Fueling A 6ft Cannon

[rustlerdude987]

I'm sorry one last question which fuel will get me farther butane or propane?

[pneumaticcannons]

I've heard that propane yields slightly increased results. However, I've had no personal experience with it. The only reason you would choose one over another in your case is because of ease of metering. Propane metering is generally quicker (just open 2 ball valves) yet more expensive than syringe metering. Even though butane can be metered like propane typically is, it is seldom done for obvious reasons.

In conclusion, it all depends on your budget, time, understanding etc..... Now go make your cannon!

[rustlerdude987]

Even though butane can be metered like propane typically is, it is seldom done for obvious reasons.

I am sorry but being new to this whole subject could you please tell me the obvious reason because well it's not so obvious to me.
P.S my cannon I already built I'm just in the procces of changing it from an Advanced Spray n Pray to something more reliable.

[jimmy101]

There is no difference in the energy of propane versus butane, at least none that even a well executed spud gun would be able to detect.

There is no reason butane can't be metered. Perhaps what pneumaticcannons was referring to was that propane comes in a nice cylinder with a nice valve which is easy to interface with. Butane typically comes in a container with an inconvenient valve (like a disposable lighter).

[pneumaticcannons]

Perhaps what pneumaticcannons was referring to was that propane comes in a nice cylinder with a nice valve which is easy to interface with. Butane typically comes in a container with an inconvenient valve (like a disposable lighter).

Yup

P.S my cannon I already built I'm just in the procces of changing it from an Advanced Spray n Pray to something more reliable.

So I've heard
.......
I just saw your other thread and see you chose syringe
Good luck
Btw, for some reason, I was under the impression that your chamber alone was 6' long until I saw the other thread lol

[ramses]

The fact that the cans say 8 oz on them means that they contain 8 oz of liquid butane
liquid butane expands to thousands its original volume once in gas form @ atmospheric pressure.

most likely 8oz by weight. So use the molar mass of butane to find how many moles of butane you gave. There are 22.4 liters in one mole. You will have almost 90 liters of butane in one of those bottles at STP

[sgort87]

What diameter pipe did you use for your chamber? You said the launcher is 6', but it's not exactly clear what the chamber is like.

What I'm getting at here is that if you have a small diameter chamber, fan or not, getting the fuel mixture right is gonna suck. Long chambers work much better with multiple fans and multiple simultaneous injection points.

If you do need multiple injection points, I suggest propane. It'll be easier and more reliable.

[rustlerdude987]

the chamber is a 3" x 24" so i think im just going to inject butane. I just put in a 60 mm chamber fan yesterday and it works wonders.