January, '06: I've been trying to figure out how to build fireball shooters so that I can properly arm the gun deck of Short John Silver. Da plan is to have two to a side and to be able to fire them individually or in tandem as needed. The things will be camoflaged to look like deck guns, but pointing more upward than outward, so as to comply with the regs (no fiery objects below 10ft altitude). The things I've seen so far are now all vague recollections, because either the camera wasn't working at the time or I didn't have one with me. Anyway I'm pressing on regardless. Following, in photos and text, are descriptions of what I'm trying to accomplish. Any input from folks wiser than me would be greatly appreciated!
|Photo #1: In progress: first of four fireball shooters which will eventually occupy the midship gun deck. In operation propane enters thru the quick-connect fitting and fills the expansion chamber. A salvaged bicycle brake handle is used to activate a whistle valve atop a length of pipe. I'm a little concerned about the connecting cable binding, but the solution must wait for the next iteration. Still to be added are a battery powered piezo sparker and a nozzle which will be made from a stainless steel egg cup, the only off-the-shelf item with the requisite geometry. The expansion chamber is a relatively thin wall aluminum cylinder, available in a variety of sizes from Catalina Cylinders, in Hampton, VA. These are low pressure cylinders and are only rated to 1440psi. That's a safety factor of 10, as the propane that will fill them will only be pressurized to around 150psi.These cylinders only weigh a fraction of an equivalent scuba tank, so even the fully assembled device will be portable.|
|Photo #2: Good old Lunkenheimer. I took the valve handle off with the intention of making another one that was at the correct angle to work with a straignt string of pipe, but the handle's already designed so that it can be flipped over. Problem solved, and easily.|
|Photo #3, the bad news: I got this thing at a swap meet and it's got a crack (hilighted) that needs fixing. Will ask my pals at sci.engr.joining.welding to learn the best method of fixing this.|