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Is it just me or is TOT getting very slow?


Slick
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The difference in height between it's lowest track before the curve and the base of the tower is not significant - there might be a metres difference in height. Certainly nothing anywhere close to 10m difference. I've negated friction and air resistance as I said earlier, because it is impossible for me to come up with a friction coefficient value without doing some pretty heavy analysis of the design of the car, right down the bearings etc. on the wheels. Friction (mechanical friction, air resistance etc.) is the only force, aside from gravity, that will create a loss of speed. In short (without getting into some basic vector geometry), without friction, the loss of speed of a body traveling up a curve is exactly the same as the same body traveling vertically to the same height. Most assumptions I made I outlined. Just in case you missed them, I'll list the untrue assumptions I made in all of the calculations I've used here. -We are operating in a frictionless environment. -The acceleration of the car is constant. -It uses induction motors, not synchronous motors to operate. -Dreamworld's publicity figures are accurate (despite being only to one or two significant figures). Because we're only working with around two significant figures (hence my speeds above of 161km/hr and 157km/hr are technically not correct, though with two significant figures they'd both be 160km/hr, which doesn't do much for these arguments), it means that these assumptions and other things I've disregarded or assumed can be perfectly justified as they don't effect anything at the level of accuracy I'm working at. By the way, while I remember, your example with the fridge magnet earlier is largely incorrect. A fridge magnet uses magnetic attraction to stick to the fridge. The braking on Giant Drop doesn't use magnetic attraction, it uses magnetic flux. You'll find that those fins on the tower are some alloy (presumably largely copper because of its conductivity) that isn't attracted to magnets to ensure that there is no magnetic attraction. The brakes on Giant Drop will always provide the same force of braking (which is never enough to counter the downward force of gravity by the way). What a change in speed does is increases the current flowing through the fins. This is why the humming sound it makes as it slows starts off with a high pitch and becomes lower until it stops - at the top of the brake run it is traveling fastest, so more electricity hence a louder sound. As it slows, the current decreases, as does the motor sound. Just think of it as the reverse of a linear induction motor if that makes it any easier. Where they pump in electricity which is used to make a magnetic field to give motion, Giant Drop (or any magnetic braking system) takes motion, passes it through a permanent magnetic field (i.e. made from natural magnets) which converts this motion into electricity.

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Yeah, that sounds correct. It uses a combination of the magnet on the tower, and something on the back of the Drop car? or vice versa I can't remember. So in other words, yes the speed can alter in the breaks (ie. it drops from half way, which I have seen before), however it won't just stop in the breaks because of the power involved? Because that is what I have been told and when I did see it drop from halfway, it went as per usual through the breaks, and for the GD to actually get caught in the breaking system just could not happen because the attraction between the mechanisms (both on the back of the car and the tower) would continue as per normal once it is released. Think of it this way, if there isn't enough force to hold it there when the winch is going to the top, then why would there be enough force to stop it when its falling. The winch has to compete against gravity to pull it through the magnets, whereas a free fall doesn't. Is that right Richard? Or did I misunderstand. Finally, the reason why I was curious about the TOT speed is I have heard these days it is functioning at a slower speed, slower then the 157. Could be true, could be false, but we can't be completely sure unless we have a radar. I also never knew that the decelleration up a 90 degree angle was the same as the curve.

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There are two sets of magnets on the back of each gondola, which effectively lock around the two fins on the tower, which as I mentioned previously would be made from some alloy that can't be magnetically induced (i.e. be attracted to the magnets). This point is pretty critical to understanding how magnetic braking works, because there is no attraction between the magnets and fins and it is not a force of magnetic attraction that causes the braking. I'm not totally sure what you're getting at with your third paragraph. There's never enough force to hold it still in the brakes, and there never can be. It relies on a constantly changing area of the conductor (the fins on the tower) within the magnetic field (created by the two N-S alligned magnets on the gondola which surround this fin). If there's no changing area (i.e. it's not moving), then there is no braking force, so it wound naturally start to move. The exact moment it moves though, there is a change in area so the braking force comes back in. The result of this is essentially why when falling or being towed through the brakes, you will be traveling at a constant velocity. Increase the magnetic field (with better magnets, spacing them closer together), and this constant velocity will be slower than with a weaker magnetic field (less powerful magnets, further apart). I can't easily explain the deceleration due to gravity (I'd rather call it acceleration in the -y direction, but that's just how it'd be put on an engineering paper) without using vectors and the thing with that is if you're at a maths or physics level where you understand vectors, then this wouldn't need explaining to you. Just take it from me that something that's been shot up a 90º curve will have the same speed at the end as something that's been shot vertically up from the exact same starting point, if we're operating in a frictionless environment.

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Yeah I believe you, I just found it interesting because it was something I didn't know. Anyway, in short all of our babbling do we agree the giant drop could not get stuck in the breaks (besides something extreme happening)? I've only had the GD explained to me in simple terms, but I thought I had an OK understanding of how it works

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  • 1 year later...

At the moment, my understanding of the launch system is that it's basically a row of electromagnets that turn "on" one after another and effectively pull the pod out of the station at extreme speeds. If this is way off then please tell me. I've got a few technical questions regarding TOT's launch / braking system: 1. Is the launch sequence (i.e. the "turning on" of magnets one after another) timed or varied based on the speed/position of the pod? 2. If the launch process is varied based on speed, how does the system (continuously throughout the launch process) calculate the speed of the vehicle? 3. Is the breaking force varied based on speed or the position of the pod? Thanks.

