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cartridge?
Posted: Sun Oct 08, 2006 7:12 pm
by dragon finder
could it be possible to have a cartridge with both the fuel and ammo?
using a precussion cap as the ignition? or a contact ignition?
i was thinking of how big it would have to be and what type of fuel. like should one use butane, propane, lighter fluid, hydrogen, or other fuels.
Posted: Sun Oct 08, 2006 7:34 pm
by jrrdw
When i seen the title, about a gazillion thoughts went through my mind. Then as i thought about it some more, that gazillion shrank to dhaaaaa! I think you would have to design the most of it around the loading mechanizum.
How about pieces of pcv with metal inserts in 1 end to hold sparker/precusen caps, fill with fuel, shove ammo in, theres your preloaded cartridge.
Tennis ball preloads sound easy.
Posted: Sun Oct 08, 2006 8:24 pm
by FreakyShotGlass
I thought of exactly that and made a flash animation.

It would be an easy way to get either semi or magazine loaded bolt-action.
Posted: Sun Oct 08, 2006 8:46 pm
by Atlantis
I've seen a useful design on SpudTech, the only difference was that the bolt had 2 circles on it, one inside the other, they matched up with 2 points on the cartridge, that way, no matter how much the cartridge spun it would always touch the 2 circles.
Posted: Sun Oct 08, 2006 8:48 pm
by FreakyShotGlass
Concentric electrodes is a good idea, has anyone ever actually made a working cannon with this design, I think i will try to produce a bolt-action using pre-loaded marble shells.
Posted: Sun Oct 08, 2006 8:56 pm
by Atlantis
Somebody made a prototype. I'll try to find it tomorrow. I believe the topic title was Cartridge Combustion or something on SpudTech.
Posted: Sun Oct 08, 2006 11:36 pm
by Pete Zaria
The problem with this is that the amount of power you can produce with a fuel/air mixture AT ATMOSPHERIC PRESSURE is limited directly by the volume of the combustion chamber. In this example, the combustion chamber (inside the "shell") is pretty small. Without pressurizing the gas/air mixture, you can't get much power out of it. Pressurizing the gas/air mixture makes your gun technically a hybrid, which presents some design challenges. The first one is how you'd keep the pressurized gas inside the "shell" after you've disconnected your source. Maybe you could make reusable metal shells with a shrader to fill them with.
The easy solution would be to make each "shell" long, but reasonably thin (with a small-ish projectile, like a marble). This provides a fair amount of fuel/air behind a projectile, given the size of it, which could produce more power (by ratio).
I like the concept. Let me know what you come up with.
Peace,
Pete Zaria.
Posted: Mon Oct 09, 2006 12:14 am
by BC Pneumatics
illegal, and it has been done...
Posted: Mon Oct 09, 2006 1:20 am
by frankrede
Yes, prefilled cartridges are illegal but really, I would still do it;)