JL Chute Release questions

[RalPh8]

At the last Tripoli launch I was at there were a number of us using the JL Chute Release. I bought my JLCR back in 2015 or 2016 when they first came out. That said, we had a number of people (including myself) have their rockets hit the ground with the parachute not unfolded. After I got my first rocket back and assessed the damage, a few of the club members came up and said that they "don't trust the chute release because they've seen it fail almost 50% of the time". At least in my case, both my flights had an open chute release on the ground when I recovered the rocket. So I assume it opened at altitude. I had the altitude set for 400ft (thinking it would lose about 100ft by the time it registered, released, and the parachute inflated). I know one guy said his chute release never popped open and another mentioned that it opened but the rubber band got stuck on the parachute and prevented the chute from opening. Previously I've always had great luck with the JLCR opening every time and the parachute inflating so I'm not sure why this time was so different for myself and others. Could it be the wind? Wind was 15mph gusting to 19mph at ground level. Also, in the past I've always set my CR to 800ft. Would the 400ft lower altitude setting be too low (read too close) for the CR to accurately determine altitude with the gusting wind when compared to ground level? Maybe it's just a parachute packing problem? Is there an update that needs to be installed? Does anybody know the failure rate of the JLCR? Just trying to think of ideas for the number of recovery failures.

 

[PayLoad]

Not associated with the company, but I swear by the product.. Chute must be folded well, and rubber band stretched well over the parachute (can't "dig in")

And TEST TEST TEST - You will learn from the testing the best way to fold the laundry. Then test again.

Only failure I ever had was I forgot to re-arm it after testing.

 

[Antares JS]

I am 1 for 4 on the chute release. The first two flights with it, the rubber band got stuck to the parachute. I switched to a hair band on the third flight and it worked as intended. On my fourth flight with the chute release, the parachute came out of the device at ejection. The rocket was okay but it was a long walk.

Despite these problems, in my experience, the device itself has always functioned as intended, releasing the pin at the right altitude. The issues come from the way your parachute is packed. I highly recommend the hair band in place of the stock rubber bands as it produces almost no friction with the nylon parachutes at all. If that's not an option for some reason, then your best bet is to leave the chute release packed for as little time as possible so the rubber band doesn't settle into the parachute too much.

 

[Antares JS]

Extra thought - the Chute Release 2 could have a second servo and band running at 90° to the first one, attaching to the top and bottom of the device. This would prevent what happened on my fourth flight with it.

 

[Bat-mite]

Agree with others. The machine works, but often the results are not as desired. I am sure there is a "proper" way to wrap, fold, and band chutes to get a good deployment every time, but I never found it. Still have mine, but don't really use it any more.

 

[crossfire]

I have had good results with my JLCR. I make sure I use right size band. Wrap needs to be tight so it dosent slid out from under band at ejection. Last week I flew my 3" WM Punisher on a DMS I500 main set at 500' all worked perfect. I issue you must make sure device is turned on. If you run a preflight test you need to turn it back on. Some of the pins are to small and will not hook into device.

 

[teepot]

I replaced the rubber band with a silicon band because the rubber band stuck to the chute a couple of times. I also z fold my chute and tuck the shroud lines between a fold in the chute. I then roll up the chute and attach the band. The silicon is stronger than the rubber band and really pops when released. I haven't had a problem since.

 

[Ronz Rocketz]

Is this the official way to fold the chutes? This is from their website.

 

[RalPh8]

Not associated with the company, but I swear by the product.. Chute must be folded well, and rubber band stretched well over the parachute (can't "dig in")

And TEST TEST TEST - You will learn from the testing the best way to fold the laundry. Then test again.

Only failure I ever had was I forgot to re-arm it after testing.

I always test the opening before flying. It opened both times perfectly before the flights. My hunch is that it probably did indeed open at the intended altitude but maybe the wind tangled it up on descent.

 

[RalPh8]

I am 1 for 4 on the chute release. The first two flights with it, the rubber band got stuck to the parachute. I switched to a hair band on the third flight and it worked as intended. On my fourth flight with the chute release, the parachute came out of the device at ejection. The rocket was okay but it was a long walk.

