Page 1 of 3

update 11/07: TOW tube launcher is done, success!

Unread postPosted: Sun Sep 23, 2007 9:27 pm
Author: GTLandser
All,
I have a spent TOW missile tube, which I plan to use to launch t-shirts. Trouble is, I have no idea what I am doing.

I would like to put a 3" barrel inside the tube, to make it look like a plain missile launcher when shooting the shirts. What is the proper term for this tube-within-a-tube arrangement, and how do I best carry it out?

The tube appears intact, and is made either of fiberglass or aluminum, so it might have a pressure rating. I don't know how strong it really is, but it is in quite good shape and fairly heavy for its size. I also have a ~4500 psi nitrogen tank from a friends paintball rig, a 1" sprinkler valve...and that's about it.

Any assistance would be welcome.

Unread postPosted: Sun Sep 23, 2007 9:32 pm
Author: trae08
the gun it sounds like your talking about would be a coaxial. and picks and more info on the tow tube would be great.

Unread postPosted: Sun Sep 23, 2007 9:36 pm
Author: HaiThar
Yes, coaxial is what you're looking for...kinda hard to start with I believe....You will be using nitrogen as your compressed air source? You'll probably want to mod your sprinkler valve as well...and you'll need a regulator...

Unread postPosted: Sun Sep 23, 2007 9:37 pm
Author: mopherman
this thread has a diagram in the first post that would work great
http://www.spudfiles.com/forums/viewtop ... tml#109602

Isnt the crowd going to be kinda freaked when you point a missile tube at them?

Unread postPosted: Sun Sep 23, 2007 9:52 pm
Author: thespeedycicada
make it co axial but dont use it for launching stuff at crowds people get very angry/scared when something even slightly resembles a firearm it would be a cool paintball or airsoft gun though.btw where did you get an empty tow tube i want one!

Unread postPosted: Sun Sep 23, 2007 10:23 pm
Author: GTLandser
Wow, for a forum dedicated to making potentially hazardous projectile weapons, some of you sure sound afraid of making something resembling an actual weapon...

To answer your questions, the t-shirts are to promote Army ROTC on my campus, so no one will be shocked to see a missile tube pointed at them; we're a regular presence on the field.

I don't have any idea who got the tube or how, but we have had it in storage for some time, and now we have a reason to use it.

I don't have any data on the tube, unless someone wants to call Hughes or Raytheon or whoever and ask them about it.....sorry

Anyway, some more thoughts:

As it is coaxial, I presume I will need a bulkhead to close off both ends (the tube is approx 48" high by 6" id)--my first thought is that I will need a pretty hefty bulkhead to contain the gas....

Second, modding the sprinkler valve won't be a problem, I have seen the guides using a ball valve (safety) and blow gun (trigger)...unless there is a better method; I would love to know how to move that assembly to a more convenient location than the traditional location one right behind the sprinkler valve (this might allow me to place it where one would imagine the trigger on a man portable rocket launcher goes, because the TOW is for tripod or vehicle mounts, so the tube doesn't really have a 'user interface' by itself).

Unread postPosted: Sun Sep 23, 2007 10:45 pm
Author: Pete Zaria
@GTLandser,
I would consider building a traditional, PVC/plumbing parts coaxial launcher to fit inside the spent TOW tube.
That tube very well might not be air-tight, even with properly sealed-up ends. Also, building a launcher into that tube would probably require a fair bit of machinery and experience.
Building a coaxial launcher, say 4" with a 2" or 2.5" barrel, would be easy enough to do, and would fit easily within the launch tube - if you can track down some 6" pvc that will fit, that would be ideal.

Read around this site (the Wiki, the How-To section, and the Pneumatic Showcase) on existing coaxial designs, and emulate ones you like. Coaxials can be built with piston or diaphragm valves, and can be piloted a variety of ways, giving you options to make this as realistic as possible.

Hope that helps.

Peace,
Pete Zaria.

Unread postPosted: Sun Sep 23, 2007 11:05 pm
Author: turbohacker
^^^hey I made that :wink:
Idealy you should make an entire gun that can slip into the tow tube just for asthetics.

It is not as simple as you may think to make a good t shirt gun, I have spent thousands of dollars in R&D and have only sold 7 or 8 guns.

I recomend getting one of these regulators as everything is their and complete.http://www.palmer-pursuit.com/cart/index.php?main_page=product_info&cPath=8_9_28&products_id=175

^^dag-nabbit!! Pete! Beat me to it.

Unread postPosted: Mon Sep 24, 2007 8:51 am
Author: GTLandser
Thanks all for the replies; I'm definitely aware of the uncertainty in getting the tube completely sealed, but my insistence on a 3" barrel stems from the need to fit the t-shirts.

Since sealing the tube would be so difficult, suppose I put a large piece of PVC into the launcher tube to act as a chamber--I guess that would be a 6" piece, I assume those are available at plumbing supply places?

I like the 'TOW tube just for looks' idea, so what about if the chamber was inside the tube, and the barrel extended outside?

