LRTC-50

[Killjoy]

LRTC-50
Long Range Tactical Cannon-50mm
This is by far the largest and most powerfull cannon that I have ever constructed. It also was the cannon that gave me the most problems and took the longest to construct.
It started off as a design I came up with after I had had a little to much rum. (some of my best designs I come up with seem to be thought of when im drunk). Anyways, I first started on the valve, originaly a 4" diam to 3" diam chamber sealing piston valve. Immediatly I was unable to find an o-ring to fit a 3" piece of pvc pipe, so I was forced to cut a large diameter o-ring to fit and then calk it into place. still, I was unable to get the piston to seal, and had leaks both from the o-ring and the wheel thing I expoxied into the the inside of the pipe to try and seal the pipe. I messed around with the design and set up of the piston for about a month during the summer, but then school started so I was forced to stop working on it until a holiday. Right before my school got out for christmas, I was looking at the piston valve and said "F*ck this", and decide to change the valve into a barrel sealer instead of a chamber sealer. By doing this I was able to use the leaks to my advantage cause i could fill up the main air chamber and piston chamber at the same time. I went to home depot and got the parts and within 3 days of glueing and re-machining parts, I had a functioning cannon. After that i built a stand, but because of the massive recoil, I decided on letting the cannon be able to slide in a cradle so that the stand wouldn't be torn apart by the recoil.
I used a rubber cap for a 3"pipe which I cut to fit as the sealer on the front of the piston, which I cut to small the first time and it was actually blown out of the barrel after a couple if shots, so replaced it with anouther one which I cut to the right size and the cannon has worked perfectly ever since.
Here are the dimensions and specs of my cannon
Air Chamber-4" pvc pipe 7 feet long (Actually eight of you include the part leading to the piston) 1206 cubic inchs
Barrel-2" pvc pipe 10 feet long. 376 cubic inchs
-3.2 to 1 chamber to volume ratio
-Breach loading
-3" barrel sealing piston valve. Has a 4" stroke (travels back 4" when cannon is fired)
-1" modded sprinkler valve (to empty piston chamber)
-Primary ammuntion is potatos and golfballs
-Maximum recorded range- 1/4 mile (30 psi). Actual maximum range unknown (probably about 1/2 to 3/4 mile depending on ammo and operating pressure)
-Operating pressure is 30 to 70 psi.
-Semi automatic capabilties, just have to leave compressor connected to cannon. Able to fire about 15 shots per minute (not loading ammo, just filling chamber)

To give you an idea of the cannon's size, im 6' 5"

The Piston. The tab of metal is to pull the piston forward if it moves back to far.

The Cannon pushed all the way forward before fireing.

The cannon after being fired. A blank shot will move it back about 6", a loaded shot will move it back about 2'; which is the maximum travel distance for the cannon on the stand.

The back of the cannon. Note how the valve isn't in the end cap (which i did because i didn't want to weaken the end cap). I also added 2 gauges, the top gauge shows the pressure in the main air chamber, and the bottom gauge show the pressure in the piston chamber (which also is the flow pressure from my compressor). I did this only because I had some extra parts and a gauge lying around and it seem cool to have two guages instead of one.

The Cannon tilted up (this is about the maximum firing angle for this cannon.) A used a large gate hinge to allow me to tilt it.

I gorilla glued a male threaded 1" connector to the bottom of the piston chamber so that I wouldn't weaken the end cap and would be able to attach the sprinkler valve so that it would be pointing down. I also had problems sealing the connector so i used hot glue, which did a good job sealing it and added some support.

[experament_u2]

thats huge kool gun get some damage pics up

[Insomniac]

Woah! Nice gun, gut some videos of it fireing! Bet its damn loud lol.

[Pete Zaria]

That Wye and cleanout don't look pressure rated. If you're only taking it up to 70 or 80 PSI I think that'll be fine, but I wouldn't go over 80 psi with DWV parts.

Very nice stand setup. All around, great design except for the DWV parts.

Explain how the recoil system works, please.

Peace,
Pete Zaria.

