Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
stevenarroyo wrote:i try to find pictures of the spark gap.
and ya i didnt add the 2 elbows into the math.
I just did a quick and dirty and it looks like you're somewhere in the 1.6-1.7:1 range. You need to account for another couple of chamber inches in your couplers on both ends as well.
Another foot or 2 on your barrel would make a noticeable difference in your performance.
Well you won't in it's present configuration. You could cut the barrel off and replace it with a cam coupler or PVC screw adapter and would allow for removal of your barrel. I was really being more rhetorical about lengthing your barrel.
By my rough calc, you have 110 - 115 CI of chamber volume including the rear U and about 68 CI of barrel volume.
OK i an just going to leave it how it is.
finish my big cannon I've been working on for some time and then maybe make one more before i leave to study.
OK that's fine. You could easily build another strip that incorporates dual gaps....another noticable performance improver....center of the chamber spread equidistant from the ends.
In looking at your meter again, it does seem a little largish for your chamber so a relatively low psi setting for the meter pressure seems reasonable. I have a meter about the large on a gun with about double that chamber size and requires about 70 psi.
Nice look! I really like the way the handles are configured. You should really come up with a way to house the propane tank on the gun somehow. Perhaps attach it to the 180 degree elbow vertically so that it won't flood your meter.
Did you use glued PVC on the elbow or threaded, it looks glued. The reason I ask is it's kind of nice if you need to improve or change something if it's threaded rather than fixed. Makes it a lot easier to change the barrel size, length and configuration.
One last thing that hasn't already been asked, how does it shoot? Do you have any damage shots?
thats good to know, i have not fired a potato out of mine, am planing on doing so soon. maybe tomorrow?!? i dont whenever i do i'll record it and show every1 here
yes i like how the wiring is all clean and does not show to much of it
