PET-bottle water rockets are fun. And if you have children, you already have an engineering-, launch-, and recovery team. Let an adult take responsibility for safety: Exploding pressure tanks (i.e., water rockets) are dangerous! To learn more about water rockets, check out the excellent articles by Air Command Water Rockets. The usual way to create a very simple rocket is:
- glue fins to PET bottle
- glue nozzle to PET bottle
- tape nose cone to PET, possibly adding some weight for stable flight
Then bring your launch pad to some vast, empty area, fuel your rocket with water, pressurize using a bicycle pump, and launch.
Tricky part: Glueing to PET.
Solution: Screw-on fins that also provide a thread-adapter from PCO-1881 (PET-bottle thread) to 1" British Standard Pipe Thread (Gardena(tm) tap-connector).
Note that the threads in C2 do not act as seals: The lip of the bottle C1 will directly seal to the gasket inside the tap connector C3.
Some bottle-shapes may not fit into the fin-adapter. Coke bottles work nicely, though. It should not matter much which type of garden hose connector you use as long as it has a 1" British Standard Pipe Thread (often abbreviated as G-1"). I use these.
These variants for C2 are currently available:
| Part-# | Name | Picture |
|---|---|---|
| PN1 | 3 narrow fins |  |
| PN2 | 3 broad fins |  |
| PN3 | 5 narrow fins |  |