hybrid cannon shells

[Crimson]

First, let me state that this is my first project with any cannon, maybe a tad ambitious, but I'm optimistic about it.
The plan for this is to be used in simulation combat, me and my friends will go out for 1-2 weeks at a time, usually involving vehicles, I was tasked with arming and armoring them, while covering them with plywood is easy, I need some assistance designing the cannons.

I've seen a bunch of hybrid cannons, some designs that use shells, but so far I haven't noticed any hybrid shells.
here are some plans that I've drawn up, missing some bits here and there, but I drew these at 1:30 last night :/

This is my central focus, the shell


and here is the concept for the barrel, and I still have no clue how I'm going to do the chamber, so suggestions would be great


I'm planning to pressurize it to around 40-50 psi, and I am hoping to be able to use enough explosive to propel it to the 150-200 yard range with decent accuracy. the likely propellant is propane, but I feel as if there would be better choices.

So would pvc work as a combustion chamber? if not, would adding an external sleeve be able to compensate?

and does a tennis ball have the weight to be accurate at longer ranges?
I'm assuming it doesn't, but I'm trying to design this to be paintball/airsoft field safe, it's only going to be used on other vehicles/bunkers, but missing and nailing somebody isn't unlikely, so I don't want to cause any concussions or anything.

[Juggernaut12121]

Welcome to Spudfiles!
I quite like the idea of using cartridges in hybrids, but I think you might have some misunderstanding with the operation of hybrids (either that or I misread your schematics).
Anyhow, you'll need a sparker/step up generator, they're pretty cheap, you could get one on amazon or ebay for $5-7 (Such as this one http://www.amazon.com/Step-up-Module-Hi ... B00JVJDEZE).
Along with that you'll need a spark gap (two metal wires or similar objects to allow a spark to be generated in the chamber/cartridge).

I'd highly recommend that you find and download a program called HGDT (for hybrid gun design tool), it will allow you to get a better idea of how large your chamber/cartridge should be (it's also free, by the way).
As for the chamber (the chamber is the part of the cartridge that would store the gases and contain the combustion), I'd say that you should really go with metal fittings, as PVC will not withstand high pressures or repeat firings.
Also, the solenoid valve should be replaced with a burst disk (made from a modified union).

Finally, I'm not sure whether you want the shells for a greater sense of realism or not but I feel that it would be more cost/materials/space efficient to go with a single fixed chamber rather than several mobile ones. And if you only need the tennis balls to go 150 or more yards then you may want to go with a combustion or pneumatic based launcher (albeit, one that may be somewhat larger), as it won't need a burst disk to be replaced after each firing.
Try checking around the forum for some similar tennis ball launchers. And good luck!

[Crimson]

I originally designed the cartridge for a pneumatic type, but forgot to modify it for the hybrid function
and thank goodness hgdt exists, I'm not good with trig.

The shells are for a sense of realism, and because people would just grab used balls and stick it back into the cannon, and repressurize, they're always cannon trigger happy. With the shells, shots can be regulated, and cannons don't have to be loaded from the front.
As for the price? not to much of an issue for me, I have a decent income.

[Juggernaut12121]

Out of curiosity, how were you planning to connect to cartridges to the barrel?

[jackssmirkingrevenge]

Some threads that might be of interest:

http://www.spudfiles.com/hybrid-cannons/topic21761.html

http://www.spudfiles.com/hybrid-cannons/topic19504.html

http://www.spudfiles.com/miniature-cann ... 22465.html