Jolly Logic Chute Release, chutes not inflating....

[DankMemes]

So, I flew my chute release for the first time at Bama Blastoff, followed the instructions did the ground test and a puff test to make sure all was good... flew it in a bt-60 firestorm two stage and it worked great...


Tried it 5 times in a row in my Trajector doing the same pre flight test and with a variety of folds and bands and every time the chute never inflated but the release did fire. Even when the release would come flying off the chute on a ground test I’d end up with results like this picture...

By the way this is an 18” Estes nylon pro series chute... and fortunately the Trajector survived the weekend

I’m banging my head here, and got some tips from many friendly folks at Bama Blastoff and we still couldn’t get it to go...

Any thoughts?

 

[Glasspack]

Is that an unretouched photo from the landing site.........Wow it's amazing that the pin got stuck like it did. Are you sure your selecting the right size band? That should snap open and not be able to wrap back around the chute like that. Wonder if it would work better to attach the CR tether further down the line. So as it opens it will want to pull away from the Chute more. My sons V2 landed like that, but the as it was free falling the shroud lines came out of the fold and tangled the whole thing up. That failure was the result of a tangled chute and recovery harness, before the CR unlocked at 300 feet. Obviously THAT didn't happen to yours.

 

[Glasspack]

Here are the photos I tried to add a minute ago to my response.

DankMemes, I am sure John from Jolly Logic can help you explain and minimize any future failure.
Great man and a great company.

Here is some more info from my Chute Release mishap:
https://www.rocketryforum.com/threads/inexperience-with-chute-release.142785/

 

[DeepOvertone]

Dank, I’m not sure how that happened but I do see one thing that I’d have done differently. Not sure if it’s the right thing to do but it’s always worked for me.

I’d have given that chute another fold in half. Just to clarify, I mean folding it in half such that the length would be half of what it is and the thickness would be double. I’m not sure if that would have fit in your rocket body but the more tension you have on the band and pin, the better. Based on that photo, I can pretty much say with confidence that there wasn’t enough tension on the band.

 

[DankMemes]

Yeah I was experimenting with different folds and bands, in this photo I believe was one of the times I actually went around the chute twice with the band twice before plugging the pin in... the chute release came roaring off in a ground test

 

[DankMemes]

There were other times where the release was long completely loose on the ground next to the chute, but the chute was still folded

 

[snrkl]

There were other times where the release was long completely loose on the ground next to the chute, but the chute was still folded

The only time I had that happen to me, was when the open altitude was too low, and by the time the band was off, the rocket was on the ground..

 

[Bat-mite]

The only time I had that happen to me, was when the open altitude was too low, and by the time the band was off, the rocket was on the ground..

That was going to be my question! What altitude was set for release? Depending on the descent speed, the rocket can drop another 100 - 200 feet between the time when the pin comes out and the air causes the chute to open. I would never set my release altitude any lower than 400. I've tried 300 and ended up with broken rockets.

 

[roytyson]

Yep, seen it happen numerous times. The rubber band is overstretched during assembly, then when it is released, the "grooves" in the rubber band clamp down on the chute and it will not release. My tips: do not overstretch the band, apply liberal amounts of baby powder to the rubber band and chute every other flight, never go below 300 feet as the chute will open and inflate around 200. Also, it appears your band is too long. The rubber band should "snap" around the chute and hit your hand holding it when doing your test.

But that's just me. Very frustrated to look at your broken rocket, and the chute release has a released pin and a perfectly folded chute.

 

[DankMemes]

Yep, seen it happen numerous times. The rubber band is overstretched during assembly, then when it is released, the "grooves" in the rubber band clamp down on the chute and it will not release. My tips: do not overstretch the band, apply liberal amounts of baby powder to the rubber band and chute every other flight, never go below 300 feet as the chute will open and inflate around 200. Also, it appears your band is too long. The rubber band should "snap" around the chute and hit your hand holding it when doing your test.

