Steam vs Air

Post questions and info about pneumatic (compressed gas) powered launchers here. This includes discussion about valves, ratios, compressors, and anything else relevant to launchers powered by compressed gas.

Postby rdx » Wed Jan 17, 2007 1:11 pm

i`m makeing small steam cannon :mrgreen: ,steam is going to be pressurised to 80-90psi and heated wery hot... but i want to know if the steam is going to be more powerfull then same cannon used with air,and how much :?:
and valve is burst disck.
rdx
 
Posts: 51
Joined: Wed Dec 14, 2005 10:54 am
Location: Finland
 

Postby Navigator7 » Wed Jan 17, 2007 1:38 pm

yes.
Navigator7
 
Posts: 2635
Joined: Sat Jul 17, 2004 12:00 pm
Location: USA
 

Postby benstern » Wed Jan 17, 2007 6:04 pm

Better make it all metal
benstern
 
Posts: 1346
Joined: Sun Mar 27, 2005 1:04 pm
Location: USA
 

Postby An Apple Pie » Wed Jan 17, 2007 6:45 pm

Very true, PVC does not do well under heat.

What kind of size is this thing going to be? And what are you going to use to heat up the water? Propane? Coal? Wood?
An Apple Pie
 
Posts: 423
Joined: Mon Apr 03, 2006 9:05 pm
Location: USA
 

Sponsored

Sponsor
 
 

Postby Navigator7 » Wed Jan 17, 2007 6:48 pm

So then you fire it, the metal will be around 260º+, everything you touch will burn you, if all the water is not boiled off a steady stream of hot vapor will be coming out the chamber, the union may or may not be a bitch to loosen and retighten.
If the cannon is still hot it will start generating steam immediately with the addition of water....and can the projectile resist getting parboiled?

There is a lot to steam. A burst disc seems inappropriate to me....but I'm weary of getting burned by steam.
A custom made, metal, barrel sealing piston valve with blow offs is far more appealing.

I also like the idea of a steamer unit separate of the chamber. Could be run on charcoal briquets provided all the safeties are included.
A steam line charges the cannon.
Condensate is collected via a valve at the base of the chamber.
The condensate can be pumped back into the boiler with a hand pump.


Or you could just throw everything into a pit of fire?
Navigator7
 
Posts: 2635
Joined: Sat Jul 17, 2004 12:00 pm
Location: USA
 

Postby spuzi14 » Wed Jan 17, 2007 8:58 pm

Yeah, I was thinking a seperate chamber to. One for steam and then one for holding the steam. Not sure if this is efficient or anything, just agreeing.
spuzi14
 
Posts: 1235
Joined: Tue Aug 09, 2005 1:02 pm
Location: USA
 

Postby Navigator7 » Thu Jan 18, 2007 4:01 am

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by spuzi14
[br]Yeah, I was thinking a seperate chamber to. One for steam and then one for holding the steam. Not sure if this is efficient or anything, just agreeing.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

It allows for aiming the cannon better.
It's not very efficient as the steam will turn back into water and collect in the cannon.
The water needs to be drained off.
The boiler needs to be fired and kept full of water.
The cannon should be insulated.


All in all....it'd be way cooler than air.

90 psi of steam will scare the crap out of most steamers.
Depending on the size of the cannon it will sound like the screamin demons of the Indiana Jones and The Raider of The Ark when the German goons open the Ark of The Covenant.

Steam is very throaty when it makes an exit.
Navigator7
 
Posts: 2635
Joined: Sat Jul 17, 2004 12:00 pm
Location: USA
 

Postby MrCrowley » Thu Jan 18, 2007 4:45 am

Anyone see the mythbusters episode with the steam cannon? Awesome gun, thought they didnt make it very well and probably spent hundreds on copper piping.
MrCrowley
 
Posts: 91
Joined: Tue Jul 11, 2006 1:30 am
Location: New Zealand
 

Postby fullmetaljacket » Thu Jan 18, 2007 6:04 am

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Anyone see the mythbusters episode with the steam cannon? Awesome gun, thought they didnt make it very well and probably spent hundreds on copper piping.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

The one they were trying to make used water added to a hot chamber that would turn to steam instantly and fire the projectile, but there was no way of getting it to work efficiently.

The solution they eventually went for is a boiler to generate pressure that is then released into the barrel through a valve, in the same way pneumatics work. In order to replicate this system, you´d have to make sure your components are well insulated and capable of taking the heat.

Given the power acheivable with conventional pneumatic cannons, I doubt it´s worth the bother.
fullmetaljacket
 
Posts: 1684
Joined: Mon Jun 14, 2004 1:33 pm
 

Postby rdx » Thu Jan 18, 2007 7:54 am

i´m just makeing cheap test version :),chamber is 1/2l and barrel is 15mm copper pipe and valve is going to be bust disck...
chamber is 48.5mm seamless steel pipe, i lathed endcap and bushing for 1/2"threads, then my friend welded them.water is loaded through union and i will lathe teflon ring to be sure that union will not leak .
i heat the cannon with Propane or Coals. ... and if this cannon is power full and worth a lot of time then i`m makeing new and much better one =D and if somebody dont know how it works:i put little water in the chamber than i heat it ;)


...do you think i can use 0.4l co2 bottle for the chamber it would look better then the chamber that i made:?:
rdx
 
Posts: 51
Joined: Wed Dec 14, 2005 10:54 am
Location: Finland
 
 
Next

Return to Pneumatic Launchers

cron