Sneak Peak: Jolly Logic's Easy Dual Deployment

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Rick,

It looks like you're using flat chutes. Try Kevin's method here. I've never had a parachute fail to inflate using this folding method. You can deviate slightly to give a little more material to roll up, but the Z fold is the key. The chute is basically forced to pop open by the folds.
Poor inflation is one reason I don't use flat chutes anymore. It just seems too easy for them to not inflate fully if they don't catch the airflow just right. They can 'sideslip' and the canopy stays closed, especially if they don't have a lot of time to flutter in the airstream.

AlfaBrewer - were all your failures using flat chutes? If so what was the opening altitude set at? The photo of the rocket on the ground with the chute out but un-inflated to me says the chute was released properly but did not inflate. It does not look tangled or otherwise compromised. So it would be useful to know if all the failures were with flat chutes and at what altitude.

I have yet to start using my CR but I would sure like to benefit from everyone else's experience and try to start off with the best practices.

Thanks,


Tony
 
Tony - EXPJawa had the picture you're asking about. I did have a failure to inflate with a flat chute, but that was due to a poor nomex burrito allowing the ejection charge to fuse my chute closed.
 
I guess I don't know enough about it to say what it would be if not a flat chute. Almost all of my chutes are thin-mil nylon chutes from Top Flight, though this one is an Estes 18" nylon chute. I guess they're flat when spread out. On the flight shown previously, the CR was set to 300'. Up to this point, I've used both 200' & 300' settings. In this case, it does appear that the chute never fully opened, much less inflate. The previous occurrence had the chute mostly rolled with the CR on top of it. So, I'm inclined to believe that my problem is as you & John have said, due to folding technique more than anything else.
 
Last edited:
Tony - EXPJawa had the picture you're asking about. I did have a failure to inflate with a flat chute, but that was due to a poor nomex burrito allowing the ejection charge to fuse my chute closed.

Sorry for the post confusion. Not the first time I've done that nor I'm sure will it be the last.

I guess I don't know enough about it to say what it would be if not a flat chute. Almost all of my chutes are thin-mil nylon chutes from Top Flight, though this one is an Estes 18" nylon chute. I guess they're flat when spread out. On the flight shown previously, the CR was set to 300'. Up to this point, I've used both 200' & 300' settings. In this case, it does appear that the chute never fully opened, much less inflate. The previous occurrence had the chute mostly rolled with the CR on top of it. So, I'm inclined to believe that my problem is as you & John have said, due to folding technique more than anything else.
A 'non flat' chute is made of gores - more than one piece of material. Like the kind PML includes with their kits. In my experience they tend to open more reliably than a flat chute made of a single piece of material.

Based on my experience by having and videotaped and watched many 100's of flights, I think anything under 400' is too low to be reliable. Remember that John says "It typically takes 50 to 150 (15-45 meters) to slow your rocket to landing speed". But I have many recordings of flights where it took the chute 5 seconds or longer to fully inflate. If your rocket is falling at 60FPS that translates to 300 feet or more. For any of my flights I never open below 500' but I generally fly larger rockets. Even still, I would be very hesitant to open much below that as there are just so many variables in getting a chute to open quickly and reliably. I'd rather walk a bit farther and have a rocket in one piece than a short walk to a broken rocket.

I have videotaped hundreds of flights over the years and have done a number of 'failure analysis' videos. More than anything I've learned that reliable chute deployment is still the number one challenge in our hobby.

I am planning on using the CR at BALLS this year so I'm really interested in what works and what causes issues. So all my input is based on typical dual-deployment. Time will tell how well that experience translates to using a CR.

Thanks to everyone who has shared info on using the CR, it helps the rest of us have much better odds of success on our first try.


Tony
 
I advise folks to start higher (~500 ft) and work down based on your own personal inflation rate, which you should measure with something like AltimeterThree. Other folks can chime in, but once you develop a smooth setup, it's a waste to drift more than necessary. Learn your tumble/drogue descent rate for each rocket, develop a snappy release and inflation, and then drop them down low and slow.
 
I advise folks to start higher (~500 ft) and work down based on your own personal inflation rate, which you should measure with something like AltimeterThree. Other folks can chime in, but once you develop a smooth setup, it's a waste to drift more than necessary. Learn your tumble/drogue descent rate for each rocket, develop a snappy release and inflation, and then drop them down low and slow.
That's one thing that's definitely different with the CR - the chute is already partly deployed out in the airstream. I can see where with the right kind of chute and packing it should be possible to inflate a chute much more quickly than I'm used to which counts the time it takes for the entire recovery system to stretch out and then allow the chute to start to fill.

I've watched Jacob (firesalto) use the CR many times at Asa with great success. It was his example that got me interested and why I bought one. I just hope I can do as well.


