Who Used Chute Release for L1, L2, or L3?

[Keisling]

I did my Level 1 with a JL Chute Release back on July 8th. PML AMRAAM2 with an AT H128W and the CR set for 500'.

 

[smoon]

I used two Chute Releases in series for redundancy for my L2 earlier this year. I don't have any cool video, but my rocket was a Madcow 4" FG Nike Smoke.

Steve

 

[John Beans]

Ummmm, Folks are really taking a chance with these really low level deployments. I've seen a few smack the ground and I've had a stiff chute protector hang the chute deployment twice. Once with a cardboard rocket (destroyed) and once with a glass rocket that survived. I've since arranged the chute protectors on the harness so they get pulled free once the CR releases the band. I fly at a large venue and won't go lower than 700'. With a GPS tracker I'll release higher so
I can get a drift trend on a map. Like I said, I have a site with room to do that. There's no reason to do heart stopping low level releases at large launch sites if
one wants to walk away with a reusable rocket! You lucked out on that cert and lesson learned I 'spose. Kurt

Hesitated to reply to this so as not to be critical or stifle debate—debate is good, there's too much intolerance to debate these days—but I did want to add my perspectives, because Kurt (who has lots of experience) is not the only one who feels this way. So I wanted to add my thoughts to it.

The purpose of delayed deployment is to tumble down and then open at a low altitude to avoid wind drift and losing your rocket and avoid spending too much time tromping through corn fields instead of flying. For those of us with small fields and windy days, this is quite important.

Once the chute opens, the rocket slows to terminal velocity in just a couple of seconds, and perhaps 25-50 feet of descent. After that, it's not slowing down (no matter how heavy the rocket) it's just descending and drifting. So opening higher in order to have a softer landing is not how it works.

But I'm sure the predominant thinking is, "What if I have a heavy rocket and it takes a long time for the chute to inflate after Chute Release opens?"

The answer to that is: practice first a little higher, use a recording altimeter to get actual data on how long inflation is taking, and work your way down, improving your folding technique as you go. New rocket, new chute? New practice. Use actual data (not just eyeballing) because people don't judge altitude very well, and 200 feet off the ground looks very different depending on if it's near the pad or a distance from the pad.

And after all, if the chute NEVER fully inflates it doesn't matter what the release altitude is set for. You can set it for 700 feet and it can flutter all the way down. It would have the same landing speed from 700 feet as it would be from 200 feet. It's a fluttering parawad and the rocket is at terminal velocity with a parawad in each case.

There are members on this forum with a LOT of Chute Release experience (like Kurt), and telling them they shouldn't be using 400, 300, or even 200 foot release altitudes is not the always wise, conservative advice that it might sound like (because if they are experienced, a low release is fine and will work better). But even I would say to a first-timer that they should practice a little higher at first, in case their first attempts at folding for Chute Release don't open easily and need a little extra time, even if that is a very particular case (slow opening) as opposed to the more common (never opening).

As I have said on another thread: I'm not sure why anyone with a good amount of Chute Release experience would fly an Estes Pro Series II with anything above a 300' release, and I use 200'. Those rockets have a lot of room in them for folding chute bundles however you want, and they are very light and will probably survive a non-inflation with just a small amount of damage. I love being able to put an oversize chute on my rockets (especially swept fin rockets) so that they land very softly. You don't want to open an oversized chute way up high.

 

[ksaves2]

If anything, fly it first time with a new rocket and have a tendency to release a little higher to see how it behaves. Para wads can be prevented by packing just before launch. Me be guilty of
not doing that in the past. Make sure the protector gets yanked away after the thing is released by the CR. Like I say, I've witnessed quite a few of what I call close calls with terra firma
at wide open venues. Even remember an LCO remarking over the PA, "You chute release guys ought'a set 'em a little higher." when some of them didn't get the full chute until 15 feet
from a hard hit. Exciting to me as long as it's "your" rocket!:wink: Kurt

 

[Homer_S]

Tried it... see here.

[COLOR=#000000]Rocket:   Phoenix Bird G (upscale of Estes kit to 5.74 cm, launch weight 703 g)[/COLOR]
[COLOR=#000000]Motor:    H115DM drilled to 8 seconds[/COLOR]
[COLOR=#000000]Altitude: 3032'[/COLOR]
[COLOR=#000000]L1 attempt - falied[/COLOR]

Take a peek here for the most probably root cause, skip down to post 21 for the answer.

