JL Chute Release - latest improvements?

Handeman

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FWIW I asked one of the club officers for what they feel the failure rate is based on his experience and he answered a shockingly high number and I didn't think he was joking.

I was asking for a baseline since I wanted to use it more this season.

Of note is that I have 3 and one of them I have to send in for repair. It was the one I grabbed the night before our first launch and in testing, the pin was pulling out by itself (wasn't holding securely). I saw that the retaining bolt in the device wasn't extending out enough. This was a new surprise to me and good thing I was testing it before use.

However, in my past experience Jolly Logic has had fantastic support and servicing... top notch.
I think the JLCR has a lower success rate than standard DD, but not because of the device. It's pretty easy to pack a parachute in a tube and have it deploy correctly, we've been doing this since our first Estes rocket. It is more difficult to fold a chute in a way the JLCR holds it during decent and it opens correctly when the JLCR releases. There are also many other subtle things that can be done wrong causing the chute to open at apogee, or not open at all, among other failure modes.

I think the electronics in the JLCR are just as reliable as DD altimeters. The mechanical operations of the device I'm sure reduce that reliability somewhat. The user operation reduces the success rate of the JLCR much more than anything in the device. I think as the community learns what works and what doesn't when using the JLCR the overall success rate will increase significantly.

I only use my JLCR on two rockets, but my success rate is near 100% since I've figure out how to use it on those two.
 

momo2

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I've been a fan of the JLCR for over 6 years. I have 4 of them and rarely use traditional dual deploy these days. Just wondering if anyone had recently come up with any ideas for improving the device. I searched this forum but did not see anything other than the 2 big older ideas that I have already successfully tried:
* replace the rubber band with a woman's hair tie (the ties have never broken, the bands sometimes do break)
* daisy chain 2 JLCRs for extra security if one fails (only works with larger rockets).

My JLCR success rate is over 85% (not counting operator errors, such as failure to turn the device on), but since the consequence of a failure can be quite severe, I'm always looking for ways to make the JLCR even better.

I've been a fan of the JLCR for over 6 years. I have 4 of them and rarely use traditional dual deploy these days. Just wondering if anyone had recently come up with any ideas for improving the device. I searched this forum but did not see anything other than the 2 big older ideas that I have already successfully tried:
* replace the rubber band with a woman's hair tie (the ties have never broken, the bands sometimes do break)
* daisy chain 2 JLCRs for extra security if one fails (only works with larger rockets).

My JLCR success rate is over 85% (not counting operator errors, such as failure to turn the device on), but since the consequence of a failure can be quite severe, I'm always looking for ways to make the JLCR even better.

FWIW I asked one of the club officers for what they feel the failure rate is based on his experience and he answered a shockingly high number and I didn't think he was joking.

I was asking for a baseline since I wanted to use it more this season.

Of note is that I have 3 and one of them I have to send in for repair. It was the one I grabbed the night before our first launch and in testing, the pin was pulling out by itself (wasn't holding securely). I saw that the retaining bolt in the device wasn't extending out enough. This was a new surprise to me and good thing I was testing it before use.

However, in my past experience Jolly Logic has had fantastic support and servicing... top notch.
I suggest you read the KICKer article in the November/December 2022 issue of Sport Rocketry magazine. Some neat tips for more reliable chute inflation with the CR. I talked with the FVR guy, and the author had 82 consecutive successful Chute Release deployments with the KICKer device before he finally committed a user error. If it matters, he did mention that the KICKer had only been used with chutes 36" or less. So there was no testing or experience with chutes larger than that.
 

KenECoyote

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I believe I read about this in a NAR magazine article and it seems to work well for me (so far):

"Plastic clamshell packaging spring"
View attachment 580205

I hot glued it on.

I suggest you read the KICKer article in the November/December 2022 issue of Sport Rocketry magazine. Some neat tips for more reliable chute inflation with the CR. I talked with the FVR guy, and the author had 82 consecutive successful Chute Release deployments with the KICKer device before he finally committed a user error. If it matters, he did mention that the KICKer had only been used with chutes 36" or less. So there was no testing or experience with chutes larger than that.
Was the KICKer what I referenced and showed in post #2?

I've been using that this season and so far it's been working well.
 

KenECoyote

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I ordered some from Amazon. I got a variety of sizes/lengths.
Ah, I went to the hair tie section of the supermarket yesterday since I was already there for groceries and saw these, but the price was pretty steep.
20230514_140902.jpg
I figured it should work given others had used the non-silicone hair ties, but I didn't buy them.

Edit: I see the same on Amazon for $6.
 

Buckeye

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I did not suggest it, somebody else did upthread, based on their experience.


So you are saying this is normal. If so then redundancy is an improvement in the system. You can't argue for no redundancy when you admit there are shortfalls in the outcome. Well maybe you can, but it doesn't make sense.

I don't use one of these so I have no bias either way about the device. I do have a bias towards redundancy to make flights safer.

