Jolly Logic Chute Release

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Scott Chase

Fly29mm
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I'm going to buy a chute release. I Have some questions
1) I have some Aerotech motors all with long delays so my rockets are heading straight for the ground when the ejection charge deploys at high speed. will the high speed deployment damage the chute release? Or can I use these motors with the Chute release?
2) How do I figure out how fast the rocket is going just before the ejection charge fires? Can I find out by running a open rocket simulation?
3)If you knew nothing about testing a Jolly Logic Chute release how would you proceed?

Thank you,
Brian
 
1. It might. It also might damage the rocket. I would suggest putting those longer delay motors in lighter rockets and getting some shorter delay motors.

2. Open rocket will tell you the speed of the rocket at ejection. It will also provide a warning if the speed is too fast. I don’t know offhand what the warning threshold is.

3. I would read the instructions provided in the manual. The JLCR is very easy to use. Just make sure you reset it after you test it. The chute release does not turn back on automatically after you ground test it. You must turn it on manually.
 
Chances are pretty good that you will "zipper" your air frame with a late ejection charge which may also shred your parachute even with a JLCR. Depending how long your delay is, you could even end up with a lawn dart. John beans has a pretty good video on his websiste for testing.
 
JLCR is ideal for rockets like a 2" Jart on a relatively larger motor, put an altimeter in the NC (Coker/Intellicone style) to get the nose cone off at apogee and use the JLCR to fully deploy the chute at a programmed altitude. There's definitely a limit to what you can do with motor eject... once you get to L1 motors you can easily start hitting it.
 
I'm going to buy a chute release. I Have some questions
1) I have some Aerotech motors all with long delays so my rockets are heading straight for the ground when the ejection charge deploys at high speed. will the high speed deployment damage the chute release? Or can I use these motors with the Chute release?

You can definitely use AT motors with JL Chute Release.
Most AT motors' delay charges can be drilled out to shorten the delay timing.
Ideally, you want to fire ejection charges and break the rocket apart a,t or near the apogee. This minimizes the chock on the harness, and the drift of the rocket.
Still, if you deploy JLCR-bundled chute, it will act as a "streamer", and slow down the rate of rocket's descent. Then, when the JLCR releases at a preset altitude, the chute will inflate as designed, regardless of the altitude at which teh rocket separated.

The only way this goes pear-shaped is if your delay charge fires after the rocket hits the ground. :eek:

2) How do I figure out how fast the rocket is going just before the ejection charge fires? Can I find out by running a open rocket simulation?

Yes, you can simulate the horizontal/vertical speeds at each point of rocket's flight.
The speeds will be the lowest at apogee, which is why you want to fire ejection charges around that point of the flight.

3)If you knew nothing about testing a Jolly Logic Chute release how would you proceed?

Prep for the flight as you would for any other rocket, then setup JL CR to control when the chute opens up.
This will minimize the drift under open chute, and shorten your walking distances to recovery. Otherwise, make the flight preparations the same way as you would w/o JLCR.

HTH
 
Chances are pretty good that you will "zipper" your air frame with a late ejection charge which may also shred your parachute even with a JLCR. Depending how long your delay is, you could even end up with a lawn dart. John beans has a pretty good video on his websiste for testing.

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.
 
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.
 
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.

Folding the chute with shroud lines rolled inside is a standard practice.
Rolling the chute into a burrito is an optional (and advanced) technique that slows the speed of inflation, and lowers g-forces during deployment.

I see nothing obviously wrong with what John Beans demonstrates in his video.
If you do, please elaborate.

Otherwise, I will have to take John's advice on successful chute folding for JLCR deployment over a random internet guy's exaltation.
 
Folding the chute with shroud lines rolled inside is a standard practice.
Rolling the chute into a burrito is an optional (and advanced) technique that slows the speed of inflation, and lowers g-forces during deployment.

I see nothing obviously wrong with what John Beans demonstrates in his video.
If you do, please elaborate.

Otherwise, I will have to take John's advice on successful chute folding for JLCR deployment over a random internet guy's exaltation.
Um...literally every single thing he did to that chute either increases the risk of line entanglement or prevents proper chute inflation.

Rolling with the lines in it a parachute is basically the worst thing you can do to it in terms of deployment. It would actually be better if it just bunched it into a ball.

But hey, I'm just some guy on the internet, right? I'm certainly not a guy who is a qualified Army parachutist studying to be an FAA rigger, who learned how to pack high speed drogues, large cargo chutes, and man-rated chutes from master riggers.

If you can spare any time from making pithy, uninformed comments, spend about 5 minutes learning about, anecdotally, what I believe to be the cause of most rocket failures - recovery failure. Google parachute packing and see how many chutes are rolled like a burrito and let me know...I'll wait.
 
