56 replies to this topic

[DX-Robert]

My clan has a pair of full cannons, 3" PVC air chamber and barrel, both almost 6ft long. I tested filling the barrel with darts earlier today, actually, but did not have enough darts to get even close to halfway filling the barrel.

Reloading and priming takes about 30 seconds to a minute, bad if you are in "heavy traffic." We use ours for artillery, literally for shelling fortified positions from hundreds of feet away.

[Zach]

This comment is related to Duxburian. To decrease on loading/priming time, I'd say go for a double ball valve and double tank setup. Behind the first ball valve would be a huge tank, possibly enough for five hsots. After the first valve would be a smaller tank to hold one of those five shots and after that would be a second ball valve. You'd only have to reload the barrel without priming it. All that you would have to do is keep the valves open and closed in an order so that the air didn't escape. This layout also gives you room to use one powerful shot or five (or how many you wantd before) smaller shots. This concept isn't new.

~Zach

[ompa]

The problem with that is then you have to re-aim and hope you get the right range. You could try something like removable tanks though, that'd just be nice. Shouldn't be too difficult to incorporate with what you have so far. With that, you could have a bunch of pre-pressurized tanks, which you could fill before the battle/war.

Or use a huge bladder. Maybe get a few camels, I hear they have big bladders.

All jesting aside, maybe some splashzooka bladders would provide the needed volume and pressure (with some banding) you may be looking for in order to get multiple shots.

~ompa

Edited by ompa, 05 March 2006 - 10:05 PM.

[m15399]

You would need some LRT from McMaster.com. It can hold much more than a super soaker's CPS PC. The splashzooka would be far from a good choice (it's not so good compared to other CPS's).

[Spider-Waffle]

what's LRT?

[m15399]

Oh, sorry. Guess no one knows what that is...

LRT is short for Latex Rubber Tubing. It's basically a tube made of rubber that expands. You find things like these in Powerclips, Wildfires, RF20's, and probably some other ones. They are only rated for 35 PSI, so it's unlikely you would get 100+ without a better valve and larger PC/shorter barrel.

[Sponge Nerfer]

Woah!

You guys wrote alot of stuff in a really short time, thanks!

Some of these ideas sound great, but I have a few questions:

What on earth is LTR?

Ompa..... Cammel Bladder = no

Dont mean to sound noobish but, what is a sprinkler valve? Do you mean like from my lawn sprinkler? Please explain.

You guys said that it would be better to put the bullet inside of a big tube instead of putting it over a small one. How could I do this?

Replaceable tanks sounds like a great idea but how could I do this?

Thank You all for the quick response and mass of information

[techtargetmaster]

LRT is short for Latex Rubber Tubing. It's basically a tube made of rubber that expands.

m15399 has explained.

Edited by techtargetmaster, 06 March 2006 - 06:36 PM.

[ompa]

Zero Talent had something on his web site, but now it's gone. But I figured you should be able to just use a ball-valve on the end of each pre-charged tank that would screw onto wherever your input is.

~ompa

[davidbowie]

You guys said that it would be better to put the bullet inside of a big tube instead of putting it over a small one. How could I do this?

...You put it inside the barrel. Don't you have, like, a nerf gun? The dart goes inside the barrel.

m15399: yeah, I know what you're talking about. I've never heard anyone call it LRT, though. Usually rubber tubing or surgical tubing. Whatever.

For interchangeable tanks, you can use garden hose QD's. Some female ones automatically seal up when they're not connected, so you could just pop a new chamber on there. This would restrict flow quite a bit. It wouldn't be that bad for a 3/4" barrel, though.

[m15399]

Ya, whatever.

Sponge, sprinkler valves open quicker than ball valves, so they get more range out of your gun. Here's a link.

[GeneralPrimevil]

I stopped reading somewhere on the second page...

First off, ammo is Loghelp. I have posted that a few times for people who need BIG FBR, or big ammo, I even made a topic about it. Searching ist gut, no?

Second, I like to see that more people are using larger homemades. I still think mine is bigger...
I used 3" PVC, 46" of it, with a 1.5"x48" barrel. I made a topic of that too, and included the words "cannon" in the post. Wow, just, wow, I don't mean to be snotty or ranting, but, I'm in disbelief at how long this thread has gone and no one searched for anything. I think there is even another cannon topic on this site...

To reinforce david "the cannon man" bowie, I can shoot 3 oz. of projectile over 150 ft. with that cannon, the only limitation being the valve. That is with 60 psi by the way, the cannon has a leak...

