my new super project

[jetpilot]

<a href="http://img388.imageshack.us/my.php?image=pcj3viewportsxx8.png" target="_blank"><img src="http://img388.imageshack.us/img388/8111/pcj3viewportsxx8.th.png" border="0" alt="Free Image Hosting at http://www.ImageShack.us" /></a>
***CLICK TO ENLARGE***

these are some of the photos i screenshot from my CAD program.
heres my idea, the barrel is pretty much the length of the cannon, the chamber is surrounding it with an endcap on the end the barrel extends out(as seen on bottom right pic of viewport). these gasses will have no other choice but to expand in the opposite direction of the potato's trajectory and then expand into the barrel direction(as seen on top right pic of view port).
this is probably very confusing, but i hope the pic helps.
i got this idea from how a space shuttle boosters work.
<a href="http://img403.imageshack.us/my.php?image=rocketengineww9.png" target="_blank"><img src="http://img403.imageshack.us/img403/4053/rocketengineww9.th.png" border="0" alt="Free Image Hosting at http://www.ImageShack.us" /></a>
thats how i got the idea.

[SpudMonster]

You have just reinvented the coaxial combustion cannon.

http://www.spudtech.com/images/products/Coaxial-2.jpg

[An Apple Pie]

Already been done, although I am impressed at you coming up with this by your self.

SpudMonster- I have never really understood how that cannon works. I mean when you screw the cleanout cap on it looks like it would be hitting the end of the barrel.

[c0mpl3x]

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by An Apple Pie
[br]Already been done, although I am impressed at you coming up with this by your self.

SpudMonster- I have never really understood how that cannon works. I mean when you screw the cleanout cap on it looks like it would be hitting the end of the barrel.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

rofl i totally agree

[benstern]

Na, remember the clean out cap has that square hollow space?

[An Apple Pie]

Oh, I never realized that. Doesn't that decrease flow A LOT? I mean all the air has to squeez through a very small opening, doesn't it?

[jetpilot]

well yea i didn't quite think about that untill i went to bed, it would probably be smart to possition the barrel a good foot away from the cap, as to not turn your potato cannon into the worlds largest firecracker.

[aturner]

It does not affect flow, performance, or safety. It's fine.

The only thing I don't like about the standard coaxial combustion design is the clearance between the chamber and barrel. The clearance is a bit tight, and I tended to scrape up my knuckles on the threads on the chamber cleanout when reloading. Therefore, I extended the barrel breechward and built a chamber extension for the blackhawk...
http://loose-cannon.home.mindspring.com/blackhawk/

[An Apple Pie]

It is also almost imposible to use arosol fuel. It is hard to get it spread out through out the entire chamber.

[nicholai]

I like that propane setup you have aturner. Thats pretty cool to use a grill tank solely for your spud gun!