You may know what you're talking about, but calling someone else out for their conversational style while your own is far more combative than theirs is hardly productive.
I have zero respect for someone whose profile picture says "more science lead fear" and then faults their lack of scientific knowledge in a subject so brazenly.
 
Let's assume, just for a moment, that there might be more than one successful method for achieving almost anything, and that jumping to criticism here might not be among them. Consider the possibility, too, for example, that parachutes deployed from rockets at apogee are not operating under the same conditions as man-rated chutes from master riggers.
 
Um...literally every single thing he did to that chute either increases the risk of line entanglement or prevents proper chute inflation.

Rolling with the lines in it a parachute is basically the worst thing you can do to it in terms of deployment. It would actually be better if it just bunched it into a ball.

But hey, I'm just some guy on the internet, right? I'm certainly not a guy who is a qualified Army parachutist studying to be an FAA rigger, who learned how to pack high speed drogues, large cargo chutes, and man-rated chutes from master riggers.

If you can spare any time from making pithy, uninformed comments, spend about 5 minutes learning about, anecdotally, what I believe to be the cause of most rocket failures - recovery failure. Google parachute packing and see how many chutes are rolled like a burrito and let me know...I'll wait.
What's your recommended way to pack a parachute with the Chute Release?

Reinhard
 
Let's assume, just for a moment, that there might be more than one successful method for achieving almost anything, and that jumping to criticism here might not be among them. Consider the possibility, too, for example, that parachutes deployed from rockets at apogee are not operating under the same conditions as man-rated chutes from master riggers.
You are correct, hobby rocketry parachute deployment characteristics, methods, mechanisms differ in some respects from other types of parachute deployment, but there are far more similarities than differences. But under no circumstances should shroud lines ever be rolled in a canopy. Period. Not debatable.
 
Actually in regards to your question 1, I've found that rockets that were prone to zippering with less then ideal delay choices have actually been saved from further zippers by the chute release. Without the shock of opening, the forces seem to dissipate better. I've also been less scientific though, because about the time I started using the chute release I also started looping bands of shock cord and taping them with masking tape to help dissipate shock at ejection :)
 
Um...literally every single thing he did to that chute either increases the risk of line entanglement or prevents proper chute inflation.

Rolling with the lines in it a parachute is basically the worst thing you can do to it in terms of deployment. It would actually be better if it just bunched it into a ball.

But hey, I'm just some guy on the internet, right? I'm certainly not a guy who is a qualified Army parachutist studying to be an FAA rigger, who learned how to pack high speed drogues, large cargo chutes, and man-rated chutes from master riggers.

If you can spare any time from making pithy, uninformed comments, spend about 5 minutes learning about, anecdotally, what I believe to be the cause of most rocket failures - recovery failure. Google parachute packing and see how many chutes are rolled like a burrito and let me know...I'll wait.

Ok, so don't take this the wrong way -- it sounds like you may have some great experience that I'd like to learn from. But your delivery comes off as needlessly confrontational. "Nobody" knows you or what you do in the real world, so if someone posts a video showing something that you disagree with it's not because they don't like you or trust you. It's just that there is this video from a vendor showing how to use their product. If you have something to contribute - and again I hope so - please provide concrete, constructive feedback.

FWIW I believe it was NAR that did a study and found that recover failure accounts for the vast majority of all failures in model rocketry.

Back on topic. I have had chutes get tangled several times due to how I've packed them. I would like to learn better ways to pack the chutes + JLCR to prevent my rockets from hitting the ground at 30+fps with a tangled chute. What packing method should I follow to maximize my chances of success? How would you pack the chute to 1) minimize size and 2) maximize chances of deploying after the JLCR releases?

Example: Last week I had my shroud lines get tangled after the JLCR released. The chute got reefed by the tangled lines and the rocket arrived back on the ground at 30fps. It survived just fine but I was shooting for 19 fps. Clearly I did something wrong, but the next 5 flights were perfect. Not sure what I did wrong 20% of the time but I would very much like to avoid repeating whatever it was.
 
What's your recommended way to pack a parachute with the Chute Release?

Reinhard
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.
 

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Ok, so don't take this the wrong way -- it sounds like you may have some great experience that I'd like to learn from. But your delivery comes off as needlessly confrontational. "Nobody" knows you or what you do in the real world, so if someone posts a video showing something that you disagree with it's not because they don't like you or trust you. It's just that there is this video from a vendor showing how to use their product. If you have something to contribute - and again I hope so - please provide concrete, constructive feedback.

FWIW I believe it was NAR that did a study and found that recover failure accounts for the vast majority of all failures in model rocketry.

Back on topic. I have had chutes get tangled several times due to how I've packed them. I would like to learn better ways to pack the chutes + JLCR to prevent my rockets from hitting the ground at 30+fps with a tangled chute. What packing method should I follow to maximize my chances of success? How would you pack the chute to 1) minimize size and 2) maximize chances of deploying after the JLCR releases?

