Car Mounted Water Cannon
April 9, 2006 11:43 PM Subscribe
I'm building a water cannon that shoots out from the grill of my car. Range is lacking, and I (probably) don't have the funds for a more powerful pump. I need a better nozzle, possibly one utilizing a blowoff valve to build pressure. Advise.
posted by Derive the Hamiltonian of... to Technology (29 answers total)
Here's what I have to work with: I'm powering the cannon with a 7 PSI carburetor fuel pump, which fits to 3/8 in. hose. I ran wiring thru the firewall and tore into my center console to affix an awesome red push button trigger below the center arm rest so that the passenger (or driver) can casually crook a finger and fire the cannon. For the hell of it, an orange LED on the dash lights up during firing unless the fuse is blown. The jet fires out of the center of my grill.
Everything is installed at this point, but the jet only shoots about 12 feet! We were hoping for more like 30 feet, although I didn't bother with calculations when I started throwing this together. The nozzle is makeshift - just the nozzle from a windex spray bottle fixed onto the end of the injector hose with superglue and sealant. The nozzle aperature is basically a pinhole, and the path of the water through the injector hose terminates abruptly in a wall with this tiny hole. I'm thinking that the cannon would benefit from a slightly larger nozzle aperature and a taper into the nozzle as opposed to a sudden termination. Will this significantly increase range? What sort of household items, such as pens, can be fashioned into good nozzles? I'm also thinking of using a blowoff valve to build pressure before the cannon can fire - the pump seems heavy duty enough to survive working against some back pressure. A solenoid valve would also work, although more wiring and another button would be required. A more powerful pump would help, but funds are lacking. Help me improvise and scavenge my way to finishing this project.