Tower of Terror- how does it work?

[Roo Girl]

I really really think there is a "trick" to how the elevator takes you to the floor before the freefall begins- I know it is Disney magic, just wondering if anyone has any idea how the trick works? I know it may contain spoilers but I really want to know!

[Mufasa]

Hmm, not quite sure what you mean by any "secrets" of how the Tower works, but it's set-up the following way-

First, when you're at the loading platform, you're actually on what we'll call floor 2. In the loading area there are 4 elevator loading zones- these feed into 4 lift shafts which we call Alpha, Bravo, Charlie and Delta. The lift shafts contain the show scene (the corridor scene)- the 3rd floor contains the show scenes for Bravo and Charlie, while floor 4 contains the corridor scenes for Alpha and Delta (because of the way in which some of the effects are positioned to make the corridor scene work it's not possible to have them all sit on the same level as they would overlap).

The 5th Floor of these lift shafts then is what we call the 5th Dimension- this is the area where your ride vehicle then physically exits the lift shaft and transitions into a drop shaft. Alpha and Bravo lifts feed/merge into 1 drop shaft (known as Echo), while Charlie and Delta feed/merge into another drop shaft (known as Foxtrot)- and these are the shafts that you see on the outside of the building as you're facing the tower.

The ride vehicles themselves are known as what we call an AGV for autonomous guided vehicle. Basically, that means that these are "smart" ride vehicles which are self-powered by an onboard battery and they get their guidance information from communicating with a wire which is embedded in the floor. (The ride vehicles can send and receive a signal wirelessly without contacting the wire in the floor back to the ride control computers to indicate where they are in the tower and to "steer" the vehicles).

As they travel from the lift shaft to the drop shaft, they will lock into what we call a VVC (or Vertical Vehicle Conveyance)- this is the lift/drop mechanism that powers the up and down movement in the drop shafts and could be thought of as being the actual "elevator" car (so your ride vehicle basically locks into another box which transports it up and down the drop shaft). The design is a little different from say most standard elevator cars in that there's constant tension above and below the VVC on the cables which create a loop to the motors above so the VVC is under positional control at all times which allows for the fast up and down motion and stops in the drop shaft.

[Ian]

The design is a little different from say most standard elevator cars in that there's constant tension above and below the VVC on the cables which create a loop to the motors above so the VVC is under positional control at all times which allows for the fast up and down motion and stops in the drop shaft.Interesting ... so I assume this is the method that's used to effectively get your ride vehicle to drop faster than gravity?

You use the cables to power the cab down the shaft?

I always wondered how they did that. What's the power mechanism for the cabling?

[JPL]

As always thanks for the great insight Mufasa:thumbsup: Always great to see you around :mickey:

[Mufasa]

Interesting ... so I assume this is the method that's used to effectively get your ride vehicle to drop faster than gravity?

You use the cables to power the cab down the shaft?

I always wondered how they did that. What's the power mechanism for the cabling?

The power mechanism are a set of large electric motors at the top of each drop shaft that can generate massive amounts of torque and reach full speed in about 1.5 seconds. The motors in turn are connected to drive drums.

The VVC is actually suspended from a drive drum by two cables. Beneath the VVC, two more cables travel downward to a tensioning sheave in the pit, then upward to a counterweight that rides along the side of the shaft. From the counterweight, two additional cables travel up to the drum on the opposite side.

The result is a closed cable system that pulls the cab upward and downward in the desired motion in relation to the rotation of the motor/drive drums and unimpeded by the limitations of gravity . The twin cables throughout provide safety redundancy.

Were both cables somehow to fail, the elevator cab is also equipped with standard elevator safety brakes and there's a hydraulic buffer zone at the bottom of each shaft.

As an additional safety precaution, two velocity tachometers on the motor shaft and a tape encoder attached to the elevator cab monitor speed and measure velocity every 2 msec. If the measured velocity deviates from the commanded velocity, or there is a discrepancy between measurements, a system stop is initiated.

In all, some 100+ processors control the ride's operation, communicating to a supervisory system over an Ethernet link.

[Ian]

Man ... that's a complicated ride system. Very impressive. Quite a feat of Imagineering!