Example: Last week I had my shroud lines get tangled after the JLCR released. The chute got reefed by the tangled lines and the rocket arrived back on the ground at 30fps. It survived just fine but I was shooting for 19 fps. Clearly I did something wrong, but the next 5 flights were perfect. Not sure what I did wrong 20% of the time but I would very much like to avoid repeating whatever it was.
Fair statement and feedback. Also, that video was by the actual vendor for JLCR?? I'm a little sad about that. I bet every time the boys at Loc or Madcow see that video they get excited because it means someone is about to lose an airframe and reorder!

I am actually working with a guy using a 9' chute and have a new chute arriving next week and the plan was to make a video for him...now I think I will do a series and do 18" engine ejection recovery up through 10' dual deploy. There isn't a lot of good info out there on the internet and what I have seen makes me cringe. I'm friends with a few people who used to grab a handful of silk and just haphazardly shove their chute into the forward end of their rocket, wire it up, and fly. Despite all the evidence about recovery being the highest cause of flight failure, there is resistance to do it any way but the old way.

I try to keep the JLCR as far from the shroud lines as possible. I also use the smallest rubber band I can (even cutting and tying my own) and use nylon rope to connect to the pin to limit the possibility of the rubber band getting sliced at ejection on the lip of the airframe. I had a 4" fiberglass kit on a baby M shred my rubber band so my main came out at 15,000 onna very windy day. I haven't forgot that lesson. The JLCR is an elegant solution to a tough problem but I am a true believer in DD. I use JLCR only when the airframe design forces me to. I have my first flight with cable cutters in July and they seem to remove the tangle tendency you see with JLCR but present their own issues in terms of set up and wiring.
 
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.

Thanks. I'll keep that in mind the next time I play with packing the chute. You didn't mention it, but I like how you put the shock line below the Chute Release to keep everything inline and reduce the chances of pulling out the lines from the chute.

One thing that I suspect explains a bit the different approach of Jolly Logic is the observed failure mode where the Chute Release opens, but the bundle still doesn't unfurl because the rubber band "cuts" into the bundle and stays there because the sticky rubber band generates quite some friction. The "roll-up" method makes it easier to create a very firm bundle, preventing the band from pinching the bundle. While it would be completely inappropriate for a serious chute, small hobby chutes with only few lines seem to be more tolerant to rolling them simply up. With smaller chutes, I'm guilty of that too and haven't had a problem yet (not knocking on wood ;) ).

Reinhard
 
Thank you for posting the photos - very helpful! I'll try that next time I'm using the chute release. I had my rubber band break @ 5,000' so I can only imagine the pain at three times higher :eek:

I'm working on a hybrid deployment for the LOC Nuke Pro Maxx - altimeter ejection at apogee and chute release at 700'. I don't have room in the booster for both drogue and main so having the JLCR gives me a good option there.
 
Thanks. I'll keep that in mind the next time I play with packing the chute. You didn't mention it, but I like how you put the shock line below the Chute Release to keep everything inline and reduce the chances of pulling out the lines from the chute.

One thing that I suspect explains a bit the different approach of Jolly Logic is the observed failure mode where the Chute Release opens, but the bundle still doesn't unfurl because the rubber band "cuts" into the bundle and stays there because the sticky rubber band generates quite some friction. The "roll-up" method makes it easier to create a very firm bundle, preventing the band from pinching the bundle. While it would be completely inappropriate for a serious chute, small hobby chutes with only few lines seem to be more tolerant to rolling them simply up. With smaller chutes, I'm guilty of that too and haven't had a problem yet (not knocking on wood ;) ).

Reinhard
I always try to keep things vertical. I use JLCR on a 5.5" Nike booster I flew last year and I loved how it recovered... in that situation I have a 24" drogue to pull everything out and get in line and then 15 or so feet below the drogue I have the JLCR set up on an 84" main. A chute that big is really pushing the JLCR in terms of strain on the physical device. That much chute, even folded, really pushes back in the airflow. I am going to use cable cutters in that setup in the future and leave the JLCR to chutes 48" and smaller.

Rolled chutes may eventually unfurl after falling long enough but all it takes is one shroud line getting out of the roll and position themselves above the roll and you just created a point of friction that most descent speeds aren't going to force the chute to overcome. Fold gores to the right, fold the chute in thirds, accordian told the lines, and that will open most chutes a majority of the time.
 
Thank you for posting the photos - very helpful! I'll try that next time I'm using the chute release. I had my rubber band break @ 5,000' so I can only imagine the pain at three times higher :eek:

I'm working on a hybrid deployment for the LOC Nuke Pro Maxx - altimeter ejection at apogee and chute release at 700'. I don't have room in the booster for both drogue and main so having the JLCR gives me a good option there.
Wind carried the rocket 4 miles in the air and drug it another mile on the ground until the airframe got stuck in an irrigation ditch with about 20lbs of mud in the airframe.

