Sheldon's rocket

During the next three weeks, I will be building a water-powered rocket. I'm thinking that it should look like the one above. It should have a tennis ball inside the nose for it to be heavy enough to fall off (for the recovery system), and a parachute hidden in the fuselage. But, I'm going to build the fins differently.

We have (and will watch) watched a few movies/cartoons that will help us build a successful rocket. There was one movie that showed us what the Wright Brothers did.
I will have 3 bottles, 2 tennis balls, 1 manila folder (for the nose cone), 1 strip of Avery reinforcement tabs, and 1 plastic bag (for the parachute) for making the rocket. Everything else (e.g. tape, scissors) is shared by the class.
We'll also make altimeters, instruments that measure the altitude of our rockets.
Here are a few links to water rocket websites:

http://www.ast.leeds.ac.uk/~knapp/rockets/
http://www.outsideconnection.com/rockets/
http://users.bigpond.net.au/mechtoys/waterrocket.html
http://www.sciencevideos.com/products/space/waterrockets.html
http://www.learning-tree.org.uk/evt321rocket.htm

Here's a "water rocket jet pack" movie. The Japanese at the bottom means: "He flew higher than we expected!": http://www.ast.leeds.ac.uk/%7Eknapp/rockets/1.mov
Here are my friend and my launch results. As you can see, we didn't do a good job of recording: