Hello! The plugin that makes it work is Movecraft, found here:
www.planetminecraft.com/mod/movecraft-reloaded---loraxe42s-fork/
Of course, the guns work even without any mods or plugins, since they are just redstone devices. Also, if you are interested in getting this sort of thing in single player or a vanilla (unmodified) server, you may be interested in this:
http://www.planetminecraft.com/project/working-full-featured-airship-in-minecraft-18---no-mods-or-plugins---a-movecraft-style-airship/
That airship works with no plugins or mods, however it is not as complex.
Working Air Warship and Fighters - Trident Submersible Fighter Tender on September 29th, 2014 12:17 PM EST
Ah, I see. Well, as Movecraft is not available for 1.8, and with the current legal sillyness that seems unlikely to change anytime soon, I don't think I'll worry about it just yet. Just curious: how did you paste in the schematic in 1.8? I didn't think any schematic handling plugins worked in 1.8 yet.
Working Air Warship and Fighters - Trident Submersible Fighter Tender on September 6th, 2014 11:33 AM EST