273 replies to this topic

[Top_Thrill_Dragster33]

I don't think I have a choice on finishing this coaster. Cosi is almost ready to have a press release about it. This means I will Defiantly finish this coaster.

[KiNg Of Da Ka]

Man you better not make some crappy supports.You have to make a really strong base to stop any shaking.Good luck and use almost all those pieces.

[coastercrazy10]

Here are some suggestions that will help you survive.

1) Make a DETAILED plan of how you will build the coaster. I reccommend using graph paper and building the coaster in small sections to be assembled later. This is how i built Kingda Ka.
2) Do NOT NOT NOT build supports without an idea of how they will go together in the long run
3) build the coaster on it's back in a long room to work out any kinks in the design. The supports will sag back, but you'll be able to tell if you're short a red rod or something somewhere
4) pullups should be approximately half of the height. Scary thought, i know. If you must go smaller, don't go more than 3 feet smaller.
5) figure out how strong your rubber bands are. do the math with your small coaster: How many feet of launch (X) to get the car over Y feet? Make that a ratio (X:Y) and take your height of your tower and figure out how big your launch should be.
6) Use as many cross braces as possible! They keep the tower from swaying significantly.
7) Height:Width ratio is 5:3 (as seen on TTD and KK)
8) instead of a single back column, make it two wide. This adds a lot of sturdiness.

As you can see, there is a HUGE amount of planning that goes into a big coaster and honestly, i don't see you having done these things. good luck, but you're gonna have to be prepared.

-CC10

[PlanetSaturn56]

What and/or who is cosi? You say he has a ton of pieces, is he a merchant that people on the site could buy from?

-PS56:king

[RC-Freak]

Good tips cc10.

could you email me those support pics.

They don't show up on my browser

[MF Rocks]

^^ Cosi is a science facility/museum type place based to teach people about science stuff.

Good Luck with this. You'll need it for that 15+ feet pull up. LOL

[Top_Thrill_Dragster33]

^How do you Know about cosi? Do you live in Toledo/Columbus?

Also, I know how to make pull ups perfect now, thanks to my math teacher!

[pkiknex25]

Pretty much anyone in Ohio knows about Cosi.

Good luck with this.

[MF Rocks]

Actually I live in Michigan, about 40 minutes north of detriot. My brother has gone to Cosi for a field trip and I've drove through Toledo all the time to see my relatives in sandusky, so I've also passed it on the road.

[Top_Thrill_Dragster33]

Ok, instead of a 15 foot high pull up I have built a 5 foot experimental pull that will not go on the coaster but will probably be the basis for the real one. Pics in about 2 mins.

Edit: Sorry to keep you waiting, here they are.






The pull up uses the property of exponential growth. each support is 2x as big as the last.

[coastercrazy10]

I just made it a perfect quarter circle...that's really what makes pullups look good on towers.

-CC10

[Antinos]

^^That is a really good idea about exponential growth...I never thought of that, but I guess I kind of used that, seeing as all roller coasters use that if you put boxes under their pullouts.

[poizone]

eponential growth is x square, so if it is one support in, it would be one high, two is four high, three is nine high and so on. Your just using 2(x-1)ish.

[coastercrazy10]

It's basically the graph of the square root of X.... or X = Y^2 That yeilds a horizontal parabola.

-CC10

[Tyrant]

Also, I know how to make pull ups perfect now, thanks to my math teacher!

Hate to break it to you, but expoential growth is not how real coaster pullouts and lead-ins are created. If you really want to know, this picture explains it well.



It requires some differential equations and some basic calculus knowledge. What is boils down to is a constant rate of curvature which is k(t) = 1/R, where R is the radius, the angle Psi is equal to the overal change in angle (beta) times the arclength, all of it being squared.

-Tyrant

[RCT2123]

^Could you put this into something I could understand?...

If you have the time even make a excel spreadsheet to know the exact position of the supports...hehe...I always have to add that in there...

Really though, just a short explination that I could understand so support making will be much easier...

-Rct2123:cool:

[RC-Freak]

Hate to break it to you, but expoential growth is not how real coaster pullouts and lead-ins are created. If you really want to know, this picture explains it well.



It requires some differential equations and some basic calculus knowledge. What is boils down to is a constant rate of curvature which is k(t) = 1/R, where R is the radius, the angle Psi is equal to the overal change in angle (beta) times the arclength, all of it being squared.

-Tyrant

corect!

I was actually thinking about this a lot this weekend and using this should give you the perfect circle.

using exponential growth will make it steeper and steeper line, but never
a complete circle that you can use for a pullup

[Tyrant]

This won't in theory give you a perfect circle, instead its going to give you a spiral. This equation is used primarily for connecting a straight section with a curve of constant radii. It causes the radius to go from infinity to a set radius smoothly, or on a continious line. If you get into calculus you start to learn about continuity, or discontinuity. Discontinuity is when at a given point a line "jumps" to another point without a connecting line, an equation like y=mx+b will give you a continious line, as there is a line connecting two points. However, if you were to derive that equation, and a line connecting two points would be disconitinuos. However with an equation like y= x^2, the derivative will be continious, but the 2nd derivative will not be; this is called C1 continuity. If you get into higher order polynomials, you can start getting C2 and even C3 continuity. C2 continuity is what is needed for a smooth connection of forces, as the 1st derivative of a position function is velocity, and the 2nd derivative is acceleration (force) of an object on a give position profile.

A perfect example of the accleration continuity. All highways are designed with that tranistion spiral, things such as on-ramps and off-ramps are designed such that you can continue rotating your steering wheel at a set speed and you will go around the curve perfectly at the set speed. So the angular acceleration is constant. So what the spiral is saying is that as you change direction, your acceleration is going to be constant.

Sorry if this is a big jumble of words for some.

I just want to make sure that this isn't confused for a perfect circle, or for an expoential growth type of equation, cause it is far from either.

-Tyrant

[imakecoasters]

So what the spiral is saying is that as you change direction, your acceleration is going to be constant.

-Tyrant

Wait, the spiral can talk now, ? We should give it a name!


-IMC-

[RC-Freak]

ugh, I'm in pre cal so ehh, not quite there.

very interesting though.