Scioly.org

1/3 indeed was the sweet spot for me with the 1L bottles a few years ago. But that's really something you should optimize yourself for best performance. Not very difficult to get data on.

calgoddard wrote:The current wiki for this event on this web site seems to paraphrase the 2011 rules at the beginning in stating that 1L bottles will be used, and then later on it discusses a so - called "standard design" that uses a 2L bottle.

This is a little confusing. I don't know if we should be experimenting with 1L bottle rockets or 2L bottle rockets. Bottle rocket design considerations are seriously affected by the type of bottle.

i seriously dont know but i think it is 2L because they are more common

People used all kinds of bottles last year. See the image gallery.

Sasher Applesauce wrote:

calgoddard wrote:The current wiki for this event on this web site seems to paraphrase the 2011 rules at the beginning in stating that 1L bottles will be used, and then later on it discusses a so - called "standard design" that uses a 2L bottle.

This is a little confusing. I don't know if we should be experimenting with 1L bottle rockets or 2L bottle rockets. Bottle rocket design considerations are seriously affected by the type of bottle.

i seriously dont know but i think it is 2L because they are more common

Your pressure vessel must be a 2L (3.a)

so what can we use and not use....

Read the rules! That is the only official source for that information - don't get misled by anything else! If you haven't obtained and read the rules, you need to do so before starting work on the event.

My post quoted above was dated Agusut 22, 2010, BEFORE the official 2011 rules were published.

The 2011 BOTTLE ROCKET rules require that the "[r]ocket pressure vessels must be made out of a single 2-liter plastic carbonated beverage bottle."

so would I be able to do the following....to poke a few holes into it to make air go inside and keep it floating longer (I won't poke holes into the actual bottle, just the nose cone thing....also where would u say is the best place to put the fins and how many)

I don't see anything that prevents you from poking holes into a nose cone or any other part than your pressure vessel (make sure you fit the definition of a blunt nose cone).

But poking holes isn't going to keep it up longer. Doesn't effectively increase your drag. You really want to ensure that your rocket tumbles or falls horizontally. Read up on "backsliders" - you want your CoG (Center of Gravity) to be closer to your CoP (Center of Pressure) - this will cause it to fall more irregularly than going nose-first.

I'd like to try to have it come down the way it goes up and then make sme fins that are kind of like parachutes, except they don't move