Part Two - February 27, 2002.

The Metal Lathe

On Friday, February 15, the Chinese -made Enco metal lathe arrived. It took about 4 hours to set it all up, as it had to be hoisted and mounted upon its pedistal. The whole rig probably weighs over 1,200 pounds.

Don't even think of starting a project like this dark ride unless you invest in one of these machine tools. (You'll also want a milling machine.) This unit, plus tools and digital readout (DRO) runs about $6K. It's a bit noisy and vibrates, but it's a lot cheaper than a domestic unit - and it works.

At right, Byron machines a hub for the drive tire. Notice the coolant gooseneck above the work. The coolant recycles by pump and keeps the cutting tool from literally burning up. Heat is what usually destroys such metal cutters, but they do wear out quickly despite the coolant.

The DRO(seen mounted on the lathe's gearbox, above) allows you to set a zero at any point on the tool holder's X and Z axes, and carefully measure your cut as you make it. It doesn't drive the lathe - it's passive - but it allows the operator to work with precision. This is essential for assembly-line products, on which parts must be interchangable.

The large object to the left of the work in this photo is a quick change tool holder. This feature, which we added to the machine at extra cost, makes the operator's life a lot easier, since at least 2 or 3 tools will be used in machining any given piece. Each cutting tool is held in a keystone-slotted clamp, which slides onto the holder from above, and is then locked in using the handle.

The large silver chuck holding the work is called the headstock. At the other end of the lathe is the tailstock (see image above) which can hold either a pointed pin to center long pieces or a stationary drill chuck used to drill centered holes in the rotating stock.

Here's the tailstock performing a centering function, stabilizing the work as threads are being machined into a shaft. The piece of work you see is an axle that will hold one of the two cam followers opposite the drive wheel on the track. The wide flaired piece seen beyond the threads is part of the tailstock point, inserted into a small hole in the end of the threaded shaft being cut.

When milling on a machine like this, you don't make deep cuts all at once - you work in layers until you reach the depth you need. This is true of threading stock, and you have to repeat-cut the threads. There's a synch indicator on the lathe's drive that allows this to be done without guesswork.

Note the three-sided gold-colored milling tool, which has three cutting points. After you wear one point out, you remove the cutter with a wrench and rotate a new point into position. These little parts are about eight bucks each.

Lizzy Nears Completion

By mid-February, it was clear that we needed some modifications to the prototype car to make it work as intended. For one thing, the drive tire needed more clamping force, and this was achieved by shortening the axis of the gearbox pivot piece. "This isn't science," remarked Byron while he was re-engineering the mount bracket for the motor and tire. Another requirement that surfaced during this phase was the need to center the two rails of the track along the centerline of the car in order to maximize turning radius. Thus, we offset the drive motor a bit. It will be moved back closer to the center in the final version of the car, as we now intend for the power rail and the drive rail to share footer bolts - it's more economical in terms of drop-in fasteners and concrete bits.

Note the gusseted plate welded to the top of the frame. This piece will be made of 1/2" thick steel plate in the final version, as will the piece below it holding the guide rollers. The motor mount pivot piece will be 1/4" thick (all pieces are 3/16" thick on the prototype - thus the gussets. Yes, this metal plate does bend under weight.)

For simple systems like this, it's sometimes quicker to avoid evoking CAD and going straight for the test model. This is our chosen approach, as it's sometimes more fun to get your hands dirty and play with the big toys.

As you can see, our test model is now hacked up a bit. I call her Lizzy, as a reference both to the FordTin Lizzie and Lizzie Borden. She is almost alive, though, and will likely run on a test track sometime within the next two weeks. I intend to take the first passenger test ride with Byron and two other 'lucky' riders by early March. We'll have a rudimentary body installed for those first test rides. Lizzy will never be ridden by the public. She's a developer's toy, and is thus destined for a life of sheer torture. Pity her.

Frank Starnes has been appointed as head carpenter for the car bodies. He was responsible for directing a great deal of set construction in the House of Shock main haunt (including the Ghost Room, my imagineering responsibility for the previous three years.) Frank does very clean work, and will help me draw the plans for the car body, now slated to be built with 'furniture grade' wood (you'll be seeing this work in progress within a month or two.) These cars, though not fancy fiberglass concoctions, will be the main star of the ride - not so much for how they look, but for what they can do.