Sorry, I blended together two different points about the JLCR. Yes, weird things can happen with unfurling a bound parachute, but two or more JLCR chained together won't fix the problem. Better chute packing techniques are needed.
 

Zyzzyva1000

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Waterproofing would be cool.
We have a small pond (well technically 3, but one near our low/mid power pads) that I have landed in twice recently. Ended up sending my JLCR back to John because the solder connections corroded and he was able to fix it! Amazing service. I thought about how to waterproof it, but there will always have to be an air sampling hole, and once the servo actuates to pin hole will be open. At this point I am just more careful about flying depending on the wind.
 

jahall4

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I've been a fan of the JLCR for over 6 years. I have 4 of them and rarely use traditional dual deploy these days. Just wondering if anyone had recently come up with any ideas for improving the device. I searched this forum but did not see anything other than the 2 big older ideas that I have already successfully tried:
* replace the rubber band with a woman's hair tie (the ties have never broken, the bands sometimes do break)
* daisy chain 2 JLCRs for extra security if one fails (only works with larger rockets).

My JLCR success rate is over 85% (not counting operator errors, such as failure to turn the device on), but since the consequence of a failure can be quite severe, I'm always looking for ways to make the JLCR even better.

The best way we have found to mitigate failure is to use a “Recovery” or chute sled. A success rate of near 100% should be expected when rigged properly. Whether you make your own or buy one from us don’t launch another rocket w/o one. I know I sound like a marketing hack, but here is the story…

After a failed inflation, that could not be explained, on a 72" chute at SEARS in Oct. 2016 I started investigating. Flight video from test flights showed that the shroud lines could pull out of the pack even on much smaller rockets, using much smaller chutes. Apparently, the pack thrashing about in the air stream could twist pulled lines fouling the chute. This is more of an issue on larger chutes given the JLCR’s lesser ability to compress the pack. The pack gets bigger, but of course the JLCR does not scale up with the pack.

It seemed reasonable that if the chute could be kept immobile relative to the harness that could not happen. The recovery sled does just that when properly configured, because the chute pack cannot move independent of its harness attachment point. They must move together until the JLCR releases. This can be readily inspected when packed. The chute pack is held to the sled by the JLCR, the sled is fixed along the harness at each end so where the harness moves so does the pack, and vice-a-versa.

Even use them for Triunal Deployment (back up mains):
 

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momo2

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Ah, I went to the hair tie section of the supermarket yesterday since I was already there for groceries and saw these, but the price was pretty steep.
View attachment 580623
I figured it should work given others had used the non-silicone hair ties, but I didn't buy them.

Edit: I see the same on Amazon for $6.
Walmart has the Goody and Scunci brands for under $3. There's 2mm and 4mm thickness. The 4mm size has been recommended.
 

momo2

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I've been debating getting one, but the community seems to be divided into two camps.. "the greatest thing to happen to the hobby", and "just another way to crash your rocket".

They seem simple enough.. is it operator error that causes failures? Are the people using them successfully too busy flying their rockets to go online to express how much they like the things?

In other words.. somebody talk me into (or out of) buying one.

Full Disclosure: I'm new at this, haven't even made a L1 cert launch yet, and apparently have WAY too much time on my hands.

Thanks.
Pinetree, you will love the JLCR and use it often. May I suggest you read the KICKer article in the November/December 2022 issue of Sport Rocketry magazine. Some neat tips for more reliable chute inflation with the CR. It is mostly concerned with rapid and reliable parachute inflation when using the lower altitude settings. The author reached 82 consecutive successful parachute deployments with the Chute Release and his KICKer device before he finally committed a user error. Interestingly, not one of those 82 flights used a setting above 300', with most at 200' and even a half-dozen at 100'. If it matters, he did mention that the KICKer had only been used with cloth chutes 36" or less. So there was no testing or experience with chutes larger than that. Also, the highest recorded altitude of those flights was 1455'.
 

Pinetree

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Being the new guy here, the only issue I have is the May/June '23.

But I think I'm sold now. Thanks.
 

momo2

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Being the new guy here, the only issue I have is the May/June '23.

But I think I'm sold now. Thanks.
As a NAR member you can access any magazine article for free in the Member's Resouces, Digital Publications Archives section.
 

Troy3003

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The best way we have found to mitigate failure is to use a “Recovery” or chute sled. A success rate of near 100% should be expected when rigged properly. Whether you make your own or buy one from us don’t launch another rocket w/o one. I know I sound like a marketing hack, but here is the story…

After a failed inflation, that could not be explained, on a 72" chute at SEARS in Oct. 2016 I started investigating. Flight video from test flights showed that the shroud lines could pull out of the pack even on much smaller rockets, using much smaller chutes. Apparently, the pack thrashing about in the air stream could twist pulled lines fouling the chute. This is more of an issue on larger chutes given the JLCR’s lesser ability to compress the pack. The pack gets bigger, but of course the JLCR does not scale up with the pack.