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Like Richard said, if it were in a purely frictionless environment, a timed system would be adequate, however, since we've got things such as wind and what not, there have been almost hundreds of sensors placed parallel to the alloy blocks down the track to calculate where the pod is to control the electrical fluxes. So basically the computers are given a basis model to work off, say "we need to reach X-speeds before Y-locations" and from there using almost each set of alloy blocks as a node, the computer's continually reference the sensors to check where the pod is to be as precise to the model as possible. So realistically the overall propulsion system doesn't work as one long strip, but rather heaps of tiny sets working in <i>synchronised</i> form. So taking that into account, braking would basically be a set program to say "these sets slow down to X-speed before Y-location, and then when we hit Y-location, which in thise case could be inside the tunnel, decrease X-speed." Understand? :)

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Are you inferring that you know that first hand or that you just presume? Having done some promotional work earlier on in the year with the park, I was lucky enough to hop on for a few rides by myself, which means with less than a twelth of the average passenger weight onboard the pod, the Tower shot me up the tower at just under normal pace, and I have to say, tapping the magnets is a huge difference to what we get currently. Seriously, the force, and just that small heigh difference gives a whole new feeling to really how much you're soaring over the Gold Coast.

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  • 2 weeks later...

Good idea. Yeah, the Tower of Terror, like most non-slave propelled rides will clunk out when there's no power, however, with premiums utterly sky rocketing these days, virtually every single ride will always have a fail safe. The Tower of Terror, as most people know has "rare" earth magnets (another adjective I've been asked to use) on the belly of the pod, which in a normal run interacts with the alloy boxes down the track and have huge electrical fluxes... yada, yada. However, when the power clonks out, surges, or we get a nasty little guest taking photos (cough some people in the industry in particular) the ride goes into a situation well renouned as an "e-brake." In this situation, there is a set of very large "rare" earth magnets behind the station that act as like a huge pile of quick sand, if you will. Basically, co-inciding with the same theory the Giant Drop uses, the magnets on the track counteract with those on the pod and "bog" the car in the rear of the station. Once when the car has fully stopped moving, the car is either pulled out of the brakes via a diesel winch at the very rear of the station, or if it's already rolled out of the station by this stage, the electromagnets are manually operated for it to return to the station. There's a little bit more to it than that, but that will give you the general gist of what happens.

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90 percent of all e-brakes that cause the pod to stall outside of the station are usually are usually to a guest playing up. If that happens the pod once the e-brake has officially been stopped, the magnets are then used to, in a way "manually" return the pod to the station where the certain guest is dealt with accordingly. However, if there's a power failure or what not, the diesel winch is then started and it's basically rolled back into the station where it's docked until they can safely test the ride again before letting guests back on.

Edited by SK2
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Hey guys, i am in year 11 and am currently studying physics. I don't want to make fuss but are you guys like students or like university or real engineers. When i complete school, i would like to study engineering and become an engineer working with rides (i hope). Sorry to bore you guys. Plus. Where did you get that info on the magnetic brake systems. Did you find it or just know how it works. I think it's amazing. From a new person to this site, Shano!!

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young_aus_enthoustiast, it's not just like switching on a motor. To propel the pod using magnets it requires a complicated system of sensors and a processing device (ie. a PLC/computer). An operator would not be able to replicate that "manually".

Edited by Adam
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  • 2 weeks later...

Correct, that's why I said "in a way." And plus, the Tower of Terror doesn't just have one PLC, it has hundreds. I really can't give much information away on how the operation side of things goes, however there is a form of manual resetting so when a pod stops at some point and the magnets are still able to function, it can be returned to the station without the need of engineering having to start up the winch and whatnot. Plus this happens at slow speeds, of course if you were resetting a ride you wouldn't want it flinging back at you at more than 100k/ph would you? Oh and Shano, I know this stuff from experience and first hand knowledge, but as for Adam here..... :)

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  • 9 months later...

I work for a PLC (programmable logic controller) manufacturer, although I don't think our equipment is installed in DW. But from a controls point of view, the PLCs involved in ride operation are very advanced and have numerous safeguards in case of failure e.g multiple sensors in case one fails, processor hot standby (secondary processor unit on standby and command is switched over to it in case of primary failure). Different programs can be run depending on the feedback coming from the field sensors. TOT probably also has load sensing and can deliver launch power depending on the weight of the occupants. The 'computer glitch' story is extremely unlikely, although I have heard of these urban legends in just about any control scenario..

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Cool topic, after riding Superman the Escape a little under two weeks ago, I thought it seemed awfully slow, and this topic seems to confirm that it is running well below it's advertised speed. I mainly mainly ride Superman for that long air conditioned tunnel to Ecsape the heat - I personally find both rides (STE and TOT) very boring now. As an aside on electricity consumption, I heard (and I stress heard), that every ride on Wicked Twister consumes $50 worth of electricity which, if true, would amount to a significant amount of money over a season - say 200 rides a day * $50 * 120 days = $1.2m. Chiller at SFGAdv also is supposed to chew up so much power they can't launch both sides at once. Saved me having to raise this at TPR.

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