Tangled Parachutes

[Sartori42]

Between my son and I, we have 5 rockets in our fleet. Four of them have standard plastic chutes and my Interceptor E has a nice nylon chute. I never have a problem with the nylon chute, the lines have yet to get tangled at all, but we always have tangled shroud lines in the (cheaper) plastic ones. It seems to me like the string is too thin, or it is "sticky" because it clings to the other lines, or something else. I'd appreciate some feedback if others have had this problem and how you might have fixed it.

 

[mjennings]

How are your chutes attached? Are you using fishing snap swivels? http://www.rocketryforum.com/showthread.php?t=770 (there may be a couple more similar threads if you search I just remembered this one right off the bat) How close are all your lines to being the same length? It may also be how you are packing your chutes. http://www.rocketryforum.com/showthread.php?t=1413

I know one that usually gets me is chutes I fixed with squares of duct tape got wadded because there was a small over lap of tape that touched another part of the chute.

 

[Sartori42]

My chutes are attached with fishing swivel snaps. In fact, my 24" plastic chute for my Big Daddy uses a small swivel on each line (2 attachment points), and the three swivel snaps attach to a larger swivel snap that attaches to the loop in the shock cord. The individual lines are tied to the swivel at their midpoint so they don't slip to different lengths. Still I had tangles.

I pack my chutes based on what I've read here and on the kit directions. I pull the chute to a point in the middle and pull the shroud lines down from that. I either fold or roll the parachute, and wrap the shroud lines (as carefully as I can) around the chute.

 

[Conan4480]

I pack mine the way the estes instructions say as well. Everything from the 12" plastic chutes to the 36" nylon chute. I have only had one chute tangle on my but that was my big bertha on a D12. I think the delay was to short and when the chute deployed it whipped the rocket around to get the aft end tangled in the shroud lines.

 

[Micromeister]

I do a couple things to prevent tangled chute shroud lines.

First is to attach the shroud line parallel to each other rather then around the outer edge as the instructions indicate, they reduces the shrould line twist introduced by that method. One picture is worth more on this modification.

Second: is to install a snap swivel on each one. on smaller chutes I've found #14's seem to work well, for 18" and Up #10's. for larger then 24" nylon chutes I use #2 or #3 swivels.

Third: for most of my personal models I chuck the cotton thread, replacing it with 13lb 2-strand kevlar and chrome adhesive backed Trim MonoKote 1/2" x 1/2" square tape tabs on all plastic chutes. A roll of this stuff (600yds) cost about 20 bucks from Edmund Scientific on-line. it's just great stuff to have around for all likes of lightweight tough line jobs

Some times a cardboard seperator disc helps also.

Hope this helps a little.

 

[jflis]

One common problem that I see a lot is how the shroud lines are wrapped around the parachute during the last part of packing it.

Many folks will fold and roll up the parachute until it is small enough to fit in the body tube. THEN, they will hold the parachute in one hand and "wind" the bundle of shroud lines around the parachute (like, if you were winding thread back onto a spool) Each time you do this you put a twist in the shroud lines. If it takes, for example, 5 wraps to get the shroud lines wrapped around the parachute, you now have 5 twists in the lines.

What you should do is take the rolled up parachute and "roll" it in your fingers to take up the shroud lines, this will help prevent tangles.

All of the other tips here are also good.

Hope this helps, and good luck!
jim

 

[Sartori42]

John,

My shroud lines are parallel as shown in the photo. I also use snap swivels on all the parachutes. They still get tangled. I started this thread yesterday as I was trying to untangle a couple chutes and was feeling quite frustrated. The cotton line seems to be an issue as I try to untangle them. The fibers want to stick to each other, but I don't know if that would be an issue when the weight of the rocket is hanging under the canopy and the airstream has the chute inflated. All I know is the plastic chutes get tangled lines, but the nylon chute doesn't. Grrrrr......

I'm thinking about using fishing line. Has anyone used that?

