National G. Special on coasters question

[maeryk]

Okay.. maybe my memory of ferrous metals is wrong, but in the Natl. G special they showed a Lim coaster (flight of fear, I think?).

 

They claimed that C-shaped magnets acted on aluminum fins on the side of the ride to launch it.

 

Now.. has someone invented an aluminum magnet that I am unaware of? Is that a mistake? or have I just completely blanked on some way to make aluminum react to magnetism?

 

Thanks!

[Jon Sabo]

That does appear to be rather odd. I'll search the NASA website and look at that. I understand it the "contact" point (metal) is a rare earth magnets that react to the LIM's power source and never heard of aluminum (of all metals) to be a source, because during a heat cycle the aluminum would flex quite a bit and have severe fatigue.

[PKIDelirium]

They are in fact aluminum, pure non-ferrous aluminum fins. If you want to hear more about the ride tech, I have a video of the Maintenance director speaking about Flight of Fear.

 

http://extremepki.com/videos/beastbuzz_05_fof.zip

[ahecht]

Yes, you heard right, they are aluminum. In fact, copper, which is also non-ferrous, would've worked even better.

 

Now, in a LSM launch, ferrous rare-earth magnets are used as the "contact point" (to use the term above), and the electromagnets on the track push and pull these perminant magnets. However, the downside of this is that it requires very exact timing in order to launch the train.

 

With a LIM launch, they can pulse the launch magnets in a row at any speed, and the train will eventually catch up to them.

 

The short way to explain this is that it acts like a generator in reverse. In a generator, a magnet passes over a copper or aluminum wire and generates a current. In a LIM launch or magnetic brake, the magnet passing next to the copper or aluminum plate generates a current inside the plate turning it into an electromagnet.

 

There is a website that does a really good job of explaining this stuff (and I think I've posted it here before), but I can't find it at the moment.