Tony
 
I used Chute Release yesterday for a successful L2 certification flight. I flew it on a Madcow Torrent with an AT J270-10. Beautiful flight - apogee at 3000 ft with motor ejection to deploy an 18" drogue, then CR deployed the 45" main chute at 500 ft. I had rolled the main chute as per John's instructions and it deployed very quickly. Attached is a photo of my Torrent.Sacred Monster Torrent.jpg
 
I used Chute Release yesterday for a successful L2 certification flight. I flew it on a Madcow Torrent with an AT J270-10. Beautiful flight - apogee at 3000 ft with motor ejection to deploy an 18" drogue, then CR deployed the 45" main chute at 500 ft. I had rolled the main chute as per John's instructions and it deployed very quickly. Attached is a photo of my Torrent.View attachment 293822

Great looking rocket! Congrats on the L2!
 
I used Chute Release yesterday for a successful L2 certification flight. I flew it on a Madcow Torrent with an AT J270-10. Beautiful flight - apogee at 3000 ft with motor ejection to deploy an 18" drogue, then CR deployed the 45" main chute at 500 ft. I had rolled the main chute as per John's instructions and it deployed very quickly. Attached is a photo of my Torrent.View attachment 293822

That was a great flight. I think I forgot to congratulate you at the field, so... congratulations!
 
Great job on you L-2 flight. What type of 45" chutes was it? I have used my CR 4 times now all flight deployed very well. I flew a LOC Mini Magg for all flights with a CTI H400 V-max. 1st flight I set CR at 200' to low. 2nd and 3rd flight set at 300'. 4th flight 400' that seemed to work out the best.
 
I had an interesting experience with my CR at an event a couple weeks ago. I set the chute release for 300 feet but it opened at 100 feet, if that. It was noticeably lower than my other flights set for the same altitude. Best I can figure is, with the 15mph breezes we were having, came a change in pressure. It was a while between when I set my CR and launch, due to setting up early between rounds and having launch controller problems during my round. So maybe in the area of 45 - 60 minutes. If the CR calibrated, and the pressure dropped say 0.15" during that time, then the CR would have thought it was at 150 feet at launch, then deployed at what it thought was 300 feet but in reality was just 150 feet.

Moral of the story, with any breeze, give yourself a little margin of error and try to turn the unit on as close as you can to launch time.
 
A standard TFR nylon chute -- one of yours, right? I like 500 ft for CR deploy with bigger rockets; its gives a little safety margin in case of slow deploy, although I have never had a slow deploy in my 5 flights using CR. I roll the TFR chutes tightly and they have always sprung open quickly when CR releases them. I tie the CR tether to a shroud line.
 
Par45 that's good to know the largest chute I have used so far is a 36" The launch site at Bong has been very soft so far this year. I tie the CR to the Q-link where the chute is tied to. Been working out well. I what to try to just reef the chute all the way up to the canopy with the CR for larger rockets to act like a drogue chute until lines are let free.
 
That sounds like an interesting configuration. Has anyone tried to use the CR to hold a D-bag closed and have a small pilot attached to the CR latch?

A pilot attached to the rubber band or the CR itself? I wouldn't think it necessary as long as the chute protector is placed on the shockcord so it falls away after the charge blows and its job protecting the chute is done.
The CR reefed package can flutter in the breeze and hopefully the rubber restraint is strong enough to keep the chute restrained until release altitude. Attaching a pilot to the chute itself might risk the main working free
from the rubber restraint.

Be aware if the shockcord twists around the package, it might restrain the chute opening when the rubber restraint is released. I had that happen with the CR set to release at 700 feet. Shockcord kept the chute from deploying.

I've had good luck with a BP cable cutter (Archtype/PrairieTwister) using a pilot drogue that attaches through a loop at the apex of the main chute. A small puck of hard foam is threaded on the loop and the chute is folded so the ziptie up against the foam block that restrains the main in the chute protector so the drogue can't pull it out. The ziptie can be cinched down very tight. The charge blows, breaks the ziptie and the drogue can now pull the main out of the protector. Works very nicely. Not my idea as I saw posted by another flier here. Yes this is with electronics and more BP which one is trying to get away from with the CR. Point is this technique is fine with a cutter but I don't think would be advisable with a JLCR.

I won't trust this protocol with the JLCR because the rubber restraint is not as secure as a ziptie. The drogue could pull the main free prematurely.

If purposely using a reefing technique that allows the chute the streamer more, one could run the risk of it working free from the rubber restraint. It would be best to test ones technique with lower powered motors before going higher. If going
to explore that realm, you would have to consider how much farther you'd have to walk if you get a main at apogee that's "way up there". Kurt
 
Last edited:
I've had good luck with a BP cable cutter (Archtype/PrairieTwister) using a pilot drogue that attaches through a loop at the apex of the main chute. A small puck of hard foam is threaded on the loop and the chute is folded so the ziptie up against the foam block that restrains the main in the chute protector so the drogue can't pull it out. The ziptie can be cinched down very tight. The charge blows, breaks the ziptie and the drogue can now pull the main out of the protector. Works very nicely. Not my idea as I saw posted by another flier here. Yes this is with electronics and more BP which one is trying to get away from with the CR. Point is this technique is fine with a cutter but I don't think would be advisable with a JLCR.

