Jolly Logic Chute Release tips and technique

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blackwing94

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I would like to start an ongoing thread for people to post usage tips and experiences and ask questions about using the Jolly Logic Chute Release.

I use a chute release on every flight now. I fly mostly 38mm and 54mm rockets. I use electronic deployment at apogee and a chute release for main deployment. For smaller rockets I use motor ejection. The biggest rocket I've used the chute release on was 16 lbs.

For me, using a chute release means my rocket only splits in one place, usually the av bay coupler. I end up with the booster section on one end of the harness and the "av bay coupler/payload bay/nosecone" on the other end of the harness. I attach the main chute 1/3 of the way down the harness from the upper section. That way the booster section lands first. Having the main chute bundle attached to the harness seems to allow the "draggy" wrapped main chute to to trail above the whole free fall formation and remain free of entanglements prior to deployment. I have not had any tangled deployments yet.

Where do you attach your main chute?

I've seen videos where the main is attached to the nosecone. Does your main chute bundle ever get wrapped around the harness during free fall causing problems during deployment?

Do you think a longer harness could be used to provide a little more drag and separation to the falling formation?

I always tether the chute release to a shroud line. Never lost a chute release yet.

I'm curious to hear about your free fall decent rates and stability of your falling formation. Do you do anything to try to effect the formation your rocket assumes when its in free fall?

I almost always see free fall decent rates at less than 100 ft/sec. Most of my rockets fall flat. I do have one big tube fin rocket that tends to orient the booster section and sail upwind during free fall. Kinda funny to watch.

And finally, what did you do wrong? What lessons did you learn by using the chute release the wrong way?

Besides forgetting to turn it on (guilty), I've used the chute release where the main bundle was just to tight for the diameter of the rocket and the main chute never came out of the booster section.

Share your experiences, tips and techniques. :)
 
I have had 4 failures with chute release although it was not the chute release that failed. All 4 failed events were due to main slipping out of chute release at or near apogee which unfortunately resulted in long walks. I always perform the shake test before launch so not sure what is going on. Have tried several methods folding chutes and securing chute release to shroud lines and always use the right size band per Mr. Beans' recommendations so sometimes I get leery using the chute release.
 
I have used the JLCR with very good results. This year I have 8 flights using it and had 1 failure due to rubber band breaking. So I now check band over before each flight.
 
I love the JLCR and use mine all the time, in the neighborhood of 20 flights. We have a fairly small field so the JLCR really opens up motor options and allows high flights.

I have experienced two issues but neither were the fault of the JLCR and in both cases the rocket survived.

No.1 Forgot to turn it on. Easier to do than you think. You install it, you test it, and then forget to turn it back on.

No,2. The bundle has to be the right size and slide easily. You are adding mass and bulk by using a JLCR and you need to be sure it ejects. I made my “package” to big and it didn’t eject.

But again this is a great device.


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I'm curious, do you use swivels? Where?

That's a really good question. I buy my chutes from Sperachutes and Julie usually includes a swivel. So yes, most of my chutes are connected to the harness with a swivel.

The next question is, do you need a swivel where the rocket parts connects to the harness? In free fall, it looks like the booster is spinning and probably needs a swivel where it connects to the recovery harness. My go to harness is 25 feet long and seems to absorb a good amount of free fall parts spinning. (I move a harness from one rocket to another as needed. Same with chutes.)

I'm still interested in if there is any way to effect, or better control, the free fall portion of recovery.
 
I have had 4 failures with chute release although it was not the chute release that failed. All 4 failed events were due to main slipping out of chute release at or near apogee which unfortunately resulted in long walks. I always perform the shake test before launch so not sure what is going on. Have tried several methods folding chutes and securing chute release to shroud lines and always use the right size band per Mr. Beans' recommendations so sometimes I get leery using the chute release.

That's interesting. What kind of chute are you using? It would be good to know if one fabric is more prone to slippage than another.