But that's just me. Very frustrated to look at your broken rocket, and the chute release has a released pin and a perfectly folded chute.

Thanks man I’ll give it a shot I also have theorized just morning that it may be hung up inside the nomex blanket after ejection so the chute and release are still inside the burrito so may fly on wadding to test that along with the tips above

 

[roytyson]

Thanks man I’ll give it a shot I also have theorized just morning that it may be hung up inside the nomex blanket after ejection so the chute and release are still inside the burrito so may fly on wadding to test that along with the tips above

If you fear that is the case, make sure the nomex is permanently attached to your shock cord at least 12" from you chute attachment point. You should always attach nomex so there is no chance it interferes with your chute. But I just don't see a burrito roll still intact after deploy.

 

[Jozef]

Yeah I was experimenting with different folds and bands, in this photo I believe was one of the times I actually went around the chute twice with the band twice before plugging the pin in... the chute release came roaring off in a ground test

The band should be sized to go around the chute once. It looks line you you have a long lead to some attachment point on the harness or nosecone...cant tell from the photo. Attach the JLCR tether to a swivel or quick link to which your chute lines terminate and attach that to a loop in the harness below the nosecone. The photo seems to have a lot of lines twisting together.

 

[John Beans]

A few bits of advice that I would offer:

1. Aim for a firm (not fluffy) bundle. A band won't get caught up in a firm bundle, it will spring off. I suspect this is the OP DankMemes' issue. Until I saw it myself for the first time, I would have thought it improbably that you could get a pin release and not inflation, but it happens. Usually the slipstream will blow the bundle open anyways, but sometimes it just seems find a stable descent configuration and doesn't buffet the bundle enough to unstick the band. It just stays wedged in a fold.

2. You should fold your chute differently than you would without Chute Release, because you can use Chute Release to hold your bundle closed. More a comment for others, not DankMemes. Lots of people used to wrap the shroud lines around the chute before Chute Release; don't do that. Keep the shrouds inside the bundle. Prevents them from getting twisted up (like photo above) during descent, and contributes towards the ultimate goal: quick inflation in less than 50 feet of descent.


3. DON'T tether Chute Release so that it gets yanked off the bundle by the shock cord. That yank will likely lead to an apogee deployment at ejection or even a rapid disassembly of Chute Release if it's violent enough. You should be able to pull your nosecone and fuselage apart until the shock cord is at full stretch without affecting Chute Release at all.

Hope that helps?

 

[DankMemes]

A few bits of advice that I would offer:

1. Aim for a firm (not fluffy) bundle. A band won't get caught up in a firm bundle, it will spring off. I suspect this is the OP DankMemes' issue. Until I saw it myself for the first time, I would have thought it improbably that you could get a pin release and not inflation, but it happens. Usually the slipstream will blow the bundle open anyways, but sometimes it just seems find a stable descent configuration and doesn't buffet the bundle enough to unstick the band. It just stays wedged in a fold.

2. You should fold your chute differently than you would without Chute Release, because you can use Chute Release to hold your bundle closed. More a comment for others, not DankMemes. Lots of people used to wrap the shroud lines around the chute before Chute Release; don't do that. Keep the shrouds inside the bundle. Prevents them from getting twisted up (like photo above) during descent, and contributes towards the ultimate goal: quick inflation in less than 50 feet of descent.


3. DON'T tether Chute Release so that it gets yanked off the bundle by the shock cord. That yank will likely lead to an apogee deployment at ejection or even a rapid disassembly of Chute Release if it's violent enough. You should be able to pull your nosecone and fuselage apart until the shock cord is at full stretch without affecting Chute Release at all.

Hope that helps?

I think you might be on to something John, with that first point, my first flight on the firestorm which was successful, the chute was folded pretty tight so I could it and the release down the throat of a bt60 tube and fit a blanket around it...

 

[scott johnson]

I regularly use the CR on a BT-60 size tube. Tuck your shroud lines inside the chute, fold in thirds and use a swivel. Baby powder helps, too!

