parachute wrapping for DD

I was setting up my rocket for an echarge test, and what i found was that i have to run my wire to the back/front end of the tube i want to compress (like the end opposite of what will open up).

i have a 1.5" wide by about 9.5" long tube, and both ends have an eye bolt which take a little space, but they don't take the entire area so stuff (shock cord and wires) can fit.

what is the best method for wrapping a parachute? I can use shock cord to tighten it if necessary.

With nylon parachutes, you fold them. Wrapping them with the recovery components, or with the shroud lines, is asking for trouble.

If someone doesn't beat me to it, I'll see if I can't find some pictures.

-Kevin

troj said:

With nylon parachutes, you fold them. Wrapping them with the recovery components, or with the shroud lines, is asking for trouble.

If someone doesn't beat me to it, I'll see if I can't find some pictures.

-Kevin

Click to expand...

i do fold it, it's a 30" x type, so i put the shroud lines in the middle, fold the sides into the middle, and then try to fold, but it's hard getting it not to be really tight inside the tube :O

anyone got tips? :O

Here's my folding technique. I've since refined it slightly, but the technique shown here should work well enough to ensure reliable deployment. In these pictures, I'm using a 24" spherachute, but this should work with just about any reasonably standard parachute.



First, lay the chute out such that on one side, you have two of the cord attachment points touching, with the fabric between them stretched out to the side (as seen in the left side of this photo):


Take the next shroud line and place it on top of the first two, again putting the fabric out to the side:


Take each subsequent shroud line and continue placing them in a stack, making sure that each time, the fabric between is stretched out on the same side:


Once you have done this with all of the shroud lines, take the final piece of fabric and fold it over on top of the rest. Your chute should now look something like this:


Next, take the shroud lines and lay them on top of the chute, like this:


Fold the chute down from the tip (I like to fold it in thirds) over the shroud lines:


Finally, roll the parachute from one side:

Taking the time to flake the gores (as shown in the 5th photo) makes a huge difference in how flat you can fold things.

You can roll the parachute after a fold or two, but don't wrap the lines or cord around it.

Folding parachutes is a bit of an art, and takes practice. I have an upscale Mars Lander where I have a heck of a time getting the parachute to fit. A friend, however, can fold it and fit it easily.

-Kevin

troj said:

You can roll the parachute after a fold or two, but don't wrap the lines or cord around it.
-Kevin

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If you "wrap" like you roll up a water hose, i agree is a bad thing...
But you can Roll the shroudlines around a folded chute.
I have had success with that technique.

troj said:

Taking the time to flake the gores (as shown in the 5th photo) makes a huge difference in how flat you can fold things.

Click to expand...

Oh, absolutely. There are several different methods that I've used that work, but all of them involve flaking the gores. It makes it pack smaller and causes a substantial increase in reliability of opening.

This is from Fruity Chutes:

How to pack a Fruity Chute

Greg

GregGleason said:

This is from Fruity Chutes:

How to pack a Fruity Chute

Click to expand...

Most of that is really good info, but I disagree strongly with wrapping the lines around the canopy. If not kept tight the entire time until deployment, you can have lines shift such that when things pull tight while it's trying to deploy, an earlier stow is held down by a later stow, resulting in a parachute that won't deploy.

Of course, once it hits the ground and there's slack again, it unrolls. I've seen it happen far too many times. An easily preventable problem by never wrapping the lines around the parachute.

Consider the fact that man-rated parachutes never do this. Those systems are designed for reliability.

-Kevin

troj said:

Most of that is really good info, but I disagree strongly with wrapping the lines around the canopy. If not kept tight the entire time until deployment, you can have lines shift such that when things pull tight while it's trying to deploy, an earlier stow is held down by a later stow, resulting in a parachute that won't deploy.

Of course, once it hits the ground and there's slack again, it unrolls. I've seen it happen far too many times. An easily preventable problem by never wrapping the lines around the parachute.

Consider the fact that man-rated parachutes never do this. Those systems are designed for reliability.

-Kevin

Click to expand...

Thanks Kevin. I didn't realize that this technique had a risk associated with it in certain conditions. I'm always looking for high-reliability techniques for recovery.

I would think that as chute size increases, the greater the need to adapt every man-rated process that is practical to insure a successful deployment.

Greg

I absolutely agree with Kevin - NEVER roll the lines around the canopy. Ideally, you would want to have a deployment bag with line stows, but in the absence of that option, I carefully place the lines inside the canopy as shown in my sequence above.