Again, it is nice to see larger homemades come about. I still am working on my combustion powered, but I need to find a new coil. So far, the chamber, propane tank holder, barrel, and propane meter are finished. Those pics are kinda dark, but I had shitty lighting for photography. It is actually really bright due to 45w flourescents mounted 30' above my head. Yep, my Shop (a.k.a. KPS bus garage facilities).

Anyway, for removeable tanks, ball valve with either a large QD (camlocks) or a smaller air chuck QD (found on an air compressor) would do, however, the garden hose QDs would be superior to the air chucks since they have more flow. I dunno how well a camlock would hold higher pressures for continual time periods either. Garden hose QDs seem to win, due to price, availability, ease of use, etc.

[Sponge Nerfer]

General Primevil,

Great Cannon! But I think that almost everyone here has forgotten my problem. I have a working cannon that has the potential to propel an object a great distance. My issue is, what do I shoot out of the dang thing? So, my question to you Greneral Primevil is, what on earth do you shoot out of your cannon???? I realize that you have given me the site LogHelp, but is this your source of ammunition? And if it is, do you modify the chunks of foam that you get there? How much weight do you put on? What do you use to for wieghts? I would greatly apriceate it if you would answer these questions.

Edited by Sponge_Nerfer, 07 March 2006 - 05:12 PM.

[GeneralPrimevil]

Truthfully, I use that cannon for airsoft, as it is not yet Nerfing season where I live. Once the mud clears, then it is time for Nerf. We in my area like to do all sorts of combat sports. I have yet to order that stuff, but once I do, I'll let you know. Chances are, it will be next week.

If it were me making 1.5"x4" Stefans for my cannon, I would use steel ballbearings for weight. Or, if those proved to light, I would either make my own out of cast lead (use plaster of paris or whatever it's called as a mold) or use very large (3/4 oz. or heavier) lead sinkers. Not the split shot sinkers, the bass fishing sinkers or bullet sinkers.

Anyway, I currently shoot 3 oz. of BBs in a plastic bag (rolled around itself and taped shut), and do NOT shoot anyone with that. It will hurt, alot. Like, big bruise and MANY welts. Since I use it for another activity, I just shoot a tree branch over a bunker and let it explode over the bunker. You are using a 3/4" barrel, no? I would recommend switching that to 1", that way, about four regular micro Stefans can be shoved in the barrel after wadding (paper towel). Then, it would be more like artillery or a shotgun. I have 3/8" FBR here at my local Lowes, so I might try that along with the 1.5" FBR. I don't have the 5/8" stuff, so I can't try four mega Stefans in my barrel. I can, however, fit seven micro Stefans in my barrel, I just have yet to try it since I still have to make new darts (lost ALL of mine SOMEWHERE. There were a good 200 darts total.)

Back to you, try stuffing either four 3/8" Stefans (using some sort of split shot, experiment) in that 3/4" barrel or four micro (1/2") Stefans in a 1" barrel.

I hope that helps, although I'm sure it won't.

[Sponge Nerfer]

General, thank you very much.

In a single post you have solved all of my cannon problems, I greatly apreciate your help.

[LastManAlive]

You could actually use paintballs or micro stefans and put 1/2 inch CPVC in the 3/4 inch with e-tape around it to hold it in. I amagine your barrel is removable right?

[GeneralPrimevil]

General, thank you very much.

In a single post you have solved all of my cannon problems, I greatly apreciate your help. cool.gif

I feel special. I did what three pages of posts could not do. I literally fell down laughing after I read that. Oh yeah, I now know what I mainly shoot out of my cannon: donut holes. I have connections with my local Meijer (midwest superstore) so that I get all of their stale, expired donut holes as ammo for my cannon. They like it too, because they don't have to toss as much stuff. They still write it off as a loss, but meh, it's my fortune. So far, I have gotten a donut hole to shoot a little over 100 yards with that cannon at a little over 100 psi. I am planning on replacing the valve with a modified gate vavle, if I can get it to work. Pretty much, I am replacing the handscrew with a solenoid (either purchased or custom made). That would work with pretty much any gate valve, either inline, the right angle kind, the other which is used for faucets, you get the picture. I have about a half dozen of each I can mess around with, so...
I also need this valve in 1/2" porting for a project where a 3/4" valve will have too MUCH flow, amazingly. Actually, I don't want the gas to expand when it goes from 3/8" to 3/4" then back down to 3/8", so realy I could go with a 3/8" valve then, since the tubing after the valve will be the limiting flow variable.