Homer

 

[John Beans]

Sorry to hear about this. See my reply in the above-referenced thread.

Here's what you see when you open the manual:

If we changed the way Chute Release worked, the battery life would suffer, it would get a little LESS reliable, and everyone would have to add GOOD vents to their rockets. Trade-offs.

 

[Homer_S]

Thanks for the reply!

Agree, no need to change behavior. The product is awesome! See further up in the thread for a successful launch with it in the same rocket. The picture after deployment clearly shows JLCR tethered and hanging freely by the payload if you zoom in.

Homer

 

[RomCat]

Just got my L1 cert using the JLCR. Flight was on a 5.6 lb MacPerformance Zodiac 3" using a H242T motor. Recovery was single deployment. I didn't have an altimeter in it, but the sim indicated apogee at about 1200 ft. From the ground, the sim seemed pretty accurate. The JLCR was set to release at 600ft. It worked perfectly. Great product!

Interestingly, I did end up with a ground level release of the JLCR during a pre-launch test. I packed everything to test the fit and then as I was removing the e-bay from the booster tube (e-bay was unused for this flight, everything was packed into the booster), I heard a "click" and "snap" and realized the JLCR released due to the low pressure environment I had just created. The precision fit of those MacPerformance parts creates some significant suction when you try to pull them apart. For what it's worth, the pull was long and slow (definitely 3+ seconds), so it's no wonder it fooled the JLCR.

 

[afadeev]

Just flew my L2 cert on J270W motor in PML BumbleBee.

Flew to 3,572 feet (vs. 4,600 sim-ed, will investigate the delta later), pulled 20 G's, hit 457mph.

JL CR worked as advertised, releasing at 300 feet. Chute inflated fully and slowed the rate of descent from 52 fps to 21 fps by 225 feet (as per JL altimeter 3). I will post the flight graph later, when I get home.



Alex

P.S.: Looking at the flight chart, it looks like J270 may have ended its burn after 1.45 seconds instead of the specified 2.6 seconds. I don't know to what extent I can trust Alt3's detection of end of burn, since it suggests the motor burned only 55% of the propellant, yet generated 20G instead of the simulated 15G, but that might explain lower altitude and lower max speed of 457 mph vs. 561 mph simulated. The more likely explanation is that J270W data in OR is either wrong, or outdated.

P.P.S.: If anyone cares: folded JL CR chute has the simulated drag equivalent of a 12.5" chute.


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[spence]

Nice Flight... watched it today.....

 

[afadeev]

Nice Flight... watched it today.....

Thanks.
It was pretty heart stopping to watch the rocket roar into the clouds for ~60+ seconds, before it finally floated back down after a 93 second flight. As confirmed, yet again, I can't judge cloud height distances, not at all. They looked a 3-4 thousand feet up, but evidently, were closer to 1-1.5K feet.

I was already mentally going through fall-back plans for a re-test on another rocket, while scanning the horizon for any signs of BumbleBee. It did not help that the same cloud swallowed another guy's rocket on G-motor (he was aiming to break the sound barrier), not to be seen again.

All in all, J-motor roars with authority.
I can't wait to light-up another one!
Now the question is: which one.....

a



Sent from my Pixel using Rocketry Forum mobile app

 

[spence]

Well....we have yet to leave a rocket in the clouds!

 

[billdz]

I used JLCR for both L1 and L2. I had assumed an L3 chute would be too large for a JLCR but would love to use it if possible. John said in the first post in this thread:
"I heard someone L3'd with redundant Chute Releases at LDRS, which may have been a first." Would like to hear more about this, any pics? Were the two JLCRs daisy chained or what? Did these count as the two required redundant recovery systems, or were altimeters also used?

Here's my L2:
https://youtu.be/huzui4JgoSU
Rocket - LOC Expediter 4" with transition to 3", weight without motor 1843g
Motor AT J180
Altitude 3960'

 

[deangelo54]

I just ordered a Madcow Torrent with a 38mm MMT from Apogee Components. I'm thinking of using it along with a Jolly Logic Chute release. What modifications did you make to the Torrent? I would be curious as to what you think of the Torrent and any suggestions building or flying it.

