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Winter Break Project - I want you guys to check out my idea

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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What do you think I should do?

Listen to you guys rip me a new one and then redesign from scratch?
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Go for it as is?
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Stick with the overall design but make some minor tweaks?
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Stick with the overall design but make some major tweaks?
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Total votes : 1
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Winter Break Project - I want you guys to check out my idea

Unread postAuthor: ToppRamen » Wed Nov 19, 2008 6:04 pm

Hey guys, I'm back. I'm the guy with the curly hair.

I have done as much research as possible and I can honestly say, now, that my last cannon... sucked.
I'll be the first to say it. It's true. It was poorly designed even though the performance was good for my first, and I learned a lot. I had the mechanics I wanted for my first, just not the design and aesthetic I desired.

So, I decided that this winter break would bring forth the construction of the "BIG ONE". The tennis ball/anything launcher. Piston valves. Breech loader. 10 feet of 2.5" barrel. This is going to be it.

HOWEVER, I want to put my idea on here for you guys first. I want to see if my design isn't just what I think is a good idea for a potato cannon, but is actually a good design, both in execution and aesthetics.

Hit me with your best shot. The design is an "exploded" view, and NOT TO SCALE. I designed this with space, sturdiness, and performance in mind. I am not ignoring the turbulence and dead space caused by the path the air has to take after the valve, I just need some form to come before function. This thing needs to fit in my garage.

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Unread postAuthor: jackssmirkingrevenge » Wed Nov 19, 2008 6:16 pm

I wouldn't bother with dual piston valves and chambers, a single piston and chamber should give you more than enough performance with half the effort.
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Unread postAuthor: FishBoy » Wed Nov 19, 2008 7:01 pm

i agree with jack, the main reason for dual valves is if you can't make one that's big enough( 2" barrel, might use 2 1" or 1.5" valves)

edit- now that I think of it, your hair kinda looks the way (Top) Ramen does when you take it out of the bag
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Last edited by FishBoy on Wed Nov 19, 2008 8:02 pm, edited 1 time in total.
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Unread postAuthor: VH_man » Wed Nov 19, 2008 7:02 pm

I disagree..... Not many Dual Valves on this Site.... Ive always dreampt of one.
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Unread postAuthor: Fnord » Wed Nov 19, 2008 7:59 pm

I remember you. The guy with the Hair.

:)

I agree with those above, it would be better to go with a larger valve instead of two smaller ones. Two 1.5" valves will be only a little better than a 2" porting valve. A 4" tee will cost more, but in the end you'll probably save money by only using half the number of fittings. You could probably use 2.5" porting with a 4" tee.

You could also use a single 4" chamber and still have around a 3:1 CB. Again, probably money saved.

Other than that, the aesthetics and such are fine. Make sure the barrel is strapped down tight to avoid recoil stresses on the valve and valve connections.
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Unread postAuthor: starman » Wed Nov 19, 2008 8:04 pm

I'm of the opinion that 2 valves are overkill, overly complicated, more expensive, hard to get timings right between the 2, and just plain not necessary. However, very powerful cannons can be made with one or two.

Bad to the bone Newtons Law; 1 valve

and Coagulation; 2 valves
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Unread postAuthor: rp181 » Wed Nov 19, 2008 8:23 pm

omg... that Newtons Law canon is awesome...


Anyway.. i think 1 valve is your best option, until you've built a couple gun and have the time,money,and experience to try a 2 valve gun.
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Unread postAuthor: VH_man » Wed Nov 19, 2008 8:40 pm

All things considered, Id stick with a single valve for starts. Its just simpler. And gives PLENTY enough power.

Dual valves are best left to those with the facilities and machinery to make them almost the same, as to let them open as one single unit.
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Unread postAuthor: pizlo » Wed Nov 19, 2008 9:36 pm

I want to add this, piston valves are hard to make. Yes they seem simple enough, but sometimes stuff just doesn't work. The rest of your design doesn't matter unless you have a working valve, so I would concentrate on that.
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Unread postAuthor: ToppRamen » Wed Nov 19, 2008 10:16 pm

You guys are like the Oracle, exactly what I needed to hear.

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Here is the Big One 2.0.

10'x2.5" barrel with 8'(total)x4" chamber, for a C:B of just over 2:1.
Is that a good ratio to start with? I can always go for the full 10' length of 4" pipe and just use it all, letting fate take care of the exact decimals and figures. I just know that I want at least 2:1.

Mind the breech loader.
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Unread postAuthor: starman » Wed Nov 19, 2008 10:49 pm

C:B at 2:1 will be plenty, especially with this chamber volume and a relatively light weight projectile (tennis ball). You'll be getting lots o' power coming out of the barrel though.

Note that if you're shooting for distance, the light weight and drag coefficient of a tennis ball is going to be your limiting factor and you can equal this distance with a much smaller cannon. However, if you are shooting for damage power, the first say 30 yrds, you're going to be very high and impressive.
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Last edited by starman on Thu Nov 20, 2008 9:00 am, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Thu Nov 20, 2008 12:56 am

I like version 2.0 better :) 2:1 is already overkill as a ratio, but as long as you're not pumping it up manually and don't care a lot of your hearing or the neighbours, go for it.

Remember, there is no spoon ;)
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