Launches

[Hank]

Coasters that have launches, like Maverick at Cedar Point - what under the train meets with the launch "thingy s" on the track which propel the train forward? Are the brake fins ever used for this purpose?

Also, if the launch thingy's don't match-up properly with the train's under thingy's, what would happen? Could the ride resume from that spot (assuming it was stopped) or would the train need to be dragged back to the start? Maybe the individual launches can be adjusted for such occasions?

I'd like to know - especially if launches are coming to more coasters - steel & wood.

[ProdigyRider]

I think, down the center of the train, is a steel bar that connects with each car. For Instance, under Diamondback's train is a silver bar or casing that the brakes can grab hold of to stop the train. The launch fins on the track get an electric charge and turn magnetic, pushing the train similar to Linear Induction Motors found on Flight of Fear and Backlot Stunt Coasters. This is Maverick's case, but there are other ways to achieve a launch, like catch cars or drive tires.

[homestar92]

Well, there are a number of different types of launches. During KIC day back in June, a man named Matt from the maintenance department gave us a little insight to Backlot and Flight of Fear's launch systems. Those rides work in a very similar (if not identical) fashion to one another. I believe there are fins off to the sides that sit between two rows of LIMS, and the magnetism from the LIMS (which are basically powerful electromagnets) repels the train, launching it into the ride. The fins can be seen in this picture:

Coincidentally, when Matt was kind enough to explain all of this to us, he also happened to have one of the LIMS from Backlot Stunt Coaster that had gone bad in the bed of his truck, as seen in this picture:

If I remember correctly, he said that there are 48 of those on Backlot's launch strip, and they cost roughly $8000 apiece to replace. I don't remember the exact number, but there is somewhere in the neighborhood of twice that many on Flight of Fear. The number 80 sticks out in my mind, but that may not be completely accurate. Either way, that's a lot of magnets!

That is only one type of launch. I know Dragster uses a hydraulic launch, and if I understand correctly, there is essentially a catch car at the end of a cable that hooks into the underside of the train. When the motor is turned on, it pulls the cable at a high speed, propelling the train over the hill. This is a very rough understanding of that ride's systems, so take it with a grain of salt, but that is my understanding of how it works.

Rides like Maverick use yet another different system. I know little about this launch mechanism. Maverick has a white fin looking thing along the two launches, so I can only assume that this fin creates the force that launches the coaster, but this is totally conjecture. I do know that Premier has started using that system on their rides as well since Maverick was built, as you will find a similar launch system in place on rides like Kennywood's Sky Rocket.

Finally, there is a tire launch like on The Incredible Hulk at Universal, in which a pair of tires squeeze against a fin on the underside and the faster they spin, the faster the train moves. Spin the tires really fast, and you have a launch. The same idea is used (only much slower) on many smaller coasters such as Flying Ace Aerial Chase in lieu of a chain lift.

NOTE: The images in this post are my property. Do not re-post them outside this forum without my permission. If you want permission to post them elsewhere, ask, and you will most likely receive. If you want to post them elsewhere on KICentral, feel free, but make sure I get credited.

[silver2005]

Maverick as well as a few other newer launch coasters use a different system known as Linear Synchronous Motors (LSM). I have a coaster book that sort of explains them. I'll compare them to LIM's.

LIM's are magnets being used at the very basic level, using magnetism to pull/repel metal objects. A hair dryer uses this same technology, but produce rotary motion. LIM's take that technology and straightens out the magnets. Its essentially using magnets like a tire launch. As homestar92 pointed out, LIM coasters have metal fins or bars that interact with the magnetic motors for speeding up or slowing down.

LSM's are quite more complex. While they use the same principals as LIM's, they require more interaction between the ride vehicle and the motors. The magnetic interactions take place within fractions of a second, so instead of being like tires, they're more like gears. LSM's are much more precise both in the speed achieved as well as more efficient energy consumption (you don't need the same amount of power each launch due to many factors). You can produce much more acceleration off of LSM's than LIM's. Heck, LSM's were the first launch mechanism used to get a coaster to 100 mph.