Interesting. Do you have some pictures for explanation and/or the link to the other TRF member's thread?
 
Dont put drogue load on any part of Chute Release!

If you want to use your drogue to pull your chute from a bag, create a setup with a ring and an eyebolt and just have chute release hold the rod against the side of the bag. When it releases, the rod is free to flip and slide out of the ring and let the drogue go to pull the chute from the bag. Before CR lets the eyebolt flip, the tension goes around the bag.
 
Interesting. Do you have some pictures for explanation and/or the link to the other TRF member's thread?

I'll take a picture of the parachute with the pilot attached. The link to the technique last I looked several months ago the pictures were lost from the link so one
couldn't visualize it.

That was the problem with the cable cutter. Even though the ziptie was broken by the charge, it could still remain around the nomex protector. With the pilot/drogue that was out in the airflow, once the tie was cut, it could pull the chute free from the protector. Kurt
 
Used the CR twice on Saturday, and had 2 successful deployments. One was a Leviathan on an H159 Green that went to 2800 feet, out of sight but landed 400 feet from the pad, and I would not have flown that combination without knowing the CR would bring it right back down. I now refuse to launch anything bigger than an F without either a CR or full dual deploy.
 
Speaking of JLCR at WOOSH... I discovered another benefit of the doo-dad this past weekend. Launched my son's Demon Sport on an I204 IMAX to 5754ft... I may have forgotten to close the quicklink to the chute bundle... in either case, we recovered the rocket sans chute following the tracker. In order to find the chute, we just walked downwind about 100 yards, and BAM, chute.
Since it was all bundled up all the way down to 400ft, it didn't really drift all that far and thus was easy to find. Glad the JLCR was on it otherwise, bye-bye chute...
 
I made 4 more flights today at URRF3 with my Chute Release. Now folding my chutes the recommended way, I've so far had complete success with deployment. Hopefully, there will more to report from tomorrow & Sunday. Lots of positive comments about the product, I even demonstrated how to set it up to another flyer that just bought one but hadn't used it yet...
 
FAIW, when NARHAMS redid their flight card, they included "Chute Release Alt" as a field.
 
I made 4 more flights today at URRF3 with my Chute Release. Now folding my chutes the recommended way, I've so far had complete success with deployment. Hopefully, there will more to report from tomorrow & Sunday. Lots of positive comments about the product, I even demonstrated how to set it up to another flyer that just bought one but hadn't used it yet...

Pay it forward. Very nice!
 
Thanks John. I made 6 more flights with the JLCR over the weekend at URRF3, all completely successful. I'm still getting the hang of Z-folding the chute such that it still fits in the tube with the CR attached, but the only issue I actually had over the weekend was wind-related. Even with a 300' release altitude, the winds can still push a drogueless rocket pretty far when dropping from ~2700'. But it was still recovered intact, no issues. I just have to also work on suitable rail angle. With that said, I did witness a non-deploying flight (not mine) that dropped on top of a motor home in the parking area, and another (also not mine) that came in ballistic. The latter was no fault of the CR, but the CR did apparently break the case on impact. But, there's only so much you can do about the laws of physics...

I'll iterate one more time that if you ever devise a more compact version that fits in BT50 tubes, you'll spark a lot more interest. I'd be one of the first in line. I get that its already pretty damn small, especially considering what it potentially replaces, and was probably a lot of work to package what you have now. But just think how cool would it be - and how appealing to fliers - to be able to take high-flying small rocket (Goblin, Cherokee-D, or a minimum-dia 24mm rocket), and be able to drop it back within near walking distance under a parachute?.. :cool:
 
I'll iterate one more time that if you ever devise a more compact version that fits in BT50 tubes, you'll spark a lot more interest. I'd be one of the first in line. I get that its already pretty damn small, especially considering what it potentially replaces, and was probably a lot of work to package what you have now. But just think how cool would it be - and how appealing to fliers - to be able to take high-flying small rocket (Goblin, Cherokee-D, or a minimum-dia 24mm rocket), and be able to drop it back within near walking distance under a parachute?.. :cool:

Thanks for the report!

As for the idea for a smaller Chute Release: working on it.
 
Thanks for the report!

As for the idea for a smaller Chute Release: working on it.

Awesome. Have you considered a curved one? Why keep trying to fit a square inside a circle? Semi-circle shaped circuit boards are easier to have manufactured then they used to be. I'm imagining a CR shaped like half of the inside or a bt50 tube, or better still, as a bt50 'piston' with a rod attached to the top of it and the release incorporated into this rod. This way the circuit board could stay flat (in the centre of the piston) & the only competition for chute space is the off-centre rod attached to the top of the piston.

Sorry not trying to design it for you, just some crazy ideas.
 
Last edited:
Back
Top