******************

Jim,

I'm quite careful to wind the shroud lines straight, but I can't claim anything for my son. I let him pack his own chutes and that may be one of the problems. His are the worst of the tangled messes. But, mine did get tangled as well. I guess the gist of my question is why do the plastic parachutes get tangled when the nylon one doesn't?

Thanks guys.

Steven

 

[mjennings]

John, on your parallel installed shroud lines, what lengths of shroud lines do you use? Your illustration makes it look like you use 2 different lengths.

 

[gpoehlein]

John,
Jim,

I'm quite careful to wind the shroud lines straight, but I can't claim anything for my son. I let him pack his own chutes and that may be one of the problems. His are the worst of the tangled messes. But, mine did get tangled as well. I guess the gist of my question is why do the plastic parachutes get tangled when the nylon one doesn't?

Thanks guys.

Steven

My question is: are the shroud lines on the nylon chute a different material from those on the plastic chutes?

I know that cotton thread can get the "fuzzies" that cause the separate strands to grab and hang on to each other (kinda like velcro). One thing I have used with some success is to get some beeswax and coat the cotton thread with that. I found mine at Michaels in the sewing supplies - just start at one end of the thread and run the wax ball down the length of the thread, pressing the wax ball hard against the thread. As I said, I have had some luck with that holding down the frizzies, and, so far, it hasn't caused any problems with the ejection charge.

mjennings - John's illustration is not to scale - all the shroud lines should be the same length.

 

[Micromeister]

mjennings:
All shrould line are equal length regardless of the number. I use 3, 4 and 6 lines. 4 and 6 mostly on competition mylar chutes, but all 6,8 or 12 ends are attached to the canopy parallel to each other. When they are pulled in at the load end of the shroud loops, they "even out" As Greg menitoned the illistration is not to scale. but even if it were the lines Wouldn't look like they were the same length.

Steven: I'd be very careful what type Fishing line I'd try to use for shrould lines.
most monofilament lines will be very stiff and unruley to handle. Braided nylon line would probably be OK, but i'd say away for Spider wire or other Spectra blends as it can't take even a little heat. We use it sometimes for Burn strings with HD models
That's one of the reasons I mentoned the Kevlar thread. it looks like it's to fine but it's much stronger then it looks and it's Heat resistant. KEVLAR is not flameproof.
You might also want to try buying Kevlar line on-line from the Thread Exchange. they have a ton of different lines to choose from if you thing the 13lb test material is to light.

By the way Kevlar lines also make Excellent Shockcords and/or Anchors.

 

[foose4string]

I've also used Kevlar for shroud lines. As Micro pointed out, it's super strong and heat resistant. I think it is less prone to tangle when using the "bonded" type. Thread exchange is an excellent source. The sizing can be confusing at first, but the new layout of the site should make it easier. . The key is getting the bonded type or you'll have the same problems as cotton thread...or worse. Kevlar can be a bit expensive compared to nylon or cotton lines, and frankly, a bit of overkill as shroud line material, but it's a good alternative if you're having problems with the other. Dacron fishing line may be another alternative. I've use this on nylon chutes and it holds up pretty well. Again, less tangle prone. Not as heat resistant as Kevlar, but not as susceptible to heat as the newer braided fishing lines.

 

[Pat_B]

I've used a brand of fishing line called something like Spiderwire and it worked well. There are so many different types of line that can be used. I agree that the thin cotton is just too flimsy and is likely to get tangled up too often.

When choosing line, be care not to choose a wound product that has a twist to it. Stick with braided products or single line product.

 

[MKP]

I've used regular old dental floss with fair success. It's quite strong and I've never seen it burn through. Minty fresh when you tie knots with your teeth as well.

 

[hcmbanjo]

Once again - Mr. Poehlein has a great tip.
Running your shroud lines through beeswax is a great way to clean up shroud line fuzz. It'll also stiffin up the line a little and can make tying knots a little easier.
My uncle used beeswax on model ships. When rigging lines have been pulled through bees wax, the lines wouldn't absorb moisture in the air and sag.