I like the design of the JLCR, it makes single-break airframes more attractive to fly high. M
Double the size and make one out of aluminium and I'd buy it.
 
I saw the comments on the rubber bands. The attached pictures show the hair bands that I use in place of the rubber bands. I've been using the hair bands for maybe three years. I use the red band for 42" to 50" chutes. The black & white band I use on the chutes smaller than 42", down to 24". I use a twist tie to pull the bands thru that small hole on the Chute Release. So far I have not had any bands break.
IMG_7794.JPGIMG_7804.JPG
 
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.
Can you give some data, what size engine, how high did it go and how far was the free fall before chute release? All launches/recoveries are successful. Because why I think this is a great product, from what I read on the high power side of the hobby...Chute Release is go for low power models that will not free fall too much...otherwise zippering and chute damage can happen.
 
I have had several late deployments when using the chute will no ill effects. The drag caused by the chute bundle was not enough to zipper the airframe. (Quantum tube in one case, cardboard in the other.) The drag caused by the nose cone and bundle flapping in the airstream slowed the rocket enough that when the chute release let go, the chute was fine, which is how it normally works anyway.

HOWEVER, if the deployment is late enough that the rocket is below the altitude of the chute release setting, it may open quickly enough to cause a zipper or other issues. Or, if not securely packed, the chute may open during the ejection into the fast air and cause issues.

Would I intentionally use a long delay with a chute release? No. But through the wonders of the 'Aerotech bonus delay' I've suffered late apogee charges with no ill effects when using a JLCR.

After watching a fellow flyer at a recent launch suffer several failures with a chute release, all I can say is practice, practice, and then practice some more packing and testing your chute on the ground.


Tony

PS: a larger chute release would be a great addition to the product line
 
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Can you give some data, what size engine, how high did it go and how far was the free fall before chute release? All launches/recoveries are successful. Because why I think this is a great product, from what I read on the high power side of the hobby...Chute Release is go for low power models that will not free fall too much...otherwise zippering and chute damage can happen.

I can't speak for others, but I have flown as large as a 4" rocket and as large a motor as a J270 with a chute release. In fact the larger rockets make it easier to use the release since there is more room for the chute, nomex and chute release in the body tube.

Right now my typical rocket is a 3.1" or 2.2" LOC kit flying an H, I or J to 4 - 5k' AGL. I usually open the chute on odd altitudes so 700' is typical. That gives me about 4,300' at about 60fps freefall. I want to land at <20fps.

I have another project I'm working on which is a 2.2" rocket that I'll fly on larger J's but there isn't room for the longer motor and a chute in the bottom section so I'm going to do altimeter ejection of the main + JLCR. I expect between 7 and 9k AGL for these flights and main at 700'. Standard dual deployment might work but there will be only an inch or two in which to fit the harness and drogue. The chute release gives me another option to just eject the main at apogee and let the JLCR do the rest.
 
Can you give some data, what size engine, how high did it go and how far was the free fall before chute release? All launches/recoveries are successful. Because why I think this is a great product, from what I read on the high power side of the hobby...Chute Release is go for low power models that will not free fall too much...otherwise zippering and chute damage can happen.

I flew JLCR the other day in a Madcow Screech on an i327DM to 4,978'; RRC2 altimeter triggered separation at apogee and the rocket tumbled to 500' (pretty sure it was 5, but it might have been 700). Either way, no issues, great chute inflation and recovery.

The biggest airframe I've used JLCR is my 5.5" Madcow Nike booster with an M2020 that hit 10,155' and my altimeters popped the apogee charge. I had a 30" drogue pull everything out and the JLCR released the main (84" or 96", can't recall exactly) with no issues. That pig weighs 6.65 kg with no motor so it is beefy.

Weight isn't the issue per se, but higher weight means bigger chutes and big chutes are tough to reef and secure with JLCR. For me, 48-54" is the biggest I am 100% confident JLCR can secure without drogues and some specific shock cord set up.
 
This is also a good opportunity to advocate for electronic (baro or accelerometer) deployment over motor deployment.

You solve so many problems by avoiding motor deployment.

Just my personal opinion but worries about zippers, ease of recovery harness set up, and a host of other issues go away with electronic deployment.
 
So with JLCR and the worry about using rubber bands on large chutes at high altitude, is there any merit in using cable (zip) ties as a substitute for the bands?
Seems to me to be a bit more secure. Thoughts?
Cheers,
Mark
 
So with JLCR and the worry about using rubber bands on large chutes at high altitude, is there any merit in using cable (zip) ties as a substitute for the bands?
Seems to me to be a bit more secure. Thoughts?
Cheers,
Mark
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.
 
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