Despite these problems, in my experience, the device itself has always functioned as intended, releasing the pin at the right altitude. The issues come from the way your parachute is packed. I highly recommend the hair band in place of the stock rubber bands as it produces almost no friction with the nylon parachutes at all. If that's not an option for some reason, then your best bet is to leave the chute release packed for as little time as possible so the rubber band doesn't settle into the parachute too much.

Good ideas. Appreciate it.

 

[RalPh8]

I replaced the rubber band with a silicon band because the rubber band stuck to the chute a couple of times. I also z fold my chute and tuck the shroud lines between a fold in the chute. I then roll up the chute and attach the band. The silicon is stronger than the rubber band and really pops when released. I haven't had a problem since.

I might try that.

 

[RalPh8]

Another thing I just thought of: both my flights went drogueless. Would a drogue chute have helped with stablization of the rocket, maybe allowing the chute to unfold better?

 

[Handeman]

I always test the opening before flying. It opened both times perfectly before the flights. My hunch is that it probably did indeed open at the intended altitude but maybe the wind tangled it up on descent.

Probably not. When the rocket is dropping, it is moving with the air mass. There is zero relative wind horizontially. The only air movement is in the vertical direction as it's falling. The wind you feel standing in one place on the ground won't be felt by the rocket.

 

[Handeman]

Another thing I just thought of: both my flights went drogueless. Would a drogue chute have helped with stablization of the rocket, maybe allowing the chute to unfold better?

I fly the JLCR a lot on my Callisto. The wrapped chute acts as a drogue. It also inflates very fast since the rocket is falling fins first and the chute is above everything. YMMV, but I would not want to put a drogue on that rocket.

 

[bobbyg23]

I have a 100% success rate with mine. Test on the ground and make sure to turn it back on. I hold the chute right next to the rubber band when testing so it keeps the same shape and pack when you put it back on for flight.

 

[bobbyg23]

Here us my L1 flight with it. I used it on my L2 also. Both were windy days and they landed relatively close to the pad.

 

[MetricRocketeer]

Hi everyone,

I am planning on buying a JLCR as a means of doing dual deployment. I am making this post just so that I can keep track of this thread.

Stanley

 

[bobbyg23]

Hi everyone,

I am planning on buying a JLCR as a means of doing dual deployment. I am making this post just so that I can keep track of this thread.

Stanley

Great idea for the thread. You will love your jlcr.

 

[dhbarr]

Mine has worked correctly every time, including on my L2 with a Toroidal chute. It really is all about packing & testing & repacking.

 

[DaHabes]

Always test that it releases at your prep table, then re-pack the same way and go to the flight line. My only "failure" was on a rocket with a resin nose cone. It was so heavy that the nose cone was below the parachute which was below the airframe. When the JLCR released, the parachute was positioned canopy down and never inflated. I used a drogue the next flight (after a bunch of repairs) and it was all good.

400 feet is a bit low for opening the chute. Unless the wind is an absolute gale, higher is better. I wouldn't assume 100 feet is enough to open the chute. If it is packed really tight, if it is cold out, if the rubber band sticks somewhat, it may take more air and time for the parachute to pop. It's not like it's opening at 2,000 feet; 600-700 feet is like what a parachute will open on a typical LPR anyway....

 

[Crumb fire]

Does anyone have a link to a "silicon band"? I'm curious.

 

[afadeev]

I have a 100% success rate with mine. Test on the ground and make sure to turn it back on. I hold the chute right next to the rubber band when testing so it keeps the same shape and pack when you put it back on for flight.

Mine has worked correctly every time, including on my L2 with a Toroidal chute. It really is all about packing & testing & repacking.

Same here.
I've had higher success rate (and much lower hassle factor) with JLCR than with traditional DD setups.
Both have their place.

The only practical bits of advice I would add are:

• Do not prep JLCR anywhere other than at the field.
• ALWAYS re-pack the chute with JLCR just before flight.

Both of the above force you to reinitialize JLCR on site 100% of the time, minimizes band overstretching (works best if bands pop open with vigor), and does not allow the chute to 'settle' into folded shape, which helps with unfurling.

