Ripstop nylon for chutes

Hello:

I'm looking at several online vendors who supply 1.1oz ripstop nylon for making my own parachutes (12" to 48"). They offer it in uncoated and silicone coated. Most vendors have more color choices available in coated ripstop. Can anyone share an opinion as to whether the coating will affect parachute performance?

Thanks!

ghp3

Having made the majority of the chutes I own, but not having any solid data to back it up, the coated nylon will give a better CD than the non-coated nylon. Less porosity equals a higher CD.

However, the coated nylon is usually stiffer and will not pack quite as small for a given size.

FWIW, I think the descent rate difference between the two is negligable.

But I prefer the material many L1 kits come with, the stuff standard TFR, PML and LOC chutes use, I love my more advanced chutes (TAC-1, covert recovery, rocketman, and I dont have any but quantom chutes are nice) but the material is very slick and harder to pack... but it also seems much thinner then the TRF, PML and LOC material...

Is the slicker material silicon coated?

The REALLY slippery stuff, like that in Rocket Rage chutes is ZPN. It has the highest drag, and feels almost impossible to hold.

Stuff like PML chutes is LPN, which doesn't have as much drag, but is easier to fold just because it isn't sliding around like a wet noodle...

idea what TAC-1 and covert recovery are using? My TAC-1 chute is pretty slippery, but my big CR chute is the slipperiest I have ever used... havent used a QT so I dont know how to compare the two.

Tac and skyangle feel somewhere between the rocket rage and the PML. Skyangle cert 3 and classic 2 feel like the rage, but are MUCH thicker (the rage is just as slippery and a lot thinner, which gives it the "wet noodle" feel).

Tac is pretty slippery - feels almost like the RR, though not quite there. Never used a CR, so not a clue about that one.

is a pretty thin slick material so I would assume its similar to QT from what you desribe... would be a pain in the @$$ to pack it normally, but Jeff at covert included a custom (I didnt like the basic design of his D-bags) pilot chute released D-bag to my specs, very nice service!

The D-bag makes the slick chute a LOT easier to pack, I think the biggest benifit is that I dont have to worry about it unwrapping after I put it into the airframe, some of my other slick chutes that just get folded normally are nice and neat but then when I put them into a large diameter tube they unravel a bit, so I usually end up wrapping the shrouds around to keep them rolled nice and tight, works nicely and slows down the deployment.

Originally posted by jraice
idea what TAC-1 and covert recovery are using? My TAC-1 chute is pretty slippery, but my big CR chute is the slipperiest I have ever used... havent used a QT so I dont know how to compare the two.

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If it's really slick, sounds like a trash bag when you rumple it, and you can read a newspaper through it, then it's zero-porosity nylon.

ZP is great because it's exactly that -- zero porosity. Air doesn't go through it, which means higher drag per unit of material, so the chute can be smaller.

ZP is also a pain because it's slippery as snot. In the skydiving world, many riggers won't pack ZP reserves, because they're such a pain to pack.

I have some ZP chutes made by a rigger buddy; great stuff! Hard to pack because it's like trying to fold a handful of worms.....

-Kevin

for rocketry use do most ZP chutes have a spill hole? or does the air just dump out of the sides?

Originally posted by troj
If it's really slick, sounds like a trash bag when you rumple it, and you can read a newspaper through it, then it's zero-porosity nylon.

ZP is great because it's exactly that -- zero porosity. Air doesn't go through it, which means higher drag per unit of material, so the chute can be smaller.

ZP is also a pain because it's slippery as snot. In the skydiving world, many riggers won't pack ZP reserves, because they're such a pain to pack.

I have some ZP chutes made by a rigger buddy; great stuff! Hard to pack because it's like trying to fold a handful of worms.....

-Kevin

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Most parachutes use a spill hole for stability.

The drag difference between ZP and porous rip-stop is equivalent to a 5% or less difference in the spill hole size. Point, ZP doesn't matter much for chute design in our size rockets.

I have a 20" Recovery Technologies chute that is as Kevin describes, slippery as snot! It is the very thin, crackly, rip stop nylon. It will pack very small, when you can contain it. Most of the time, just as I'm about finished, it'll all come flying out one end or the other when rolled. Kind of like an over stuffed burrito. I prefer the type that Top Flight offers, due to the ease of handling and packing.

