SpudFiles

Hello all at spudfiles!

This is my 1st spud cannon, I got the plans from http://potatocannon.nodice.org/cannonV3.html

4 inch chamber : I calculated to be 240~245 cubic inches
2 inch barrel : I calculated to be about 125 cubic inches

1st type of fuel I used was gumout starting fluid. Unknown weight of 1st spud I shot, but from a vid I shot shooting it for the 1st time, it traveled about 5ft in 1/30 of a second (1 frame from my 30fps vid). Which calculates to 150 feet per second or 102 miles per hour.

I'll link to my YT vid once it's done uploading.

welcome to spudfiles!! thats a nice looking gun you've got there. are you going to paint it? it looks very similar to the first one i made. propane is a much better fuel so try that. also concider upgrading this one to an advanced .. or for your next build ..you'll like it much more . again welcome & keep em coming

Youtube of the vid =)



How or what would I do for an upgrade? I know propane would be a better fuel, starter fluid is what I had at home.

Joshatdot wrote:Youtube of the vid =)



How or what would I do for an upgrade? I know propane would be a better fuel, starter fluid is what I had at home.

well some of the things you could upgrade would be:
a) make the barrel about twice as long as it is now

b) add a propane metering system http://www.wonderhowto.com/how-to/video ... er-210166/

c) add a chamber fan http://www.burntlatke.com/fan.html to mix your fuel evenly throughout the chamber

d) finally add a more powerful ignition source so you can wire multiple sparks

Sweet idea for an chamber fan! I got many lil fans from old PCs.

After looking at some of the launchers here, I got to Google'ing stun guns. There's this one site that has many diff kinds, and one as little as a lipstick container!

I am at lunch, and will look into more upgrades when I get home.

Thanks for the suggestions =)

spudtyrrant wrote:well some of the things you could upgrade would be:
a) make the barrel about twice as long as it is now

b) add a propane metering system http://www.wonderhowto.com/how-to/video ... er-210166/

c) add a chamber fan http://www.burntlatke.com/fan.html to mix your fuel evenly throughout the chamber

d) finally add a more powerful ignition source so you can wire multiple sparks

How do I determine how long of a propane reservoir I would need for my chamber? I plan on filling the handles with Great Stuff mind you, so I am guessing the chamber would be about 226 in^3.

edit: I guess it doesn't really matter, as the PSI also has an effect on how much goes in the chamber.

I still need to figure out how to use a mini stun-gun as an ignitor.

ow do I determine how long of a propane reservoir I would need for my chamber?

Well i think it should be about 4% but it goes into decimals.

I still need to figure out how to use a mini stun-gun as an ignitor.

There is a good guide on how to wire up a stungun for a cannon. I'll try to find a link.

From what I found on Google MSDS & wikipedia.org, Propane needs to be a mixture of about 2.37–9.5% to air. I'd guess middle of the road would work best, so about 5.8% of propane to air.

I am guessing once I fill in my extra handles, the chamber should be about 226 in^3, 226 x 0.058 = 13.108, so I would need 13.108 in^3 of propane for my chamber. If I had a 13.1" length of 2" Black Iron Pipe (and subtract any in^3 added from other fittings, pressure gauge, and what not) that would work & 14.7 atmospheric pressure (sea level).

Or I could double the PSI to 29.4, and have a 13.1" length of 1" BIP. Or 26.2" length of 1/2" BIP @ 29.4 PSI...

Joshatdot wrote:From what I found on Google MSDS & wikipedia.org, Propane needs to be a mixture of about 2.37–9.5% to air. I'd guess middle of the road would work best, so about 5.8% of propane to air.

I am guessing once I fill in my extra handles, the chamber should be about 226 in^3, 226 x 0.058 = 13.108, so I would need 13.108 in^3 of propane for my chamber. If I had a 13.1" length of 2" Black Iron Pipe (and subtract any in^3 added from other fittings, pressure gauge, and what not) that would work & 14.7 atmospheric pressure (sea level).

Or I could double the PSI to 29.4, and have a 13.1" length of 1" BIP. Or 26.2" length of 1/2" BIP @ 29.4 PSI...

There was some testing done of the ratios that do ignite. For the most power, Look up Burnt Lake in Google.

I think its 4.2% and there are complete guides (burnt latke) on how to make fuel meters and there are software programs that calculate everything for you, such as the fuel tool download at burntlatke.com.

Oooohhhh, sweet site, burntlatake.com, so much great info!

The Fuel Tool Live is just EZ & handy!

Nice cannon for your first! As has been stated, propane is the fuel of choice...cheap, plentiful, easy to implement. You'll need a way to ventilate the chamber between shots, a PC fan and a way to meter your fuel.

Take a look at Trip Thunder for external metering ideas.

On the burntlatake LP fitting & meter pipe stuff...does anyone have a full pic of what it all looks like? I can't tell what is what in the pics on that page. In the link provided by spudtyrrant, the vid is very EZ to follow.

Also does the meter pipe measurement take in account additional in^3 from the T fitting for the press. gauge? I happen to work at a ACE Hardware store, and the only press. gauges I can find screw into some fitting similar to this http://www.usaindustrialsupply.com/cata ... -2C500.jpg


edit: DOH, I didn't realize BL's pics were clickable for larger ones. Oh, so the regulator & gauge are on the bottle part, ... oh I see =)

where does one get a small propane tank for a spud gun

kevin11 wrote:where does one get a small propane tank for a spud gun

Did you try looking at a hardware store...

Next time, research before you post or your post will be deleted.
Also, don't 'hijack' other topics by posting your own, irrelevant question in them.