I can say I have never had a chute slip out of the chute release. The chutes I use (Sperachutes 24 to 84 inches) are made of a thin ripstop nylon. It's not a stiff fabric, but supple. Almost like silk. So the chute release rubber band totally overpowers the fabric and the band fits around it tightly. I can see where a stiff smooth thicker nylon might be harder to contain.

So are some parachute material better suited to a chute release than others?
 
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I would like to start an ongoing thread for people to post usage tips and experiences and ask questions about using the Jolly Logic Chute Release.

I use a chute release on every flight now. I fly mostly 38mm and 54mm rockets. I use electronic deployment at apogee and a chute release for main deployment. For smaller rockets I use motor ejection. The biggest rocket I've used the chute release on was 16 lbs.

I also fly JL CR on every rocket where it physically fits into the airframe (including the larger 18mm ones), which adds up to ~5-10 flights per typical launch day. Since I bought CR in June, I must have done ~10 launch events, public and private, so have the sample size of ~25-50 CR flights. For the majority of the rockets, chute is attached 1/3 of the way down on the shock cord (from nose cone to booster section). On the smaller 18mm rockets, chutes are attached to the nose cone. All of my chutes have swivels. CR is always tethered to the shock cord.

I've had two (2) screws-ups in total, both my fault, both involved tangled-up chute shroud lines that prevented it from fully inflating. One time the rocket survived landing on a CR streamer unscathed, the other time I had two broken fins.

The root cause of failures was not tucking the shroud lines inside the chute bundle properly, which allowed them to be pulled out, flap around over the course of long streamer-style descent, and tangle up. Two remedial actions were taken that had eliminated this problem:
1). I now tether the CR about a 6-8" up on the shock cord, effectively strapping CR bundle to the shock cord with two attachment points (chute attachment and CR tether attachment). This way the folded CR+chute package doesn't spin independent of the shock cord, and doesn't pull on the folded shroud lines too hard, allowing them to stay folded inside the chute.
2). I make sure to stick the shroud lines inside the multi-folded chute bundle, then Z-fold the chute over, then CR strap it up. Similar to instructions here:
https://publicmissiles.com/secure/parachutepacking.asp


I'm still interested in if there is any way to effect, or better control, the free fall portion of recovery.

On my larger rockets, I get 50-60 fps speeds on folded CR while it is acting as a streamer. That's roughly equivalent to 13.5" drogue chute.
The longer rockets tend to fall almost perfectly horizontally, surfing the wind gusts. Kinda fun to watch.

a
 
That's interesting. What kind of chute are you using? It would be good to know if one fabric is more prone to slippage than another.

I can say I have never had a chute slip out of the chute release. The chutes I use (Sperachutes 24 to 84 inches) are made of a thin ripstop nylon. It's not a stiff fabric, but supple. Almost like silk. So the chute release rubber band totally overpowers the fabric and the band fits around it tightly. I can see where a stiff smooth thicker nylon might be harder to contain.

So are some parachute material better suited to a chute release than others?

I use Top Flight Recovery chutes and have never had a chute slip out of the JLRC.
 
The next question is, do you need a swivel where the rocket parts connects to the harness? In free fall, it looks like the booster is spinning and probably needs a swivel where it connects to the recovery harness. My go to harness is 25 feet long and seems to absorb a good amount of free fall parts spinning. (I move a harness from one rocket to another as needed. Same with chutes.)

I'm still interested in if there is any way to effect, or better control, the free fall portion of recovery.

I use a JLCR, but only for motor ejection rockets. I've found that things do get twisted up and I probably could use a swivel on the chute with these, but haven't found any heavily twisted cords on recovery yet. Nothing that can't be straightened pretty easily.

A little off subject, but with DD rockets, I use a swivel on the booster/fin can only. Since the fin cans spin so much, putting a swivel on the fin can eliminates all my twisting problems. Since the main chute is inside the bt until it deploys and nothing really spins or twist under main chute, I haven't found a need for a swivel there.
 
