SpudFiles

Hey guys, been a while since I have written anything here. Question for you guys, I am still working on a smaller scale launcher with a fairly quick ROF but my snag is portability. Instead of having to haul around one of those big green coleman propane tanks I would rather have a small cartridge similar to the disposable co2 powerlets.

An idea struck me recently, would it be possible/safe to have an adapter between the coleman propane tanks, and run it to a smaller refillable tank like a co2 tank? Im thinking 3.5 ounce co2 tank or even a 13 cu. in. compressed air tanks used for paintball propellants. The idea being to release propane from the coleman tank into the smaller tank until it is filled. I understand that there are huge pressure differences and that I would not be able to completely fill those tanks, rather stop filling when the pressures have equalized in both tanks.

Thoughts?
Thanks!

Hmm a quick note I just stumbled on the Thermacell line of butane cartriges. Perfect size but would it contain enough butane for multiple shots?

If this is for a combustion, unless it's too big even a simple cigarette lighter can suffice.

this is a refillable butane canister i made for my mini hybrid (the copper thing) and it works fine its just epoxied together

propane turns to liquid and is stored at a relatively low pressure. There is no need to use CO2 or HPA tanks

you can find more info on it here http://www.balloonlife.com/publications ... erfill.htm

For a small size launcher even a length of 3/4" pipe would be more than enough.

You can store propane in almost anything. At room temp, it's liquid at around 80 psi.

Use a pressure relief valve on whatever you use so if over filled and then warmed, expansion doesn't burst the container. BBQ tanks have an over fill protection device (OPD) to leave expansion space in the tank.

Propane expands a lot more than water as it warms.


Old style tanks with the POL valve had a small pick up tube attached to the vent. The filling station was required to stop filling when the vent started spitting liquid leaving the proper expansion space.

Too many untrained service station attendants overfilled the tanks and as they warmed on the way home in a warm car (often for hunters in the winter) the expansion had no where to go except out the pressure relief valve. I had this happen to me once. I rolled down the windows immediately and pulled off in a safe spot and took the tank out of the car. I opened the vent and let it vent until it quit spewing liquid, then took it home with the proper fill. Overfilling also led to liquid being fed into regulators for trailers. Fire and explosions in trailer parks due to over filling was the reason the old style tanks were discontinued.

They were safe with trained filling station operators. They were lethal when filled by untrained people.

Here is a paper on overfilling and hot air ballooning.
http://www.balloonlife.com/publications ... erfill.htm

i remember Boom_erang was trying to do what you are cause is cannon was so small a big propane cylinder relay wouldn't do suffice so he used something called "Big Air", he said you can buy it at places like bike shops or amazon. i looked i couldn't find it.

my name is Boom_erang and this is what i wrote:About a year ago I discovered these - they are used for bike tire inflation. They are called "Big Air" and can be found in bike shops, on Amazon, etc. They seem perfect for this application since they are small and light, and so far I've done dozens of shots over several days and the first cylinder is still good.

Boom_erang's 3rd combustion

Here is a paper on overfilling and hot air ballooning.
http://www.balloonlife.com/publications ... erfill.htm

lol, the same link...

I didn't follow the prior link. I just assumed it was a link on a small tank, not one of the large ones use for ballooning. Thanks for pointing that out.

Another possibility is a butane refill canister. It's bigger than a butane lighter and easier to plumb to. Probably shoot a thousand shots form one.