The Hamburger by Benjamin Wing Will Bullock Ted Kocak December 6, 2008
Abstract The goal is to make a roller coaster that lasts fifteen seconds with a budget of forty dollars. The roller coaster should not take very long to set up and should not take up too much space. The roller coaster will move a small ball bearing though plastic tubing pretzel, onto a few inclined planes, into a funnel, and down a plastic tubing spiral. The potential energy is converted into kinetic energy, frictional energy, and collisions. It is not very exact and the time varies by about five seconds due to the funnel; ranging from twelve seconds to seventeen seconds. The roller coaster is very variable, but is close to the goal.
Introduction The roller coaster must fit within a.5 meter by.5 meter by.5 meter box and must be able to be set up within 30 seconds and must be safe in its running. The roller coaster is to be made from scratch from materials totaling no more than forty dollars. The goal is to take as close to exactly fifteen seconds as possible. The roller coaster must be self sufficient and cannot be influenced in any way once started. The roller coaster is to move any vessel, such as a ball bearing or small car. Design Process We began our design of the Hamburger with an intense session of brainstorming. Initially we were planning on using a tripod so we could raise the beginning height of the coaster. After further examining of the objectives, however, we realized that the use of a tripod would immediately put us over the $40 limit. We also realized that it would be unsteady and difficult to set up within the 30 second time period we were given. We decided the best track would be a bendable plastic tube. This would give us an easily maneuverable track. We also decided that adding a set of steps would add excitement and make the coaster more enjoyable to watch. We thought of using pegboard because of the simplicity of attaching other parts such as the tubing and step section. We also decided to use a funnel in an attempt to take more time. As we began building, we realized that we needed to build a support frame. After constructing the initial sections of the coaster, we attempted to add the funnel. This proved far more difficult than we had anticipated because it was so variable and unsteady. We decided to use a piece of string, wrapped around the funnel, to hold the funnel as steadily and horizontally as possible. This was somewhat helpful but still left room for improvement. After some testing of the coaster, we realized we were still short on time. Because of this, we decided to add a helix tube in order to add more time.
Design To begin our coaster a ball bearing is dropped into a stretch of clear plastic tubing at the upper portion of the track that contains the two loops, which are fastened to the pegboard frame by zipties at critical points. The clear plastic tubing is readily flexible which allowed us not only to see the progress of the coaster at all points of its ride but to shape the track to any desired angle or form as well. The rollercoaster is built upon a cube-like frame which not only gives the coaster added strength and stability but also allows for the height of the coaster to be effectively doubled via use of two simple hinges, a bolt, and another sheet of peg board. The upper portion of track must be at a constant acute angle (approximately held at 70 degrees), otherwise, the coaster will fail to ascend the first loop. This problem is dealt with by the use of a simple locking mechanism that is similar in nature to a pinlock. After finishing the upper portion the coaster will shoot from the tubing onto a slightly angled incline from which it will travel upwards along the length of the incline until its velocity is equal to zero at which point it will proceed downwards and drop onto the next ramp where a similar scenario plays out. It is worth noting that the inclines are outfitted with bumpers (both of which are attached to the pegboard by zipties) at the ends of each of the PVC pipe inclines so that the coaster will not deviate from its intended path of travel and off the track. The ball bearing then continues into a funnel that is anchored to the pegboard by two screws and a block of wood, which serves as a foundation for the funnel. The funnel is held at a relatively constant level angle to the pegboard by a piece of string, which wraps around the base of the funnel twice and is then tied to the cube frame. The coaster then drops into a spiral, which is constructed by stacking small blocks of wood in decreasing heights and fastening them with zip ties to the tube itself. The coaster will descend the spiral and come to a definite stop at the end of the tubing, as there is a small wad of paper placed there.
Results Trial The roller coaster takes anywhere from twelve to seventeen seconds: Time taken (seconds) 1 15.22 2 12.74 3 13.45 4 16.78 5 15.88 As we began testing the coaster, we realized we had misjudged how quickly the ball bearing would pass through the different sections. It flew through the initial tubing loops and quickly passed through the step section. The funnel was the most variable part of the roller coaster, and it also takes the longest. This section could take anywhere between four and twelve seconds depending on what angle and velocity the ball bearing entered. The roller coaster itself is very hard to pinpoint. During the testing, the roller coaster took twelve seconds, and if we had used something other than the funnel it might have been a little easier to pin point. Conclusion In conclusion, we were able to complete the task given to us and completed a coaster with a 15 second runtime that was within the given parameters. We learned that even though you can plan out what you are going to do the end product usually comes out to be completely different. The main problem attributed to our coaster was its relatively unpredictable runtime which was anywhere from 12-17 seconds but was usually close to the 15 second mark. We determined that this inconsistency in runtimes was primarily due to the funnel portion of the track which could range anywhere from 5-9 seconds while held level. Despite our best attempts to correct this issue, it still remains as the biggest failure of this coaster. However, despite the disappointing inconsistency, we learned many valuable team skills and I am still extremely impressed by our team s innovativeness and on the spot solutions. All in all, our teamwork and individual skills made our rollercoaster a success. References No references were used
Appendices Original Concept