Jolly Logic Chute Release

[kbRocket]

I'd like to offer one small improvement to the chute packing technique above. This photo shows only a couple inches between where the chute protector and the parachute attach to the tether. I prefer to make a very large distance between the two, definitely a distance greater than the parachute shroud line length. This helps make sure that the parachute is pulled free of the chute protector and prevents the two from interacting on the way down which can add to tangling. The chute should be fully away from the nomex protector before the tether is taught.

I like to make chute protectors that are partially sewn at one end. Kind of like a partial deployment bag with a protective flap that wraps around. It's better protection for less fabric, but you have to make sure that the chute will not get stuck in the partial bag. The large distance helps ensure the chute will be pulled out by whatever assistance you have: momentum, pilot chute, components tugging on the way down.

 

[kbRocket]

I also like to attach my JLCR on the parachute side of the swivel. This photo shows it attached to the tether. Allowing the swivel to function on the way out can alleviate twisting. The quick link in the photo would be a good option.

 

[Cameron Anderson]

I'd like to offer one small improvement to the chute packing technique above. This photo shows only a couple inches between where the chute protector and the parachute attach to the tether. I prefer to make a very large distance between the two, definitely a distance greater than the parachute shroud line length. This helps make sure that the parachute is pulled free of the chute protector and prevents the two from interacting on the way down which can add to tangling. The chute should be fully away from the nomex protector before the tether is taught.

I like to make chute protectors that are partially sewn at one end. Kind of like a partial deployment bag with a protective flap that wraps around. It's better protection for less fabric, but you have to make sure that the chute will not get stuck in the partial bag. The large distance helps ensure the chute will be pulled out by whatever assistance you have: momentum, pilot chute, components tugging on the way down.

When I am not using JLCR and doing traditional DD, I keep my nomex parachute length +1 foot away from my attachment point. When. Using JLCR and for my drogues, I like to keep my chute attachment point within 12" and never more than 18") from what I will call the "moving part" (the av bay or NC that is being blown away). Long shock cord lines can get tangled and the chute never comes out in pull-out situations as opposed to piston push out where everything is thrown into the airstream. With only a foot to work with the nomex has to be close to protect the chute. It's a calculated risk...small chance of chute entanglement to increase the likelihood of chute extraction.

 

[o1d_dude]

There is lots of merit cable cutters (which use zip ties). I own two (plan to run them in parallel on the same zip tie. JLCR is cool but I don't think it can adequately contain large chutes (over 60") for reliable deployment.

FWIW I have successfully contained a 48” Fruity Chutes classic elliptical.

I did however use a Fruity Chutes “liner” (hard to describe but similar to a burrito closed on one end) to prevent the chute from escaping until the JLCR said it was time to go. It was my L2 cert flight.

I have the liners in 4, 5, and 6”diameter.

Edit: Inches, not feet.

 

[John Beans]

For the love of God, anyone who wants to pack their chute like this can mail it to me and I will pack it correctly for you and mail it back. Please don't do this. So many issues.

Could be worse. Could be a glue argument.



For what it's worth, I was shown the method in that video at a large club launch about 10 years ago by one of the hobby's Old Royalty—one of those guys who took part in record altitude flights and had a job in aerospace. He took a similarly brusque attitude with me and grabbed my chute and showed me "how to do it properly." The main point he made at the time was to use the shroud lines to help do the work of opening the chute for a small rocket in which the chute really needed to be kept compact.

I don't claim to be an expert on chute folding. I do get lots of requests for videos and techniques, which when I have them I'm happy to share. A number of you have videos on the Jolly Logic site in the flights section, but I'm happy to also post your How To videos as well. Always welcome!

Things can vary greatly depending on your rocket and your chute, but there are a few things that I do believe are always important, most of which you'll see in the User Guide of Chute Release:

• I've seen "puffy bundles" fail to deploy because they trap the band—avoid that
• Since shroud lines are no longer needed to hold a bundle tight, put them inside to protect them
• Flame blankets should be tethered in such a way that they get whisked away when the shock line goes taut
• Never tether Chute Release in such a way that it gets yanked when the shock cord goes tight—the tether is just there to support the weight of Chute Release after release so that you don't lose it (the 300# kevlar line it ships with is massive overkill)
• If you are folding your chute the way you did before you started using Chute Release (or a cable cutter), you can do better
• Make sure your shrouds cannot just slide out of your bundle before release (from the flap or the from the center)
• The goal is to create a bundle you can't shake loose by hand ("shake test") but which just falls apart after release ("release test")
• Make sure your bundle will eject easily ("puff test" from the engine mount)

Anyway, send me a video. Happy to post it.

 

[tOD]

I have 10 flights in row with perfect results useing JLCR. Just make sure its turned on and use a band that wraps the bundle tight. So far I have used the small band up to 36" chutes. It works very well on 30" chutes. If bundle is loose it will shake it self out.

