You may be overthinking it a bit. Adding to much "stuff" increases potential failure points and adds weight/bulk. Think in terms of minimal wiring connections since each one can potentially fail. I used nuts and bolts on my set up for ease of Nichrome replacement. After realizing how durable it is I considered a more "permanent" design, possibly wire wrap? If it wasn't so damn difficult to solder I'd have done that instead. "Keep it simple" is almost always best practice. In those terms the original Chute Release really shines, just the price is really hard to justify for such a simple device that can potentially be easily lost or damaged. Seems to be plenty of horror stories about that very thing here on TRF, here's a recent link with a few. https://www.rocketryforum.com/threa...ltimeter-4-and-other-jolly-logic-news.139205/ . A $20 Eggtimer Quark (or equivalent) and 50 cents worth of parts works identically and doesn't sting so much if you lose it, plus you can cost effectively have multiples on hand so as to not ruin you day of flying if something does go wrong. Personally I find it takes a ton of pressure off my launches by not having expensive items on board to worry about. I've lost and or destroyed enough "stuff" already, no need to pile on more...This give me an idea for a semi-reusable setup. The rubber band/elastic cord would be the expendable part, but what about using one of those electric flame-less cigarette lighters as the heat source? That way, you wouldn't have to replace the nichrome wire each time, and a case of some kind can be made to enclose the elastic cord around the heating element so resetting the thing on the ground "is a snap". The control would be any other altimeter set to fire a pyro, except the signal closes a relay to the lighter power. Once the parachute is released, a pin is pulled out of a connector to break the circuit to the lighter battery in case it gets stuck in the on position so it doesn't stay hot the whole way down.
eBruce, if you come with anything please post it. Thanks.I haven't yet lost much for electronic hardware with my rockets, but losing expensive stuff is always on my mind. As for the setup I'm thinking, it shouldn't be all that pricey. Like you said, the $20 Eggtimer would work perfect, and the lighter with battery would add maybe $2 and five or so grams. The setup in my head is a single box like the JL Chute Release attached directly to the parachute, so no additional wire to tangle or break, and the disconnect pin I mentioned could be as simple as a 1/8" headphone jack with a shorted plug that gets yanked out by the parachute.
It might be a bit over complicated, but I feel like it has the potential to be just as robust as the JL version, and could tangle less since the elastic is discarded entirely whereas the Chute release keeps it because you need that little pin. Also, I love to tinker, so the idea of building my own cheaper Chute release is appealing just from the standpoint of the challenge.
Fall will be here soon & then Winter, a time to catch up on indoor projects.Will do! Between this and an electronic "insurance policy" for guaranteed cluster motor ignition I've been working on, looks like me and my soldering iron might be busy for the next few months!
Sounds like you're referring to parachute reefing. It's done by having a string restrict how far the parachute can open at the bottom, and then cutting said string when the parachute is needed fully open. It's a classic technique that you see used frequently with landing rovers on Mars, and practically every parachute in Kerbal Space Program. If memory serves, Bama Chutes offer some reefing setups for model rocket chutes.I thought it would be cool to have a consistent, slow opening parachute. Like it starts out as a drogue chute and then works it's way to a fully opened parachute.
I've watched two rockets hit the ground under a streamered main chute because it was not falling fast enough to open . These sliders require velocity to open.
Wallace, the your YouTube link doesn't work for me. It says video is unavailable.Here's a link to my original attempt with a video of it in action. Ignoring my struggles with arming the Quantum, you can see how clean the release is using the elastic thread. You can also see how long the Nichrome wire stays hot after cutting the thread, believe I had the trigger set to 1 second? https://www.rocketryforum.com/threads/quantum-based-hotwire-chute-release.141642/#post-1713016
I really like this idea but am curious, what do you think is the maximum chute size for this setup? And would you happen to have a picture of said chute wrapped in this manner? This and the nichrome idea are wonderful.View attachment 390732 Nothing more than a nylon bushing drilled to accept an Ematch head. Thread the elastic cord through and tie it around your chute/blanket bundle. When match fires, it burns through thread and releases chute. Some have tried similar with fishing line but it lacks the springiness/release characteristics on burn through so won't always work. Works identical to Chute Release, just very slightly more difficult to set up. As you can see, I do own a Chute Release. What you can't see is that I did not pay $129.99 for it since I bought it used. It's a neat little piece that seems to function as advertised.