 

[BigDuphis]

Got my L1 cert last weekend at MDRA using my CR on a Madcow Super Batray. I set CR to 500 to be on the safe side (I normally use it at 200 w/ all of my midrange stuff). Judging by the fast inflation on the video, I have no doubt I can set it much lower than 500 for this rocket/chute. Flight was a CTI H170-7...didn't have an altimeter for stats, but brother claus got me an alt 3 for christmas, so I'll have stats for the next flight!

https://youtu.be/1aMdcmRpd00

 

[BSNW]

oops double posted....see below

 

[BSNW]

As one of the Beta testers for this product, I can say if you use a Chute that is not stiff but is a supple nylon and you pack according to the instructions, it will work. I also REALLY inspect the band after each flight.

To the point....I routinely use my Chute Release on 45 and 60 inch chutes in my 5.5 inch in diameter rockets with J and K motors. I use a larger band on the bigger chutes. The biggest factor in how fast the chute opens after release is how stiff and "starchy" the chute is. In theroy it matters not how big the motor is or anything else......the size of the chute in relation to the band and if it is packed properly are the big issues. To what Mr. Beans also said....Everytime I set it at 500 feet and it opens I say..."dang I should have set it to 300!". It works great on big chutes...for me up to a 60 inch chute.

Andrew K

 

[jahall4]

As one of the Beta testers for this product, I can say if you use a Chute that is not stiff but is a supple nylon and you pack according to the instructions, it will work. I also REALLY inspect the band after each flight.

To the point....I routinely use my Chute Release on 45 and 60 inch chutes in my 5.5 inch in diameter rockets with J and K motors. I use a larger band on the bigger chutes. The biggest factor in how fast the chute opens after release is how stiff and "starchy" the chute is. In theroy it matters not how big the motor is or anything else......the size of the chute in relation to the band and if it is packed properly are the big issues. To what Mr. Beans also said....Everytime I set it at 500 feet and it opens I say..."dang I should have set it to 300!". It works great on big chutes...for me up to a 60 inch chute.

Andrew K

I have flown 60" chutes as well. After developing a "recovery sled" we're 3/3 @ 60" and I'll try a 70" next month.

 

[deangelo54]

Inim

 

[djmattm]

I flew a Madcow 2.6" PAC-3 for my NAR level 1. It had a Jolly Logic chute release and altimeter on board. I had a drogue chute open at ejection and the main at 500'. Had a pretty good launch and flight. A little weathercocking as it went up. I launched on a H97J and expected about 2200'. Good event, drogue was working. Main opened at what I assume was 500'. Went over the hill to retrieve my rocket and got to go swimming. It landed right in the middle of a pond. No flight information was to be retrieved from the electronics. We did however send them in and you repaired both for us. Best customer service I can recall.[video=youtube;-QFkAA6oojs]https://www.youtube.com/watch?v=-QFkAA6oojs[/video] The video is my first flight on the H97, and second flight (after drying out in the sun) on a H220

 

[deangelo54]

The paint job is exceptionally great. Your post is exactly the information I was looking for. Deploying a droug via engine ejection at apogee and a main deployed at 500 feet using a Jolly Logic chute release. Soon this method will be standard operating procedure.

 

[lowga]

Just completed my L1 Cert on a Madcow Cowabunga that I kitbashed by cutting the nose cone, and adding an APE telemetry sled. Flew it with a JR Altimeter 2 in the nose cone, and a Chute Release. Maiden flight for both, and my first HPR flight ever. Sent it up on an AT H100-W, drilled for a 10 second delay. Chute Release set for 400 feet--everything worked just as it should. Great product, and really easy to learn. Thanks John Beans for making a real winner here. You're literally changing rocketry for the better, and making it safer for all of us too.

I'll be flying my L2 attempt on the Chute Release as well.

Like others, I'd love to hear more details about anyone who has accomplished an L3 certification using the Jolly Logic CR. It may be time for the NAR and Tripoli to revise their rules for L3 to recognize this quantum shift in technology.




Les Rayburn
Birmingham, AL

 

[deangelo54]

Your post is exactly the kind of information I am looking for. The Jolly Logic CR is a game changer.

 

[Handeman]

I totally agree that the JLCR is a game changer. I wouldn't want to fly some of my rockets without it. It allows higher flights with bigger motors in windier conditions then is possible without it. The thing is amazing.