This flight season I made it my goal to test various methods for using the chute release and I have had great success! Here is what I have been doing, on my heavier airframes 12-15lbs I have been using the old top popper style to just eject nose cone and chute. I use altimeter for deployment at apogee and use a timer for backup as I fly with plugged bulkhead on my Loki 54’s. At apogee I have found that using a 24” guide chute from Dinochutes works awesome to keep everything lined up. I attach that to the nosecone and then my JLCR about 3ft below on my harness. I swivel the chute at the harness and the harness at the air frame. I use a 30 ft harness and I have not had a tangle as of yet. As for tethering the CR, I have loops sewn on top of my chute so I tether it directly to that and I do not worry about it tangling in the shrouds. I roll the shrouds inside the chute and use tightest band possible! Been working great so far. Only failure I had was I pushed the release altitude to close on a windy day and chute did not have time to unfurl, guide chute helped soften the fall but had a few repairs. One more launch this season to go then build for next year!
 
I have made 2 flights with my JLCR.
The first was a chute folded and bundled into a blanket. I put the CR inside one of the Dino-chutes protective pouches. The bundle failed to open. The nomex blanket was caught on the velcro of the pouch. Rocket destroyed, JLCR still good.
Next flight I used the CR to hold the bottom of the chute closed, essentially making it a streamer. Functioned perfectly, but in the future I will set it for 400ft.
 
My first two flights with the JLCR were unsuccessful - I just packed the chutes like I’ve done for the last 30 years and wrapped the rubber band around the bundle. Never inflated.

Then I watched John’s videos about how he packs his chutes. 100% success rate after that, including my L2 cert flight.


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on my heavier airframes 12-15lbs I have been using the old top popper style to just eject nose cone and chute.

That's cool. Let me make sure I understand. Your drogue, main chute, and harness are in the payload bay. The booster section is empty. At apogee, your ejection charge blows the nose cone off, and the drogue brings the rocket down until the chute release is triggered. The main/chute release is located on the harness under the drogue/nosecone about 3 feet. That's a neat method.

Have you anything you would consider close to a tangle? Does the main chute inflate kinda off to one side, away from the harness?
 
That's interesting. What kind of chute are you using? It would be good to know if one fabric is more prone to slippage than another.

I can say I have never had a chute slip out of the chute release. The chutes I use (Sperachutes 24 to 84 inches) are made of a thin ripstop nylon. It's not a stiff fabric, but supple. Almost like silk. So the chute release rubber band totally overpowers the fabric and the band fits around it tightly. I can see where a stiff smooth thicker nylon might be harder to contain.

So are some parachute material better suited to a chute release than others?

2 flights I was using a LOC chute. Have had other problems with them as well so I’ve eliminated them from use altogether.
On the other flights I believe I connected it to a swivel instead of shroud line. Anyhow I still use it but am just a bit apprehensive on high altitude flights. Used it today to 4k with a Recon Recovery chute and worked great.
 
That's cool. Let me make sure I understand. Your drogue, main chute, and harness are in the payload bay. The booster section is empty. At apogee, your ejection charge blows the nose cone off, and the drogue brings the rocket down until the chute release is triggered. The main/chute release is located on the harness under the drogue/nosecone about 3 feet. That's a neat method.

Have you anything you would consider close to a tangle? Does the main chute inflate kinda off to one side, away from the harness?
Yes you got it! I just used rivets to attach my booster section to my ebays, as they are designed for conventional DD, so it stays attached to ebay and upper section, just wanted to do something a little different. So....main, C.R. and guide chute are in upper section just under nose cone and the guide chute (not really a drouge, it is a super long cone shaped chute that allows for rapid descent just to stabilize rocket) is deployed at apogee then main is deployed by CR at set altitude. No tangles on at least 10 flights. And yes main inflates to the side. I use a 7ft Rocketman chute for main.
 