A lot of the tangling happens at recovery when the nose cone passes between shroud lines. Instead of tying your parachute shroud line ends directly to the screw eye (at the nose cone base) Try this:

With your shock cord out and extended (loose - not stretched) divide and mark it in thirds.
Tie a 1/2" loop in your shock cord 1/3 the way down from the nose cone.
Attach your snap swivel (and parachute) to this loop.
Now your parachute is farther away from the nose cone and less chance of recovery tangles.
During recovery the nose cone will be between the parachute and rocket body.

 

[hcmbanjo]

I looked again at the illustration in Micromeister's post #5. The second one in blue showing the "Non-Tangling Disk" doesn't make sense to me.
I tie my snap swivels on the opposite way. My shroud lines go into the small loop end, not the bigger side that you open and close.
Every parachute (and streamer for that matter) in my stash has a snap swivel attached.
I can switch out different sized chutes and streamers quickly.
If you did tied it like the illustration, you would go through the hassle of removing the chute and dealing with that small knot or loose shroud lines.

To Micromeister:
I'm not trying to take anything away from all your photos and information. I often see things in a new light reading your posts. Maybe I've done it wrong all these years? Everybody has different techniques that work great for them.

 

[mjennings]

Thanks for the info John, I'll have to give that a try.

 

[Micromeister]

Apologize for the confusion:
That's not one of my drawings, it's an illistration used for attaching sensers and other Items to free parachutes and/or Nosecones

The Cardstock seperator disc is the important part of that drawing, not the swivel attachment.

I normally attach my Snap Swivels to the shroud line loops the other way also. But do bare in mind it is possible to use the swivels as shown if you attach the wire loop end to the shockcord.
I have seen this done on some scale models that sometimes use more the one chute on different parts. The snap attached the the shockcord allow different recovery grouping of pieces.

Again sorry for any confusion, The seperator disc was the intended object.
Hope this helps.

 

[gpoehlein]

I just had a thought about John's shroudline arrangement - the illustration shows how to rig six shroudlines for a hex chute. How do you rig the shroudlines for an octagonal chute?

My guess is as follows: If you number the points of the chute as:

__1....2
8..........3
7..........4
__6....5

Then I'm assuming that shroudlines would connect 8 to 7, 1 to 6, 2 to 5 and 3 to 4. Is that correct? (ASCII art don't work so well on this forum! )

 

[Micromeister]

I just had a thought about John's shroudline arrangement - the illustration shows how to rig six shroudlines for a hex chute. How do you rig the shroudlines for an octagonal chute?

My guess is as follows: If you number the points of the chute as:

__1....2
8..........3
7..........4
__6....5

Then I'm assuming that shroudlines would connect 8 to 7, 1 to 6, 2 to 5 and 3 to 4. Is that correct? (ASCII art don't work so well on this forum! )

Absolutely Greg:
I do 6, 8, 12 and even 16 shroud Competition chutes the same way. Or perhaps in the direction of you dotted lines.... Took me a minute to understand your written discription but recognized the graphic pattern immediately LOL!!!! In any event, by simply keeping all the shrouds going in the same direction it really prevents a lot of line twist as the loops are gathered to the center load point for attachement to our snap swivel that further reduces the amount of line twist created during packing. As someone pointed out earlier try to get in the habbit of rolling the canopy into the shrouds rather then twisting the shrouds around the canopy. You'll be amazed at the difference.

Another point that really needs to be brought out; Shroud length and amount of loop under the tape disc or line tied through the hole need to be kept as close to equal as possible. accuretely cutting our shroud lines to the same length, then tying the stop knots and making our attachment open loops help maintain an even or nearly so pull down point under the center of the canopy.
Over time I've learned that adding an overhand knot about 3/16"-1/4" from each end of the shroud helps prevent line pull outs using a 1/2" half loop under my tape strips.
Keeping these line lengths pretty close and adding a 3/4" or 1" spill hole in the dead center of the chute all but eliminates the dreaded "Plastic Canopy" air spill oscillation swing seen so often on Plastic and mylar chute models. After these chute modifications most models decend hanging nearly vertically below the chute regardless of wind speed aloft.
Hope these comments help.

