Big Freaking Water Rocket Launcher

pinshape

SummaryI want to turn a 15 litre water cooler bottle (the non-deposit kind made of of heavy pop bottle plastic) into a big freaking water rocket. This design is untested, use at your own risk. I for one don't plan on being anywhere near the launcher when I put pressure in. Just uploading it for comments/ideas. TODO: -Release mechanism (in progress). The base design has spots for o-rings, and could operate by just letting it go whenever the pressure is stronger than the friction. I would like to add arms that lock on to a ring on the bottle later on, after I figure out if it will work at all.InstructionsPrinting ====== The STL won't print as is: the two parts have to be seperated. I didn't think the hose barb would print well even with support unless it was vertical. It still needs work for overhangs. Build Thoughts ============ Probably needs to be printed with 30-60% infill with extra shells/perimeters and I plan on using ABS rather than PLA on this one. An acetone vapor treatment or a brush with acetone slurry might be a good idea to make sure it's air tight. The barb end is sized for 1/4" id air hose, but may need to be seperated: it's probably not going to print nicely that way. The rings on the riser should hold a set of O-Rings. They don't all need to be filled - just the 2 or 3 that the cap of the bottle touch against. The style of bottle I am using (see pictures) is smaller than the normal cooler bottles, and doesn't have a handle, so it should balance more easily. None the less, the legs of the launcher have holes to peg into the ground or screw onto a larger base. Potential issues ============= The cap may completely pop off instead of launching from the smaller nozzle. Epoxy might help there. I have no idea what kind of pressure these bottles can take. I plan on using just a little bit of water and building up Balance and aim: the bottle will likely need some fins for stability and a nose cone for aerodynamics. Need lots of space, probably bigger than a back yard. I don't want this thing hitting me or landing on anything I don't want damaged.