Stock band (I'm on my 3rd or 4th one now).
No complications with drogues or streamers - JLCR-folded chute is the drogue/streamer.
Tightly Z-folded chutes (shroud lines inside the rolled bundle to mitigate tangling), JLCR anchored to the chute side of the swivel (to mitigate tangling).

HTH,
a

P.S.: I may try John Beans's chute folding technique on larger (4+") chutes, as that approach would produce slower chute unrolling and reduce shock on the shroud lines during inflation.
P.P.S.: Details matter.

 

[boatgeek]

I had trouble at first and then found a few things that really help:

1. Always test, at least until you have something very repeatable. And you should probably test even then.
2. When you're folding the chute, the goal is to have the outside as smooth and firm as possible. Think fitness video instructor, not fitness video audience. You don't want the band to work its way into a fold or it may not release.
3. Unless the chute plus JLCR bundle fits very loosely in the body tube, I like to have fabric (chute or fire blanket) between the body tube and the JLCR. That helps keep it from getting stuck on the inside of the tube, especially in smaller (38mm and 54mm) airframes. 3" airframes have enough space not to worry as much.

 

[teepot]

Does anyone have a link to a "silicon band"? I'm curious.

I got my silicon bands on Amazon. I ordered several sizes,

 

[rcktnut]

Here is another thread on the subject, I don't use rubber bands anymore, PITA, no problems with deployment or bands sticking to chute, easily adjustable - post # 50: Jolly Logic Chute Release | The Rocketry Forum

 

[MALBAR 70]

2. When you're folding the chute, the goal is to have the outside as smooth and firm as possible. Think fitness video instructor, not fitness video audience. You don't want the band to work its way into a fold or it may not release.

This.
I have had a 99.9% success with my JLCR using this philosophy. (The 00.1% was from me not turning it back on after a test)

 

[crossfire]

I see not so perfect deployment from the standard DD at each launch. So JLCR works for me so I am happy with it.

 

[Zman1961]

I had trouble at first and then found a few things that really help:

1. Always test, at least until you have something very repeatable. And you should probably test even then.
2. When you're folding the chute, the goal is to have the outside as smooth and firm as possible. Think fitness video instructor, not fitness video audience. You don't want the band to work its way into a fold or it may not release.
3. Unless the chute plus JLCR bundle fits very loosely in the body tube, I like to have fabric (chute or fire blanket) between the body tube and the JLCR. That helps keep it from getting stuck on the inside of the tube, especially in smaller (38mm and 54mm) airframes. 3" airframes have enough space not to worry as much.

+1. I have used JLCR on mid and high power over 30 times. It failed twice, but it was my error - the chute protector blanket was tied in too close to the parachute, the JLCR opened, but the air slip stream kept the chute protector in a position where the chute didn't catch enough of the air to open because the release pin also got stuck in a chute fold. Now I attach the blanket to the shock cord at least two feet below the chute, and make sure the travel path of the pin is only going to cross a perfectly smooth (no folds or wrinkles) side of the folded chute. And have had no problems since. On HPR, I use a Dyno Chutes guide chute (attached near the nose cone), it keeps things nice and stable on the way down until the chute opens, while minmizing drift. It has never tangled.

 

[Orien]

Just got mine yesterday! Going to use it in my 3" LOC Iris with an upgraded 42" chute. I'm also incorporating a streamer and RRC3 for apogee deployment and motor backup. I know it makes it almost as complicated as traditional dual deploy, but I still have my entire payload section freed up and I don't like the idea of using only motor ejection (no backup, difficult to deploy at apogee).

 

[SkyFire]

Here is another thread on the subject, I don't use rubber bands anymore, PITA, no problems with deployment or bands sticking to chute, easily adjustable - post # 50: Jolly Logic Chute Release | The Rocketry Forum

Great tip! I got a roll of 3/4" elastic band material for $5 on Amazon. Works perfectly bench testing. I have flown four times with my JLCR using a rubber band without issue but was concerned about the band catching on the chute or being too tight or too loose. One new rubber band broke while installing it. This promises to be a much better set up.