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Co2 ejection system

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LBarron

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If anyone is interested in a clean and inexpensive parachute ejection system, check out this little gizmo I made. It uses a small black powder charge to open the CO2 cartridge, and (most of) the BP gas is vented out the side of the rocket, keeping everything inside clean and free from burning or melting. I tested it on an 11.5" x 10" chute compartment and it worked perfectly. Next I'll test it with shear pins but I'm not ready to drill the holes just yet. All parts were from a hardware store and Home Depot and it costs about $15 to make. It weights 4oz, 6oz with a 16gr cartridge, so it could be used on smaller rockets too.
 

cls

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hey, that's just what I need for an upcoming project.

can't tell from the pix, how exactly is the co2 cartridge opened?

I wonder, could the powder charge be replaced by an electric solenoid?
 

LBarron

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cls,

yeah, i forgot to put the igniter in the picture which would have helped... sorry.

looking at the second picture, the e-match and small bit of BP go into the last brass fitting on the right. the threaded section holds about .25gr of BP which is held in place with a double layer of Saran Wrap. that gets screwed into the next fitting, which is then screwed into the piece with the big silver washer on it which has inside it the silver piece with the pointy end.

the BP charge ignites, sends to silver pointed piece through the tube, it pops open the Co2 cartridge while letting the BP gas escape through the vent holes which are just visable to the right of the washer (the BP gas is contained in the pvc piece and vented out of the BT), then the Co2 gas pushes the silver plunger piece back which opens vent holes to the left of the washer (can't see them in this picture) that allows the Co2 gas to escape and pressurize the chute compartment. i hope that makes sense...

i did think about using a soleniod to pop open the Co2 but never tested it. one reason is that the current from the deployment controller is very low and would probably not even be sufficient to operate a relay, let alone the solenoid itself. if you can figure out how to boost the current to 9 or 12 volts it might work, but i'm still not sure if a solenoid would have the power to break the seal on the Co2 cartridge - it takes qiute a bit of "oomph" to open it.

leland
 

wyldbill

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Originally posted by LBarron
but i'm still not sure if a solenoid would have the power to break the seal on the Co2 cartridge - it takes qiute a bit of "oomph" to open it.
The power supply to power a solenoid to do this, as well as the solenoid itself, would probably be very weight prohibative. BP may be nasty from some perspectives, but energy/unit weight is very high...
 

LBarron

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yup - i agree. can't beat the trade-off between .25 grams of black powder vs several pounds of electric parts.

lb
 

cls

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can't beat the trade-off between .25 grams of black powder vs several pounds of electric parts.
it might not be pounds and pounds - I was thinking that there is a 9v to power the altimeter anyways. a couple altimeters come with 2 9v batteries, one for the altimeter and one for the pyro charges.

other options include using a spring for energy for puncturing the C02 cartridge, and the solenoid just pulls the pin on the latch holding the spring, etc. etc. sorry, getting a bit creative here.

still, energy density of batteries is just simply poor!!
 

LBarron

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i thought about the exact same spring operated mechanism you mentioned. i tried a few springs contained inside an aluminun tube and found that it would require rather powerful spring to get the piston moving with enough force. then i called a guy who works for a solenoid manufacturer and was told that it would require a pretty strong (that is, large and expensive) solenoid to release the spring with all the tension on it. that's just about the time i quit that idea and built the BP version. if you figure it out, let me know.

leland

also, i believe you're right - the 9v or 12v from the altimeter would be enough to operate a relay but i don't know about a large solenoid switch.
 

LBarron

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hey - that's cool!!

ok, back to the drawing board for a non-pyro device.

thanks!
 

cls

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would nicer if it can use cartridges instead of a fillable tank. filling a tank takes more GSE.

I have an auto-inflating life jacket. I haven't looked closely at the trigger mechanism but it doesn't take much of a tug to pop it. also the cartridges are bigger :) and more expensive :( buy a couple and the cost of CO2 GSE looks great.
 

rocwizard

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An option that i have been looking ino is using refillable CO2 tanks, like those for paintball guns.

The one i am designing uses a 9oz. tank. Yes that is a LOT of gas, but the rockets recovery bay will be 7.5" x 40" up around 55K. If i get lazy when it comes to building it, there I could always use redundant CD3 systems with 45g tanks :cool:
 
A

Austin

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Rocwizard,

I was not aware that the CD3 Systems were still available. I checked Bob Fortune's site and couldn't find them listed anymore. You know something I don't? Inquiring minds... :)

Carl
 

rocwizard

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I didn't realize they had been taken off. I might have to go ask what's up with that
 

rocwizard

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I just checked the site, and they are still there, you just have to scroll down a bit.;)
 

bsexton

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Aerocon does still carry the CD3 deployment system. Although a little more expensive than the homemade units discussed here...
 

praveen1chaubey

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hii, i want to use this co2 deployment system for our sounding rocket which would fly around 3 km high, can anyone suggest me how should start?
 

praveen1chaubey

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hii, i want to use this co2 deployment system for our sounding rocket which would fly around 3 km high, can anyone suggest me how should start?
i was trying to ejacuate using pyro method but that was not feasible enough
 

dhbarr

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hii, i want to use this co2 deployment system for our sounding rocket which would fly around 3 km high, can anyone suggest me how should start?
i was trying to ejacuate using pyro method but that was not feasible enough
This discussion was in 2004. Look at Peregrine or CD3 CO2 ejection systems.
 

praveen1chaubey

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Thank you so much for your reply, I live in India and bit remote place so shipping is really difficult so i decided to make one of my own cd3 co2 ejection system , so can you please help with the design as it is much required.
hoping to get a reply soon from you
 

Dan Griffing

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I'm looking into mounting the Tinder Rocketry Peregrine CO2 ejection system into an "e-bay" that fits into a 54mm x 14" nosecone compartment -- (much like people do with the Multitronix "Kate" GPS system).

My motivation for packing parachute ejection electronics and mechanisms into the nosecone is for backup redundancy to standard motor BP ejection, and to fly with motors such as Contrail hybrids that don't have motor ejection, but without having to add the length of a dual deployment e-bay.

Its pretty tight because the 1.75" Tinder mounting flange barely fits onto the 2.00" diameter 54mm e-bay plywood bulkhead. The 14" compartment should also have room in front of the Tinder for an altimeter ejection controller and a Eggtimer GPS.

Outside venting for the altimeter and switching for the ejection electronics also need to be addressed.

Have any HP rocketeers on the forum had experience with this to offer advice?
 
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