<p>ok, probably the best physics lab of the year is here. i need some design ideas that will help me keep a 2 Liter soda bottle in the air as long as possible. only rules are that i cant do anything to compromise the integrity of the bottle that the water-fuel will go in (no hot glue on the actual bottle for the propulsion) and that the main thing is to keep it in the air as long as possible. so basically, i need it to go as high as possible and i need to go down as slowly as possible. i need aerodynamic ideas for on the way up and basically a parachute system on the way down. any ideas/tips? anything would be helpful.</p>
<p>Are there any limitations on the size of the rocket you can strap on this thing?</p>
<p>I did this freshman year... the only thing I remember that could help was that four fins worked better than three, though I guess that could depend on your actual design. And fill up the bottle with around a quarter to a third of water.</p>