Today we built our rocket tube. We scratch built it so we could have it weigh the smallest amount possible. Andrew did a small demonstration in the morning teaching us how to make them. We learned that you use wood glue and thick paper that is cut into strips. You use a PVC pipe and wrap that paper strips along it. You need to make sure that the seams are fitted correctly and that they align. Since Genevie and I are using the one that Andrew made during the demo we don't need to make our own, but we still know how to make one.
Our next step is was to build our fins. We knew the shape and material which were, clipped parallelogram and balsa wood. We needed to calculate a few things before knowing the size of our fins. We had to find the center of mass and center of thrust, and from there calculate the surface area of the space above and below the center of thrust. Once we found the top half and bottom half, we had to make the fins a size with the surface area that would equal out the top and bottom parts of the rocket. After that, we made four fins, by using razors to cut the balsa wood. Our initial plan was to have four fins, but we got misinformed that each fin counts as double the surface area, but it actually only counts as one. So, that threw us off a bit, and instead of resizing the fins we already made we just chose to make four more fins, with a total of eight. That equalled out the surface area to where we needed it to be.
For our nose cone, we were going to build and shape our own, but then Andrew showed us something that would work even better. It was a PVC pipe cap. Since it was the same size as the PVC it fit perfectly in the body tube. It also just happened to be the right weight and have the right amount of friction so when the parachute needs to come out, it will be deployed properly.
For the parachute we used a plastic trash bag. We got a brand-new one and then used a makeshift compass so we could have a close to perfect circle. Then we duct taped four of the edges and hole punched them. We then used fishing line to connect the parachute to the shock cord.
Our next step is was to build our fins. We knew the shape and material which were, clipped parallelogram and balsa wood. We needed to calculate a few things before knowing the size of our fins. We had to find the center of mass and center of thrust, and from there calculate the surface area of the space above and below the center of thrust. Once we found the top half and bottom half, we had to make the fins a size with the surface area that would equal out the top and bottom parts of the rocket. After that, we made four fins, by using razors to cut the balsa wood. Our initial plan was to have four fins, but we got misinformed that each fin counts as double the surface area, but it actually only counts as one. So, that threw us off a bit, and instead of resizing the fins we already made we just chose to make four more fins, with a total of eight. That equalled out the surface area to where we needed it to be.
For our nose cone, we were going to build and shape our own, but then Andrew showed us something that would work even better. It was a PVC pipe cap. Since it was the same size as the PVC it fit perfectly in the body tube. It also just happened to be the right weight and have the right amount of friction so when the parachute needs to come out, it will be deployed properly.
For the parachute we used a plastic trash bag. We got a brand-new one and then used a makeshift compass so we could have a close to perfect circle. Then we duct taped four of the edges and hole punched them. We then used fishing line to connect the parachute to the shock cord.