Hi guys,
Has anybody tried to build a cardboard rollercoaster for physics class?
We need to build an 8 inch diameter loop out of anything cardboard and our attempts so far have been unsuccessful. I really appreciate any ideas you guys may have thanks a lot.
-Jordan
Unsuccessful in which sense? Does the car not make the loop? Does the whole thing fall apart in a spectacular crash? Does the car have to start from a certain height on a hill?
More details would really help here.
we can use cardboard and clear tape, with a maximum height of 7 feet. A marble needs to make it around an 8 inch diameter loop we have tried to use cardboard tubing by cutting it in half and slitting the sides so it would curve the ball couldn’t make it up the loop I guess it was too flimsy and bumpy.
Flimsy is ok… Not every roller coaster loop has to be a rigid shape. A little give is ok as long as it’s not too much. IN a real roller coaster I would not advise this, but since you don’t have to ride this one… a little give in the overall ride would actually work to your advantage.
Also, don’t make the shape it goes around completely circular. An oval-ish shape works better for stored energy while in the top of the loop vs gained energy out of the loop.
A roller coaster loop is actually a teardrop shape called clothoid. A clothoid is a section of a spiral in which the radius is constantly changing. Unlike a circular loop in which the radius is constant, the radius at the bottom of a clothoid loop is much larger than the radius at the top.
http://www.worsleyschool.net/science/files/roller/clothoid.gif
http://www.worsleyschool.net/science/files/roller/coasters.html
Also, notice the many varieties of the clothoid and the many ways it is implemented in these photos.
http://images.google.com/images?svnum=10&hl=en&lr=&q=roller+coaster+loop
Good luck with the project!!!
The key to bending cardboard smoothly is (much like wood) to use thin pieces (corrugated is right out) and glue them together in a form, and when the glue (elmer’s) dries the shape is maintained. Trying to bend a thick piece will result in frustration.
The tighter the bendm the thinner the cardboard must be. I guess the thinnest you’d ever need is plain paper. For a 10" loop use 0.010 poster board, maybe 0.020 shirt board.
Don
use support structures along the bottom to maintain a smooth curve upwards, make a tear drop shape. cut small triangular portions out of the sides of the tube to make it easier to make a loop.
I cant tell you how much i appreciate all of your help so far. our first attempt was to take toilet paper rolls cut it longways into two halves we then cut relief triangles in it then we attached them to each other forming the required 8 inch diameter loop and then let it go in a very steep tube for the 7 foot drop and it didn’t work… The frustrating part is that we should be able to do it but its just not working. i wish i could use things other than cardboard and tape.
Thanks a lot everybody, I know we need to be saving our brainpower for next week, but i really can’t tell you enough how thankful I am. This really is what FIRST is all about.
-Jordan
