The physical launcher was pretty straightforward. I cut out a few legs from 1/2″ ply and assembled them to a couple of wood rings. Its about 3 feet wide, which should provide a very stable base. There is an initial coat of carnival red paint, but that will get additional coats if the trial run actually works..
I then picked up a few plumbing parts and assembled it up. Key pieces were a big 2″ cap with a hole drilled in the end, and I stacked that against a 1/2″ coupler to provide a stronger base.
The cap was mounted open side up. Then when you put the bottle, mostly full of water, on the launcher this cup should hold the water in the bottle. Then as propane is pushed it, some of the water should bubble out of the bottom. At least that’s the plan… You can also see the ‘feed tube’ which is where the propane will be pumped in. It should come in under the water line, then bubble up to the top mixing with the air present.
Not complete by any means, but there it is with a bottle on the launcher, sans fins of course.