CB Ratios

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
ralphd
Specialist
Specialist
Posts: 192
Joined: Mon Dec 17, 2007 8:07 pm
Location: Niles Ohio

Mon Dec 17, 2007 8:51 pm

I first read that 1.5 to 1 is optimal so that is what I designed for. It was OK but when I switched to metered propane and a combustion the gun sounded like a shotgun. Recently I emailed someone who said I should try for .7 then refered me to this site. I seen his impressive videos but if I were to design for .7 then my barrel would be 9 feet long. Any advice? I have a 3" chamber that's about 115 cubic inches and my barrel is about 34" @ 1 1/2 dia.
User avatar
DYI
First Sergeant 5
First Sergeant 5
Antigua & Barbuda
Posts: 2862
Joined: Sat Jul 07, 2007 8:18 pm
Location: Here and there

Mon Dec 17, 2007 8:59 pm

If you want the best of both (i.e. sound and portability + efficiency and power) why don't you just make a few different barrels? Also, you could use a 2" barrel, which wouldn't need to be as long to achieve a more powerful ratio.

Also, this probably belongs in the combustion cannon discussion, as it is specifically related to combustions.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
BigGrib
Corporal 2
Corporal 2
Posts: 652
Joined: Mon Oct 01, 2007 11:43 pm
Location: TriCities, WA
Contact:

Mon Dec 17, 2007 9:43 pm

i use a 4"x24" chamber and a 1.5"x6.5' barrel and i love it but i would suggest useing a camlock system for interchangeable barrels
Yea, that's definitely going to get you at least a tazer.
<a href="">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
facebook.com/biggrib
ralphd
Specialist
Specialist
Posts: 192
Joined: Mon Dec 17, 2007 8:07 pm
Location: Niles Ohio

Tue Dec 18, 2007 1:06 pm

Well, I guess I can always go to 2". I didn't install a camlock but I can remove it easily. Another projectile I wanted to launch is tennis balls and thats a 2.5 barrel.

Has anyone ever tried to extend their combustion chamber? I think I can add volume by adding a threaded adapter, a length of pipe, and a cleanout. Has anyone tried this? I guess I'll let you know.
Post Reply