Thursday, May 27, 2010
Wednesday, May 26, 2010
How does Top Thrill Dragster work? Basically, it's a giant fishing pole that pulls the train in super fast. Cedar Point contacted Intamin to manufacture the ride who chose to go with a hydraulic launch based on their speed, acceleration, and power requirements. There are 32 hydraulic motors, 16 on each side connected to an internal ring gear. The power from all of the motors is transferred to the giant cable drum by a planetary gear box. The cable connects to a sled that rides in a track within the coaster's launch track. It attached to the underside of the train and pulls it toward the 420 foot hill at 120 mph.
There are two sensors on top of the 420 foot hill. The distance between the two sensors is known so they can take that value and divide it by the time it takes the train to get from one to the other. This gives the computer the train's speed going over the top of the hill. The computer takes the average speed of the three previous trains in order to determine the power to give to the hydraulic motor. This presents a problem if the first three trains are filled with swimsuit models and the fourth train is carrying football players. The power is not going to be enough to get it over the hill. One thing I am not sure about is how they handle empty trains, or going from three empties to one full. I think maybe they can compare that average to historical data?
Why does Top Thrill Dragster break down so much? You have to remember that it's a very complicated piece of machinery. The ride is covered in sensors. Every single brake fin has two sensors to detect alignment. The cars have copper fins attached to the underside of their chassis and must line up exactly with the fins mounted to the tracks, if they were to be off there could be a huge accident, hence all of the alignment sensors. There are two huge brake runs, the fixed one after the hill and the pneumatically controlled brakes on the launch track. They come in rows of two. That's a lot of brake fins! If just one of those sensors fails or is faulty, the entire ride is shut down.
How to design a roller coaster.
Tuesday, May 25, 2010
Thursday, May 20, 2010
Want to dig a little deeper? First, let us define "roll". That's a rotation around the track centerline along the train's longitudinal axis; that is, an axis running from the front to back of the train. The back seat in each car is raised about an inch, and the running board is cut away (and covered with a board). That gives the back axle, which is mounted on a longitudinal pivot, more room to swing.
A two-bench PTC car (as currently running on Raven and Legend) has a four-foot wheelbase and about 3'2" from back wheel to front wheel between cars. Between cars there is plenty of flexibility because the drawheads have practically unlimited roll on a short effective wheelbase. So the roll rate is limited by the longer distance, the wheelbase of the car. On a standard car, as on the Raven or on The Legend, the rear axle can swing about three degrees in either direction. That means the maximum allowable roll rate (without lifting any wheels) is three degrees per four running feet, or more usefully, about 16" of running length per degree. That means that in order to get up to a 90-degree bank from flat track, the train needs a minimum of 120 feet of track.
The track gauge for a wood coaster is roughly 43". The rated 3-degree swing means there is normally about 1.13 inches of clearance at the running board for the wheel. Add another inch at the running board and in fact it is probably more than that because the wheel is about 4" outboard of the seat...and the available space increases from 3.0 degrees to 5.6 degrees. That increases the allowable roll rate to 5.6 degrees per four running feet, or a mere 8.6" of running length per degree of roll. That reduces the length required for a 90 degree bank to just over 64 feet. If the Gravity Guys built the Voyage assuming that the train could roll 1.4 degrees per foot instead of 0.75 degrees per foot, they could have very easily built places on the ride where the car chassis would actually hit the track. Not good news.
The modification on the Voyage train increases its performance, therefore, the train would have no problem running on the other coasters. But because the other trains don't have that mod, they might have problems running on the Voyage. I believe Gwazi was the first coaster with PTC trains to get this modification, but though it's been standard on all of the rides the Gravity Group has built. I am certain that both Voyage and Ravine Flyer II have this mod, but I don't know if CCI ever used it.
Wednesday, May 19, 2010
The ride was manufactured by Vekoma.
The mountain is 199 feet taller. If it were any taller a red beacon light would've had to been placed on top ruining the effect and theme.
The ride has 13 trains, 7 of which can be used at one time. Each train is only supposed to run continuously for a maximum of 5 hours. This is something I've often wondered about because most regional amusement park's coasters have only two trains and they run ten or more hours a day. Is this a Vekoma or Disney imposed rule?
The interesting thing about this ride for me as an engineer is the fact that it is actually three separate structures that never touch each other: the coaster, the mountain and the yeti. The coaster is a dynamic structure that vibrates and can yield a little bit without getting damaged. The coaster supports are colored black. There's that old saying for coasters "if it doesn't shake it's going to break." The mountain is a static structure. The fake rock work is constructed from plaster which would crack under vibrations. The mountain supports are red in color. The yeti structure is also dynamic.
The anti-roll back device uses magnetic fields so that it doesn't make the typical click-click-click sound while going up the lift hill.
This is another ride where I could draw you the entire layout of Expedition Everest even though I've never been on it (or even near it). The last time I was at Disney's Animal Kingdom was 2003. Everest opened in 2006.
Hello and welcome to Amusement Authority. I am a premier expert in roller coaster and amusement park knowledge. Some people are baseball fans, civil war buffs, or really into cars and can tell you any model just by looking at it. I am into roller coasters and have an uncanny ability to memorize everything about them. I can draw you the layout of every major coaster in the U.S. If you show me a picture of a small portion of the ride or maybe even just the train I can identify it. Most of this knowledge is completely useless but that is what this blog is for. A place for me to share this knowledge with you and like minded individuals. Also, if you are in the amusement industry and looking for consultation then you've come to the right place!