It seemed reasonable that if the chute could be kept immobile relative to the harness that could not happen. The recovery sled does just that when properly configured, because the chute pack cannot move independent of its harness attachment point. They must move together until the JLCR releases. This can be readily inspected when packed. The chute pack is held to the sled by the JLCR, the sled is fixed along the harness at each end so where the harness moves so does the pack, and vice-a-versa.

Even use them for Triunal Deployment (back up mains):

I was just getting ready to refer them to you Allen!
 

TRWXXA

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I did not suggest it, somebody else did upthread, based on their experience.


So you are saying this is normal. If so then redundancy is an improvement in the system. You can't argue for no redundancy when you admit there are shortfalls in the outcome. Well maybe you can, but it doesn't make sense.

I don't use one of these so I have no bias either way about the device. I do have a bias towards redundancy to make flights safer.
Just spitballing here... In the name of redundancy, has anyone "daisychained" two JLCRs together -- the release pin of one JLCR attached to the other? With them joined in series, only one would need to work. This would probably only work for larger, mid-power and HPR chutes.

Thoughts?
 

billdz

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Just spitballing here... In the name of redundancy, has anyone "daisychained" two JLCRs together -- the release pin of one JLCR attached to the other? With them joined in series, only one would need to work. This would probably only work for larger, mid-power and HPR chutes.

Thoughts?
Yes, daisy-chaining works just as you say, although Buckeye seems to disagree (see post 37 above). And yes, it needs to be a fairly large rocket.
 

TRWXXA

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Yes, daisy-chaining works just as you say, although Buckeye seems to disagree (see post 37 above). And yes, it needs to be a fairly large rocket.
Missed that one. It's probably more of an academic exercise. For the cost of 2 JLCRs you can be well into a good, 2-altimeter DD system.
 

OverTheTop

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Just spitballing here... In the name of redundancy, has anyone "daisychained" two JLCRs together -- the release pin of one JLCR attached to the other? With them joined in series, only one would need to work. This would probably only work for larger, mid-power and HPR chutes.

Thoughts?
Exactly what we are discussing.
 

Dave S.

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jahall4 - I like the idea of your recovery sled.​

It looks like you have two knots on the shock cord that prevent the sled from sliding up or down on the cord much. But from looking at the pictures it wasn't clear to me how you attached the JLCR to the shock cord. In the photo of yours I have below I couldn't really tell.​

Did you have a recommended attachment method and location?​


recovery sled.jpg
 

rcktnut

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LOL! Typical TRF approach. "Must always have redundant electronic gadgets even though they are the most reliable part of the system!"

Redundancy for what? To keep the chute bundled, or unbundled? Seems like former makes more sense, since chutes can shake loose from the rubber band. If the latter, it is a pricey, and totally unnecessary approach.
I'm with you on this, still scratching my head on what 2 CR's are going to accomplish as far as preventing damage from high speed impacts which some seem to imply the redundancy preventing. To prevent unbundling I get it, but otherwise I don't get it. I use the 3/4 in. elastic on my 2, 100% success so far. Using the rubber bands that come with the CR is the worst thing a person can do.
Confused Halloween GIF by This GIF Is Haunted
 

jahall4

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jahall4 - I like the idea of your recovery sled.​

It looks like you have two knots on the shock cord that prevent the sled from sliding up or down on the cord much. But from looking at the pictures it wasn't clear to me how you attached the JLCR to the shock cord. In the photo of yours I have below I couldn't really tell.​

Did you have a recommended attachment method and location?​


View attachment 581003

Actually this pic shows a rigging mistake that resulted in deployment at apogee. Do you see it? Look at the other photos.

But yes it is very important that the sled (and the JLCR) not slide along the harness. What you don't see in this pic is the tape on the chute side of the sled.

Watch this video, rigging exactly as it needs to be:
 

Dave S.

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I’ve watched the video several times and don’t see what you’re trying to point out.

Do you attach the tether of the JLCR to the hole in the sled that is closest to the rocket body tube?
 

jahall4

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I’ve watched the video several times and don’t see what you’re trying to point out.

Do you attach the tether of the JLCR to the hole in the sled that is closest to the rocket body tube?

Yea, its sort of small. I need to do video on how to rig.

The sled needs to be kept from sliding along the harness. Often that's as simple as sliding it on since when the harness straightens the sled "binds" against the harness. The tape is used to keep it from moving while the harness is relaxed. The tether needs to attach to harness in front of the aft hole on the sled to keep it from moving which is what happen in the pic you noted. The two give a better view, smaller cute, but rigging is same.
 

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Dave S.

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Got it - Looking back at the photos you posted I see that now.

Interesting that in the two photos in post #58 above you have the shock cord going thru the nomex blanket in the middle of the sled. In post #39 there is also a picture where the nomex is on the cord separate from the sled.

Which do you recommend? Either/or?
 
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