There are plenty of bottle rocket plans out there, but I hadn't seen anyone use a quick release coupler as a launch mechanism before. Plus, all other launchers are so large, it seemed to me all you need is the coupler and a valve. I decided to make two so me and the girl can go to the park and have a shootout (after all, the bike pump is hers).
Step 1: Collect your parts.
A set of quick-release garden hose couplers (I had this idea while in an Ace hardware store, and as it happens, this brand works better than the Lowe's version which won't hold under pressure.)
Rubber tire valves (auto parts store)
4" of 1/2" PVC (Lowe's Depot)
1/2" PVC cap (ditto)
1/2" PVC to 3/4" NPT elbow (NPT= National Pipe Thread) (ditto)
1-2 liter bottle (I like seltzer.)
(not shown) extra garden hose gaskets
PVC cleaner and cement (Lowe's Depot)
Teflon pipe tape (I used the pink, which is thicker.) (ditto)
Saw (pretty much anything will cut PVC)
1/2" drill bit and something to make it spin