Damn thing doesn't work at all if you don't turn it on. Don't forget to tie the tether to the shock cord. They're impossible to find when they fall 400 ft into tall grass

 

[TheTank]

Mine worked fantastic for the 6/7 flights I had it. Put it in a new rocket and deployed at apogee. Gone. Only thing i can think of (as it passed the shake test) is that the chute release on this rocket was attached to the cone and line attached further down the shock cord. Upon ejection, the shroud lines pulled tight and yanked the chute out of the release as that span was less than the shock cord length from chute attachment to the cone. Only thing i can come up with as it worked perfect every other flight on 4 different rockets and this was the only difference.

Expensive lesson learned that day between the cute release, motor hardware, rocket, and major case of poison oak from trudging through a swamp trying to find it (with no luck). Will I get another one. Yep.

 

[o1d_dude]

Damn thing doesn't work at all if you don't turn it on. Don't forget to tie the tether to the shock cord. They're impossible to find when they fall 400 ft into tall grass

I too have experienced the Chute Release “failure” of not turning it on before walking away from the pad.

Talk about feeling stupid when you find the chute bundle neatly tied up next to the remains of your rocket...and your JLCR is NOT turned on...”Go Fever” strikes again.

 

[tOD]

I too have experienced the Chute Release “failure” of not turning it on before walking away from the pad.

Talk about feeling stupid when you find the chute bundle neatly tied up next to the remains of your rocket...and your JLCR is NOT turned on...”Go Fever” strikes again.

Just finishing up repairs from the last "failure to release". The rocket landed in the high grass and only suffered the fillet pulling away from the body tube. I ground off the old stuff and put on a new fillet. Should be as good as new. Maybe I owe it a nice coat of paint.

 

[Wally Ferrer]

I too have experienced the Chute Release “failure” of not turning it on before walking away from the pad.

Talk about feeling stupid when you find the chute bundle neatly tied up next to the remains of your rocket...and your JLCR is NOT turned on...”Go Fever” strikes again.

Even worse, prepare it, turn it on, pack it, then pick up and launch the other rocket you brought, and wonder why it didn't work. Search a bit for the lost JLCR after trekking for a half mile to recover the rocket but give up knowing it's hopeless, decide NOT to launch your second rocket because you don't want to trek another half a mile to recover it. The good part is changing your mind because you have a smaller motor, and you decide to repack the chute 'just because', and find your JLCR.

 

[Cameron Anderson]

Could be worse. Could be a glue argument.



For what it's worth, I was shown the method in that video at a large club launch about 10 years ago by one of the hobby's Old Royalty—one of those guys who took part in record altitude flights and had a job in aerospace. He took a similarly brusque attitude with me and grabbed my chute and showed me "how to do it properly." The main point he made at the time was to use the shroud lines to help do the work of opening the chute for a small rocket in which the chute really needed to be kept compact.

I don't claim to be an expert on chute folding. I do get lots of requests for videos and techniques, which when I have them I'm happy to share. A number of you have videos on the Jolly Logic site in the flights section, but I'm happy to also post your How To videos as well. Always welcome!

Things can vary greatly depending on your rocket and your chute, but there are a few things that I do believe are always important, most of which you'll see in the User Guide of Chute Release:

• I've seen "puffy bundles" fail to deploy because they trap the band—avoid that
• Since shroud lines are no longer needed to hold a bundle tight, put them inside to protect them
• Flame blankets should be tethered in such a way that they get whisked away when the shock line goes taut
• Never tether Chute Release in such a way that it gets yanked when the shock cord goes tight—the tether is just there to support the weight of Chute Release after release so that you don't lose it (the 300# kevlar line it ships with is massive overkill)
• If you are folding your chute the way you did before you started using Chute Release (or a cable cutter), you can do better
• Make sure your shrouds cannot just slide out of your bundle before release (from the flap or the from the center)
• The goal is to create a bundle you can't shake loose by hand ("shake test") but which just falls apart after release ("release test")
• Make sure your bundle will eject easily ("puff test" from the engine mount)

Anyway, send me a video. Happy to post it.

Haha, oh glue! Great way to ruin friendships.

First off, love the chute release. Seriously though, you make a heavy duty chute release out of aluminium and with two release points and I'll buy 2.

I like all your points but want to expand on one...shroud lines inside a packed canopy.
Just lay them accordion-folded (not wrapped like an electrical cord and not grabbed by a handful) between two folds, and try to set the folds up where they open up and the lines fall out when the chute release actions. The folds keep the lines in one spot. I've seen lines come taut so fast when they're between canopy gores under pressure that they burn holes in the canopy. I've also had a rocket impact so fast that my nylon chute friction-burned itself into a fist-sized ball of plastic. Nylon is touchy with heat. But back to my original point...gingerly lay your carefully folded lines in your canopy at a point where, without the chute release closed, everything falls apart.

