Final Blog Post

After five days of bottle rocket launching, the process is finally over. Our rocket has been through more than we ever thought was possible. We learned a lot about physics through this project. I learned a lot about aerodynamics, design, center of pressure, center of mass, and using resources conservatively. Our first bottle got stuck in a tree after our second launch, so we had to deal with starting over from scratch as well as redesigning our rocket when certain aspects of it failed. I learned to observe closely and troubleshoot the problems that our bottle experienced. This was necessary in order to keep increasing the time that our bottle was in the air, as well as be successful in our endeavor. The details to our 5 days will be listed below:

Day 1) Our bottle rocket consisted of a 2 liter bottle, filled with one cup of water and pumped up to 40 psi. Our second launch came with the most success, about 3 seconds in the air.

Day 2) Our bottle rocket got upgraded on day two. We added three cardboard fins, duct-taped for aerodynamics, which were hot-glued onto the bottom of the rocket. We also installed a small piece of wood to the top of the bottle in order to create a top heavy rocket. This, we discovered, would make the Center of Mass higher than the Center of Pressure and make our rocket travel higher and in a more controlled way. Our first launch lasted about 5 seconds. This is an upgrade from day 1. Our second launch got stuck in the tree and we were forced to start from scratch.

Day 3) Our new bottle rocket was created to look exactly like the previous rocket. We added a paper cone, to make our rocket more aerodynamic. Under the cone, we attached a parachute, a plastic bag that was attached to our rocket with string. The parachute was unsuccessful in deploying properly. We also found out that the paper, no matter the shape it was in, only distracted from the time the rocket was in the air. After figuring this out, we took off the cone and added two cups of water and pumped our rocket up to 60 psi, gaining a successful 7.7 seconds in the air.

Day 4) On day 4 we installed a new and improved cone to our rocket. The cone consisted of the bottom of another 2 liter bottle. Duct taped heavily for aerodynamics and attached to a small rock for a higher CM. Under the cone, we attached a much larger plastic bag (a garbage bag to be exact) to the rocket. This parachute was much more successful. When it deployed, it picked up a lot of wind and slowed down our rocket's decent. Our new cone, however was in consistent in falling off of our rocket when we needed it to. Therefore, we had a bunch of successful and unsuccessful launches. Our best timed for 8.8 seconds.

Day 5) Our last modification consisted of a new cone. Our cone was both heavy and aerodynamic. It was a small traffic cone, which fitted exactly on our bottle. The cone was big enough so that our parachute could fit securely under our cone and yet, be loose enough so that it could deploy easily in mid-air. We attached our cone to our rocket so after it fell off it would still be attached. After many disappointing launches, we timed in at 9.5 seconds, just short of our 10 second goal.

"Post Lab"

What worked best was a semi-heavy traffic cone as a bottle rocket cone. The parachute worked best when it was extremely large so that it could catch more wind and slow down our rocket even more. The smaller the strings that attached the rocket to the parachute, the better. The longer the strings, the more likely they were to get tangled when confined in the cone. Our fins worked very well. They kept the rocket from twisting and spinning uncontrollably. We also learned that the more water there is in the rocket, the higher the rocket will fly when launched. We also made sure that we pumped the rocket to about 60-80 psi to ensure that it launched with maximum efficiency. Thus concludes our conclusion of our bottle rocket adventure. We wouldn't do anything different if we had to do it again.