What powers the ride?

Because one set of fins are permanent, the other set needs to be retracted each launch.

Don't forget, LIM/LSM takes up a lot of space. On Superman: The Escape, there are a bunch of sheds between the two tracks, which I believe is where the electricity is converted into the LSMs. Wicked Twister has a big electrical room running along side of the launch too. I can't remember where I saw this or who said it, but this person said that one of the factors is because LSM takes up too much space.

gregdawg said:
Why are the launch track magnets smaller and spaced apart more than the brake run magnets? When the train rolls back is it not going as fast as in the brake run, should'nt both the launch and brake runs require the same amount of brake fins to stop the train?

bholcomb said: Because one set of fins are permanent, the other set needs to be retracted each launch.

This may sound stupid but, aren’t the magnets more powerful on the launch side since they are spaced apart? They stop the trains a hell of allot faster then they do on the brake run.
I know Intamin designed them the way they are for obvious reasons, I'm just wondering in general.

Electricity is converted into LSM's? Let me know how to do that so I can start making them at home.

It always seems that the steeper the brakerun the faster the train slows. The steepest brakerun is on KK which slows from about 80mph in about 200 feet. TTD has a somewhat level brakerun that slows the train from 115mph by 400+ feet.

Is there any truth to this, I really don't know? It's something I've noticed over the years of the Rocket Coaster era.

OK Jeff, let me try this again. That's not quite what I meant. Electricity is taken into the rooms from one line and then that line is converted into a series of electrical lines which then go out to the LSMs. Once again, one line is divided into more lines which then go to the LSMs. Got it Jeff? Good! I hope that clarifies it for you. I'll let you know how to do that so you can make that at home too. I hope your backyard is big enough Jeff. *** Edited 8/7/2005 9:01:16 PM UTC by Jethro***

Jeff, California Screamin uses LSMs which can get wet. LIMs dont work when wet. Due to this, LIM coasters dont operate while its raining and have their motors under a shelter.

There is no reason that LIM's can't work when they're wet. If they're waterproof, they're waterproof.

Cali' Screamin' uses LIMs. Those aren't LSMs.

Correct me if I'm wrong, but isn't the brake system on TTD the reverse of MF: the permanent magnets are on the train, with copper/aluminum conducting fins on the track?

Yes

Incidentally, so long as you waterproof the coils, you can run a LIM when it is wet. So here's an idea for you:

A LIM works by magnetically pushing a conductive, but non-magnetic plate. The idea is that the coils generate a magnetic field in the plate, but because the plate is non-Ferrous, it is not itself attracted to the electromagnet magnet coils. But who says that the reaction plate has to be a metal plate? Or even that it has to be a plate at all? It just needs to be conductive and non-magnetic. So here is a brilliant idea: Use a circular coil that generates a very large magnetic field in the center...that is, a solenoid. Instead of a metal plug or plate, use *salt water* as the reaction plate. What you end up with is a pump with no moving parts for pumping (highly corrosive) seawater.

Mount that pump on a boat, and you have a "magneto-hydrodynamic drive". While the "Red October" is still a few years away, and at present the technology is not as efficient as a diesel engine, Mitsubishi did build a cargo ship that used such a propulsion system. I don't know if it got past sea trials. Point is, LIM technology can work just fine under water. :)

--Dave Althoff, Jr.

LIM's seem like a thing of the past, and are pretty inneficient.

As for Intamin overthinking their rides, that is total bs. It takes a helluva lot of power to get a 2 ton train to go 120+ mph in less than 4 seconds.

As for not understanding hydraulics, here is one of the most used links in the history of Pointbuzz forums:http://www.pointbuzz.com/ttdtech.htm

And, by the way, wouldn't using a steam launch, like that on aircraft carriers, be much more powerful? (although I would guess that it would use huge amounts of energy)

All those photo's you guys are looking at are not "magnets" they are special bronze alloy brake fins. Some go up and down - some are permenant. The "magnets" are mounted up under each train (on each car) and are permenently mounted. They ARE extremely powerfull and can not be dis-assembled, because of possible injury by mishandling them. The way the process works is that the extreme magnets (they are mounted side by side - maybe 2" apart) create a very desnse magnetic field - so dense that nothing can pass through it very quickly. As the vehicle goes around the track the "special brake fins" pass through this 2" opening and do their best to get through the dense magnetic field, which in turn slows the vehicle. This is also the "heat waves" you are seeing - the energy disapated cause extreme heat. The permenant fins are trim brakes. This same design is used on the pick up car to slow it down at the end of the launch and to slow it down when returning to the staging area (magnets mounted under pick up car)

I've never heard anyone call the plates "bronze alloy." Top Thrill Dragster does have more copper in the alloy than Millennium Force. It's probably 90% and 80% copper respectively. The rest is mostly aluminum but some other metals.

Do you happen to know what the flux density of the magnets used? I would use my gauss meter if I could get close enough. :)

ForgottenEE and Jim Hancock should get married. At least they'd have plenty to talk about... ;)

MrScott

It's good to know this kind of stuff. It could come in handy.......somewhere.:)

Seriously though, thanks for that educational post Jim.
I also have a quick question that pertains to Intamins magnetic system. What are the inducers(more than likely not their real names)made out of on Wicked Twister? They appear to be some kind of plastic....but that's just me.
http://www.pointbuzz.com/Gallery.aspx?i=819 (not the brakes)

*** Edited 12/8/2005 4:50:13 AM UTC by TTD 120mph***

You're looking at the coil packs just past the brake calipers (not really the right name for them, but it works for now), at the extreme left edge of the photo, right?

That's an interesting design. There are actually two LIM coil packs, which is typical for double-sided LIMs, similar to those used on, say, Kings Island's Flight of Fear. Inside those large oblong containers are coils of wire, probably sealed in epoxy. The interesting thing is that Intamin apparently (remember, I have never seen the inside of one of these LIMs) took advantage of the fact that the coil produces a magnetic field on BOTH sides. Outboard of the coils are metal (presumably steel) backing plates so that the motor configuration is effectively a double-sided LIM on the center fin (which is copper-colored) and two single-sided LIMs on the outboard fins (which look to be aluminum). The outboard fins, obviously, are also used for braking.

(yes, there are three fins on each car)

--Dave Althoff, Jr.

I more wonder who the coils are oriented. I'm pretty good with rotational motors, but linear throws me a curveball logically speaking.

Thanks for the answer Dave.