Props Promo Tee-shirt Delivery Unit

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Here's a quick model of the valve as I'm working on it now. th_valve-1.jpg
The chamber would be to the left, the barrel to the lower right, and the upper right would be plugged, with a tap to fill the chamber, which would also act as an air pilot to open the valve. The open end of the slanted bore would be plugged with a solid plug after connecting the two other bores.


Any co-axial valve that I could think of was too restricting for efficient air flow. And the electric lawn sprinkler valve, besides being inefficient for air was way too big. The big eureka moment came when I figured out to have the air from the chamber push the valve core open and then "side-step" it.
 
LeeKegan said:
Great Idea! How will it hold in place until you fire it?


Once I get a bit more time to refine the geometry, the top bore will have a step in it at the left end, which will stop it from traveling all the way through. The core will be stopped at the right by the fill/pilot plug. The pressure between the pilot chamber and the air storage chamber should be equal (I may have to add a capillary around the check valve in the core) the equal pressures will make it so the core sees no force from the storage chamber until the pilot line is dumped to atmosphere. There may need to be a weak spring to encourage it to stay in place, but I'm still really early in design, so I hadn't thought that far ahead before you mentioned it. ;)
 
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Loess said:
Once I get a bit more time to refine the geometry, the top bore will have a step in it at the left end, which will stop it from traveling all the way through. The core will be stopped at the right by the fill/pilot plug. The pressure between the pilot chamber and the air storage chamber should be equal (I may have to add a capillary around the check valve in the core) the equal pressures will make it so the core sees no force from the storage chamber until the pilot line is dumped to atmosphere. There may need to be a weak spring to encourage it to stay in place, but I'm still really early in design, so I hadn't thought that far ahead before you mentioned it. ;)

Thats what I was thinking. You may need the spring to maintain position until you release!

I like where you are going with this! Brilliant Idea!
 
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th_valve-2.jpg
Here is the modeling that I got done today, in the time that I had outside of helping Annie get her gardens built. I'm not complaining, though, she cuts me quite a bit of slack for my odd hobbies, and her hobbies will make us lots of food this summer.

The ideas for how this will operate are all coming together, a little refining and then I can start looking to get a prototype made.
 
Loess said:
th_valve-2.jpg
Here is the modeling that I got done today, in the time that I had outside of helping Annie get her gardens built. I'm not complaining, though, she cuts me quite a bit of slack for my odd hobbies, and her hobbies will make us lots of food this summer.

The ideas for how this will operate are all coming together, a little refining and then I can start looking to get a prototype made.

That looks awesome, can't wait to see the proto type!
 
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Oh, hey. I don't really need a check valve in there at all, do I. :D

A sufficiently small orifice will limit the air lost through the pilot line, and the pin that the spring runs on can have a rubber bumper to seal it when the core seats against it!


th_valve-3.jpg

That realization has to have reduced the cost of these things by at least $100, just for all the machine time it saves. Four boring operations, and three tooling changes eliminated! Plus one tapping operation, a spring, a seal, and a drilled plug gone. :lol:

Designing devices that I can almost make with tools I already have..... Priceless

Maybe I do have to start looking at Taig or Sherline lathes......

Edit*
A little preview of a side project. This is nowhere near ready to build, but it's getting there. :cool:
th_concept1.jpg
 
Oooohhhh, I know whatcha mean, all this buzz on the forum lately.. Weapons, Classfieds, molding, Ithica.. Lol
Funny I put "Ithica" on there. Well, he's livened things up.

You forgot LeeKegan, Link4044, rube, and a whole buch of others my friend.

That Launcher will look badass when it comepleted!!!

I want to see it done and on my desk by the end of the day Trooper!!! Thats an order!!

-Pony (y) (y) (y)
 
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Coincidentally one of my co-workers came to me yesterday and asked me if I'd be interested in working with him to make a SpNkr air cannon! I was like... uh there's somebody else already working on one at the 405th!

My buddy does Scenario paintball games... he's planning to go to a big one down in Florida in December that's all themed Warhammer 40K, and wants to bring a working SpNkr paint balloon launcher. Appartently with these bigger scenario games they allow vehicles in the game. The only way to take out a vehicle is with a RPG device, which is just a simple air cannon that launches a paint balloon. He'd like to make one that looks the part, and knowing that I make Halo stuff he cooked this idea all up on his own and just wants a little help.

I guess I wanted to tip you off here that your device has a larger potential than just shooting T Shirts at 'cons.

Well, my buddy wants to build his own, and I might help him out a little. He's got a pneumatics background, so I don't doubt that he'll have something working shortly, I'm just gonna help him dress it to look a little more replica-like. I'll keep you guys informed here and share anything helpful that we come across.
 
Sean Bradley said:
Coincidentally one of my co-workers came to me yesterday and asked me if I'd be interested in working with him to make a SpNkr air cannon! I was like... uh there's somebody else already working on one at the 405th!