[brad192]

Thanks Musafa! :thumbsup: As an engineer, I'm always wondering how things work at the various attractions/rides at WDW, and trying to pick out the little techie details when I'm there. :spy: Your explanation of ToT was great! I now have a new appreciation for the ride.:)

[2Epcot]

Your explanation of ToT was great! I now have a new appreciation for the ride.:)

My thoughts exactly. I love knowing all the details about how attractions works. I appreciate all the visual design the Imagineers put into the attractions, and even more so when I learn more about the engineering part.

[TheRustyScupper]

Thanks for the info Mufasa.

[Ian]

Thanks for the info Mufasa.Don't you mean:

1. Thanks
2. For the
3. Info,
4. Mufasa

??

Just kidding ;)

[Roo Girl]

AHA! I was overthinking it all this time. DH and I theorized that when you're at the corridor scene, the ride car moved horizontally into position- since sometimes when you exit in the 5th dimension you're sometimes on a different "side" than you loaded into the ride vehicle. Know what I mean? We would ride ToT over and over and over to see if we could "sense" the horizontal movement, and of course we thought we could. Duh!!

Now I see it is lifting you to a different floor based on what care you are in (A, B, C or D.) VERY interesting nonetheless.

[Inkdrainer]

Wow, very detailed and interesting! Thanks for posting that.

[LudwigVonDrake]

Imagineering at its best! :smickey:

[allie_to_you]

Thanks for the awesome information Mufasa. It's so neat to see how this all works and it's amazing all the technical thought that went into it.

How often do the cables have to be changed out or do they?

[mook3y]

Thanks Mufasa! :thumbsup:

What a great writeup on a cool ride!

[c&d]

Thanks Roo Girl for asking this question and for Mufasa for answering. I was trying to figure out how the ride worked the last time we were. I had cars going all over the place in the ride trying to figure it out.

[Mufasa]

How often do the cables have to be changed out or do they?

As with all our attractions everything is inspected regularly and parts are replaced on an aggressive, strict schedule to be proactive against any possible wear and fatigue based on things like the number of ride cycles, exposure to temperature fluctations, etc.

The Tower differs from a normal elevator in that we use a winch drive rather than a more traditional traction system (under the same conditions with a conventional elevator traction style design the system could experience slippage). By extending cables below the VVC and back up in a closed loop- we're able to pre-load/tension the system so there's no slack in the cables.

With the design on Tower of Terror, from a mechanical load standpoint- the counterweight is set up to balance out both the weight of the VVC and ride vehicle plus I'd say roughly 40-50% of a possible maximum load with a ride vehicle so the measured load requirements placed on the motors is the difference in passenger weight compared against the counterweight (significantly less horsepower then needed to handle the weight of the VVC)

The motors/cables are over-engineered and rated to be able to handle an extreme load- for example, the motors are rated to be able to safely take say a 10 ton load and accelerate it up to 2,680 feet per minute (about 30 miles per hour) and bring it to a complete stop.

In order to accomplish this they'll generate torque of about 110,000 foot pounds, 4,000 horsepower and use regeneration for deceleration control. It's not a standard elevator motor in any way (at the time some of the most advanced motors regularly in use in high rise buildings only generated less than 25% of our acceleration and torque requirements for the attraction) and the attraction also called for us to engineer a new speed and control system that at the time was 10 times faster than what we had used in previous attractions.

[magicman]

Ride fun. Me like zippy Tower Ride. ;)

Maybe it's just me, but after reading through this thread I feel eeeliterate.

[gueli]

Cool :thumbsup:
Thank You very much Mufasa for the insight.
Are there any other rides that are so complicated ?
:D

[thejens]

Last year I got up my nerve to ride and, although I was terrified indeed, I loved the floating sensation when I was actually lifted up from my seat. I think I read on Intercot that the comforting over the shoulder harnesses are no longer part of the ride and there is a mere flimsy seat belt thing. Is this true? I really don't think the ride needs to be any more "thrilling!" Any reassuring information explaining how it is impossible for me to break free and crash at a speed closer to gravity would be greatly appreciated.

[jefmblrd]

Actually there was never an over the shoulder harness on the TOT; before the seat belts it had a lap bar that covered everyone in their section.

