3/4" Valve Preformance

[mega_swordman]

With the end of the school semester and my return to the states looming over my head, I decided it would be best to start planning what my next cannon would be. I have eventually decided upon using the model from the Bergles Cannon
This proposed cannon will have a 3" chamber and a 1.5" barrel. My proposed idea is that this will be activated by a 3/4" (modded) sprinkler valve. My question is: will my performance be drastically reduced in comparison to using a 1" valve? Also, would it be worth the extra money to buy the 1" valve?
(Note I include extra money. Many of you will think "it's not that much more" but I seem to have very bad luck when it comes to modding sprinkler valves. But please don't re-direct me to different tutorials, I know how to do it, and I have recently discovered my error.)

[octane89]

The bigger the valve, the more flow. Which means more power. I always see 3/4 valves the same price as a 1in, Id say just get thte 1inch. There would be a somewhat noticable performance decrease too with the 3/4.

[Ragnarok]

A 1" valve has almost twice the flow of a .75" valve. That won't mean twice the performance, but it will still be a HUGE increase.

It's worth the extra money, as long as the difference in cost isn't vast.

[grumpy]

having built several of the bergles cannons i agree with octane89 go with the 1"valve , if you realy want to unlock the full potental of this system you should get one of the 2" spinkler valves. just some advice when you build, do it so that later you can upgrade the sprinkler valve.

[mega_swordman]

Thank you for the advice. Grumpy, I have tried making the gun so it could be easily modified, but I can't seem to find a way to design it without the valve being stuck between two male adapters with no room for it to be removed. How do you suggest I make the cannon so it can be modified? (or at least, have the valve taken out and replaced easily)

[grumpy]

i asume you will be using a threaded sprinkler valve. somewhere on the barrel side simply put in a union. that way when you want to change out the valve simply unscrew the union, then just unscrew the valve and their you go.
also what loading system are you going to use?

[mega_swordman]

I am planning on using a breech loader similar to that of Advanced Spud's version

[grumpy]

i guess that design would work for you , but it would be to slow reloading for me.

[mega_swordman]

I sincerely apologize for kicking up this thread, but I just need to clarify what Grumpy said. I have here a diagram (or part of it) of what the Bergles Cannon will look like.

Now then, The long horizontal section of pipe on the left, if I put a union there, will I be able to unscrew that? (Sorry if this is a bit of a n00bish question, I haven't seen/held a union in the "physical world" so I'm not exactly sure how well it will work)

I would also like to apologize to Grumpy for having to deal will my lack of understanding, do you have any pictures to help me out?

Also, to clarify, the sections on either side of the sprinkler valve are elbows with one side of them being male adapters. I would like to use these to cut down on the length of the back section.

[grumpy]

no need to apologiize i was not offended and do not mind ansewring questions, what size is the inner barrel going to be? well hope this turns out ok.

[mega_swordman]

The barrel will be 1 1/2" and the sprinkler valve ( and corresponding parts around it) will be 1".

Thanks a lot, I get it now.