Need plans for a monster

[randas]

Ok, ive already made 1 cannon before finding this site. Its very loud but dosent get good range. Now i want to try again and buld the most powerful possible.

Ive already build a camera flash+coil ign system and im going to use a chamber fan and regulated propane. I also got a set of cam locks to quick disconnect the barrel.

Now my only question is what would be the best dimensions to achieve max power? I understand the c:b ratios, but what size chamber should i use? I assume theres a point where too big isnt good? Ideally i would like a 4" chamber and probably a 1.5" barrel. So what length should my chamber be? what has worked good for you guys?

[Pete Zaria]

Read around this site and our expansive Wiki (link at the top of the page), don't forget the Showcase and How-to sections of our forum. I personally have posted a pretty detailed set of plans in the How-to section you may be able to use.

For a "beast", go with a 4" diameter chamber - the exact length depends on the length of the barrel you want to use. This is C:B ratios. You want around a 1:1 C:B ratio if you intend to use metered propane.

This page is very helpful in calculating C:B ratios: http://www.online-calculators.co.uk/vol ... volume.php

This page is very helpful in figuring out your fuel meter setup: http://www.burntlatke.com/ft_live.html

Let us know if you need more help.

Peace,
Pete Zaria.

[iknowmy3tables]

dude if its very loud but is not strong enough then the problem is obvious the barrel is too short so all the energy is being used as sound

[MikeNice]

I know lots of people here dig on the 1:1 c:b ratio, but the gun I built that was 1:1 wasn't powerful or consistent. I had a real hard time getting the fuel load right to get it to shoot half way decently at all. Maybe 1:1 works well with metered propane but i had a bear of a time getting this gun to work well on Tag. Eventually I ended up chopping the barrel down until I got the performance out of it I wanted. I am well aware that loud bang does not = power. This gun didn't have half the range or power my 1.5:1 over unders using similar dimensions did until I cut the barrel and got it closer to 1.5:1

Anyway, here's a link to my site with my 1:1. I just uploaded it and I'm still working on the site almost daily so there's a lot thats just not finished.

http://iplaaz.freehostia.com/html/myguns.html#121

BTW, the dimensions I use are all over my site.

[jackssmirkingrevenge]

Well done with the site Mike, some of the cleanest cannons I've seen on this forum, I particularly like the tan-green-brown camo, kudos.

[MikeNice]

thanks a lot, I appreciate it. The camo guns were a pain . . . .

[randas]

so propane should be 1:1? im reading conflicting opinions

[DYI]

With metered propane, it can be between .6:1 and 1:1. Outside of that range, you will notice a severe drop in power.

[randas]

hummm.... i dont like these numbers
with a 1:1 ratio a 4"x12" chamber needs a 1.5x85" barrel.. and i would like my chamber bigger than that. i was hoping more like 18", remember i want this to be a beast.

[DYI]

If you want a monster gun, you have to be prepared for the unique engineering challenges that come with it, however I wouldn't consider supporting gun with a 7' barrel to be a real challenge. I made a well balanced stand for a 16' launcher (yet to be posted, due to severe sealing problems), in half a day with four 10' 2x4s and some scrap wood. If you want a shorter barrel, you could just make it larger calibre, like 2"-3", maybe with interchangeable barrels.

Killjoy made a much more simple stand for his LRTM-100, which has a 4"x5' chamber, and a 4"x5.5' barrel. It is a nice, simple design for a relatively large combustion, and may be of interest for your project.

[BigGrib]

The design I used for my latest gun is a 2' x 4"sch 40 chamber with a 4' x 2" barrel. right now i'm working on a meter for it but you can always adjust your meter to get the right ammount out of it. right now I can't give and difinitive distances on mine because where i have been shooting is a hill which i consistently clear the peak of which i think is about 150 yds away maybe dont quote me on that though

BigGrib

[DYI]

BigGrib: just to let you know, the C:B ratio on the gun is hideous. You're wasting a large amount of the potential power in the chamber. You should double the length of your barrel to get a 1:1 ratio, and the power will more than double from what it is currently.

[BigGrib]

Yeah I have been playing around with interchangable barrels but when i built this one I needed something that wasn't too tall as to present a challenge in loading it, but no that I have converted it to a breech loader I'm going to up the barrel length. If I plugged the numbers in right on advancedspud.coms spudtool program the c:b ratio is like 5:1. the best gun i have ever made though had a 2' 3" chamber and an 8' 2" barrel. that thing was a monster but was a bit difficult to load (standard muzzle loader)

BigGrib

[DYI]

At standard pressures, with a fixed chamber size, a C:B ratio of about .25:1 will give you the most power. Unfortunately, it will also give you hideously long barrels.

[BigGrib]

At standard pressures, with a fixed chamber size, a C:B ratio of about .25:1 will give you the most power. Unfortunately, it will also give you hideously long barrels.

Yeah no kidding for a 4" x 2' chamber you would need a 30' barrel to achieve .25:1 but it would kick some ace