MagLev C

[Jdogg]

Part of what I noticed is that the torque from the motor spinning also tilts it one way or another.

Lowering it would help mitgate the issue, but has anyone else come up with a potential solution, since we're not allowed to actually use another motor?

As long as the motor is mounted along the center of the vehicle's chassis and the propeller is symmetrical... Torque shouldn't cause a problem since it runs along the direction of the motor's shaft. Try adjusting the angle at which the motor is mounted or lower your center of mass. Hopefully that helps.

[joeyjoejoe]

We finally got around to completing Mark I of our Maglev design- just one problem: ...What usually winds up happening is that one side gets pulled down/to the side, but the bar magnets themselves never touch the track (the side of the magnet running parallel to the rail and perpendicular to the magnetic strips is doing this)

If it never touches the track, then what is preventing it from doing so? If the car is tilting and it is not due to an imbalance of any sort, it would seem that it would be magnetic forces causing the tilt. Therefore, there must be a N-S attraction somewhere. We have seen this many times when the car wasn't heavy enough and the gap between the bottom of the car and the floor of the track was 3/4 inches or more. What would happen was that the car would wobble (for whatever reason) and, if the bottom and side gap was large enough to allow a big enough tilt, then the magnets on one of the outside edges of the car would be attracted to the inside edge of the same side of the track. To demonstrate this attraction, simply hold two ceramic magnets over each other with like poles facing each other. Now, keeping the same distance between the magnets, move one of the magnets to one side until the two magnets snap together side by side. You have to limit the ability of the car from moving like this and one way is to minimize the gaps between the sides and bottom of the track. For the side gap, you can obviously adjust either the width of the car or the track. For the gap between the car and the floor of the track, we added more weight.

[darkwinters]

We finally got around to completing Mark I of our Maglev design- just one problem: ...What usually winds up happening is that one side gets pulled down/to the side, but the bar magnets themselves never touch the track (the side of the magnet running parallel to the rail and perpendicular to the magnetic strips is doing this)

If it never touches the track, then what is preventing it from doing so? If the car is tilting and it is not due to an imbalance of any sort, it would seem that it would be magnetic forces causing the tilt. Therefore, there must be a N-S attraction somewhere. We have seen this many times when the car wasn't heavy enough and the gap between the bottom of the car and the floor of the track was 3/4 inches or more. What would happen was that the car would wobble (for whatever reason) and, if the bottom and side gap was large enough to allow a big enough tilt, then the magnets on one of the outside edges of the car would be attracted to the inside edge of the same side of the track. To demonstrate this attraction, simply hold two ceramic magnets over each other with like poles facing each other. Now, keeping the same distance between the magnets, move one of the magnets to one side until the two magnets snap together side by side. You have to limit the ability of the car from moving like this and one way is to minimize the gaps between the sides and bottom of the track. For the side gap, you can obviously adjust either the width of the car or the track. For the gap between the car and the floor of the track, we added more weight.

Thanks.

This is probably the fix I"m looking for (indeed, the sides of the bar magnets we're using are attracted to the track).

The torque thing only really became apparent when I attached a rather large (unbalanced/slightly asymmetrical fan) to the cart itself.

[joeyjoejoe]

You'll minimize torque by keeping the weight as close to the base of the car as possible. A car with a high center of gravity is going to tilt very easily and, in our experience, wobble throughout the run. The prop necessarily needs to be mounted relatively high in order to clear the track but try to mount everything else as low as possible. We have even seen other competitors mount their motors on the base of the cars and attach them to the props via a pulley. This has the added advantage of allowing for a modification in the RPM of the prop by choosing the appropriate hub diameters for the pulleys.

[darkwinters]

You'll minimize torque by keeping the weight as close to the base of the car as possible. A car with a high center of gravity is going to tilt very easily and, in our experience, wobble throughout the run. The prop necessarily needs to be mounted relatively high in order to clear the track but try to mount everything else as low as possible. We have even seen other competitors mount their motors on the base of the cars and attach them to the props via a pulley. This has the added advantage of allowing for a modification in the RPM of the prop by choosing the appropriate hub diameters for the pulleys.

That's actually quite clever, though I'd imagine they'd run into the issue of slippage.

On the topic of lift:
Would it be legal to cut into the board such that you could (theoretically) lay down some thick(ish) bar magnets such that they were flush with the rest of the track?

It seems like it'd be a neat way to stick potentially more powerful magnets in the track.

[joeyjoejoe]

Would it be legal to cut into the board such that you could (theoretically) lay down some thick(ish) bar magnets such that they were flush with the rest of the track?
It seems like it'd be a neat way to stick potentially more powerful magnets in the track.

That shouldn't be necessary. If you are using the Kelvin ceramic magnets or ones similar to them, you should be able to double up on the track magnets and still fall within the 2-5cm height difference between the magnets and the top of the track. I guess it depends on the height of your side railing though.

[feynmanlover]

AHHH!
I need help.
I still don't even have a working maglev car yet .
How do you make a shielded propeller?
https://www.google.com/search?q=landing ... B300%3B300
That is a pic of the propeller I have right now, and I don't know how to shield it.

[feynmanlover]

Also, what material are you guys using for your bases?
I have a metal base (just recycled the one that was used last year).
I am thinking about building another with a wood base, but I fear that a wood base won't be heavy enough to compete.
What is your guys' opinion?

[FawnOnyx]

How do you make a shielded propeller?

I've used those propellers too. What I did was make a solid ring that's like an inch wide go around where the propeller would spin, then cover the front and back with like that mosquito screen door material, so it's like a grate on the front and back. Had to cut a small hole in the center of the screen for the back to get the motor shaft through.

Also, what material are you guys using for your bases?
I have a metal base (just recycled the one that was used last year).
I am thinking about building another with a wood base, but I fear that a wood base won't be heavy enough to compete.
What is your guys' opinion?

A metal base sounds pretty sketchy, especially if it's plain steel that's magnetic or something because that would interfere significantly with the field and probably make it sink lower. I used wood last year and that worked well, now I use plastic and that works too. You can always add more ballast weight with other materials on top like lead shot. (not magnetic and really dense)

[torqueburner]

I'm supervising Maglev at an invitational next week, and just downloaded the scoring spreadsheet. Everything seems to work fine, except that when I enter a construction violation, it doesn't deduct the 20 point penalty. Is anyone else having this problem? Does anyone know who would I contact to have this corrected?