SpudFiles

It’s been quite a while since I posted anything (seems like around two years since I posted any type of cannon). Though I’ve made the occasional thing here and there, college applications and subsequently being at college have consumed most of my free time. I finally found some time to make something. Anyways, enough of that…

6.3L Wogglecannon

<img src="http://a.imageshack.us/img688/9687/sideviewl.jpg" border="0" alt="Photobucket"></a>

Despite being in the game for what must be seven to eight years, I have never made a combustion. Until now.

Few Pictures:
<img src="http://a.imageshack.us/img62/8844/frontviewi.jpg">

<img src="http://a.imageshack.us/img405/2638/withbarrel.jpg">

<img src="http://a.imageshack.us/img121/7093/sideviewoutside.jpg">

<img src="http://a.imageshack.us/img842/1926/fand.jpg">

<img src="http://a.imageshack.us/img217/5408/meterview.jpg">

And a <a href="http://s94.photobucket.com/albums/l112/ ... ">video</a>
(warning: may contain abrasive language)

The name “Wogglecannon” comes from a nickname for our beloved golden retriever, who passed away a few weeks ago to stomach cancer. May she rest in peace.

Here are the basics:
Chamber:
*4” SCH 40 x 24” (~6.3L)
Barrel:
*3” SCH 40 x 72”
*3” SCH 80 x 72”
Features:
*One-touch onboard propane metering
*Camping chamber fan
*Camera Flash + Automotive coil ignition
*3” aluminum camlocks
Meter Pipe:
*65 mL volume
*Regulated to 60 PSI

Building a combustion was a completely new experience for me; I definitely ran a few unforeseen problems.

<img src="http://a.imageshack.us/img713/5402/electronics.jpg">

The first was the electronics. Stuffing all of those components into that small project box was a challenge. In that 2.5”x3”x5.5” box, I’ve got two momentary switches, one on/off toggle switch, the internals of a disposable camera, an automotive relay, an automotive coil, and a whole mess of battery clips and wires. Filling the box was made more difficult by the fact that the camera flash circuit kept burning out. I eventually chose a momentary switch for charging the camera flash circuit instead of an on/off type. If the circuit recharges too frequently in a short period of time, it’ll burn out. The on/off type switch facilitated this problem, for as soon as you hit the fire button, the camera flash circuit would recharge.

<img src="http://a.imageshack.us/img705/5430/threescrews.jpg">

Attaching the project box to the combustion was another issue. I eventually secured it using three screws. The two outside screws act as the electrodes. One of them is drilled out, and a paper clip is soldered into the screw. The paper clip is then bent and put in close proximity to the other electrode. This system allows me to adjust the spark gap, which is beneficial, for (as I have heard) the electrodes can erode over time. The center screw is also drilled out, and the two wires for the fan go through the screw.

*****

I was always into the pneumatics, thinking that combustions only had a limited potential power-wise, whereas you could always crank up the pressure on the pneumatics. However, on my larger pneumatics, I was always afraid of pumping the pressure too high because of the danger of a failure, which is more likely to happen with the sustained pressure associated with pneumatics. While this combustion probably generates a similar high pressure, it is only for a split second.

Shoutout to a couple of members who inspired me for this project. Most notably:
*Sgort, for the one-touch metering system (seen on his Blue Flame III)
*Starman, for the color scheme (seen on his Triple Thunder Noise Cannons)

looks great, especially for a first real combustion effort. I love the one touch metering, ATM I'm looking into one touch metering for hybrids, but its purely conceptual. I have no combustion plans for the time being

Looks good, but surely you can do better than a bit of foam also, aren't you tempted to put a burst disk in that camlock and pressurise the chamber to 15 psi...

I just watched the video, and it seems you only use the fan for short bursts; Burntlatke proved that combustion performance is better when the fan is left on the entire time

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Thanks for the responses everyone.