And guys, all my assumptions are just that--I really don't know what it would take to get a t-shirt into the air (chamber volume, psi, etc etc) so any info on that especially would be helpful. Given the right specs, I could play with the layout until I had something--I just don't want to move in a particular direction only to find it won't work.

Unread postPosted: Mon Sep 24, 2007 8:54 am
Author: GTLandser
Oh, another question; the nitrogen tank I have comes with a fill-tube and quick-detach female end for a 1/8 fill stem--wouldn't this preclude the need for a regulator? Is there a reason I can't just read a pressure gauge on my chamber and turn off the flow when satisfied? I can't imagine how the gas comes out the other end into a paintball gun at thousands of psi as it is, unless there are some pretty impressive regulators on paintball guns...

Unread postPosted: Mon Sep 24, 2007 10:10 am
Author: Pete Zaria
GTLandser wrote:Oh, another question; the nitrogen tank I have comes with a fill-tube and quick-detach female end for a 1/8 fill stem--wouldn't this preclude the need for a regulator? Is there a reason I can't just read a pressure gauge on my chamber and turn off the flow when satisfied? I can't imagine how the gas comes out the other end into a paintball gun at thousands of psi as it is, unless there are some pretty impressive regulators on paintball guns...


Expanding compressed gas is very cold - PVC gets brittle when cold - need I say more?

Most paintball guns, to the extent of my knowledge, DO have regulators.

A regulator setup shouldn't be that expensive if you just look around.

Building a 3"-in-6" coaxial to fit inside your TOW tube would be pretty awesome.

To give you ROUGH specs, I'd estimate that a 3" barrel with anything over 100ci @ 70-100psi behind it should have no problem getting a Tshirt airborne, but again, look around this site at people who have done it before, and see what they used.

Best of luck.

Peace,
Pete Zaria.

Unread postPosted: Mon Sep 24, 2007 11:19 am
Author: HaiThar
What you'll probably want to do is(elite spudders correct me if I'm wrong) not even use a chamber. You can put a regulator and a modified sprinkler valve attached to your tank, and just plug away. There isnt really any reason to use a chamber if you have a CO2 tank, but again, I'm VERY new to this, so I might be wrong...

Unread postPosted: Mon Sep 24, 2007 11:25 am
Author: Fnord
I don't think regulators have high enough flow to do what you're describing.

Unread postPosted: Mon Sep 24, 2007 11:43 am
Author: williamfeldmann
I have made a T-shirt cannon with a 3 inch barrel before, and you really should think about a smaller barrel. You could almost shoot sweatshirts out of mine. It was hell trying to get the tshirts to form a tight fit in the barrel. As for how much air and pressure you need. If you have a four foot coaxial gun, you should be able to hit pretty high in the stands from the field with around 100 PSI, the smaller the barrel diameter the less air pressure you will need given a fixed diameter of air chamber.

For the 6 inch pipe you will need to go to a plumbing specialty store or the internet. Lowe's, etc don't carry pressure rated that big. Make sure your fittings and pipe all say NSF-PW. Very Important.

Depending on the size of the paintball canister, you might only get a few shots with something 4 foot by 6 inches. I built a 3 foot 4 inch coaxial chamber once and got 2 shots at 100 psi off a 68 cu. in. paintball tank. A small air compressor on the sidelines might be a faster method of charging and cheaper than paying for paintball refills, especially if you are only shooting during timeouts or something like that, where 1 or 2 shots max per break is possible.

@HaiThar
Granted it is possible to make a gun with out a coventional chamber (usually a vortex), with the pressures that are in that paintball tank you will DEFINETELY want a safety chamber. DON"T FORGET THE BLOWOFF SAFETY VALVE. Since PVC can only handle 150ish PSI before being close to critical failure, that chamber is the only thing saving parts of the gun from going above, especially if the tshirt gets jammed or wedged in.

Unread postPosted: Mon Sep 24, 2007 1:21 pm
Author: jimmy101
GTLandser wrote:Wow, for a forum dedicated to making potentially hazardous projectile weapons, some of you sure sound afraid of making something resembling an actual weapon...

No people are not concerned with "making something resembling an actual weapon" they are concerned with pointing any weapon towards people you do not intend to maim or kill.

If you ignore the most basic of firearm safety rules then you still have the problem of pointing what looks like a weapon anywhere near people. Make an M-16 look alike and try walking around a school campus with it and see what happens.

The TOW tube is no different.

GTLandser wrote:...the t-shirts are to promote Army ROTC on my campus, so no one will be shocked to see a missile tube pointed at them; we're a regular presence on the field.

I think there is an ROTC officer that needs a serious refresher course on weapons safety if he thinks it is OK to be walking around on campus pointing a TOW tube towards people. Even if the tube is unloaded, decommissioned or fake. Sounds like a great way to get booted out of the service.

A TOW tube based launcher is cool. Using it by a military organization as a toy, on a college campus, is not so cool.