SpudFiles

Oh you.

Stop mocking!

DYI, I am impressed. Looks like you used some pretty energetic fuel and some oxidizer. I presume that is your fuel tanks in the shot. Very impressive shot. That would have been LOUD.

DYI, I am impressed. Looks like you used some pretty energetic fuel and some oxidizer. I presume that is your fuel tanks in the shot. Very impressive shot. That would have been LOUD.

The fuel was propane, at 30X. The tanks you see are oxygen and nitrogen. The fueling order was propane, oxygen (to ~120psi chamber pressure), then nitrogen to bring the pre-ignition pressure up to 250psi.

The acoustic properties of that particular test area were excellent for damping noise, hence the lack of an echo. Fired in my older testing area, it sounded worryingly loud from 2km+ away. At the 50m distance I tended to activate it from, the concussion was felt as a sharply defined, coherent impact, and would certainly have been over the threshold of hearing damage for unprotected ears. It didn't compare nearly so well to any spudgun I'd built before as it did to high explosives.

As cameras are terrible at capturing the audio effects of loud noises, I felt that, for the purposes of a contest, visual effects were more valuable. The shot in the video is the only time the cannon was fired without its stand, lying on the ground, and I thought the dust cloud it kicked up around the muzzle (and the wide, shallow crater it left behind, which is still visible 2 years later) was fairly interesting.

Hey DYI, you don't have any still images of the target do you?
That was quite impressive for half-power(And I though my big combustion kicked up dust!).

Also, I find that setting up a camera for dedicated audio recording works well if you place it some distance away.
The majority of what makes a cannon sound impressive is the echo, which most cameras can hear just fine if they don't have to recover from a point-blank shockwave.

Not my shot, but I found this holiday air cannon shot.. Enjoy
[youtube][/youtube]

*Insert swear word of choice here.*

After some tests this morning, I find all of my launchers are out of commission, dangerous to the point I'm not going to use them, or still in build stages and completely untested.

I had hoped for a last minute entry, but short of making a longbow from scratch in the next few hours, I'm afraid I'm out of this.

I am a noob, but thought i may as well post this considering there is less than 1 day left and I am not going to film anything better. This is my entry. shooting a 15mm marble at a can of coke
[youtube][/youtube](how do you embed?)

You highlight the direct link Youtube provides, then click the Youtube button.
Edited by jrrdw, embedded video.

Nice mess you made caz259, who cleaned it off the side walk? LoL...

Hahaha, it was in my back yard, the dogs do a very good job but they dont like the gun much.

@tech Ultraslow is on my subscriptions, I watched that video already. But, it would be a fun way to stuff a turkey

@caz not a bad shot at all What camera was the video shot with?

[youtube][/youtube]
This is my last minute entry.

the video was shot with a casio ex fc-100, another shot that i was contemplating putting up is my egg shot ( which i am not entering into the contest because the overall vote with my friends is the coke is cooler

caz259 wrote:I am a noob, but thought i may as well post this considering there is less than 1 day left and I am not going to film anything better. This is my entry. shooting a 15mm marble at a can of coke

I like how you can't see the marble until after it exits the coke can, and bounces off the fence.

It does look very cool, just a little puff of air with something so deadly inside it 8)