Search found 1575 matches

by Moonbogg
Fri Jan 02, 2009 2:00 am
Forum: Combustion Cannons
Topic: Hybrid safety valve
Replies: 19
Views: 1091

Some stupid kid would not know how to make it go... Do you realize just how complicated it is to 1) put in a very strong burst disk 2) meter out the correct amount of propane 3) get a compressor and fill it to exactly the right pressure 4) fire it Nobody who picks it up, who has not been given a lo...
by Moonbogg
Thu Jan 01, 2009 9:43 pm
Forum: Combustion Cannons
Topic: Hybrid safety valve
Replies: 19
Views: 1091

Well I am concerned because I want the cannon to be idiot proof. If some stupid kid gets ahold of it and doesn't like to follow directions, hes going to add his own burst disk, or pile them up, then fill the cannon at 10x when its only designed for 2-3x.
by Moonbogg
Thu Jan 01, 2009 8:18 pm
Forum: Combustion Cannons
Topic: Hybrid safety valve
Replies: 19
Views: 1091

Hybrid safety valve

Is there a kind of burst or high flow blowout valve that can be used to ensure chamber pressure doesn't go too hi? I know there are pop valves, but I don't think they would vent the gas fast enough to prevent a dangerous pressure spike. Maybe a large coupling for a special safety burst disc would wo...
by Moonbogg
Mon Dec 29, 2008 12:42 pm
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Thanks, i'll definately use that. I didn't even know it existed.
by Moonbogg
Sun Dec 28, 2008 5:28 pm
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Well sealed, looks like I need to use a burst disc with anything besides a standard 1x mixture. That would be a given. What kind of chamber pressures could I expect from a 2x hybrid? 200ish psi, + or - ... :wink: Oh good. I am using Solidworks to run stress tests on the chamber, and I am using 300p...
by Moonbogg
Sun Dec 28, 2008 4:04 pm
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Oh OK. So compressed air is just cheaper and always available. Seems easier to calculate also. What kind of chamber pressures could I expect from a 2x hybrid?
by Moonbogg
Sun Dec 28, 2008 2:29 am
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Why dont people use pure O2 instead of air with hybrids? You could cram a lot more fuel and O2 into a chamber than you can fuel and air. So, for the same chamber PSI you could have 80% more combustion taking place, right?
by Moonbogg
Sun Dec 28, 2008 2:10 am
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Adding another 21% chamber volume of O2 will raise the overall pressure but not as much as if you used air. Be sure your chamber is well sealed. Don't worry about DDT with this setup. You've still got lots of nitrogen to buffer out your ignitions. Yes, go with at least a couple of gaps... spread eq...
by Moonbogg
Sun Dec 28, 2008 2:09 am
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Using a 83.2% oxygen/16.8% propane mixture will give you an adiabatic pressure of about 260PSI, roughly the same as a 2x hybrid mixture. If you're looking for the best performance without using a pump or compressor, just eliminate the nitrogen from the picture, and use a pure oxygen atmosphere to b...
by Moonbogg
Sun Dec 28, 2008 12:51 am
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

You would use 21% of your chamber's volume for the O2 shot into the chamber, just like you use 4.2% propane. That would give you 2x worth of O2 counting the ambient fresh air to start. Is this assuming the chamber remains at 0 psi? Injecting 21% of chamber volume with O2 will displace air if the pr...
by Moonbogg
Sat Dec 27, 2008 10:58 pm
Forum: General How-To & Discussion
Topic: Low mix hybrid vs oxy/propane
Replies: 14
Views: 536

Low mix hybrid vs oxy/propane

I have designed a steel cannon and was going to use basic propane combustion. I now want to make something with a little more power than a regular advanced combustion and get the most out of the steel, but not something so powerful that spuds and other common ammo will vaporize in the barrel. The go...
by Moonbogg
Sat Dec 27, 2008 12:45 am
Forum: General How-To & Discussion
Topic: Propane Bottle Adapter
Replies: 7
Views: 1168

I knew it had to exist
by Moonbogg
Fri Dec 26, 2008 2:15 pm
Forum: Pneumatic Cannons
Topic: Building a new cannon
Replies: 24
Views: 1417

LOL thats a friggin total beast. Awesome. Also, I wish I was good at welding. I know how as I took classes, but...
by Moonbogg
Thu Dec 25, 2008 12:53 pm
Forum: Combustion Cannons
Topic: Ranges of other people's Advanced Combustions
Replies: 15
Views: 966

High Energy: http://www.youtube.com/watch?v=sdFK5eVmZ3o&feature=related Just saw this now. Sorry to resurrect the thread, but had to say thats a BIGASS gun! Oh yeah, I've only made one gun. Its an advanced combustion and potatoes will go what seems like 200 yards or so if the shot is lucky, meaning...
by Moonbogg
Thu Dec 25, 2008 12:19 pm
Forum: Combustion Cannons
Topic: A glimpse of whats coming
Replies: 9
Views: 626

Looks good so far. You do know this can be easily built with PVC without going to the expense and trouble of metal construction.... Damn voices of reason. It was fun to design, but its gonna cost so freakin much i'm afraid to even bother getting quotes. The metal might be useful for a stronger type...