), I will tell you that I didn't re-write this at all. I just copied the post I made on SpudTech here. 
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Mark's Gen. II Hybrid Gun
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After much talking and tweaking, I have my hybrid up and running.
The hybrid is a generation II variant. The chamber is 1-1/4 x 8" SCH-80 seamless steel pipe, and the fittings on the chamber can each hold at least 3,000 PSI. The mix tank is 2x12" SCH-40 and the two are separated by a ball valve.
I originally planned this thing to be a sort of rifle, and was going to make an onboard water pump and everything. But, after much though, effort, money, and experimentation, I just couldn't make it all compact enough. So, here she is:
I fill the whole thing to a 2x/2 atm mix, (more to mix the fuel than anything), and then open the hose into the mix tank to pressurize the ignition chamber even further. Then, the ball valve is closed and the chamber is ignited.
I use three layers of aluminum foil as a burst disk, and I shoot 13/32" steel ball bearings out a 3/8" type L copper pipe 36" long. I had to add a gasket to both the union and the hose adapter, because they were leaking like sieves.
The ignition is installed by drilling two small holes through a piece of 1/4" OD anodized aluminum rod, and then passing them through and epoxying into place. Then, the rod segment is attached to the chamber with a 1/4" OD compression adapter. The igniter is placed inside a small ring of 3/4" SCH-40 which is pressed into a 1" hole bored through the base.
The base is simply two pieces of 2x6 which have been glued together, sanded, charred, and then coated in polyurethane which is used for wood flooring. The spacers are all cut from 2x6 and the entire thing is strapped together with a 13' cargo ratchet strap which was cut to the correct length.
Farthest I've taken the launcher to was 60 PSI compression. This one fired with a pretty loud POP and I didn't quite figure out what the ball hit. I think it hit our oak tree, so I'll check there later. I have a small video at the bottom, (no sound, sorry), of a 40 PSI compression shot.
Now, here are all of the photos...
- chamber-in.jpg (39.29 KiB) Viewed 2908 times
- A view of a burst disk after being subjected to a 40 PSI compression shot
- far-away-full.jpg (16.37 KiB) Viewed 2908 times
- front-system.jpg (38.64 KiB) Viewed 2908 times
- Where the garden hose connects to the mixing tank
- The BBQ igniter
- Where I inject propane, inject air, and where the Oh Shit! hose connects to the mixing tank
Thanks,
~Mark
It's cargo strapping for tying things like boats or ATV's to trailers. I chose it because I could use one continuous length and because it's easy to undo if I ever need to get to any of the components on the launcher.