 

[jahall4]

So, I flew my chute release for the first time at Bama Blastoff, followed the instructions did the ground test and a puff test to make sure all was good... flew it in a bt-60 firestorm two stage and it worked great...


Tried it 5 times in a row in my Trajector doing the same pre flight test and with a variety of folds and bands and every time the chute never inflated but the release did fire. Even when the release would come flying off the chute on a ground test I’d end up with results like this picture...

By the way this is an 18” Estes nylon pro series chute... and fortunately the Trajector survived the weekend

I’m banging my head here, and got some tips from many friendly folks at Bama Blastoff and we still couldn’t get it to go...

Any thoughts?



View attachment 365296

I think I saw all 5 times . Pretty sure I could have fixed all your ills and thought I had spoken with you about it. If not my apologies. I have had spurious issues like these with John's release as well. The recovery or "chute sled" is the answer. I actually posted about it prior to BBoff on the Event page... https://www.facebook.com/events/251326039020364/permalink/281482922671342/

 

[ksaves2]

Don't roll the lines. Make sure you have the chute protector attached downstream from the chutepack so it pulls off the JLCR chutepack as soon as the apogee deployment occurs. One doesn't need a chute protector anymore. As long as the chute stays reefed by the JLCR, even if some of the lines pull free one still won't have a long walk. Use a swivel. Personally, I don't deploy lower than 600 feet.
If you have the venue, why do such stupid low deployments? It's your rocket me thinks a few extra footsteps is worth foregoing airframe repairs. Kurt

 

[DankMemes]

Looking back at the pic and John Beans’ feedback I’m convinced I didn’t pack it tight enough and the bands dug into the chutepack combined with the nomex riding up the harness..

Doing some experiments I was able to reproduce the behavior on the bench. I had to experiment with some different folds to hard pack the thick chute with the release into the 2” tube... but I think I have a much more reliable setup... with the smaller bt60 rockets I flew I wasn’t having this issue and the JLCR flew just fine.

But yeah at Bama Blastoff next time I’ll release higher.. 600 or so.. it’s a huge field... apogee deployments were no fun as I did fly my ascender to an apogee deployment intentionally an with the 20mph or so wind gusts that was at least a 2.5 mile walk... that I’d like to avoid again haha

Anyway looking forward to trying again with the new folds and modified nomex setup soon at the next SRA launch

 

[John Beans]

As is true for many things, there's no one right release altitude when using Chute Release.

• Sometimes, especially with a big-finned rocket that tends to weather vane into the wind, you NEED some drift on chute to get back closer to the pad
• On days with confusing wind (sometimes wind blows in different directions at different altitudes, so rockets don't all land in one area) and with cloud cover you need extra time on chute to spot your rocket
• On some windy days, you can't afford 500-1000 feet of release altitude; you need to drop it down HALO style to keep it reasonably close to the pad and not in the middle of a corn field or a stand of trees
• Release altitude has no effect on landing speed—a rocket that inflates its chute at 200 feet lands at the same speed as a rocket that inflates at 600 feet; the only difference is time on chute and drift (and some insurance for a chute that may inflate slowly)

If someone said they had a new rocket and chute that they were flying for the first time and they were setting the release for 600 feet, I'd say that's a good idea—especially if they were collecting data and checking their performance afterwards. If a few months later they were setting it for 200 feet and getting reliable results, I'd would say that they were getting really good at it.

On the other hand, if I KNEW someone had a just-built, heavy rocket and was trying Chute Release for the first time, I'd make sure to have eyes on it no matter what release altitude they chose, and I'd probably NOT mind my own business and I'd butt in if they said they were setting it for 200 feet.

 

[ksaves2]

Also pack the chute fresh onsite and don't let it sit for hours or days all scrunched up. Kurt

 

[YodaMcFly]

I loved my first Chute Release so much, that when I lost it, I bought another.