With that said, I don't think the JLCR is a proper replacement for dual altimeters and redundant ejection in large L3 rockets. It may be adaptable to some, but for the most part, the recovery requirements for large rocket tend to move to very large chutes with deployment bags and very sequenced and controlled deployments. IMHO those type of requirements are handled better with dedicated DD altimeters and standard deployments. Because of the fact that you will have dual altimeters just to ensure apogee deployment since L3 motors don't have motor eject, I don't think JLCR will improve your recovery reliability, in fact, I believe it would significantly reduce the reliability.

 

[dhbarr]

Dual baro altis + dual JLCRs should be a perfectly serviceable L3 config.

Consider that a pair of JLCRs in series can replace half the avbay plus a good chunk of excess harness when thinking of complexity.

 

[lowga]

My experience level is too low to judge, so I yield to your greater experience.

That being said, for M class flights on smaller L3 rockets, I think motor ejection with dual JLCR's would be at least as reliable as dual deploy using black powder and/or cable cutters. I've been an amateur radio operator for over 40 years, so I know that hobby much better. Many old-timers like myself who had earned our Extra Class licenses "the hard way" opposed rules changes that allowed for standardized testing, eliminating the 20 WPM Morse Code test, etc. Some said that it would destroy the hobby, and "dumb it down." Quite the opposite happened. The hobby has grown, and attracted all sorts of innovative people with expertise in computers, "makers", etc. Many of whom were turned off by the requirement to learn Morse Code.

Amazingly, Morse Code has also flourished. Now that the requirement to learn it is gone, it's more popular than ever.

I think rocketry might see something similar happen as technologies like the JLCR continue to develop and flourish. It is a complete game changer. Can't wait to attempt my L2 certification flight using one.

Les Rayburn
Birmingham, AL

 

[billdz]

I think motor ejection with dual JLCR's would be at least as reliable as dual deploy using black powder and/or cable cutters.

L3 motors don't have ejection charges, perhaps because the delay is so long (21 seconds on my current L3 project). So I suppose Handeman's point is that if you are going to have 2 altimeters in the L3 rocket anyway to eject the drogue, why not use the same altimeters to eject the main chute. As dhbarr says, however, a pair of JLCRs would save the cost of a drogue, a harness, and some wiring in the av-bay.

PS - I've also been a ham for over 40 years.

 

[Handeman]

Dual baro altis + dual JLCRs should be a perfectly serviceable L3 config.

Consider that a pair of JLCRs in series can replace half the avbay plus a good chunk of excess harness when thinking of complexity.

I hear what you are saying but the JLCR isn't going to replace much in the av-bay, if anything, and probably won't reduce the amount of harness you need. You will still be using dual altimeters for apogee deployment with an L3.

It maybe possible to use the JLCR, but from my experience with my 9' diameter 24 gore main chute, I would never try to fold that the way I fold smaller chutes for use with the JLCR. It's just too big. I uses a d-bag and although someone may find a way to do it, I just don't see how to use a d-bag and JLCR together.

People have talked about failures because they stretch the rubber bands too tight and the release didn't release. I would see that as a very likely possibility if you put enough tension on the bands to hold a very large chute in together while it falls.

The JLCR is an amazing device for the size chutes it's designed for, but I don't believe it was ever designed or intended for very large chutes on very heavy rockets. Just like a Ford Ranger pickup wasn't designed to tow a 5 ton trailer. It can probably be adapted to the very large chutes but I believe the standard deployment using altimeters you already have in the av-bay along with deployment bags and pilot chutes are much more suited to large rockets than the JLCR.

Just my opinion, YMMV

 

[lowga]

Your expertise far exceeds my own, clearly. I'm certain for large rockets with huge parachutes, the JLCR would not work. On the other hand, some people chose to fly "minimal" L3 rockets with M-Class motors for their certification attempts. The JLCR might work fine for those situations. As for failures, those abound with almost any system. It all depends on how well you design it, test it, and prepare for the launch. Failures are not limited to JLCR.

Used within it's limitations, the device is very reliable. Given sufficient interest, the technology might be upscaled to work with larger parachutes. Rubber bands with high latex content can be very large, are super-strong, and resistant to breakage.

One question that I'm having difficult getting answered is pretty simple:

Has anyone actually completed L3 certification using two or more JLCR's as a part of their recovery system? In other words, is it even possible or is this just an academic debate?

 

[dhbarr]

https://www.rocketryforum.com/showthread.php?141523-Chute-Release-with-large-chutes