[allie_to_you]

Were both cables somehow to fail, the elevator cab is also equipped with standard elevator safety brakes and there's a hydraulic buffer zone at the bottom of each shaft.

What does a hydraulic buffer zone mean?

So if the safety brakes failed, what would happen?

[mousetrapper]

AHA! I was overthinking it all this time. DH and I theorized that when you're at the corridor scene, the ride car moved horizontally into position- since sometimes when you exit in the 5th dimension you're sometimes on a different "side" than you loaded into the ride vehicle. Know what I mean? We would ride ToT over and over and over to see if we could "sense" the horizontal movement, and of course we thought we could. Duh!!

Now I see it is lifting you to a different floor based on what care you are in (A, B, C or D.) VERY interesting nonetheless.

Wait a minute now....do you ever move horizontally?? I thought you did as you go through the eyeball, clock etc. area...?

[thejens]

Okay then, why did they take away the nice reassuring bar over my lap and are you sure the replacement seat belts aren't too flimsy? And what exactly am I supposed to grip my fingernails into while I scream in terror?!

[joelkfla]

What does a hydraulic buffer zone mean?

So if the safety brakes failed, what would happen?
If the car were to fall all the way to the bottom of the shaft, it would land on a big piston which would squish hydraulic fluid out of valve, slowing the car to a hopefully safe stop instead of slamming into the ground.

[Disneydol]

Okay then, why did they take away the nice reassuring bar over my lap and are you sure the replacement seat belts aren't too flimsy? And what exactly am I supposed to grip my fingernails into while I scream in terror?!

How about your neighbor's thigh?? Sounds good to me. haha

[Gekko959]

Thanks for the posting! I'd love to be an imagineer... that would be my dream job.

Gekko

[TiggerRPh]

Man ... that's a complicated ride system. Very impressive. Quite a feat of Imagineering!

I've heard this explained (though not in as much detail) on a couple of Travel Channel shows. It is quite impressive.

[TKSax]

ToT's ride vehicals are vey cool and I was amazed when I heard how it all worked. I was also flabergasted to find out that on dinosaur that ride vehicals do all the moving and that the floor is smooth.

[Disney4]

The power mechanism are a set of large electric motors at the top of each drop shaft that can generate massive amounts of torque and reach full speed in about 1.5 seconds. The motors in turn are connected to drive drums.

The VVC is actually suspended from a drive drum by two cables. Beneath the VVC, two more cables travel downward to a tensioning sheave in the pit, then upward to a counterweight that rides along the side of the shaft. From the counterweight, two additional cables travel up to the drum on the opposite side.

The result is a closed cable system that pulls the cab upward and downward in the desired motion in relation to the rotation of the motor/drive drums and unimpeded by the limitations of gravity . The twin cables throughout provide safety redundancy.

Were both cables somehow to fail, the elevator cab is also equipped with standard elevator safety brakes and there's a hydraulic buffer zone at the bottom of each shaft.

As an additional safety precaution, two velocity tachometers on the motor shaft and a tape encoder attached to the elevator cab monitor speed and measure velocity every 2 msec. If the measured velocity deviates from the commanded velocity, or there is a discrepancy between measurements, a system stop is initiated.

In all, some 100+ processors control the ride's operation, communicating to a supervisory system over an Ethernet link.


And you all wonder why it costs so much for a park ticket! NASA would be proud! :laughing:

[PirateLover]

Last year I got up my nerve to ride and, although I was terrified indeed, I loved the floating sensation when I was actually lifted up from my seat. I think I read on Intercot that the comforting over the shoulder harnesses are no longer part of the ride and there is a mere flimsy seat belt thing. Is this true? .

Okay then, why did they take away the nice reassuring bar over my lap and are you sure the replacement seat belts aren't too flimsy? And what exactly am I supposed to grip my fingernails into while I scream in terror?!

If you rode the ride last year, you had the seatbelt. I'm pretty sure the belts have been in place for a number of years now, because I don't even remember the lap bar.
I think it's safer than the lap bar because you can adjust it on your own. So for instance, if you are a small person in a row with large people, you will have a lot more space between your lap and the bar. I like the seat belts a lot.

As far as holding on, there are handles on the side of each seat area. The inside seat has a handle on the wall.