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Allinea wrote:

Flavorflav wrote:

Allinea wrote:Had my first practice today with the track and set up the magnets for some practice on the bottom of the sled. It seemed to float really well until the last bit of pushing it down the track, when it started and stopped a lot. From this, does anyone recommend continuous strips of magnets on the track or placing them side by side, and why?

I'm not sure what you mean by that, but it sounds like your problem is friction with the side rails. It is likely that the rails are not perfectly parallel, and taper slightly towards the far end - possibly just because they lean in. Do you have acrylic rails, or aluminum?

I highly believe they're aluminum. I'd think it was friction too, but after the troublesome portion goes smoothly again. I didn't get a chance to see if there were any other weird spots because some of the magnets were flipped and we had to switch them around, and I didn't get a chance to try the track again that day.

It's pretty easy to tell - aluminum rails will be silver, and all of the acrylic ones I have seen have been transparent. It sounds like the track magnets are blocks, is that right? One tip which is probably coming too late is to mark the same pole of all the magnets as soon as you unpack them - I used white-out. This makes it very easy to make sure that you are laying them down with the right orientation.

Flavorflav wrote:It's pretty easy to tell - aluminum rails will be silver, and all of the acrylic ones I have seen have been transparent. It sounds like the track magnets are blocks, is that right? One tip which is probably coming too late is to mark the same pole of all the magnets as soon as you unpack them - I used white-out. This makes it very easy to make sure that you are laying them down with the right orientation.

Yeah, they're most definitely aluminum then, though I kind of assumed that. I'll see if I can get in to work for a bit on Monday.

Since the rules changed to allow student-built tracks, would it be considered legal to connect various pieces to the aluminum side rails of the track (i.e. grease, magnets, graphite, water)?

JTMess wrote:Since the rules changed to allow student-built tracks, would it be considered legal to connect various pieces to the aluminum side rails of the track (i.e. grease, magnets, graphite, water)?

I was wondering the same thing... I mean, the rules don't specifically outlaw anything like that, so I'd say it's fair game. Does anybody know for sure?

scm424 wrote:

JTMess wrote:Since the rules changed to allow student-built tracks, would it be considered legal to connect various pieces to the aluminum side rails of the track (i.e. grease, magnets, graphite, water)?

I was wondering the same thing... I mean, the rules don't specifically outlaw anything like that, so I'd say it's fair game. Does anybody know for sure?

My mentor and I were debating adding groves to the sides and then doing something with that, e.t.c. The rules say inadvertent contact is permitted in terms of the vehicle levitating, which would imply intentional contact with the sides is illegal. Then again, I don't see anything about adding things to the sides of the tracks such as grease. I see a rules clarification occurring for this.

I figured out why the vehicle was catching on the sides! The balance was off so it got caught on the tape.

I think they're going to have to give some latitude on contact with the sides, since true levitation of a static object with ferromagnets is impossible (see Earnshaw's Theroem). What we are really doing is pseudo-levitation. The best competitor-built tracks will be able to make a saddle, but the standard track is always going to produce some contact with the sides. Not allowing you to reduce the impact of that contact would not seem to be in the spirit of the event.

My students built a beautiful MagLev track. The only problem is that the cart will flip because the north of the track attracts the south of the cart and vice versa. Has anyone else had this problem? What would the solution be?

venglef wrote:My students built a beautiful MagLev track. The only problem is that the cart will flip because the north of the track attracts the south of the cart and vice versa. Has anyone else had this problem? What would the solution be?

Sorry, can't follow what you have/what the problem is here.
Whether using individual magnets glued end to end or magnetic strip (the individual magnets will work better than the strip in terms of field strength), you have one rail with (let's say) N pole(s) up, the other rail also has N pole up. On the vehicle, you have magnets with N poles down (so repelling from the track)- on both sides.
What am I missing?

Balsa Man wrote:

venglef wrote:My students built a beautiful MagLev track. The only problem is that the cart will flip because the north of the track attracts the south of the cart and vice versa. Has anyone else had this problem? What would the solution be?

Sorry, can't follow what you have/what the problem is here.
Whether using individual magnets glued end to end or magnetic strip (the individual magnets will work better than the strip in terms of field strength), you have one rail with (let's say) N pole(s) up, the other rail also has N pole up. On the vehicle, you have magnets with N poles down (so repelling from the track)- on both sides.
What am I missing?

Flipping? Do you have a wide enough vehicle? That's the only thing I can think of.

Balsa Man wrote:

venglef wrote:My students built a beautiful MagLev track. The only problem is that the cart will flip because the north of the track attracts the south of the cart and vice versa. Has anyone else had this problem? What would the solution be?

Sorry, can't follow what you have/what the problem is here.
Whether using individual magnets glued end to end or magnetic strip (the individual magnets will work better than the strip in terms of field strength), you have one rail with (let's say) N pole(s) up, the other rail also has N pole up. On the vehicle, you have magnets with N poles down (so repelling from the track)- on both sides.
What am I missing?

The standard tracks have N up on one side, and S up on the other. I'm not sure if there is any advantage to that arrangement, but it has the disadvantage that the OP noted, a tendency to cause the vehicle to roll. Usually this can be corrected by slightly increasing the spacing of the magnets on the vehicle - the effect is much more pronounced if they are closer together.