Originally posted by CQBArms
for rocketry use do most ZP chutes have a spill hole? or does the air just dump out of the sides?

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Depends on the design.

I have two ZP drogues; neither has a spill hole. I have another parachute that has one.

The biggest difference a spill hole makes is in stability -- if air spills out the side, the parachute will tend to oscillate back and forth (or in the case of a cruciform, which is what the Rocketman chutes are, they pulse like a jellyfish). A spill hole gives the air somewhere to go, so the descent is more stable.

That's why the parachute I had made for my 2x Mars Lander has a spill hole -- oscillation = broken legs.

-Kevin

Cool and thanks for the info guys. I was just wondering if being less porous it would make them less stable in the same design.

Originally posted by troj
Depends on the design.

I have two ZP drogues; neither has a spill hole. I have another parachute that has one.

The biggest difference a spill hole makes is in stability -- if air spills out the side, the parachute will tend to oscillate back and forth (or in the case of a cruciform, which is what the Rocketman chutes are, they pulse like a jellyfish). A spill hole gives the air somewhere to go, so the descent is more stable.

That's why the parachute I had made for my 2x Mars Lander has a spill hole -- oscillation = broken legs.

-Kevin

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I have no idea what is what as far as mil or coated, but this is all ripstop I've picked up on the $1/per yd table at Wal Mart, and $1.50/yd clearance at Joanns. The silver/grey stuff on the far left is very thin, smooth, and slippery,. Good stuff for tight packing and small BT diameters. Although, without talc it wants to stick together like a trash bag....static I suppose. The purple, burgundy, and light grey are like the stuff Top Flight chutes are made of. The black is just a hair thicker than the others and has a very tight weave, and much much smaller ripstop squares. Doesn't pack quite as tightly, but still not bad, good for larger chutes. The brown has the thickest mil and may not get used unless I have a need for a very large chute.

Bottom line is, I've made sheets and chutes out of all of the material shown except the brown. All of them will work, I just buy whatever appears to be ripstop and on sale. I've even mixed and matched materials on the same chute with pretty good results. Here is a 16 gore I made today out of three different colors and mils....

Very cool chute! I wish I could do that.

You can CQB! I just started messing with the sewing machine a couple days ago. Never sewed a day in my life before now. Wife gave me a few pointers, VERY few in fact, and I went to town. I had been doing the cutting and pinning while she sewed, up until now. And I must say, mine turned out better than hers!

I took pics and documented it most of the way. I may do a short step by step of the process, although it is not a sewing tutorial by any means. I wouldn't begin to try and explain sewing since I'm such a newb, but it could be helpful to some folks on how to make an actual chute. I just used knowledge I gathered from a few threads here, I can't take much credit, but it might help to make it more concise.

Yeah a parachute build thread would be great.

I like the little attachment tabs on the chute, would be nice for LPR nylon chutes (not sure what that chute's size is from the pic...) because you could still use the cheap light materials but if a shroud got burnt or broken you could just untie it from the more solid nylon "attachment tab", and attach some more...

Originally posted by jraice
I like the little attachment tabs on the chute, would be nice for LPR nylon chutes (not sure what that chute's size is from the pic...) because you could still use the cheap light materials but if a shroud got burnt or broken you could just untie it from the more solid nylon "attachment tab", and attach some more...

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Or tangled into a huge knot! I like this method.

Originally posted by CQBArms
Yeah a parachute build thread would be great.

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There have been several CQ I'm sure a search would get you alot of hits. I know i posted full size gore pattens for several size rip-stop Hemi's
We sew the shrouds right into the seam lines. Like you I'm not to good with the machine but my wonderful better 2/3rds is more then willing to help, so I cut the gores and help her Pin up the pieces she does the stitching

Whenever we're out we stop by the fabric shop(s) just to check for nip-stop nylon, when we catch it on sale we pick-up a few yards of whatever colors are available. I now have a pretty good selection of colors mostly in the very thin stuff. Don't overlook some other materials while your looking like real silk, it does pack a good bit tighter then even the thinnest rip-stop nylon