Frank Mezzatesta
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Walt Disney Imagineering 1993/1994

1993/1994 Tower Of Terror, Disney-MGM Studios

Disclaimer and Sorry
This was the hardest project I ever worked on both technically and politically. I received some of the best management feedback and was almost fired during this project. The first draft of what is below was twice as long as this and I deleted all I could and it is still long and boring, sorry.

Playing around with ideas
The original idea for Tower of Terror (TOT) included the idea of a real hotel and attraction in one big building. I imagined walking down the halls of the hotel and wandering into the attraction. I'm sure that was not the actual idea at the time. That idea did not last very long. When you read that some attraction take 5+ years from start to finish, that usually means that the idea or implementation for that attraction changed many times. Some ideas hang around for up to 10 years before becoming real.

The technical implementation of the creative idea was that Tower of Terror was an indoor rollercoaster with track that would provide zero g's. Somewhere in there it was a very complicated system where the vehicle was handed off between many different systems like a container routing system in a factory. The "freefall" was some small one story freefall.

It wasn't until someone said, well it's suppose to be an elevator, why not implement it as an elevator? That we had the final design. There is a whole page story about this which I will not write now.

Two Teams
This attraction has two totally separately ride systems. They are the horizontal and vertical. Though I helped a little on the horizontal system that floats across the fifth dimension I am only going to talk about the "elevators".

Stop here for a note
Many were concerned that if we built an elevator and called it an elevator that it would have to meet elevator codes and requirements. That is, of course, not possible because elevators have all sorts of requirements and equipment that limit the speeds to boringly slow operation. So Mark decided to call them VVCs, Vertical Vehicle Conveyance. If you know me there is no way I was calling them that so in the electronics and software they were called "lifts".

Now we have to design this new thing
Well we went to a famous elevator company and asked if they would build a 13 story freefall elevator for us and the answer came back NO, we spent our whole existence making elevators not freefall. We asked a large motor company and they said NO as well. So the mechanical design was led by the best WDI engineer Mark. An elevator company did help Mark with pieces of the design and manufacturing so he was in good shape. The building was being designed along with everything else except the Ride Control System. Mickey Steinberg, COO of Imagineering called me into his office one day and said we have a number of no bids for the control system so you have to just do it, OK? The OK was a rhetorical by the way.

We have no previous designs to help with this
Usually we reuse most of the hardware design and some of the software for each new attraction. The processors we used at this time, mostly PLCs, that ran the software in 60 milliseconds (that is 0.060 of a second). Due to the extreme high speeds the safety part of the software had to run every 2 milliseconds (0.002 seconds). Also there were no equipment rooms for the lifts so we had half the space we normally did so nothing we used before would work for this attraction.

Discussions with the many WDI engineers were stalled because no old way would work and any new (crazy) ideas were rejected. Well I did what I always did in this case, boot off all the engineers except those crazy enough to try something totally new in less time than ever before. So that left two other people. Chris for electronics and Bill for software. Chris and I started on the hardware electronic design in June of 1993. We designed the main control system include new computers, special controllers for the motor brakes, and controllers for the lift doors. Did all that is 3 months, then rushed them into production.

So due to a bad political climate Bill was working on other projects with my boss not caring that nothing was getting done on software. It wasn't until the start of October, 1993 that Bill and I sat down to design and then write the software. We had 7 weeks before we were to fly to Florida for the "freefall test". We designed the software in a few days and started writing 7 days a week for 7 weeks. If you read my previous history, Bill and I basically wrote a wrote a system at Barrett in 8 weeks. By the time we got on the plane we had enough software for the test.

Freefall test
Years later when OLC built a Tower of Terror in Tokyo, they spent the time and money for a full scale drop tower. OLC always did the job right. We did neither. Instead it was December 1993 and the building was only partially complete but enough to use it as a test tower. Not enough, by the way, to keep the cold winter winds from blowing through us 13 stories up. At night after the construction people went home we could test and had to walk up all 13 stories to get to the top where the equipment was. So after preparing for 3 weeks in the field, a few days before Christmas we executed our first 13 story freefall drop. This was to prove that all the design of the building, mechanical systems, and control systems came together to provide the desire effect. It wasn't perfect but good enough that we committed that it was possible. By the way it would be months before any human would ride this system. Only an accelerometer was onboard for this test. We were told if the test failed they would delay opening from July to at least September. So why did we not fail so we could have more time? Not sure.

