What different in Combustion and Pneumatic?

[spudd]

What is the major difference? god and bad? in two same sized cannons

[potatoflinger]

Well, combustion cannons only create a pressure of about 50-70 psi., when a pneumatic cannon is using 100 psi (most of the time). The only bad thing about pneumatics is that unless you are using a triggered burst disc, the valve is taking away some of the power. Either way you look at it, pneumatics have more power, but less portability.

[hi]

if you do it right a combustion is entirely self supportive, but a pneumatic requires a pump or and air compressor.

presonally like both, but enjoy making pneumatics better. in the end pneumatics are more powerful, but there s a limit to them, which is where hybrids come in.

[f.c]

if i where you i would build a combustion for my first. as pneumatics have little to no portability and combustions are completely self supporting.

[potatoflinger]

Another thing you may want to think about is price, it will probably cost you less at first to build a combustion, but since you have to buy fuel, a pneumatic could wind up cheaper in the long run, depending on how much you use it.

[frankrede]

I built a nice piston pneumatic for only $50.
and thats including a sprinkler valve too.

[bassmaster1228]

omg dude...............u got to be kidding

[spudd]

I have built a mini combustion but it was crappy power so now ive found a small 13 bar tank and going to build a pneumatic with that. We got a really huge compressor at home that loads 14 bar or 196psi.
But i wonder if i put one of those quick conectors on my tank it will leak some air when i realease the air hose from the compressor?
And if its dumb to use a ball valve.

[jackssmirkingrevenge]

And if its dumb to use a ball valve.

With that sort of pressure available, if you have a long enough barrel and big enough tank, even a ball valve will give you decent power - though if you can get yourself a sprinkler valve or QEV it will be better and more practical.

[Redcoat]

Put it this way.

These are two videos of relatively same sized cannons.

One Combustion:
[youtube][/youtube]

One Pneumatic:
[youtube][/youtube]

Well you can tell which ones more powerful and there oth the same distance.

Happy Spuddin'

[spudd]

That pneumatic seemed to have more power, thanks for answers but keep writing all you guys know about those cannons, it can be helpful for others to decide what type they should build.
And what speed can i get in a pneumatic or combustion, Meter per second?
I saw a AK-47 reached 700m/s

[jackssmirkingrevenge]

In practical terms you will never get more than the speed of sound, typically less than 350 m/s. Some small calibre long barreled pneumatics get close to or exceed this figure by a little, but I'd say your average spudgun would do around 150-200 m/s.

[DYI]

A large enough combustion can exceed the speed of sound due to the hot gases that are generated, and a pneumatic using high pressure helium, hydrogen, or steam, can exceed the speed of sound by a large amount if it is done properly.

On the practical side, you will most likely not exceed the speed of sound with any normal, portable launcher running on normal, sane pressures. The highest velocity that I have ever heard for a spud gun is over 1500 fps with a golf ball fired from "FEAR", a ~60' long, 4x hybrid.