With regards to using it as a 2x hybrid, I am surprisingly not inclined...mostly due to the larger diameter pipe, the (thinner) SCH 40 thickness, and to the electrodes being drilled through the pipe alone. I'm a scardy-cat when pressurizing my pneumatic (which has a 3" SCH 80 chamber) to above 60 PSI, so you can imagine the convulsions I'd go into if I turned this guy into a hybrid.

Before I can upload some better shots with better projectiles, I need to find a suitable place to fire. This thing is loud (ears ring when putting on a pair of (probably cheaper) noise suppression headphones (like the ones they use when shooting real guns)). I'm also not so sure how happy my parents would be if I shot a concrete filled can or something like that in the video instead of a piece of foam .

I'm not surprised that keeping the fan on would improve performance; however, this fan drains 9V batteries like nobody's business. I'll take a look into rechargeable batteries, and maybe then I'll keep it on during the combustion process.

I tried to work some LED's into the project box, but, as you mentioned Spudblaster15, I am pretty short on room. I don't have a lot of electronics experience, and thus I'm not really sure where to wire the LED into the circuit. I tried to use the the original LED (used on the original disposable camera as a flash indicator), but I didn't have a lot of success.

I've been doing a lot of thinking about the rear vent. Removing that 4" threaded endplug is NOT fun, especially when you accidentally tighten it too much. It seems to be a much more natural motion to twist the plug to the right than to twist it to the left when using my right hand, making venting a struggle at times. I considered a ball valve vent, but that is a little too bulky for my taste. I also considered building a <a href="http://www.launchpotatoes.com/index.php ... Id=50">pop vent</a>, but I know I would end up standing the cannon up by accident and breaking it. I have an idea for a twist type of vent. I'll drill two 1" holes in the endplug, and then, by means of a disc in the endcap that can be rotated from the exterior (either by a handle on the plug itself or something built into the female adapter), a simple quarter turn will allow the user to vent the cannon, and another turn to seal it up. I'm still considering a few designs, obviously trying to pick the most reliable and durable. When/If I make that upgrade, I'll definitely post it.

I understand your concerns, my suggestion was more along the lines of me being a little hybrid-mad of late as opposed to any practical advice

Looking forward to some proper damage at a later date

BTW, where did you get your three-way valve. I'm having trouble finding one with a third threaded port

Good stuff, I've got a set of 3" camlocks sitting on a shelf that I'd love to put to use in a combustion like this.

nice cannon I'm building one just like it and i mean JUST LIKE IT the only use a real PC fan and no three way valve. and sorry a bout woggle i lost a cat once.

Hey man thanks for the shoutout. Don't worry about a 2x hybrid...a 1x will amaze you.

Get some 3" scotch Blue masking tape, 7 layers criss-crossed on that male camlock and neatly trim the edge with a sharp knife. At the 3" opening, that comes to about a 65 lb break pressure...just perfect for a 1x'er.

Get a couple of rubber belt oil filter remover tools to get that plug out of the back. I'm with Spudblaster, build up a ball valve vent for that rear. Handier for venting and safer too. And, a beefier power supply will make life a lot easier on you as well. Some rechargable hobby batteries are the way to go.

Beautiful cannon!! You can also try it as noise cannon with a blank male camlock burst disked up.

You do realize that using an automotive relay is completely unnecessary in this circuit right? All that they do is prevent voltage drop by using an electromagnetic switch to open the circuit. In this case, you should have used a transistor, they are a million times smaller and will do the same thing.

Hey, Velocity finally built a combustion and I MISSED IT???

Sorry Velocity, I've actually been waiting for this cannon for quite some time but, like you, I've been busy with school and work.

First up: looks excellent! The metering system is a nice touch as well although I would suggest setting the regulator properly before using it for multiple shots (set pressure initially with ball valve open and three way filling meter pipe, inject to reduce pressure, and adjust until it returns to the same pressure every time). A little tricky but these air regulators aren't the most accurate things in the world...

On your electronics: very functional, but you might wanna consider some perfboard if you feel you're strapped for space. Might no be worth it now that everything is installed, but it does wonders for making compact circuits.

Other than that, it looks great and I hope you see this post before you slink off again.