 

[Cameron Anderson]

Again, not "the" way, but "a" way. It'd been successful for me. This is a 48" circular main on a common shock cord with a 24" x-type drogue. It's all sitting in my 4" Nike band will be ground tested tomorrow.

First shot is everything laid out before I decided on my chute attachment point.



Second shot shows initial layout. I put a piece of tape on the center gore and another piece on the center shroud line to help keep things in place.


This shows the initial accordion folding. The lines can go all left or all right, it doesn't matter, just pick a side. I use pliers for weights. Actual packing weights are amazing if you can get them.




All accordion folding is done and I did the final half fold over to get the chute size down for the JLCR.



Lines laid out.



Here is a close up of how I tape my quick links and swivels. I attach swivels with double figure 8 knots or girth hitches. The tape is sacrificial and just meant to keep things in place until tension is applied. I tape the back side of the quick link so it can't unscrew.



Now I accordion fold the shroud lines.



Now I gather up the lines. They aren't tangled or wrapped in the canopy...I lay them down and fold 1/3 of the canopy down over to secure them.



I run the shock cord behind the chute, making sure the JLCR goes arouns shock cord. Position the lines so the swivel and quick link (if used) is exposed.



Fold your drogue and place the main directly on top. Put any shock cord that runs between the drogue and the main under the main as well. Wrap the sides of your nomex in first and fold the top flap down last.



You can't easily see from the pictures the entire shock cord layout so I will describe it.

Starting at the forward end I have my interstage coupler with my Raven 4 in the av bay. Aft of the av bay are two 3-gram rocket junkies charge wells on a bulk plate. Next to the bulk plate is my shock cord mount. The nomex is tied to the shock cord far enough back from the ISC that when the shock cord is extended the nomex comes fully out of the ISC coupler and it can't get bound up. A few inches aft of the nomex i have the drogue mounted. The main is mounted further back on the shock cord; it's far enough back that when laid flat, the drogue and the main cannot touch one another. Finally, and most importantly, the main is mounted far enough forward on the shock cord from the booster air frame that it is impossible for the chute to remain in the airframe when the shock cord is fully extended.

 

[Cameron Anderson]

Here is the last picture...couldn't add it to the previous post. drogue and main wrapped ready to load.

 

[matthewdlaudato]

I just got my first JLCR. Fairly comfortable with how I pack the chutes. One thing I’ve noticed during tests is that the orientation of the pin and the receiving hole is very important. On an otherwise tightly packed bundle, I orient the pin at a tangent to the bundle. This seems to reduce the chances of the band getting stuck.

 

[crossfire]

I just got my first JLCR. Fairly comfortable with how I pack the chutes. One thing I’ve noticed during tests is that the orientation of the pin and the receiving hole is very important. On an otherwise tightly packed bundle, I orient the pin at a tangent to the bundle. This seems to reduce the chances of the band getting stuck.View attachment 433114

You need the bundle wrapped tight. From picture which band are you useing? Dosen't look tight and it might shake loose at apogee ejection.

 

[ChicagoDave]

You need the bundle wrapped tight. From picture which band are you useing? Dosen't look tight and it might shake loose at apogee ejection.

Also I found the tighter the rubber band the better the chute opens. A failure I had (I think) was that the rubber band wasn't tight enough and the chute failed to open fully because the rubber band didn't fall away properly.. I suggest having the rubber band snap back a bit to release the chute - at least for me it seems to open much more reliably this way.

~Dave~

 

[matthewdlaudato]

You need the bundle wrapped tight. From picture which band are you useing? Dosen't look tight and it might shake loose at apogee ejection.

Agree - in that picture it is not a tight as it could be. I’m using a large band in that test. I’ll switch to small and see how the tests go. Thanks for the tips.

 

[matthewdlaudato]

Also I found the tighter the rubber band the better the chute opens. A failure I had (I think) was that the rubber band wasn't tight enough and the chute failed to open fully because the rubber band didn't fall away properly.. I suggest having the rubber band snap back a bit to release the chute - at least for me it seems to open much more reliably this way.

~Dave~

Thanks Dave. I’m planning my first flight on Saturday, so lots of wrapping practice and tests this week to get ready and (more) confident.

 

[AfterBurners]

I hope the pics load in the right sequence.

This is what I used for my Madcow Screech last weekend...head end deployment at apogee, JLCR at 500.

1. Girth hitch the JLCR and the chute on a swivel below the nomex. Use tape to secure the hitches. The tape isn't load bearing, it just keeps things in the right place and is sacrificial.

2. Lay the canopy flat. You will be folding left to right and folding each gore in half and lining up the shroud lines. Fold until all shroud lines are aligned.