Sprint to the finish
Chris pretty much stayed in Florida to direct installation of all the hardware and Bill and I went back to Glendale to continue to write the rest of the software. We were joined by Kevin. It was remarkable that this totally new hardware design and totally new software design came together and work quite well.

Things not going well
Anyone that was there is now saying, you leaving out a lot of the story! So it is typical that when we tell a vendor what we need that they always say yes that is easy (you are only Disney, not rocket scientist) and it many times turns out that we are asking for the impossible. Case in point, GE. In our face to face meeting with GE who provided the large 4,000 hp motor and drive unit that we told them our requirements. We needed to generate 110,000 foot-pounds of torque with n milliseconds of the start and track the accuracy of the speed with n percentage. Next we had to operate at very slow speeds as we parked at a floor with a few millimeters. YES we can do all that. Well they couldn't!

The actual story is quite long and detailed. The shorter version is they could do each piece but not both together in one system. Oops. So GE never sends their engineers to the field, they let the field people handle the customer. We were on a daily call with the engineers at the headquarters and the calls were not going well. We had some 8 people on our end and I assume about the same on their end. I hadn't slept well in weeks and we were getting nowhere. As I explained the details of the tests we ran and getting no useful response the following words came out of my mouth: "Is there anyone there half as smart as me?". The chief engineer on their end got up and walked out of the room. Well the next day the engineer and his boss were on a plane to Orlando. We ultimately worked out a technical solution that was good enough. Even in 2020 there were people at WDI that mentioned this quote.

First human ride
For most rides you can put a single vehicle on a track and manually start any motors and have a vehicle run around a track. So usually many people starting with the mechanical engineers have ridden a ride early in a project. Think Space Mountain or Small World. For this ride all the safety software had to be working so we could freefall and then stop safely at the bottom. So there were lists made and posted as to who was going to be the first riders. Was it the Project Manager or the lead creative designer or the president of WDI. Well on the night of April 16, 1994 around 8 o'clock when most everyone had left the site we were testing. I turned to Chris and said, why don't we just sneak into the lift cab and go for a ride and not tell anyone (so we can be first)? So Chris, our producer John, and I got into the cab and Bill was on the 13th floor next to the computers. We were going to radio him to push the button to execute a freefall drop.

We were hovering on the 13th floor (hover is that the brakes are open and the motor is holding your position and you can sense a slight up and down motion). I turn to Chris and say: "Bill wrote half the software with me, should I be worried that he said hell no he is not going for a ride?". There was no real answer to that and we radioed him to push the button (8:10 pm per log) and the rest is history. I love working for Disney . Somehow everyone found out the next day what happen.

Executive Update and Ride
Weeks later it was time for the executive update with Mickey Steinberg and his direct reports and it was time for their first ride. After the ride, I explained to him that the profile we had generated for the drop needed to be tweaked because we were actually peaking over the 1 g drop requirement. He and the creative lead agreed to leave it as it is. Later there was some advertising that said fall faster than gravity which was actually true.

Note: A funny story during this visit. We were in the equipment room for the Load Lifts looking at one of the motors and talking about many of our technical challenges. Mickey remarked that we really needed to get this attraction open on time. Again I'm going to blame the lack of sleep but I turned to him and said, "well Alan promised me dinner if I opened Splash on time and he never paid up so I don't know". Mickey opened his wallet and handed me a hundred dollar bill and said "here, buy yourself dinner and get this thing open". Everyone laughed and he turned and walked out of the room. I turned to Jack Davis, SVP of Engineering, and tried to hand him the money and said "please give this back to Mickey". Jack said "keep it" and turned around a left to join the others. Mickey, if you are reading this, I never spent that hundred dollars and it is sitting here in a drawer with your name on it. Call me!

Every ride goes through hundreds of hours of operational testing and safety testing (actually more like 1-2 thousand). Even though there are duplicate lifts they all get every test done independently. Sounds reasonable but GM crash tests a few cars and then builds identical ones. They don't crash each one. How would you do that?

Opening and beyond
Well a few weeks before opening I was having a baby and I left for home. This was the first and only time I missed opening day but I heard it went well. We went on to build 3 more Tower of Terrors. We called them TOT Lite until management told us to stop calling them that. None of the others have the fifth dimension scene where you come out of the lift and float across the fifth dimension. The guests seem to like each one the same but I am partial to the first and best one.

After Opening
I found a technical video on a small tweak to the software after opening which I have posted here with a technical description.

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