Large Pilot or Flow Restriction?

[kablooie]

I am building a cannon very similar to the Fish killer 2 (seen here: http://www.spudfiles.com/forums/fish-ki ... 11714.html I hope that's alright with PVC Arsenal 17). The differences are that mine will be larger, (3/4" barrel, 2" chamber), use a 1" sprinkler and I will also have a bolt action breech loader where he used the quick-disconnect.

The problem is this: I cannot decide whether to have the sprinkler valve perpendicular to the barrel, and have a large pilot volume to where I am putting the trigger (see diagram) or to have the valve parallel to the barrel (underneath) and have a smaller pilot volume but more flow restriction. I do not want to change where the trigger (blowgun) is and I can't put the valve inline with the barrel because the thing is already ridiculously long. Here are some diagrams to clear up any confusion:(click on them to see clearly)a

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I realize that a I could make the differences less drastic too. Any help would be greatly appreciated!

P.S. I don't want to hear reasons (if there are any) why I shouldn't build this cannon, It is near completion and there's no going back.

[jackssmirkingrevenge]

There is option 3 - that was revealed to me by a visitation from Yurhosithtulong, the messenger of the Gods of efficiency - that would still not result in losing your ergonomic trigger.

As per diagram, tap the blowgun directly into the sprinkler valve, ie your pilot volume is at the bare minimum, and mount the valve just before the breeck loader, ie practically no dead space.

Then all you need is some sort of rod (depends what materials you have avalable, anything that's long and strong enough will do as long as it's adequately supported) that will allow you to trigger the valve from wherever along the launcher you want.

[kablooie]

Thanks for the reply, the only problem is that length is an issue, because with the sprinkler valve in-line, the gun would be a little less than seven feet long. If the options that I came up with would have a big effect on the performance of the cannon (more than 10%) I suppose i could use it that way though.

[jackssmirkingrevenge]

In that case, the blowgun-mounted-directly-on-valve-rod idea will still work for this option.