3. Fold the gore in half leaving the lines to the right. It helps to have weights to keep the chute folded properly. You can fill a sock with lead shot (which I use for bigger chutes) or anything handy that is heavy.

4. Acordian fold the gore in thirds along it's length.

5. Acordian fold the shroud lines. Do NOT roll them up. This is also called "z folding" because you are going back and forth to gather the lines. Keep the fold length slightly smaller than the chute at this point.

6. Lay the lines under a fold in the chute. Don't fold them into it, just lay them between the folds. For bigger rockets you can use rubber bands on your lines but for anything under 10lbs I done use rubber bands because the opening shock and weight of the rocket doesn't always guarantee deployment.

7. Size your rubber band and attach the JLCR.

8. Lay your chute in the middle of your nomex. Fold the sides in first (left or right or right over left doesn't matter.

9. Fold the top of the nomex down...doing the sides first and the top last prevents any gap for the deployment gas to roast your chute.

10. Push the packed chute into the airframe.

I don't have a JLCR yet, but I have always folded my chutes in a similar way ..maybe I just figured it out, but thanks for sharing

 

[rcktnut]

FYI while this thread is back up, I'd like to show what I replaced the PITA rubber bands with. I use a piece of 3/4'' wide,good quality bungee. Pictured is a 7in piece. I have a regular full knot on the pin and all it takes is a single once thru knot on the CR., making it easily adjustable. The bungee only stretches so far and then you can pack your chute tight as wanted and still not put to much tension on the CR. The one pictured tied is set for a PML 54 in. chute also pictured ready to go. No more multiple different sized bands/ whatever needed. Just adjust length so that the bungee is fully stretched and good to go on any sized chute.

 

[matthewdlaudato]

Agree - in that picture it is not a tight as it could be. I’m using a large band in that test. I’ll switch to small and see how the tests go. Thanks for the tips.

Correction - that was a small band. Thin mill nylon chute. I’ve adjusted how I fold it to make it much tighter.

 

[rcktnut]

Correction - that was a small band. Thin mill nylon chute. I’ve adjusted how I fold it to make it much tighter.

Try the bungee, adjust it to the way the chute was folded, no worry about redoing the chute to fit a band size!! BTW I tested lots of stuff before ending up with the 3/4" bungee. It was tested on chutes from 12 to 72 inches. No matter the size of chute the bungee opened just fine, as long as it is adjusted to be fully stretched. I only had 4 flights with it though, all worked perfectly.

 

[o1d_dude]

Not sure what you mean by “bungee”.

To me a bungee is a collection of rubber strands enclosed in a woven mesh sheath with hooks on each end.

The photos you attached appear to be of a flat rubber band.

What am I missing? Is there another name for the piece you are using?

 

[Buckeye]

Looks like nylon elastic band from the fabric store.

 

[rcktnut]

Looks like nylon elastic band from the fabric store.

Correct, I call it bungee, easier said than nylon elastic band. Any fabric store should have it.

 

[o1d_dude]

Correct, I call it bungee, easier said than nylon elastic band. Any fabric store should have it.

Thanks. There’s a Joanne’s nearby.

 

[ZEDL1]

Regarding the bungee use suggestion, never having tried that method although it looks promising, would the older-style (no offense intended) white elastic shock cord material that HPR kits used to and may still come with work? I've got a lot of that material that I did not use. Thanks for any advice.

 

[neil_w]

I assume we are just talking about braided elastic, right? I have some 3/8" that would seem to be good for this (not sure if there's any real reason to need it to be as wide as 3/4")...

 

[rcktnut]

Regarding the bungee use suggestion, never having tried that method although it looks promising, would the older-style (no offense intended) white elastic shock cord material that HPR kits used to and may still come with work? I've got a lot of that material that I did not use. Thanks for any advice.

There are different types/ quality of bungee. I think the stuff I have comes in white also. The black I have is the same type Aerotech uses in their kits. Trying it out is the only way to find out if it works.

I assume we are just talking about braided elastic, right? I have some 3/8" that would seem to be good for this (not sure if there's any real reason to need it to be as wide as 3/4")...

I started out with 1/4 in. did not work as well especially with smaller chutes. Other than that I just had the 3/4 in. tried it and liked it. The wider the more energy in it when stretched. Like I said it only stretches so far and after that you can bundle the chute as tight as you want to and not have too much tension on the CR. The 3/4 in. works well as far as tension and release power.
It will also not stick to a chute.

 

[neil_w]

I started out with 1/4 in. did not work as well especially with smaller chutes. Other than that I just had the 3/4 in. tried it and liked it. The wider the more energy in it when stretched. Like I said it only stretches so far and after that you can bundle the chute as tight as you want to and not have too much tension on the CR. The 3/4 in. works well as far as tension and release power.
It will also not stick to a chute.

OK good to know, thanks.