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Are 12 gram co2 cartridges a viable power source for small rockets? Answered

Would it be practically possible to use 12 gram CO2 cartridges like those used for bb guns to power small rockets? I have high hopes for this, but I don't know how well it would work. I am going to go do some ill-advised tests, but I would like to know if anyone has tried it and what I can expect.



Ilpug, Were you able to get this to work? We were thinking about doing something similar for a space-themed camp activity.

Well, to be perfectly honest, they didn't go very far and their flight became dangerously erratic as the cartridge lost pressure

wasn't really worth it in the long run.

You definitely could use one of these CO2 cartridges to power a small model rocket, but you would have far more fun and success by using safer, more powerful, more predicable and readily available model rocket engines.

When I was a kid, in the late 1950's, CO2 cartridges were sometimes used to power model race cars, boost gliders, and even vertically launched model rockets, although I never witnessed the latter, and they couldn't possibly go very high anyway. And they all required a special hobby device that held the neck of the cartridge in an air-tight grip, allowing the hobbyist to puncture the end of the cartridge, and then release the air-tight grip of the CO2 cartridge for the take-off. CO2 is a highly compressible gas, making it far more useful than compressed air, for many model jet applications.

But the 1950's were an age of "amateur rocketry", with the German scientist Willey Ley's handbook as the bible for many amateur rocketeers. Those were the days before "model rocketry", with Vernon Estes, and his much safer and more predictable model rocket engines, all with standard parachute ejection charges.

But I do remember that local amateur rocketeers of the 1950's took a safer, more common sense approach to building a smaller, safer, and reusable rocket engine:

The CO2 cartridges at that time were made of copper, and teenagers would get an expended cartridge from a bartender or an airgun buff, and simply taper-ream out the end of the neck. Those who were lucky enough to have access to a standard plummer's copper flaring tool (used for flaring the ends of copper tubing) could then flare the soft copper of the neck into a spiffy (and quite functional) rocket nozzle.

The empty cartridge was then filled with a mixture of zinc dust and powdered sulfur, and then "tamped" until the mixture was hard, and would not pour out if the CO2 cartridge was inverted. Willy Ley's handbook advised a literal tamping of the mixture, but most hobbyists simply placed the CO2 cartridge, neck up, on a vibrating-type aquarium air pump, until the mixture self-tamped down until solid. There was absolutely no attempt in those days to produce a patterned core in the propellant cross-section, so the simpler solid form produced a much safer, longer burn.

But the zinc-sulfur mixture needed a primer, that would produce the required amount of heat and pressure, to ignite. For this, the heads of large wooden kitchen matches were very carefully crushed off the wooden sticks, in a mortar-and-pestle, until a coarse mixture (like coffee grounds) was made. The dry flammable mixture was then poured into the neck of the CO2 cartridge, and a 3-inch fuse was carefully stuck into the match-head mixture, down to and against the hard-tamped zinc-sulfur propellant, with about 2.25 inches of fuse sticking outside of the cartridge neck. Small, crumpled bits of newspaper were then carefully tamped in and around the protruding fuse, taking care to keep the fuse centered in the neck, and firmly held against the zinc-sulfur propellant. Finally, a medium-thin layer (this was critical, so as not to explode) of glue was squirted into the neck, surrounding the fuse in an air-tight seal. After the glue dried, in a day or two, the rocket motor was ready for launch.

The standard model rocket body for this crude motor was a simple, solid balsa V-2 rocket, about 9 inches long and turned on a wood lathe until about 2 inches in diameter (I'm writing all of this from vague memory), with a hole bored to receive the rocket motor. The rocket motor was rolled up in a thin sheet of asbestos, and snugly inserted into the V-2 rocket. Two small eye screws were mounted, in-line, on the balsa model rocket body, and the rocket was slipped onto a straightened out coat hangar rod, perpendicular to the ground, for launch.

After much techno-geek antics and fanfare and a proper 10-second countdown, the fuse was lit with a match. In the 1950's, I never saw one of these launched electrically. With a "swoosh" the tiny rocket would take off and maybe reach a height of 100 feet or so, and then take on a nose-down attitude, plunging down to the grassy ground. After a number of flights, each V-2 rocket assumed a rounded nose.

After cooling, the CO2 cartridge rocket motor was removed and another fresh motor inserted for another launch. Back at home, the motors were cleaned out, steel wool scrubbed, and re-filled, to be used again.

I took the time to describe all of this in detail, just to convince everyone that building a rocket motor from scratch is just not worth it. The potential for death, or grievous injury, was always there, but, back then, we didn't have many things to do, except watch the big boys in the neighborhood make and launch amateur rockets... or sometimes we'd get our jollies chasing girls around the neighborhood with dog-doo on a stick. Back then we simply didn't know we were miserable. In contrast, you kids have so many possibilities these days for any type of hobby you want, and don't have to resort to a hobby that might blow your fingers off. Really, a typical flea market these days is a virtual Star Wars bazaar.

That is some very interesting history there sir, thanks for sharing!

I strapped one to a model car once for a comparison to rocket motors. Conclusion: Rocket Motors <60 Feet Co2 Canisters >6 Feet

Are they the same size as those used in fizzy drink machines? If they are, then "yes", since my old physics teacher put one through a wall during a lesson.

Roughly 8 cm long and 1.5 cm wide. These are intended for use in air guns.

Well, that sounds like a great source of propulsion!

Short and sharp.

My reply or the cartridges?


Neither - the thrust available. They only run for a couple of seconds, max.

Well, then again, so do pyrotechnic rocket engines.

rockets with water work better than only air, but CO2 cartriges are under high pressure, so, by themselves are a reasonbly good power source. For better results, get a water bottle, put some water inside, the CO2 cartridge inside and a cork in the opening. and open the cartrige inside using an old BB gun's mechanis (just the mechanism, otherwise it will get too heavy) and watch it

That would risk blowing the bottle up, something I have done before and do not want to repeat outside of a controlled environment.

make your own bottle from PVC pipes. Grab a pipe and put end caps on both ends. Then drill one of the end caps and put everything inside.

Depending on your needs you might find that water rockets are as effective and cheaper to make/run.

I think that a water rocket is too big for what I have in mind though...

They can be big or little as you wish. Just use a smaller pressure container.

They will work but not as well as a rocket with a solid booster. You can buy rocket cars that use those CO2 cartridges to power them down the track. Look them up and you may find some handy plans for building the starter for a race track and adapt it to puncture the cartridge for your vertical takeoff.

Hmm, great idea on how to find a puncture system...