Also, with that Fruity Chute method, you could decrease pack volume and increase reliability by flaking the gores after gathering the lines (they do say to organize the gores, but it's hard to tell what they mean by that statement). It's more effort, but IMO, it's worth it. The difference in reliability is pretty close to negligible, but the pack volume difference is not.

troj said:

Most of that is really good info, but I disagree strongly with wrapping the lines around the canopy. If not kept tight the entire time until deployment, you can have lines shift such that when things pull tight while it's trying to deploy, an earlier stow is held down by a later stow, resulting in a parachute that won't deploy.

Of course, once it hits the ground and there's slack again, it unrolls. I've seen it happen far too many times. An easily preventable problem by never wrapping the lines around the parachute.

Consider the fact that man-rated parachutes never do this. Those systems are designed for reliability.

-Kevin

Click to expand...

If you have a large parachute where it is webbing and not cord, i dont see that occuring. If it is rolled in a spiral fasion, i also see that problem eliminated.

i pack my chutes, the pml/top flight method CJL shows, and with rolling as the fruitychutes shows, and aslo the GLR tac 9 shows to pack with rolling.
Never had my lines tangle from either one, but have had lines "twist" together from looping them back into the canopy just like in CJL's picture. If you had a slider, this could foul it. (maybe why you cut to a reserve when you have a streamer main, in skydiving)

Removing trapped air from the canopy is the biggest factor in removing volume from the pack from what I have found. The cords have the same volume on the inside vs outside of the canopy packing.
Organizing, gathering, or flaking gores, i think is an understood principal in removing air from the canopy as its rolled, or folded.

anyone have a tutorial of how to tightly wrap an x type? the way cjl describes doesn't work since the entire edge of the chute has shroud running through it to increase strength. i was able to fit it easily without the folding, but then the shroud lines easily popped out when i pulled at the shock cord. is that a problem? like will the shroud lines be pulled, and the actual chute will be left sitting in the bay, or should i ground test first, ask questions later?

Funny you should ask...... yes I do.

The first time I open & use a new chute, I take pictures so I can remember how to fold it. [different types of chutes]
Every chute I have bought comes folded in the smallest volume you can find.

Here is how Topflight folds X chutes. This is a 54 and folds to a size like a handkerchief goes in your suit pocket. If you do it like this.

Every time you fold, you are folding in half over itself. except when you fold the pointy tip down/up [picture orientation] to make a rectangle.

Notice how all the shroud lines end up next to each other in this method also.

Chute is rolled in nomex burrito style,

After chute is tucked in, shroud lines and shock cord are Z folded in nomex flap.
[chute is underneath in first fold]

Then the flap is folded over the lines & the whole thing rolled up and slid in airframe.

I use a standard round 30 inch chute in my 38diam. rocket. 9.5 inches of length to pack it all in & have no problems making it fit loosely with 15 of Kevlar and a 8x8 nomex cloth. Final shot is what goes in mine.

my topflight 72" x-type is darn near folded like CJ's. Only part that is different, is tis folded in triangles like a flag instead of square at the end.(by thier instuctions.

X-type chutes, are much easier to get a larger size in a smaller volume. Although a 72" x-type, only provides as much drag as a 55-60" hemispherical chute.
I love them.

Jim i tried it that way, but the x type ultra has way thicker sides, like as thick as the shroud lines, and when i fold/roll it as tight as i can, the sides still come out wayyy too thick. is it a problem if i leave it alike a longer burrito and just make sure the nomex has got my back?

A point to be stressed is that not all parachutes of a given size or style can be packed in a small airframe. You need to use common sense in the selection of fabric weight. Heavy weight fabric is incompatible with compact and lightweight parachutes. 1.1 oz fabric is frequently used for man-rated parachutes so it is sufficient for people sized rockets.

Bob

bobkrech said:

A point to be stressed is that not all parachutes of a given size or style can be packed in a small airframe. You need to use common sense in the selection of fabric weight. Heavy weight fabric is incompatible with compact and lightweight parachutes. 1.1 oz fabric is frequently used for man-rated parachutes so it is sufficient for people sided rockets.

Bob

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really, people sided rockets...???
i thought i had a bit much at margarita thursday...

the weight of the fabric has much more to do with pourosity than does strength. *(doesnt it??)*.. being added silicon coating and such..

i agree a 1.1 oz can pack tighter than a 1.9 oz. to some degree.... but just us a space pack and a vaccuum cleaner...! it will get both as small as can be...

edwin, try the triangle fold... my ultra is packed that way, i can fit my 72" into a 3" no propblem...

