That depends on the motor that will power it. typical 40-48 inch rockets are 2 inches diameter.
The width should be 1280 and the height should be 928.
big rocket
The Big Day - Rocket Power - was created in 2004.
100ft
30000000m
Its not big at all. If you look at you pinky's nail that's how long it is. The width is the width of your pinky.
Its not rocket science, develop muscles specially lats , deltoids to get a broader look
At the very bottom is the nozzle, after that is the fuel. Depending on how big the rocket is and how much fuel it needs determines the size of the chamber
A water rocket should probably have three to four fins.
The aquarium should at least be by 24 (length) x 12 (width) x 16 (height)
near the nose of the rocket
In a big enough rocket.