I loved that one so much, that after losing it last month, I'll be buying another before next flying season. I may name it "Swamp Castle".

Seriously, though, the only flight I ever had issues with was one that, I'm pretty sure, I packed everything too tight and blocked the vent holes, so that the CR couldn't get accurate pressure samples.

As for release altitude, at my field, we frequently see the wind direction shifting at different levels, so I'm of the "set the CR for as low as possible" school of thought. I usually set it for 400 or 500 on the first flight, then go down from there.

Remember, the CR has a test feature; I use it every time ... Pack it; test it, then re-pack it.

 

[crossfire]

I agree with post 17. This summer I had a recovery were the JLCR released but when got to the rocket all was folded up just like I packed. I now attach protector at least 12" from chute attachment point. All have worked well since.

 

[drkruse]

Dank Memes, looking at the picture, I would suggest attaching the JLCR with the tether end pointing to where you have it tethered. This will reduce the chance of the rubber band wrapping around the the tether and not falling away from your chute. I have been using the JLCR on every launch that I can fit it in. Wish there was a smaller version available for smaller tubes.

 

[scott johnson]

Had my first JLCR failure yesterday...the chute release didn't malfunction, my folded bundle got wrapped up in the shock cord. Technique is key for success. I got sloppy......

 

[Homer_S]

I loved my first Chute Release so much, that when I lost it, I bought another.

I loved that one so much, that after losing it last month, I'll be buying another before next flying season. I may name it "Swamp Castle".

Seriously, though, the only flight I ever had issues with was one that, I'm pretty sure, I packed everything too tight and blocked the vent holes, so that the CR couldn't get accurate pressure samples.

As for release altitude, at my field, we frequently see the wind direction shifting at different levels, so I'm of the "set the CR for as low as possible" school of thought. I usually set it for 400 or 500 on the first flight, then go down from there.

Remember, the CR has a test feature; I use it every time ... Pack it; test it, then re-pack it.

Please remember to turn it back on as a ground test turns it off. Learned that the hard way...

Homer

 

[jahall4]

Had my first JLCR failure yesterday...the chute release didn't malfunction, my folded bundle got wrapped up in the shock cord. Technique is key for success. I got sloppy......

Unfortunately this can happen with even the "cleanest technique". The cure is using a "Recovery" or Chute Sled.

PackedChuteSled

• jahall4
• Dec 18, 2018

 

[DAllen]

While I haven't read EVERY post in this thread...;looking at the OP's picture I think your rubber band is too long. Your pin is wrapped past the CR. I think you need to have a fair bit of tension on that pin so when the CR releases it sort of springs open.

 

[Normzilla]

I had a failure to release this weekend.



All was set up ok, CR was still attached and not tangled.

I had noticed a trend for late release, emailed JB, and was told get the hang of setup and it takes time to inflate.

I've used CR on every flight since I've owned it, I've nailed the setup, and I know its releasing late.

 

[Oberon]

I've had multiple failures where a JLCR activates without chute deployment. One of these resulted in a broken Eggfinder and Quantum (I was using the Quantum to deploy at apogee and the JLCR as the "main" in a stubby rocket without room for traditional DD). I have since reflown that one successfully with a different packing technique and increased tension (I use a sewing elastic band and adjust the knot to tailor tension for each 'chute, holds up a lot better than the rubber bands which all deteriorated on me).

One rocket I always have issues with is the MDRM - my JLCR deployments on that one have about a 50% success rate. I think the main issue with that one is that the huge fins and light weight of the rocket mean that it falls relatively slowly in a tumbling fashion. It's almost as if it doesn't achieve enough downward velocity to result in a solid positive inflation of the chute. My rockets that fall faster seem to have chutes that snap open with authority.

 

[Oberon]

Oh, and for the OP, it looks like you wrapped the band around your chute pack more than once? That's a really bad idea! If you need more tension, use a shorter band or pack differently, a multi-wrap is just asking for a hang up.