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I'm wondering if there is a simple way to deploy a parachute without any ejection charge. I'm working on a Thrust Vectoring system, similar to BPS.space and a few designs here on Thingiverse. My system would not allow for an ejection charge, so I'm trying to brainstorm ideas for deployment. Servos? Pyro? What are your thoughts on this?
Thanks in advance!
Jolly Logic Chute Release could be used for more than just wrapping around your parachute. You could use it to open the parachute bay at a defined altitude without any pyro. Develop your own similar electronics using Arduinos and 9DOF or 10DOF breakout boards.
Besides being banned, as @charles_mcg pointed out, glass in a rocket isn't too good an idea anyway. An alternative would be a metal ball bearing in a cage with wire contacts. You can make one or you can buy one. Commercially these are called ball bearing tilt switches.
Not suggested practice. And this article is from 2004. Mercury switches for airstarts have been banned since.https://www.rocketryforum.com/threads/mercury-switch-deployment.79631/
Just printed my first prototype version of the TVC gimbal. I used paper clips as axles. I'm also looking into compliant hinges.
Thank you all so much for your input on parachute deployment - it has been one of my most underlined questions in my notebook since I started this project! I'll make sure to post any interesting thoughts/ideas/findings in the Estes Rockets group.
Do you mean no -motor- ejection charge? Because you mention 'pyro' as an option. There are lots of altimeter-firing-black-powder options available. I've used them for hot-wire release and servo - but not chute deploy, except with a small black powder charge.
A small black powder charge would be great if fired from an altimeter. What would I use to ignite it, especially without scorching anything?
An e-match. It sounds like you haven't practiced 'dual-deploy' before?
A little altimeter kit: http://eggtimerrocketry.com/eggtimer-quark/
Sourcing the black powder I'll leave as an exercise for you. It's usually held in little canisters. Here's a combined example.http://pratt-hobbies.com/proddetail.asp?prod=SEC-5B
I've used the Quark linked above to also heat a nichrome wire that melts fishing line and releases a rubber band restraining a chute from opening early - but I still use a charge to get the nose cone off and the chute in free air. It can be done without pryo - often in the big water rocket community, where pyro can be off-limits.
I have not tried dual deployment, but it is on my radar. Thank you so much for your help! I now see how this can be used for deployment. I'm glad that the e-matches aren't too expensive! I assume, then, that you just dump current into the wires to trigger them, just like an engine igniter.
Yes. But ematches are lower current than estes igniters (which I have used for this purpose, too - at least in ground testing, if not in flight. I have also used ematches to light motors.)
The above linked Eggtimer Quark will run and fire ematches off a 1S Lipo battery. I use 2S for nichrome.
Caveat on the Quark - it needs to reach at least 200' to work - that's its hard coded 'launch detection altitude'.
Yes, the "modern", high tech way would be to use an accelerometer; some form of micro-computer/controller; and a servo/solenoid. For a more low tech version, check out this toy rocket from back in the 70's or 80's - https://www.thingiverse.com/thing:2811755 ... If I'm not mistaken, I want to think I remember Estes using a similar system way back when in one of their rockets, but I don't remember which one. If you need, I can go through my old catalogs and find it tonight.
Awesome! Thanks so much for your input. I'll be giving a few systems a try and this will definitely be one of them. I'll let you know when I get a working system!
Whatever you go with, I would love to see it!
Thanks for the support! It's my current project.
BTW: I have a Tarantula, too! Good to see someone with those great machines! My profile photo is of mine working in top shape ;-)
They are, aren't they? They do not deserve the bad reputation I see on reddit. I know you have, so what kind of upgrades have you done to yours?
Want me to PM you? I don't want to get too far off topic ;-)