SpudFiles

Hello Folks!

This is a post I made on a machinists forum, so bear with me a bit.

I saw a post about someone wanting to rifle a barrel for a PVC potato cannon in search for a solution myself. My friends and I had this idea to make a potato howitzer. We're taking this pretty seriously.

These are the details:
Rifled PVC sched. 80 barrel, 2"
Precharged shell w/ 3" combustion chamber
4" chamber (shell-holding)
Threaded elevation adjustment
Firing mechanism is electronic with spark plug
Muzzle break serves no purpose

For the potato-kings out there;
I'm going to use starter fluid as the propellant
barrel will be 4 feet long,
The name is 100% inappropriate, but rightly fitting. Initials are PI

Here's the solidworks working sketches;
The shells imaged in the second photo are a little too long, and the A-frame is gonna be a tad different. We're trying to model something like the M119 but with split-legs. Don't bother lookin it up, it doesn't nearly resemble it.

Here's the cutter I machined without the blades made just yet. We're going to try and make a triangular "cutting" rifling.
This is what I just made on the forge. This will be welded to the threaded rod on the cutter. A jig will be made to guide the twisted plate into the barrel, which will be clamped to the end of the pipe.
I'll update this post if it interests anyone, otherwise I'll be posting results here:
https://www.facebook.com/nu.slxw

I am asking for feedback, idea, help, anything you can give me. I'm not 100% sure this is all gonna work, especially the rifling and the shells concept.

With highest regards,

Mr. Pyle,

You obviously have some skills, BUT....

Mr. G Pyle wrote:Muzzle break serves no purpose

It's muzzle BRAKE...not BREAK....in this case, one reduces recoil...the other just makes gunny angry.

Get it right or gunny will have you doing pushups until you're old and grey.

Seriously though....looks like a cool project. 8)

This is the rifling jig so far

This isnt a Howitzer but when i seen this cannon for some reason i thought of your post. I found this on youtube some website that builds things and puts the how to videos on youtube called sonicdad.

This version is for carbide but i dont see why it couldnt be scaled up and used with a different fuel to propel potatoes.

I bought about 90% of the parts today for the carbide version im planning to build it this weekend.

Its got a little ball pump built into the design to replenish the air, or to add air to the mix wich i found interesting.

Here is what mine looks like



And it tears down for easy transportation.

OK so there's a good part of it built, I'm makin the door and a closed firing mechanism now. Here's a link to a video with the first firing.



Did NOT expect to hit the target, and no, it's not supposed to recoil. I wish though...

thats cool

BowerR64 wrote:thats cool

+1 looks cool

This is really neat as it allows you to make precharged hybrid shells without always having to change the burst disk on the cannon. Make a bunch of shells that have replaceable burst disks and have a field day!!! Later on that night you can reload your shells.

One question through. How do you pre charge the shells? A standard thread-in type shrader valve wouldn't be heavy duty enough for a combustion let alone for a hybrid. I may consider this idea for my mini Sherman tank. It'll definitely look more authentic being able to breech load cartridges.

I thought of a good idea for the ignition so you're not always hooking up wires to the shell. Two rings made of copper, brass, steel or any other conductive metal strip would line the outside of each shell spaced 1cm apart and be screwed or glued on to it. Each ring would have one probe going inside the shell. These rings would touch two contact points inside the breech. The contacts would be wired to your firing control box. No matter how your shell goes in there would always be two points of contact, this off course would be a little more work but totally authentic looking!

This is the final build post. I scrapped those canisters for an even simpler shell, but there's no way to make it hybrid, only combustion.

http://www.spudfiles.com/combustion-can ... 25895.html