Yes you got it! I just used rivets to attach my booster section to my ebays, as they are designed for conventional DD, so it stays attached to ebay and upper section, just wanted to do something a little different. So....main, C.R. and guide chute are in upper section just under nose cone and the guide chute (not really a drouge, it is a super long cone shaped chute that allows for rapid descent just to stabilize rocket) is deployed at apogee then main is deployed by CR at set altitude. No tangles on at least 10 flights. And yes main inflates to the side. I use a 7ft Rocketman chute for main.

With that set up, do you find the decent rate quicker than standard DD? I would think the rocket drops pretty much vertical and fin first. I get the same effect with my Callisto when it pops the nose and the main bundle. No drogue, but at 2 lbs, the bundled main works like a drogue. It seems to drop pretty quick in the orientation. It hasn't hit the ground without the main opening first, yet, but had one close call when the JLCR was set to 100ft/30m. I now went back to 200ft/60m
 
With that set up, do you find the decent rate quicker than standard DD? I would think the rocket drops pretty much vertical and fin first. I get the same effect with my Callisto when it pops the nose and the main bundle. No drogue, but at 2 lbs, the bundled main works like a drogue. It seems to drop pretty quick in the orientation. It hasn't hit the ground without the main opening first, yet, but had one close call when the JLCR was set to 100ft/30m. I now went back to 200ft/60m
It drops pretty quick and yes fin can downward. According to my JL Alt3 the initial decent rate on most flights are around 100 FPS so coming down faster than my standard dd decents (Which do not really fall fin down as you can imagine). You would think drift would be issue when using that guide chute but since it falls so fast I have not experienced that either. My last launch we flew in breezy conditions 15-20 mph and my apogee was a just shy of 4500 ft and recovered airframe about 250 yards down range with CR set at 600 ft., still a short walk but considering wind I felt that was not too bad!
 
With that set up, do you find the decent rate quicker than standard DD?
Just looked at data on last flight at 4578ft apogee my decent was at 70 FPS at 1500 ft. Initial was 108 fps. Once 7 ft main deployed at 600 ft slowed to 25 FPS on landing. You need a stout recovery system for sure! If that helps!
 
I took a different path then DDSrocdoc on seeing what I could do differently with a chute release. I used two rocket builds for this experiment. A 3 inch MAC rayzor, and a Madcow Adventurer 3. One canvas phenolic and the other fiberglass. Both 3 inch rockets.

With only one parachute, either the booster section or the payload bay would be empty. I decided to put the main chute in the booster section. That gave me the option of using motor eject as a backup if available. So now the payload bay was empty! What if we move all the electronics out of the AVbay coupler and into the payload bay? So I built a payload bay cage. I had (plenty of) room to include a tracker in the cage with an altimeter. The cage is made out of wood so it won't effect the tracker. And the cage fits in the payload bay of both rockets!

The AV bay coupler is now empty except for the wires running through it to connect the altimeter to a charge well.

Installing the cage in the payload bay gave me pause. I didn't want to have to align screw holes in both rockets payload bay tubes with the cage. I took inspiration from an Aerotech reload adapter system. Use spacers. Amazon sells pool noodles and physical therapy foam tubes in 3, 3.5, and 4 inch diameters. I ordered several to try out. After some testing, I ended up with foam spacers to fit the cage into payload bay of both rockets. The foam is dense and the fit is very tight. Also, I used an Eggtimer Quantum so I don't need an external switch to turn anything on. The tracker is a teleGPS by Altus Metrum.

Here is the layout of how the cage fits into the MAC rayzor payload bay.
AV-bay coupler | blue foam spacer | cage | black foam spacer | nosecone.


payload-bay-cage2.jpg

I put a shelf in the nose cone, so the black foam spacer sits against the top of the cage and the shelf in the nose cone.

