It is a glorious day for SCIENCE! I took a break from my current batch of cannon test prints to knock out an idea that's been bouncing around my brain for a while. After seeing the inside of of one of the swivel fittings I use, I wondered if I could build a larger version of that into a cannon magazine. After a few hours with drill press, dremel, and soldering gear, I had a hacked-together tee built from two different sizes of compression fitting. I found an o-ring that fit perfectly, printed a couple of bits to make the magazine fit nicely, and threw the mess together. Behold, I present the Pivot Cannon, Destroyer Size! Coming soon to a pond near you I just finished initial testing. The cannon fires fast and hard at the 120PSI my shop compressor puts out. I'll see about getting chronograph readings later. The swivel fitting pivots very easily, so easily that even a tiny destroyer servo could pivot this thing. The physical limit on its range of motion is the length of the hose to the magazine. It was initially reluctant to feed, but a couple of rare earth magnets were enough to overcome gravity and get things working reliably. I ended the night with two full mag dumps, 100 trigger pulls for 100 rounds down range. Very satisfying.
Just like any cannon with a magnet on the tee, really. The pressurized gas in the magazine escaping down the barrel when you fire drags the next round up to the tee for the magnets to grab, and then the magnets hold it there until you fire again.
Looks fantastic! If I recall, isn't the max pivot going to be +/- 15 degrees off the bow or stern stems, as allowed by IRC rules?