ClayD said:

the weight of the fabric has much more to do with pourosity than does strength. *(doesnt it??)*.. being added silicon coating and such..

Click to expand...

Not really - porosity is more based on coatings and type of fabric than on weight. 1.1 oz ZP (zero porosity) nylon is probably my favorite chute material, but not very many chutes are made out of it. It's what most high-performance skydiving rigs use. You can spot it because it feels kind of slippery and crinkly.

cjl said:

... Also, with that Fruity Chute method, you could decrease pack volume and increase reliability by flaking the gores after gathering the lines ...

Click to expand...

I am not familiar with the term "flaking the gores". Chris would you mind explaining what it means and why it is helpful for chute reliability?

Greg

Flaking the gores simply means to stretch out each gore with your hand in sequence, usually while keeping the shroud lines centrally located. I do it in my method shown above - it's the step in which each gore is stretched out to the side, in roughly the second or third through the fourth picture. The fruity chute method already somewhat includes this, but if you explicitly do it with each gore, it helps to ensure all of them are correctly arranged. As for why it helps with chute reliability? It makes sure that all of them are in the correct position to catch air when the chute comes out, and also helps the chute inflate evenly. It's not really important on small chutes, but I do it anyways.

edwinshap1 said:

Jim i tried it that way, but the x type ultra has way thicker sides, like as thick as the shroud lines, and when i fold/roll it as tight as i can, the sides still come out wayyy too thick. is it a problem if i leave it alike a longer burrito and just make sure the nomex has got my back?

Click to expand...

It's and Ultra X, yep your toast. That's kinda overkill for such a small project.

Ditch it go with something standard and all your troubles will be over! If this is for your 38mm minimum diam. a standard 24in should do the trick and be very easy to pack.

If you insist on using it & the nomex can do it's job, you will be fine.

blackjack2564 said:

It's and Ultra X, yep your toast. That's kinda overkill for such a small project.

Ditch it go with something standard and all your troubles will be over! If this is for your 38mm minimum diam. a standard 24in should do the trick and be very easy to pack.

If you insist on using it & the nomex can do it's job, you will be fine.

Click to expand...

yeah, i'll probably end up getting a normalish chute when i get to nsl, but until then, planning for the most difficult always works lol.

it was cheap and sounded strong. so tehre's no problem of shroudlines shredding if the chute opens with drogueless recovery?

cjl said:

Flaking the gores simply means to stretch out each gore with your hand in sequence, usually while keeping the shroud lines centrally located. I do it in my method shown above - it's the step in which each gore is stretched out to the side, in roughly the second or third through the fourth picture. The fruity chute method already somewhat includes this, but if you explicitly do it with each gore, it helps to ensure all of them are correctly arranged. As for why it helps with chute reliability? It makes sure that all of them are in the correct position to catch air when the chute comes out, and also helps the chute inflate evenly. It's not really important on small chutes, but I do it anyways.

Click to expand...

Ok great.

Thank you for clarifying and it makes sense.

Greg

Reference used for parachute material weight.

https://books.google.com/books?id=2...v=onepage&q=weight of parachute cloth&f=false

Bob

ClayD said:

the weight of the fabric has much more to do with pourosity than does strength. *(doesnt it??)*.. being added silicon coating and such..

Click to expand...

No.

Fabric weight is just that -- fabric weight. 1.1oz nylon is lighter than 1.9oz nylon -- the fabric itself. Coatings and treatments, such as making it zero porosity, are independent of fabric weight.

Coated 1.9oz nylon is heavier than uncoated 1.9oz nylon.

Zero porosity 1.1 oz is lighter, and lower porosity, than 1.9oz nylon. ZP 1.1oz is the same weight, but lower porosity, than standard 1.1oz.

-Kevin

troj said:

ZP 1.1oz is the same weight, but lower porosity, than standard 1.1oz.

-Kevin

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troj said:

Coated 1.9oz nylon is heavier than uncoated 1.9oz nylon
-Kevin

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(you confuse me with that statement:smile

The places I have found that sold 1.1 (coated) didnt call it 1.1 . they called it 1.x. they added the coating into the fabric weight.

i understand 1.1oz fabric as a substrate can be a standard 1.1, or a 1.9oz zp if it has .8oz sqft of coating.

I completely mistated what i was thinking in my previous post... (must have been the margaritas...)... again, i am just going off what I have seen on the internet when i have shopped for parachute fabric.


Purosity, makes removing the air from the pack, much easier.