JL Chute Release - latest improvements?

[Pinetree]

@Angel_of_the_Skies

Nope.. we've had to cancel the last three launch dates.. hopefully this Sunday it'll go up.

 

[wsume99]

This has been mentioned before but I'll say it again because I did this myself a few launches ago, make sure you turn the CR back on after conducting a ground test. The good thing about the CR is it definitely can survive a hard landing.

 

[Pinetree]

We had one of our (older) members forget to attach the lanyard and lost his CR at our field once.

I'm starting to think that a pre-flight checklist would be a good idea.

 

[jahall4]

We had one of our (older) members forget to attach the lanyard and lost his CR at our field once.

I'm starting to think that a pre-flight checklist would be a good idea.

Check lists are always a good idea.

 

[jahall4]

They work very well. Probably the biggest issue is folding the chute. It needs to be in a tight bundle so that the rubber band (actually, I use a hair pony tail thingy) doesn't dig into the chute and get caught and it needs to be folded such that the chute doesn't sneak out of the JLCR's grasp. A bit of practice and experience goes a long way. I've combined ideas from the various chute folding threads here to come up with something that has had no failures in perhaps 50 launches.

Hans,

Using a recovery sled will mitigate to the point of eliminating both problems you mention, but yes always an organized tight pack, sized for the airframe.

 

[COSTransplant]

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 want to pack my BT-55 exactly like this! Very clean and neat. Where do I get the sled?

 

[jahall4]

I want to pack my BT-55 exactly like this! Very clean and neat. Where do I get the sled?

How are you getting a JLCR to fit inside a BT-55 (33mm) tube? 38mm is absolute min. BT-60 is the practical min.

 

[COSTransplant]

Hah! I actually had not tried yet! Ack.

 

[jahall4]

Hah! I actually had not tried yet! Ack.

I have encouraged John to make a smaller version of the JLCR so it would fit comfortably into so many of the 38mm rockets.

 

[COSTransplant]

Would work for me of course as I hope to be producing a BT55 based kit.

 

[DaHabes]

I still see the word rubber used after all the threads about using alternatives. Ditching the rubber and using something else will eliminate at least one form of failure.

I use these, they last several flights longer than the rubber bands - https://www.amazon.com/gp/product/B00DFSHD5O/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

 

[rcktnut]

rcktnut said:

I still see the word rubber used after all the threads about using alternatives. Ditching the rubber and using something else will eliminate at least one form of failure.

I use these, they last several flights longer than the rubber bands - https://www.amazon.com/gp/product/B00DFSHD5O/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

I have been using 3/4" elastic, you can stretch it out all the way without to much tension on the JCLR, easy to adjust, can make chute bundle very tight, and does not stick to chute. 100% successful deployments since using.

 

[Pinetree]

For the record, I used mine for the first time last Sunday and it worked perfectly.

I did substitute hair ties for the bands that came with it... Pretty much only because I have long hair and I have a bunch of those things.

 

[4regt4]

For the record, I used mine for the first time last Sunday and it worked perfectly.

I did substitute hair ties for the bands that came with it... Pretty much only because I have long hair and I have a bunch of those things.

I have several, and use them lots. It can be a nail biting experience watching the thing free fall, all the while wondering if the device is going to work and if the chute is ever going to open. But it does.....

Hans.

 

[Handeman]

I have several, and use them lots. It can be a nail biting experience watching the thing free fall, all the while wondering if the device is going to work and if the chute is ever going to open. But it does.....

Hans.

I've never had one that didn't work, but I agree about the nail biting experience! That is usually for the LCO when I set the release level to 100 ft.!

 

[4regt4]

I've never had one that didn't work, but I agree about the nail biting experience! That is usually for the LCO when I set the release level to 100 ft.!

LOL. I had an LCO screaming "It's coming in hot!". But it popped right on schedule.

Hans.

 

[Pinetree]

Yep. The guy standing next to me said "that's why you use dual deploy".. and then the chute opened.

 

[4regt4]

Yep. The guy standing next to me said "that's why you use dual deploy".. and then the chute opened.

As I mentioned, I use them a lot. But each recovery seems scary. It's as if John Beans is trying to make us all crap our pants.

Hans.

 

[Capt. Eric]

The only time I've had it "fail" is when I forgot to turn it on. (now I put some tape on the NC to remind me)
Doh!

 

[Ronz Rocketz]

I’ve had one land in the canal and one land on the field lights. Makes me hesitant to always use it in the park.