My teacher, as an end-of-the-year "fun" project, partnered us up and wants us to build water bottle rockets using two liter bottles. The only rules are that the rockets must not be propelled by anything else that uses fire, for obvious reasons, and that we must have a parachute or other recovery system. That leaves my options wide open. I've never built a rocket like this, so I'm looking to y'all for some advice. The contest is for the longest hangtime and highest altitude. I really want to win. I've considered heating a 2-liter and extending the bottom into a rounded-point nose. If I use a parachute, I want to make it as big as possible to cause as much air resistance as it can. I've thought about using wings instead of a chute, but the idea seems a bit complex. I have no idea how to calculate anything, like the ratio of chute size to descent time or even terminal velocity, as it's never been covered in our curriculum. If any body has ever made anything like this or has any sensible ideas, please, please let me know! We launch next week, so time is pretty short! Thanks, Bran.