Superman @ SFMM and Tower of Terror in Australia were a bit ahead of their time. Instead of being energy efficient, they required loads of energy. Heck, Superman needed its own separate line off the California power grid to operate. I imagine they improved those systems with the refurbishments they each got a few years back. However, the industry has got more used to them and now they're pretty reliable.

I'm sure its far more complex than what I'm describing.

[thedevariouseffect]

Also it's worth noting, magnetic eddy braking technology, the ride cannot be fully stopped. It can be put to almost a near dead stop. Most of the time you will see drive wheels as well in the brake run, those are the final set of brakes essentially for the ride to keep the trains in place during braking.

The brake fins are a separate entity than the launch motors. On Maverick for example all of the LSMs are fixed in place and unable to move. The brakes vary. For trim/brakes that always engage, they are fixed placement as well. For blocking purposes some brakes retract under the track and out of contact from the elements on the train, allowing them to move.

Here's a picture of what I'm talking about under the train. So that groove interacts with both the LSM motors and the eddy brakes.

[TombRaiderFTW]

The following post in no way states any specific inside information on the maintenance and/or design of any ride at any park. Hopefully this doesn't come across as confusing as I fear it could be in my head:

In essence, homestar92 is pretty close. The main difference between Premier launches like Backlot and Flight of Fear and launches like Maverick are that BLSC/FOF use linear induction motors (LIMs), whereas Maverick uses linear synchronous motors (LSMs).

First, think of a normal electric motor, similar to one you might have in your Lionel train engine set (the kind that you have to plug into the wall.) There are two general parts to that motor: a rotor (which rotates--that's your shaft and all the stuff attached to it) and a stator (the part that doesn't move--that's everything else.)

The stator has what's called inductors in it. Without getting into the details, an inductor creates a magnetic field when you put an alternating current through it. (I never understood what an alternating current was until I got to college, so for the folks who don't know: the electricity that comes out of your wall has an alternating current. A AA battery doesn't have an alternating current. That's the easiest way to remember it. An alternating current just has features that change with time.) When those features change, it changes the poles of your inductor. Basically, if you held a magnet near an inductor, it would be pulled toward it, then pushed away from it, then pulled toward it, then pushed away, etc.

In an induction motor (not a linear induction motor, just an induction motor--we'll get to that in a bit) your stator--the part that doesn't move, remember?--will include multiple inductors in a circle. Remember how I said your magnet would keep changing its mind about its attraction to an inductor? If you put your magnet in the middle of the circle of inductors, it will actually spin in a circle. The reason for this is because the inductors can be adjusted so that, just as one inductor starts to switch over to repelling your magnet, the one beside it will switch over to attracting it. When THAT inductor starts to switch over to repelling your magnet, the inductor beside THAT will switch over to attracting it. It's kind of like a game of Hot Potato--the guy in the middle wants to catch the potato, but the people on the outside keep passing it in a circle around him, so he keeps turning around to try to get it. (...Maybe that's not actually how to play Hot Potato. You get the point.) And actually, that's exactly how an induction motor works--there's a regular old magnet (rotor) in the middle of a circle of inductors (stator), and they've got the rotor spinning like crazy. Attach something to that rotor, and you've got a motor doing work for you. It's also important to note that how "strong" your electricity is (i.e., how strong your current is) will determine how strong your motor is. If your power fluctuates at all, your motor strength and speed will change accordingly.

A synchronous motor works exactly the same way, except the guy in the middle of the (super lame) Hot Potato game isn't a magnet. He's an inductor, too. So why does that matter? An induction motor can very rarely, if ever, line itself up perfectly so that it won't spin. A synchronous motor's inductor rotor can self-adjust and correct itself, and you won't have to bump/turn it to get the rotor going. It also can be advantageous to use synchronous motors where the power fluctuates; its speed is based on how quickly your alternating current features change, not how strong your electrical power is. (There are more reasons than those, and I've forgotten them. I'm not an electrical engineer! Sue me! If someone else can jump in, feel free to list more advantages to synchronous motors.)

