folding a parachute

[iamthemik]

i feel like an idiot askng this but i dont think im folding my parachutes right. i recently launched my LOC-IV with a G in it and both times i launched it, the parachute wouldnt open. it just stayed all folded up.
the way ive always folded my circular chutes was id first lay them on the ground folded in half. then id fold it in half again so i get a 1/4 circle wedge with all the shroud lines going in one direction. id fold it in half a few more times so it looked narrow enough. then id fold the 1/16ish circle wedge the long way over in half (sometimes thirds) finally id wap the shroud lines around it.

is there anything im doing wrong? should i wrap the extra shroud lines differently?

thanks for anyones help!

PS its a 3 foot diameter circular nylon chute

 

[cls]

hmmm. sounds like you are doing it about right. did you wrap the shrouds a little too tight? was it cold out? was it a brand-new chute? did you fold the chute the night before or just before flying?

things you could try: wrap the shrouds more loosely; liberal sprinkling of baby powder; run the chute through the washing machine a couple times to loosen it up... or may be easier to just get another chute.


all my LOC chutes open up pretty reliably. however I have an unknown make chute, 36" round, and 2 times in 6 flights it has failed to open. it has pretty stiff and slightly sticky siezing on the fabric and it just doesn't open reliably even after running it through the washer.

 

[lalligood]

I've never had a problem with deployment after packing nylon chutes according to PML's recommendation:

https://secure.consumersinterest.com/pml/parachutepacking.asp

I even do a similar version for my plastic & mylar chutes for LPRs/MPRs in my fleet!

HTH,

 

[edwardw]

You might end up with twisted lines if you wrap the shrould lines around the chute. If you roll the chute into the shroud lines it has a less likely chance to tangle.

Edward

 

[DynaSoar]

Originally posted by edwardw
You might end up with twisted lines if you wrap the shrould lines around the chute. If you roll the chute into the shroud lines it has a less likely chance to tangle.

Edward

Yup. Don't wrap anything around anything. It can tangle and not unroll.

Always fold over one way, then back over the other, back and forth in a zig zag. Rather than halving and halving again your hemisphere, try folding a 16th over one way, then that back over the other. The result is the same size, with nothing trapped inside the fold of another part. If you can get it tight enough that you don't have to do the one crosswise fold, it'll be a smaller diameter bundle and slide more easily.

I wrap the shrouds and shock cord around my finger in a helix coil and tuck them into the tube, then slide the chute in only as far as the nose/payload coupler needs, and put the top on. The chute needs to come out more than the shrouds, so the sooner it comes out the better. If the shrouds comne out and the chute sticks, you've got problems. If the chute comes out and the shrouds stick, the chute's more likely to pull them out.

 

[JRThro]

Originally posted by DynaSoar
Yup. Don't wrap anything around anything. It can tangle and not unroll.

Always fold over one way, then back over the other, back and forth in a zig zag. Rather than halving and halving again your hemisphere, try folding a 16th over one way, then that back over the other. The result is the same size, with nothing trapped inside the fold of another part. If you can get it tight enough that you don't have to do the one crosswise fold, it'll be a smaller diameter bundle and slide more easily.

I wrap the shrouds and shock cord around my finger in a helix coil and tuck them into the tube, then slide the chute in only as far as the nose/payload coupler needs, and put the top on. The chute needs to come out more than the shrouds, so the sooner it comes out the better. If the shrouds comne out and the chute sticks, you've got problems. If the chute comes out and the shrouds stick, the chute's more likely to pull them out.

That sounds really good. Is that what you do for small-diameter model rockets as well? It's hard, at least for me, to stuff shroud lines into an 18 or 20 mm body tube if they aren't wrapped around the parachute.

All I have are model rockets with 18 mm motors, and all of my parachutes are Estes/Quest/Semroc plastic ones. Here's what I do, and it seems to work fine except for those times when a bit of the ejection charge gets past the wadding and spot-welds the chute together.

Fold the chute in half, then fold it in thirds by folding first the left third and then the right third over the center third. Make sure the shroud lines are reasonably well lined up. At this point you pretty much have an equilateral triangle with shroud lines coming off the bottom of it. Then you fold the chute in half along a horizontal line across the center, so you've now folded the top 'point' of the triangle down over the rest of it. Then more or less roll the chute into a cylinder and loosely wrap the shroud lines around it. Insert the shock cord into the body tube, followed by the parachute, followed by the nose cone.

This works for me, although folding the parachute over itself, rolling it into a cylinder, and wrapping the shroud lines around it does sound like it could cause the chute not to open very reliably.

Another thing I do is to attach the parachute to the shock cord maybe 2 inches from the nose cone. Doing this, it seems to me, almost ensures that the parachute will come out of the body tube every time the nose cone pops off.

 

[BobH48]

What I do with the plastic chutes is this:

Hold the chute by the center and pull the shroud lines tight.

You should have all the lines together and 6 triangle shapes sticking out.

Take 3 from each side and you have a diamond shape. Put the shroud lines down the center of the diamond shape and fold it in half over the lines giving you a triangle with the lines inside.

Then just fold the point down in thirds and roll the chute into a cylinder.

I have never had a chute folded like this fail to open properly except when I didn't use enough wadding and melted it.

I don't know if I explained that very well .