The lovely people over at Rocket Fued have put together a set of 5 videos, (6 if you count the trailer), showing you how to build your own giant water rocket. When I was a kid I remember spending hours on the weekend launching small 2 liter water rockets. I’d fill them part way with water, then get out a tire pump and watch them go up. My rockets weren’t anything as sophisticated as the above, I had cardboard fins tapped on, and no parachute. But mine never made it much higher then the house, and when they came down, were just the empty soda bottle.
Eventually, I graduated to Estes model rockets, but never made anything as crazy as that V2. The video is cool, and it’s a nice way to get teenagers interested in rockets. I think it’s too complicated for anyone over 12 though. Keep it limited to single stage rockets for them.