Co2 system trigger

Hi folks! İs there anyone who had use co2 system for recovery. What am ı gonna ask u is how can ı trig system without using bp?

The UQ university team here showed me their system recently - they are using a very small BP charge to fire a small puncture down into the canister. Their charge wells are metal, machined with holes in the bottom for co2 release and capped at the top with a screw on cap that holds the small BP and puncture elements.

snrkl said:

The UQ university team here showed me their system recently - they are using a very small BP charge to fire a small puncture down into the canister. Their charge wells are metal, machined with holes in the bottom for co2 release and capped at the top with a screw on cap that holds the small BP and puncture elements.

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The contest that we participate in said 'No bp is allowed to trigger or something, that's why we must find a mechanical solution, hidrolic could be good for trigger but ı don't know how should ı do system.

Check out life vest / life raft inflator recharge kits.

I haven't seen anybody use one, but it seems to me a very short route to success.

Magin said:

The contest that we participate in said 'No bp is allowed to trigger or something, that's why we must find a mechanical solution, hydraulic could be good for trigger but ı don't know how should ı do system

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I’ve heard of a few competitions in Europe and elsewhere where there’s been a rule stipulation of 100% non pyro deployment. Personally, I reckon it’s often an unrealistic expectation on behalf of the organisers or range providers that it be 100% non pyro, especially if the participants are 1st time flyers.

I like that it encourages clever ingenuity and challenging engineering (often for aerospace & mech eng students), but as many would appreciate here, achieving a successful flight and recovery of HPR class rockets for an intensive fast-tracked learning curve is quite challenging without that constraint.

TP

The only commercial CO2, that I know of, that does not use BP, but instead is 100% mechanical is the Hawk system. I have no opinion on how well it works but it is pricey and IMO likely too big for most rockets hobby rockets. I would contact Gene at Fruity Chutes and get his opinion. https://fruitychutes.com/buyachute/...4.html?zenid=bc5ecb88ba5482dfc7b68e88b90980c0

snrkl said:

The UQ university team here showed me their system recently - they are using a very small BP charge to fire a small puncture down into the canister. Their charge wells are metal, machined with holes in the bottom for co2 release and capped at the top with a screw on cap that holds the small BP and puncture elements.

Click to expand...

A servo-operated pull pin and a spring might be able to accomplish the same thing.

You can do it with a piece of string and a resistor or bit of ni-chrome wire. I've got a box full of commercial units (not for rocketry) that use some string to hold a spring loaded spike. Resistor melts/burns string releasing spike which pierces seal on cylinder.
I've done a rechargeable cold gas unit where the string basically held a cork (piston with o-rings) in place. Same deal with release being effected by some ni-chrome wire melting the string.

Have a look here too: https://www.rocketryforum.com/threads/any-non-pyro-system-advices.149766/#post-1840357

Hi PK. Long time no hear. Hope things are well with you!

There's a thing you do in rocketry for the longest time.. You approach problems convinced that you have to come up with a solution that is simple or cheap or quick or easy or even resellable... Troy doesn't do that. As a result his solutions to problems are expensive, (sometimes) complex, unobtainable, and very, very good.

Be like Troy...

It's not clear from that thread (or I missed it) that the enabling element of his design is that there is very little axial load on the latch mechanism because the similar (but not identical) diameters of the seals at each end balance out. You could easily reproduce the latches function, with a "heater breaks string" setup.
Of course then you wouldn't have electronic actuation and reset which is elegant and , IMHO, worth the effort.

We (ie my business) make a CO2 release valve that works on a similar premise, where a resistor melts a nylon pin that retains a non constant diameter spool. It wouldn't be useful in rocketry though because there is about a +4-0 second variance to the release time, but it works just fine when your laser cutter is on fire....

OK, having shot my mouth off referencing "commercial units" which are only available to the Illuminati. Here are some pics. There is a twin CO2 cylinder variant too. Hopefully the function is self evident.

Can’t use black powder.
Use smokeless

MClark thinks like I do when reading contest rules. LOL!

A Jolly Logic Chute Release could be used to release a spring trigger on a COTS CO2 canister actuator. Mount the CR on a sled with the actuator, and hook the spring to the CR pin.

https://www.propulsionlabs.com.au/Pyroless_Release/index.html

Have this one saved in my "things to try folder", no idea where I got the link from. Very clever design for larger rockets.

That's Troy's solution