Final Blog Post

Well this is it. The final blog post for this Physics Bottle Rocket Blog. Overall the project itself was a challenge, but a fun one as well. It was quite the challenge because we had to build the rocket itself from scratch and modify it as the days went along. We've done this kind of thing before in the past, but the difference was that the parts and items were included in the kit for assembly. In case you are unfamiliar with our project, here is a complete list of all of the previous blogposts and the multimedia in it:

http://bottlerocketshoi.blogspot.com/2012/02/bottle-rocket-launch-1.html
http://bottlerocketshoi.blogspot.com/2012/03/bottle-rocket-launch-2.html
http://bottlerocketshoi.blogspot.com/2012/03/bottle-rocket-launch-3.html
http://bottlerocketshoi.blogspot.com/2012/03/bottle-rocket-launch-4.html
http://bottlerocketshoi.blogspot.com/2012/03/bottle-rocket-launch-5.html

For the rocket, we had to use 2 coke bottles and several hand made accessories that helped the rocket out. The fins that we used were made out of strengthened paper and cardboard in order to serve the purpose that it needed (to keep the rocket flying straight up and to add an aerodynamic factor to the result).

For our first launch nothing was modified and the launch time was about 3-4 seconds. The second time fins were added and the rocket stayed in the air for about 4-5 seconds. The psi usage was different each time, specifically we used about 10 pumps the first time, 15 pumps the second time, and about 20-30 pumps for the rest of the times. We had to use more psi in order to make up for the added amount of fuel, which went from 500 mL to almost 800 mL by the last launch. The data proved that the more fuel added, the more psi had to be used in order to launch the rocket higher. The more pumps, the more room for potential launch.

The functionality of our rocket went pretty well I must say. The weight was evenly distributed at launch and after the bottom became heavy, which allows the rocket itself to fall and the parachute to open up. The cone on our final launch day evenly distributed the weight from the bottom of the water bottle (weight of water, and fins combined) The cone also made the rocket fly straighter at launch. After the launch reached its maximum height the cone fell of and released the parachute. Everything we put on the rocket worked as planned. We made the fins start at the middle of the bottle and curve around the neck of the top of the bottle to distribute weight and make it more streamline. The cone did what we thought. It flew straighter and distributed weight evenly. The parachute also functioned well but we don’t have any physical model or final evidence of our rocket because it is now on the auditorium roof. The thing that didn’t go well was the launch. At launch it flew high and straight but then the wind came and our rocket was gone and that was not planned at all. The main modifications that we would make in the future is to make a better parachute that is less ruffly and thin. The next is the make a better cone ejection parachute release thing. Its something fun and makes us always want to try to get a better grade.

Final launch

Alright... soo here is our final launch day. It didn't go to well. I had a little more than an hour to reconstruct our groups rocket because the absence of my partner caused me to make a makeshift rocket that I must say went pretty good for pulling it out of materials lying around in class and in an hour. As you can see, its obvious I didnt reach the 10 second time goal. And its obvious the rocket is now gone. It was unretrievable and is now somewhere on the roof of the auditorium. Somethings I would do to change our rocket was to make a better circle parachute, a snug cone and a better mechanism that can release the parachute. Our rockets needed a lot of improvement. I think if the building was not there I would've made the time, but I got 5 seconds to the roof. Overall I think it was pretty good for just making the rocket in an hour but we could've did a lot better.

Bottle Rocket Launch 4

Today all of the groups had to launch our bottle rockets AGAIN. Except with a couple of changes. For one thing, the bottle rocket had to stay in the ayer for 5 seconds. Secondly the bottle rocket had to have some sort of parachute in a capsule device. For our rocket we outfitted the rocket with a new set of fins with an extension to give the rocket more center of balance. We also put a capsule (another coke bottle bottom) that would end up holding our parachute. For the parachute we used a trash bag that was pretty much unmodified. This would end up being our downfall since the parachute couldn't really open up and catch air, leaving the rocket in the air for about 3.9 seconds. Another factor that influenced the time the rocket spent in the ayer was the rain of course. It was pouring pretty hard, and that ended up acting as an added downward force, which caused the rocket to launch less off of the ground, and fall down faster. Next time we are planning to make a proper parachute to let the bottle stay in the air for 10 seconds, our final launch.

Bottle Rocket Launch 3

For this launch, it was required that the rocket stay up in the air for at least 3 seconds with a parachute. Initially we weren't worried about the outcome of this launch because our previous launch stayed in the air for about 4 seconds. While my partner was finishing up attaching our ghetto parachute I went downstairs to go and set up the launching apparatus. That is when I got worried. I saw that the other groups were having difficulty with keeping their rockets in the air. That was probably because there was too much mass or uneven distribution of weight on the rocket. On top of that you have to have enough fuel to compensate for the added mass. So what our group did was attach a light parachute to the rocket from last time, and this time we added about 700ml of water for fuel since we were adding mass. My calculations were correct because our rocket stayed in the air for about 4.72 seconds. It is still a long way till the end but in the future we will build a more suitable parachute and holding apparatus for the parachute.

Bottle Rocket Launch 2

For this second launch of our Bottle Rocket project, our group made a little modifications to the rocket itself. This time a different shaped bottle was used. Instead of using a Dr. Pepper Bottle, we used a normal shaped coke bottle for the rocket body. Modifications wise we decided to add some economical fins on the sides of the rocket. They are economical because they were made with simple printer paper and duct tape. This way the rocket had more length and center of balance while keeping the ballast to a minimum weight. We also attached some more duct tape near the nose of the rocket to add more balance to the rocket. Instead of using 550ml's of water for fuel, we used about 600-650ml of water to compensate for the added mass. Initially we faced problem because our launchers kept on malfunctioning (Several of the pumps had holes in its tubes). But when we launched out rocket it stayed in the air for more than 3 seconds (3 and a little more than 4 seconds respectively. I'd say that in the future we would have to make a little more modifications to make the bottle stay in the air a little longer.