I can fly the Rayzor, pull the cage out, slide it into the Adventurer, and it's ready to fly. Modular electronics. Thanks to the chute release and a wifi altimeter, I'm able to burn through motors faster then ever. $$$ :facepalm:$$$
 
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Here is the cage (sitting up side down) with both rockets payload bays and parts. The Rayzors nose cone is getting a make over.

payload-bay-cage.jpg
 
For those of you that replace the included rubber bands with aftermarket bands, make sure you use a band that's grippy. I borrowed a friend's release and he used what looked like slick elastic and type thing. I folded it as I normally do (the Jolly logic approved method) an gave it a successful shake test, but upon deployment, it shook loose at apogee.

Just something to look out for.

And I'll throw yet another reminder out there: Turn it on before you fly!
 
whats the biggest parachute that would be safe to use a Jolly Logic with? I've seen accounts of successful 60" deployments, but are there any bigger?
 
whats the biggest parachute that would be safe to use a Jolly Logic with? I've seen accounts of successful 60" deployments, but are there any bigger?

How much bigger do you want to go?
60" chute is good for 160 oz / 10 lbs / 4,500 grams, and that's for the chutes with a spill-hole:
https://publicmissiles.com/images/pmlchute.pdf

Those are reasonably sizable rockets.
I'm sure you can build even bigger ones, but then you will likely be flying on much bigger plugged motors with electronic deployment / DD, and CR becomes redundant.

Physically, the JL CR limit is not related to the chute diameter, but to your chute packing method, and whether it produces a packed pouch circumference that can be secured with the longest provided elastic strap, or not. Alternatively, you can use your own (longer) elastic straps, and then sky is the limit.

Practically, if you are flying 10+ lbs rockets, you are probably flying DD.

a
 
whats the biggest parachute that would be safe to use a Jolly Logic with? I've seen accounts of successful 60" deployments, but are there any bigger?

Student teams (and some flyers) have used the longer included bands and daisy chained 2 Releases together as a redundant deployment.

I also saw an 84" chute with a D-ring at the top (skyangle?) that was reefed at the hem with a Chute Release, and had an estes 12" chute on the D-ring. The Estes chute had just enough drag to keep the chute from flopping around, and when the Release let go, it ballooned into a perfect canopy almost instantly.
 
Student teams (and some flyers) have used the longer included bands and daisy chained 2 Releases together as a redundant deployment.

I also saw an 84" chute with a D-ring at the top (skyangle?) that was reefed at the hem with a Chute Release, and had an estes 12" chute on the D-ring. The Estes chute had just enough drag to keep the chute from flopping around, and when the Release let go, it ballooned into a perfect canopy almost instantly.

That's a great idea. I'm going to add that to my bag of tricks. The main chute turns into a streamer/drogue with a small chute at it's top, holding it vertical during free fall until deployment. I love all the new ways people are doing recovery utilizing a chute release.
 
Our kids used two CRs on a 60" chute for SLI. Their parachute fabric was very thin and slippery. I think one CR would have created problems with the fabric being so slippery. When they hooked everything up with one CR, it was obvious that it was really squishing the fabric together in the middle, but letting it billow at both ends. It just looked like there would be problems.

The two used together with interlocking rubber bands kind of pulls the two CRs together against the chute and really help keep it from slipping. The interlocking rubber bands pretty much guarantees good deployment because only one of them has to work.
 
I've doubled the length of my tether, and I tie it to the shock cord / chute connection point (or there abouts..)

I try to "bundle up" any loose bit of chute under the CR to ensure there are no 'flappy bits' to catch wind.. make a nice tight-ish 'burrito' chute.

I've had a series of bands break, fresh out of the box. I've used a few 3rd party ones, and so far, no issues (except getting that larger band thru the %^&*% small opening in the JLCR unit!)

Get a protector or paint most of the case bright orange or pink. Also, tie a short bright streamer to it. Trying to find a small black object in a 'general area' in tall grass, dirt, corn, soybeans, etc.. is not easy. Andy yes, I know form experience! (why John never molded the case in orange or pink or yellow..)
 
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