 

[gpoehlein]

We're (Launch Crue) having a regional this weekend - I'll have to give this a try. I haven't made my parachutes for PD yet, so I'm going to try a 36" octo chute for that. Of course, the whole shroud line issue is more or less moot if you run your shroudlines over the top of the chute and then gather them all together at the other end and tie those loose ends into a loop. Advantages: the shrouds are easy to make all the same length, the chute is stronger and the shrouds can't pull out. Disadvantages: Those shroud lines over the top do add a LOT of bulk to the packed chute. But, I nearly beat Chad Ring with a 36" over-the-top garbage bag chute in a 30mm diameter cardstock rocket! Let's see what I can do this weekend!

 

[Micromeister]

Greg:
Good luck! hope you do well. To be honest; the only time I use over the top shroud lines are on Egglofter and payload models. As you just mentioned they simply add Way to much bulk to the packing.
If your using precrumpled 1/4mil mylar or drycleaner bag, it's just not necessary.
What are you using to hold the shrouds in place? Either way standard or over the top, I've found silver mylar packing tape or silver adhesive backed Monokote to be just about as strong as the mylar canopies once they've been burnished down around the shrouds. I can't recall the last time I lost a shroud without completely splitting the canopy into 8 or 12 streamers under Way two heavy an opening load
Did you catch the earlier post about 13lb Kevlar shrould lines? this stuff also is such small diameter it packs and falls open really well. I'm sure it's far to late to get before this weekend but Edmund Scientifics http://scientificsonline.com still has these rolls for 19.95. I just checked again last Friday for another article I was writing. Current stock No# 3034863.
Hope this helps.

 

[gpoehlein]

Most of the time I use Scotch tape on each point and punch a small hole in the center of the tape. I then tie the shroud line through the hole in the tape. The only time I have had any problems was using some orange jack-o-lantern bags I bought last October - four of the six shroud lines tore out (the plastic itself shredded). I was using silver mylar tape on that one. Don't know if that plastic was just really soft or what. Normally my attachment method works flawlessly.

We have a rough crowd flying at the LC regionals (at least three to four of our regulars placed in the top 20 nationally last year) so I do have my work cut out for me. But I managed to take a first place and two seconds at the last meet (that first place was in egg lofting altitude and kept Chad from sweeping all the first places! ) We will see what the rocket gods have in store for us this time!

 

[dave carver]

I've gone so far as to cut the shroud lines on pre-made nylon parachutes to reattach them in the paralel manner described.

 

[gpoehlein]

Just an update on our regional contest - I used the cheap black garbage bag chutes again - flew a 24" hex chute for 1/2A parachute duration multiround. First flight was almost two minutes, but the nose cone separated from the shoulder (vacform styrene glued to cardstock shoulder with CA - should have used thick CA instead of thin). Reglued the cone to the shoulder and tried again with the same chute - the model was still going up when it went out of sight at a bit over 14 minutes. I used John's shroud attachment plan (parallel shroud lines) with heavy cotton thread taped to the corners. One of the timers noted that it was doing a perfect "jellyfish" as it moved from one thermal to the other. Shroud lines stayed untangled even without a separator disk. Pity that the last 12 minutes were wasted (two minute max on 1/2A multiround). With the first flight DQd, I still got second place for the even - for a Launch Crue regional that is a pretty good result!

 

[Micromeister]

Excellent Greg:
Supurb results.
You've apparently gone beyond my pay grade I can't for the life of me pick good air. If you have that part down your now completely good to go

Just an FYI; I only use the seperator discs on older style chutes that have had twisted shroud problems. They (the disc) themselves can cause some deployment tangles if not packed in properly. Sorry; I don't want to confuse the newer flyers thinking the seperator disc is needed or required with all chutes, they surely are not. There are just another tool, to help "Un-tangle" some stubborn shroud messes particularly those using standard Estes shroud line materal.
hope this helps.