SpudFiles

Thank you, thank you, thank you. Hopefully when we go back home we'll get the stand built for the cannon, then this beast will be showcased in the Completed Cannon section of Spudfiles.

(P.S. I was quite speechless when I found out that one of the projectiles went 833FPS )

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So this video should give a pretty decent comparison of how the cannon behaved with and without the muzzle brake. Not only was there a noticeable amount of recoil reduction, but barrel flip was reduced greatly too.

Good stuff wish I had the space to use an "artillery style" cannon, I've been wanting to make a spudgun version of the '88 for eons!

Ok. So this is a not-so-good paint image of the cannon on the stand. We're gonna try to get it done this weekend (if we can acquire the materials), but time will definitely be an issue. Currently 4x4's are the main posts with 2x6's as the form of the triangle. A 2x4 will be the cross brace and 2x4's will be the hinged rear legs. I'm still debating whether or not I'll need those legs, though. Elevation is adjusted by a trailer jack. I think it has roughly 24" of travel. I'm completely open to suggestions, so suggest away. The three posts on the main stand seem a little awkward. As I said, we're open to suggestions.

Why not put it on an axle and make it a towed cannon? With two wheels and a long towing tail you have everything you need. Sounds like your elevation is already taken care of.

We were thinking something "towable" but we couldn't figure out a way cheap/free enough to do it without hacking apart our riding lawn mower/bikes. It would be neat though. Oooooh! We do have an old wheel barrow or two laying around. I'll ask around and see what folks can come up with.

Agreed with kenbo, that configuration would be relatively simple.

McCoy,
What is the diameter of the "exit hole" of the muzzle brake and the inside diameter of the barrel?

why I haven't seen that before??? cool recoil dampening

I don't think you should follow JSR's advice... it seems more complicated but it isn't much better than what kenbo suggested...

though if you are looking for something more complicated you can try this

So the weather wouldn't cooperate with theGreater and I this weekend which means that we didn't get any work done on the cannon (or shoot it) . Velocity3x, the muzzle brake is roughly 1/8" larger than the ID of the barrel. I say "roughly" because theGreater bored it out with an air die grinder and some parts are a bit lower than others .

velocity3x wrote:McCoy,
What is the diameter of the "exit hole" of the muzzle brake and the inside diameter of the barrel?

The "exit hole" is 3.5". I was worried about the effectiveness of the muzzle brake before testing (we almost went with a 3" tee with a hole cut to the bore size), but the brake we have now works wonderfully. We didn't want to cut all the recoil out (mostly for show), but we did want to reduce it and reduce barrel flip at the same time without seriously reducing muzzle velocity.

As for the stand, we are going to hit the scrap yards and design a pivot type stand, much like the '88 and the howitzer in the previous post. All we have to do to completely fabricate the stand is find oxygen and acetylene bottles.

So we didn't get to work on a stand, but we did find one from our jet-kart project that worked-ish for what we need for now. This weekend we tried testing different propane loads. One at 70p.s.i., and one at 80 p.s.i. Of course we shot it twice at our regular load of 75p.s.i. and got the first visual understanding of how our muzzle brake works. Unfortunately the high speed camera was dead and the charger had been left at college (sadtuba), so we took a still from a regular ol' camera. Here's some pics for your viewing pleasure.

So as to further the proliferation of the spudgun, We may be using our monster cannon to help local high school students understand the properties of projectiles. I have e-mailed a physics teacher at a local school with a challenge. Four teams of students will have one or two weeks to construct a projectile with distance and accuracy in mind. After the competition, we'll let the students choose whether or not they want to put their projectile through various materials (plywood, old electronics, etc.).

I've looked at your muzzle brake and I think that it would be more effective when you turn it around. The two exhaust ports bend against the blast direction. In the opposite direction they would catch more of the blast energy IMO.

With the muzzle brake in it's current configuration, the exhaust gasses are redirected backwards so it "propels" the gun forward reducing recoil. Much like this on a .50 Cal.

It looks to me like the black tips on the exhausts direct the gases at a 90° angle to the barrel up and down and not backwards.