroud line (12 attachment points)-b1c_12-03-09.pdf

View attachment 8-Shroud line(16 attachment points)-c1b_12-03-09.pdf

Comp Chutes-a_25mil, KevlarThread& tapestrips_08-27-06.jpg

Plastic Hemi Chute-b1-sm_Completed 10in 6gore_01-12-00.jpg
 
Why would the middle one be any less then the others? You use the same length to attach each end and the same amount goes into the loop for the swivel. The final shrouds lengths from the swivel loop to the chute material will be the same for all six shrouds. If you use 24" long lines, of course they won't have a final length of 12", but they will all be the same.
I don't know, but I think it has to do with how Estes makes the middle line longer. So I'm assuming people thought of a reason and 'because it should be' worked for them. The reason could be valid- or not.
 
I don't know, but I think it has to do with how Estes makes the middle line longer. So I'm assuming people thought of a reason and 'because it should be' worked for them. The reason could be valid- or not.

While I haven't measured any shroud lines from one of the new factory made parachutes, there was no such longer middle line back in the day when builders had to do it for themselves.

I cite this example from the Estes Der Big Red Max (1977)'s instructions for the 18" parachute.

Estes 18 inch parahcute instructions (Der Big Red Max).png
 
Last edited:
With a hexagonal chute, the distance across the chute is the same as double the distance of two edges. So going across the chute with one of the lines works out.

With an octagonal chute, that relationship doesn't exist, so the shroud line going across the chute needs to be longer. Depending on the size of the chute, you may not notice and the chute may be pulled in a little bit.
 
With a hexagonal chute, the distance across the chute is the same as double the distance of two edges. So going across the chute with one of the lines works out.

With an octagonal chute, that relationship doesn't exist, so the shroud line going across the chute needs to be longer. Depending on the size of the chute, you may not notice and the chute may be pulled in a little bit.

Don't worry about the size and shape of the canopy. You are going for the same shroud line length from the canopy to the anchor point (swivel) of the shroud. If you cut all of your lines the same length, use the same amount to attach to the canopy and the same amount a the swivel, all of the shroud lines will be the same length from the canopy to the swivel. It can't work any other way.

The only thing that would give you an asymmetrical chute is if the distances from point to opposite point on the canopy were not the same. It doesn't matter if it is a 4, 6, 8, 10, etc. sided canopy.
 
I should have mentioned that I was talking about arrangement "B" where one of the shroud lines goes across the canopy. It works out just fine as a hex with all lines being the same length, but the length of the line that goes across the canopy has to be longer with an octo.
 
I should have mentioned that I was talking about arrangement "B" where one of the shroud lines goes across the canopy. It works out just fine as a hex with all lines being the same length, but the length of the line that goes across the canopy has to be longer with an octo.

Why? If you make that one longer, what's going to happen when you fold the canopy for packing and have all the shroud line attachment points together? When you pull the swivel, that longer line would form two loose shrouds while the rest of the shroud lines are tight.

So instead of using 4 long lines on your octagon chute, use eight individual lines. Which two have to be longer to match the longer line you say is needed?
 
I just read one of those necrothreads (about the sizzler rocket cars), thought about this and decided to dig it up.

Bump (in the night)
 
Back
Top