Edit: Here's a very large pic of the valve. The solenoid is not to scale with the rest of the valve; it may be larger than what it appears.

Edit2: Disabled link in Edit1...see next post of mine...

Edited by GeneralPrimevil, 10 March 2006 - 03:38 PM.

[Sponge Nerfer]

Sounds cool general, I think that I will try to make my cannon powered by a electric pump. I also think that I will go simple and shoot just shoot micros out of my gun, its not very cannon-like but hey, it works, I got consistant ranges of 180ft. Also it suddenly just struck me that your cannon has a tank that is about twise the size of mine! And you are able to do this because of how the barrel goes up and turns back over the tank. I might try to do this. Also I have to tell you, donut holes! Thats a funny idea that could acually be practicle, but, my mom would kill me if i sprayed donut all over our yard and possible into the neighbors yard and, unlike you, I dont have a good supply of donut holes, so I will stick with micros. I also dont completely understand what a gate valve is? Sorry if this sounds noobish but I am something of a noob to the making of nerf guns.

thanks for all ur help

Edited by Sponge_Nerfer, 09 March 2006 - 05:14 PM.

[GeneralPrimevil]

A gate valve is what a faucet valve or spiget (the thing a garden hose is attached to with the handwheel). Generally, they have a threaded area which houses a screw and a plug beneath it. When the wheel is turned, the plug goes up or down, controlling the flow of whatever is going through the valve. I plan to take one of the numerous, destructable (they have common coarse threads and can come completely apart and be put back together) gate valves that I have and remove the handwheel and screw. Then, a threaded insert (smooth interior) with a solid metal shaft is secured where the screw was. The end of the shaft is attached to the plug. A solenoid is then secured to the top of the insert. When an electrical current is put through the coil on the solenoid, many electrons are in a common area, creating a negative magnetic and electrical charge. This attracts the metal rod, which has a neutral magnetic charge, pulling the rod further into the coils and raising the plug. I messed up with that drawing, so it was deleted and replaced by this.
That shows it better, and it shows the correct orientation. The old version would require using a spring or having the space behind the plug (solenoid side) be airtight, otherwise the pressure from the chamber could open the valve. Hence I reversed orientation in that new image and put the threads in.

I have my cannon in a style refered to as O/U or Over/Under. The chamber is below the barrel. This is good for pnuematics because it shortens the length, which can be quite long as chamber get big fast. Right now I am running a little under 4:1 chamber:barrel ratio. That gives me a lot of power to work with. I have started work on a new cannon which utilizes 5' of 6" PVC and a 10' by 2.5" barrel for tennis balls and other things, like 20 0z. pop bottles and soda cans (I think...). It uses a 4" ported barrel sealing piston valve. Pretty much, the air in the chamber will dump as fast as it possibly can through that barrel as quickly as it can. The valve should open in a little over .05 seconds, I think. As a result, a sand filled tennis ball will reach orbit. Truthfully, it should go well over 200 yards at over 280 mph. Not for Nerf, but fun nonetheless.

[CaptainSlug]

Gate valve:

Edited by CaptainSlug, 10 March 2006 - 05:10 PM.

[malekith]

what about a pop can with some duct tapearound it to make it wider? you could find some way to fill it with stuff and release when it hits the ground or i like the idea that I read somewhere earlier about stefans just put a bunch in that would be cool

[GeneralPrimevil]

Pop can: just under 2 5/8" diameter.
20 oz. pop bottle (Mello Yello): just over 3" diameter.
I found my vernier caliper.

So, I have no idea what would shoot a pop can. 3.25" PVC (yes, they sell it) would be used for 20 oz. Mello Yello pop bottles.

Captain Slug, way to go with the visuals. I was too lazy to Google gate valve. I spent my time making Paint images of what it looks like after the supposed mod. Yes, I do feel pretty stupid.

Soo...this is ...awkward...

[davidbowie]

I would say no to soda-can use in nerf, just because you could easily maim with one.

Just so you know, though, 2.5" SDR-21 fits soda cans pretty well.

[GeneralPrimevil]

2.5" SDR-21? I think I'm gonna have to find some. That has to be sleaved, no?

SDR pipe is probably the best pipe for weird sizes. Like the 1.5" SDR-21 for golf balls and whatnot...

[3nerfiteers]

I'd like to know how much air pressure the thing has. You can usually determine this by putting your ear up to the end of the barrel and shooting it. If you get a very loud FWEEE i'd predict about 60 PSI, anything less its not worth your time. Please find this out for me ASAP.

Edited by 3nerfiteers, 15 March 2006 - 09:55 PM.