Final Bottle Rocket Post

Yesterday we launched our bottle rockets for the last time. Our final rocket consisted of four cardboard fins that were completely duck taped, a nose cone made out of a top of a bottle, and a parachute made out of a small trash bag. We used a nose cone so that our rocket was aero dynamic and it served as a housing unit for our parachute. Our parachute was made out of a cut trash bag, which was attached, by four pieces of string. Our triangular shaped cardboard fins were positioned as far down on the bottle as we could so that the center of pressure of the bottle would be toward the bottom of the bottle. This would cause the rocket to stabilize it in the air. If the fins were toward the top of the bottle the tail of the bottle would turn around and be facing the wind. The nose cone of our rocket was weighted by gluing a few pennies into the top of the nose cone. By doing this, the center of mass is located in the top of our rocket, which also increased the stability of our rocket so that the rocket did not go tumbling in the air. The cone we had was tied down on one side so that it could pop of and the parachute could deploy. On the first day of our launches we launched with 50 ml of water and around 60 psi of pressure with a plain bottle. For our second attempt we used different water pressure and air combinations to find the most efficient combination for our final launch. We launched twice and had times of 3.6 second and a 4 second launch. We quickly realized that we can get the rocket higher by stabilizing it, and that is when we added our nose cone, fins, and parachute. The next class the objective was to get one 5 second launch. With our modifications done we were able to get it in the air for 9.3 seconds after hitting a tree. On the final day it was really windy and rainy. Our school was pretty much in a big cloud. Our first attempt got a time of 8.3 seconds before flying down to the tennis courts. Our second attempt got a time of 4.6 seconds with a pump that did not hold the air very long. And our third and final attempt had a time of 9 seconds before floating its way down to Akahi hillside. At the end it was pretty satisfying to see our rocket doing well and having our modifications serving the purpose we built if for. Overall we did well on the rocket project but bad weather made our rockets perform worse than expected.