Already it is apparent that the car's high speed (5 fps) will definitely produce significant thrills on a tight turn, particularly for the back seat riders. It seems our turn diameter is a little over 6', with a 7' long car. That's awesome - if it works. With Lizzy, we will experiment with letting the car's rear end pivot between wide-spaced guide wheels to increase the whip. For this, a damper (shock absorber) will be added between the drive truck and the main frame. For grins, we may install a too-fast drive and see what this might be like as a thrill ride. ;-)

If you have a guest present during design testing and modification, a bad night might convince that untrained observer that you're not worth a long shot bet. The difference in opinion comes with patient observation. You see little subsystems start to work, and visualze the plan beneath the entire product. You ignore the test machine's scrappy look and weak points, knowing that in the final production run, parts will be cut more carefully, and from more adequate materials. This early stage is known as prototyping, and even NASA must go through it when dealing with an untested design.

The Floor Plan
By now, some of you may have been wondering what the warehouse looks like. Here's the answer, in graphic form, and to scale.

The track drawing is purely an exercise in grinning speculation. If you'd like to have a go at a track layout - and submit it for possible use - go ahead! Click here for a floorplan with the track removed. (The loading situation remains drawn in - you must use this configuration.) We can't pay for ideas, but we can attribute the source. You know you want to try it, so here's how:

This is a large space for a traditional dark ride, and we're lucky to have it. In a test, it takes about 40 seconds to walk the long dimension of the facility at the car's low speed. (It's half that at high speed, of course.) Consider that we want a ride of 3 minutes, if possible. Keep your whip moves (high speed transitions) to an economical minimum, as the ride is much shorter when faster. Print the plan out, and cut out a scale car outline to use as a spacer when drawing your track. Remember not to overlap the fire lane! You will also want to color code your track to show high and low speed elements. The space marked 'practice room' is to be the ride's climax, and the route through it is fixed, as shown. You have 500' - 600' feet of track to work with. Remember that if there are two cars on adjacent tracks, they must never be able to collide at any point. Watch your spacing!

There's more (as if that weren't enough.) The ride is segmented into four track zones. The first zone must be roughly equal - and preferably a short bit longer - than the other three. This is due to the fact that a car will not be be enabled for launch from dispatch (the operator's position) until the previous car has cleared zone one. This is intended to avoid collisions between cars. Each of the remaining track zones should be a little bit shorter than the one before it, for the same reason. Mark your intended zones on the plan. (Technically, each zone will have its own power supply, capable of running three fully loaded cars if necessary.) There's also a Near Miss. At one point, two cars will just barely avoid a head-on collision - see the proposed track for the location. In your layout, you must include this element in your plan. (Yes, all we want from you is a master's thesis in dark ride design. ;-) )

About Safety Systems: Throughout the reading of this story thus far, you may have had nagging questions about ride safety. I'll try to explain what we have in mind to cover them. Inside the ride, there will be an interior operator, standing high above the floor of the ride with a kill button (which will stop the entire ride) and who can look down and trace the cars, which will have green LED's on their bonnets (the vertical coffins.) A fail condition in any car will light a bright red LED. Upon seeing red, the inside operator would stop the ride. Fail conditions include loss of power, breached safety bar, or bumper contact. The inside observer (who will also have night vision equipment and radio communication with dispatch and unload) will watch for 'zone breaches'. In the event of an observer's mistake, the cars will stop quickly if the front bumper touches anything. When shutdown is signaled, the house lights will come up automatically, and the ambient sound wash will be silenced.

It's obvious that this space is a wonderful tabula raza ready to be written upon in classic scary dark ride script - and that's precisely what we intend to do. If you have a memorable effect or innovative track section in your plan, we may well use it. It's not likely that we'll use your entire ride, but don't let that stop you. If you have stunts (special effects & props) in mind, say what they are, how they work, and mark their positions in your entry.

The deadline is May 1, by the way.

There's lots more to come. Stay tuned!