Now, for that "linear" bit from earlier. The difference between a regular motor (like we've been discussing) and a linear motor is that the inductors in the stator are in a straight line instead of in a circle. Going back to the sad, sad Hot Potato game from earlier:

In a linear induction motor (similar to Flight of Fear), the inductors in the stator stand in a straight line. Instead of rotating, your rotor--the magnet--will move in a straight line. Mr. Magnet, the sorry sucker who's trying to catch the potato, starts at a full run to try to get the potato as it goes down the line. The potato stops at the last inductor, but the magnet is moving too quickly and speeds off into the sunset. (Good for him. The game stinks.) How quickly the potato gets passed down the line (i.e., the "strength" of the electricity) will decide how fast the magnet runs. Again, if your power fluctuates, your potato won't move as quickly as it needs to, and your magnet won't move as quickly. And then your Flight of Fear car rolls back, as it were. (Those fins on the side of the car are the rotor, and the gray boxes on either side of the track are the stator. Same for BLSC.)

In a linear synchronous motor, your stator inductors also stand in a straight line. Your rotor is again an inductor. I'm assuming you get the same benefits that you get with a regular synchronous motor, but I'm not that familiar with LSMs. Presumably, there would be a power source on Maverick's train that powers the inductor(s) on the bottom of the train, but I don't know if there is or not. If there is a power source, it would be recharged every time a train is in the station, and I honestly don't know if there is some kind of rechargeable battery out there that provides an alternating current. (Any knowledge I have here came from a class on generators, which are very similar to motors. Outside of that, I'm a mechanical engineer, so I do zilch with battery design or use.)

Hopefully that made sense and/or helps? It's been a few years since I did anything with induction/synchronous motor info, so this may not be perfect. If anyone notices anything that's off, please feel free to speak up.

EDIT: To add to the above posts, there also are the flywheel and gravity drop launches seen on Schwarzkopf coasters. I don't know the fine details of either.

[The Interpreter]

And THAT, my friends, is why I've spent more than three decades working with engineers, not as one.

My type says "Then a miracle occurs, and 'WHEEE!'"

[TombRaiderFTW]

^ Oh no! I was afraid of this!

Do I at least get a gold star for trying?

[rcwizard13]

Excellent information, TombRaiderFTW. I love the hot potato game comparison. It really helped. A+

[Monroe]

AC= Alternating Current In the USA we use a 60 Hz system (60 cycles per sec.) meaning the current changes direction 60 times per second. (easiest way to explain it.)

LIM= Linear INDUCTION Motor - The magnetic field (In this case metal plates on the side of the ride vehicle) is induced, created by an eddy current, (simple terms it's faked) The vehicle is pulled along the track by a constant current from the motors mounted on the side of the track.

LSM= Linear SYNCHRONOUS Motor - The magnetic field is constant and created by natural or earth magnets. The current of electricity is synchronised with the magnets. Simple terms, the motors on the side of the track turn on and off as the magnets pass. (This type of motor is used for mag lev technology)

[The Interpreter]

Monroe, fellow EAA member, splains things like I would. From that standpoint, perhaps he should be worried!

Terp, who has taught some of this stuff, from his own weird perspective.

[Monroe]

Not worried at all Terp, I spent eight years in college one full year just on the characteristics of AC alone, the one thing I took out of that year was that there is no real one way to teach it and have every one understand it. After 40 years of experience, the one major thing I have taken away from all of this has nothing to do with the physics of power, one word, respect. Oh and never mention the word capacitor to a lawyer on the stand unless you can describe it in detail including how it is made.

Monroe, Flying away for a little Sun and Fun.

[jcgoble3]

Oh and never mention the word capacitor to a lawyer on the stand unless you can describe it in detail including how it is made.

Shall I assume that you have first-hand experience with this?

[Monroe]

^The third time I was smart enough to take a cut away model with me.

[jcgoble3]

Oh, my. I have nothing else to say.