My buddy does Scenario paintball games... he's planning to go to a big one down in Florida in December that's all themed Warhammer 40K, and wants to bring a working SpNkr paint balloon launcher. Appartently with these bigger scenario games they allow vehicles in the game. The only way to take out a vehicle is with a RPG device, which is just a simple air cannon that launches a paint balloon. He'd like to make one that looks the part, and knowing that I make Halo stuff he cooked this idea all up on his own and just wants a little help.

I guess I wanted to tip you off here that your device has a larger potential than just shooting T Shirts at 'cons.

Well, my buddy wants to build his own, and I might help him out a little. He's got a pneumatics background, so I don't doubt that he'll have something working shortly, I'm just gonna help him dress it to look a little more replica-like. I'll keep you guys informed here and share anything helpful that we come across.
Cool! Paintball is what got me into air cannons. I've always wanted to get to a big scenario, but never had the time.

I was mostly focused on shooting t-shirts right now, since they throw a nice, soft, safe, low-velocity projectile. (I don't want to expose 405th to liability if I can avoid it. Years of learing awesome stuff in engineering school, and lawyers won't let me do half the fun stuff I could...:cautious:)
 
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Kewl! It's great to see a project of this nature take on such a progression.

First off, it started with Lee's plans to make a SPNKr, then me drafting the schematics for that, next with Loess posting his ideas to make a functional launcher (PT-DU), and now with Sean and a buddy of his working on another incarnation of the same prop.

Things are really beginning to take shape with just this one choice weapon :D
 
SPARTAN II said:
Kewl! It's great to see a project of this nature take on such a progression.

First off, it started with Lee's plans to make a SPNKr, then me drafting the schematics for that, next with Loess posting his ideas to make a functional launcher (PT-DU), and now with Sean and a buddy of his working on another incarnation of the same prop.

Things are really beginning to take shape with just this one choice weapon :D

Can't forget Juliet coining the name! :p (PT-DU)

Still working on the models, so I can draw up the parts and get some quotes. Too many things going on in real life and in propping to make much progress on this...... WAIT A MINNIT!

Just got an idea about how to get rid of the spring, Epoxy a magnet in the end of the bore the valve core rides in. That will be enough to hold the core in place, since at rest, the air pressure across it is balanced.
th_valve-4.jpg
 
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Seems like your building a type of pistion valve cannon. I would take a look at some of the penmatic air connon sites. There are alot of small things that need to work to get it to pilot correctly. If you do a coaxial design you wont need that spring and the piston needs to be inline with the barrel not the air chamber. Unless your valve is machined to extremly tight tolerances it will probably chatter rather than fire. As far as a check valve it isn't needed as you probably wont even need a hole to fill the air chamber with pressure. If you want to see when the piston will fire then you need to find the total force acting on each face of you piston. (psi x sq. inch). I would find a good simple piston valve on this website http://www.spudfiles.com/ it's so much easier than designing your own.

PS. for "rapid fire" look into Palmer's Pursuit tire fill stabilizer so you just need to reload a cartridge like with this http://www.instructables.com/id/GolfballAn...-One-That-Shoo/ even if it means you can go coaxial. Good luck

bah I type too slow:( any who I still question the air inlet unless u have a massive pilot valve. A simple diafram might be enough to give you a check valve to reduce the pilot volume.
 
Loess said:
Cool! Paintball is what got me into air cannons. I've always wanted to get to a big scenario, but never had the time.

I was mostly focused on shooting t-shirts right now, since they throw a nice, soft, safe, low-velocity projectile. (I don't want to expose 405th to liability if I can avoid it. Years of learing awesome stuff in engineering school, and lawyers won't let me do half the fun stuff I could...:cautious:)


Yep... that's exactly why I'm gonna keep our technical discussion off the forum. I just wanted to let you know about the idea.

Keep up the great work guys.
 
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Holy crap, Gremlin... Those are some ridiculously awesome resources. I obviously haven't been looking through instructibles enough, and that spudgun forum would've made me weep in joy a few years ago when I was hardcore into building air cannons. (it still made me a little teary-eyed, though.) This is still an early, fast-evolving design, the valve shuttle still could easily get some kind of check, probably a simple rubber flap over the face.
 
I'll just leave this here:

1243977508_142.jpg


Rocket Launcher Boom Box


Also, have you come across this?:


Under%20mount%20launcher%20Small.jpg

Metadyne Launcher

Seems like a reasonable solution to the air cannon conundrum. Measure the price against the amount of time you'd need to spend designing and manufacturing everything yourself.

At least, for those less pneumatically inclined... this could be an alternative.

Hope that helps..
 
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if this gets done before dragoncon, you are more than welcome to launch these things from the back of the atv im bringing for the parade. on top of that, the front and back of it are flat and able to hold gear. i had mentioned modding it to Ithica to make it an actual mongoose, but if this gets completed then i might not want to. several larger ammo boxes filled with t-shirt ammo strapped down to the front would make it look good without the body mods and it would save a few people from having to lug around shirts with them thru the parade.
 
Hah, I hadn't thought of using a launcher for a boom box. :lol:

That Metadyne launcher is veeery interesting, though. :whistle:
 
Loess said:
Can't forget Juliet coining the name! :p (PT-DU)...

You know it baby! ;)

Looking forward to seeing what more you come up with for this Loess. :D
 
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