Here are the pics I promised. The combustion chamber contains a piston with o-rings around the perimeter. It is backed by a spring assembly which allows the piston to travel back but keeps the unit as one piece. This makes the unit easily removable to reload. The backing plate on the other side of t...

Ah yes got it! Sorry, I somehow missed that part. A 5X mix should be doable with a small 12v compressor I think and still gives me the performance I'm looking for. I crunched more numbers yesterday and realized how expensive it will get running oxygen. So as I initially thought, I have no choice but...

Somebody please chime in on my previous post. I'll be going to buy materials tomorrow and don't want to screw this up. Also, what kind of calculation do you guys do for metering chamber losses. I imagine that as soon as I open the valve on the metering chamber to fill the combustion chamber some pre...

It would be nice but is just not practical in my application. My biggest thing now is figuring out fueling. I have already determined the ideal combustion chamber size using HGDT and from what I'm understanding it looks like I need fuel at 4% chamber volume give or take a bit. Plus a 1:4 ratio of fu...

I have considered preloaded cartridges but then each one would have to be the size of my combustion chamber would it not? It would get pretty expensive to make that many 4"x6" DOM cartridges. And I dont think I'd have that much room inside the tank. I could always make them longer but smaller diamet...

Thanks for the reply, I did not mean running oxygen through a compressor. I meant that I would add my propane/oxygen mix to the combustion chamber and theb pressurize the mix with air,to whatever pressure necessary to obtain a 10X mix, but trying to avoid having to use a compressor period so I may j...

Ok good, so that gets me closer to my goals. Now is it safe to say that when I take the 5X mix and pressurize to 2X atmospheric (which would be much easier than pressurizing to 10X with just air) that I will get the same effect as 10X? This would mean that I will still need a compressor and burst di...

I just realized something. Since this was supposed to be Oxy/Propane or Oxy/Mapp do I need to go with a hybrid setup? The reason I thought I did was because HGDT does not account for Oxygen in the mix. Just propane or mapp so the performance numbers were really low. So now I have to figure out what ...

I need it to be coaxial and breech loaded so a piston may be out of the question.

Definitely considering it but it is very hard to do right using all DOM construction without a lathe.

This is in relation to my previous post in the combustion cannon discussion. To sum it up, I have to build a cannon for a tank, yes you read that right...A scaled down M4 Sherman tank. It will be made of Sched 40 to 80 DOM tubing and will be all welded together. Fuel will be Oxy/MAPP or Oxy/Propane ...

Well I've been running some numbers and according to HGDT the performance I've been looking for will not happen from a regular combustion cannon. It looks as though I will have to go hybrid on this one which brings fourth another set of obstacles I have to factor in. First being a method to quickly ...

This is awesome and really good info to start with, thank you. I will keep this post updated as I go. As said before this wont happen for a while but I better start researching now. Going to download these two programs for now and play around.

Before I start I will add that I understand the dangers of what I am doing and accept all responsibility should anything go wrong. Over the last little while I have been gathering a few things for the tank build (I'm building a 46% scale M4 Sherman tank incase I didn't mention this before) One of th...

Well gentlemen, in reference to my previous post: http://www.spudfiles.com/spud-cannon-related/topic25937.html I have decided that a combustion cannon is the way to go. The only issue now is the type of ammo I will use. Golf balls are out of the question because they're way too big for the type of c...