Put the barrel inside the combustion chamber!

[magnum9987]

I was thinking about making my guns compact, like a rocket launcher. So i thought "Couldnt you put the barrel inside the combustion chamber, to shorten the total length?" This would make it ideal for airsoft/ combat use. It may also allow for breech loading, as the cap of the combustion chamber would also hold the round in. Steel Wool would still allow the combustion to go off (Someone also gave me the idea of titanium or iridium wires). So a combat spuddy design could benefit for this.
(Do not remind me that I still cannt build a spudgun, I'm just discussing this design.)

[brogdenlaxmiddie]

yeah... Welcome to the ideas of coaxials.

[magnum9987]

thats what they are? DAMMN!

[Sticky_Tape]

I am positive it was done by spuddin.

[Pilgrimman]

What you've described is a co-axial design. Be warned that it is hard to get these to work as combustions, especially if you intend to make it spray & pray. As for Iridium wires, be ready to shell out the $, as Iridium is fairly rare.

[magnum9987]

dont have to rub it in my face! god!

[brogdenlaxmiddie]

Plus, why would you want to spend the extra money on something not needed? Especially on wiring???

[sirspuddest]

Plus, why would you want to spend the extra money on something not needed?

That's spud gunning for ya.

[MrCrowley]

Someone made a telescopic combustion once, I think it was sgort87 I can't remember.

[frankrede]

Someone made a telescopic combustion once, I think it was sgort97 I can't remember.

IIRC it was, it also helt the fuel and some balls in the cannon too.

[starman]

Why all the esoteric ignition materials? Why not just go with a BBQ ignitor and 1/4" spark gap?

A coaxial combustion is possible, just a little more build difficulty. The only advantage is you can hide some length of your barrel. Keep in mind you'll also be stealing combustion chamber volume.

Just some things to theorize over...

[SpudFarm]

hmm scottrete did that also didn't he?

[DYI]

Just remember that a lot of the power in propane combustion lies in the heat it generates (the molar increase isn't very significant, 1:1.2). By putting the barrel inside the combustion chamber, you have more surface area for a given chamber volume, and therefore more heat loss. Heat loss is not your friend in this case, and this is why coaxial combustions are uncommon.