[frankrede]

Thats pretty big!
Ya those aren't pressure rated but I'm not an engineer(yet).
1/4 a mile?Wow, how did you measure?

[Killjoy]

yeah i know those are dwv, but im not worried cause ive pressured tested dwv parts before to 130psi and nothing happened so im not worried.
for Pete
the recoil works basically by friction. The cannon is not "fixed" to the stand so it can slide backward. I then used foam and electrical tape to add padding between the wood and the pipe which also provided friction. so when the cannon is fired, the entire cannon can slide backwards while the stand stays in on place. then all i have to do is push the cannon forward before the next shot. The only problem i have is that with heavy projectiles the cannon will slide back all the way, and the last time it did this it cracked a part of the wood, so now im planning on adding some springs to help dappen the recoil even more.
For frank
i hit my neabors house with the first shot (he came over and threatened to call the cops). so i used google earth and found that his house is a 1/4 mile away from mine.
and yes the cannon is extremely loud.

[schmanman]

I like it. but the dwv is not a good idea

you are 6 foot 5 ?

[iknowmy3tables]

wow cool gun are you shooting that of inside, it looks like your boxes are stacked in a bunker/baricade formation

[Killjoy]

yeah i know but dwv is the only type of fittings i an where i live, and like i said ive pressure tested them to 130 psi and they withstood the pressure no problem. And yes im 6 foot 5 inchs.
actually thats my garage (its where i store, work, repair, build my cannons), i just had to stack the boxs caase other wise i wouldn't have any room to work on my cannons.

[Velocity]

You could probably use the DWV fittings on the actual body of the cannon, and be ok (as long as you kept the pressure low, which you appear to be doing). However, that cleanout cap must go. Those things will pop off of a combustion chamber after just the force of the 40 PSI or so that a combustion experiences.

Consider this:

1) You are using greater pressure than a combustion creates, therefore imparting more shock to the cleanout cap
2) it is SUSTAINED pressure, which puts even more pressure on the cleanout cap
3) A friggin piston is SMASHING into the cleanout cap, which just further increases the chance that it will break


Sorry for this rant. This certainly is a very nice cannon, and I am sure that it is very powerful
I personally would not shoot that cannon again until you replace the cleanout cap. Use a threaded plug, or a male adapter solvent welded to an endcap. But for the love of god, replace that cleanout cap!!!!

[Triggahappy]

That is one nice cannon!! I hate not being able to find exactly what you need for cannons, here in Australia almost everything is DWV, but hey is you pressure tested it to 130 psi then 70 sounds fine. Great job 8)

[ProfessorAmadeus]

How heavy is that piston? It looks really heavy and is the back end closed off? if it isnt close it so there isnt so much pilot air.

[Killjoy]

well lets see rmich, ive built cannons with a clean out cap before, and pressurized them to 160 psi and sustained it for over 6 hours, with no problems and never had the clean out plug "pop" off. ive also used them on combustions, and never had them pop off either (even when the pressure exceeded 40 psi). and the piston isn't smashing into the cap; I immediatly realized the problems that would cause and built a special cushion which prevented the piston from hitting the cap and the cushion also doesn't touch the cap. I also reinforced the cap with Durnhams rock hard water puddy and epoxy. personnaly i have no problem using a clean out cap and am completly satifsfied in the safety of it, especially since im using relatively low pressure.
The piston actually isn't very heavy, and the back isn't closed off on the piston, though i am planning on doing that soon.

[alkalineall]

Nice man, I also had trouble with a 4" to 3" barrel sealer. I ended up using a 3" endcap piston and messing with the gasket forever. Works now though. Another thing that I noticed is that big reservoirs take a while to fill. I know that most people are trying to help with the comments about the DWV, but I think one comment is sufficient. I hate to hear that 12 times in a post. Once its been brought up once , enough is enough. I could also only find DWV in the large diameters and I've been using my latest for a few months now. I just stay under 75 psi. With a big gun you don't need more than that. I think you'd probably agree. Anyway good job.

[Flinchy]

impressive. yeah, its never a good idea to hit yur neighbors house, people tend to get a little pissed when that happens... i've "accidently" shot my neighbors house a few times

-Flinchy