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Post by phoenixlab on Aug 15, 2011 12:11:05 GMT -7
I read all rules and they say no magnets. Do manegts alter the readings of the best track? Can someone tell me the reason for no magnets? I am not trying to cheat. I just got a new design in my mind, but in order for it to work I need to hold thin wood panels to the car body with magnets. Help me Obi-Wan Kenobi...
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Post by advancedtechnology on Aug 17, 2011 11:41:39 GMT -7
Hmm, it seems like the "magnet" rules are no longer there for all classes: Pure Stock, Door Slammr, Modified, Super Modified, Super Pro Modified...do not mention magnets. Maybe I am going blind...but I did a "text" search too. Did not find anything related to magnets for these classes. Maybe this is a new area for development and advancement. The classes; Stock and Super Stock still mention "magnets" in Section 4...as modification NOT allowed. I read all rules and they say no magnets. Do manegts alter the readings of the best track? Can someone tell me the reason for no magnets? I am not trying to cheat. I just got a new design in my mind, but in order for it to work I need to hold thin wood panels to the car body with magnets. Help me Obi-Wan Kenobi...
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Post by down4derby on Aug 17, 2011 21:16:00 GMT -7
If the starting pins of the track are magnetic, a car with a strong magnet on the nose might be slightly pulled forward with the pin when it drops.
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Post by DNA RACING on Aug 17, 2011 22:24:56 GMT -7
it would also cause a small amount of drag every time it passed a joint where the steel bolts hold the cross braces to the aluminum. when ever thousandth counts i dont see how it could help. even at the start gate when the normal cars were freely moving, the magnet car may actually be holding back a bit to those starting pegs. not to mention it might pull the car left or right even a small amount at the joints.
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Post by txchemist on Aug 18, 2011 11:46:34 GMT -7
The real problem with a good magnet on your car is not that the magnetic bolts mess you up, they attract your car both speeding up towards them and slowing it down after you pass them so no net effect. The big problem is the Lenz effect. Aluminum makes the best magnetic brake you would want. Try rolling a perfectly round magnet down the track to see for yourself. It might make a neat turtle car where you adjust your speed by setting the distance of the magnets above the track.
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Post by phoenixlab on Aug 18, 2011 22:36:53 GMT -7
My first idea was to use magnets to hold car parts. I think really interesting the idea of magnet propulsion. I guess it would work on wood tracks. There is plenty of "stuff" about magnetic propulsion on youtube. I could not resist an got myself some small magnets to play with. Let's see what will happen.
Now 7DB, the idea of magnets as bearings would only work if the axles could be machined from other magnets with opposing magnetic fields., otherwise they would just stick to the steel ones like crazy glue. On the other hand, the repulsion may be to strong.
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Post by advancedtechnology on Aug 19, 2011 5:58:49 GMT -7
There is no "contact friction"...but there are still Eddy Currents generated which can cause a "drag" effect. This is basically a "shearing" force of the magnetic field. However, the benefits still might outweigh the losses if applied correctly. A.T. The right magnets can be used as bearings; they have absolutely no friction because the barrier between the axle and the bearing magnet would be nothing but air.
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Post by advancedtechnology on Aug 19, 2011 21:25:09 GMT -7
4.) seemed like, in relation to the video attachment, that the effects of eddy current you speak of has a lot less effect than friction. In the video, the wheel was still spinning after the 1 minute video was over and to show the wheel was not motorized he touched it with his finger and the wheel didn't gain it's speed back. When I get my lathe, I believe I will research this a little farther.I don't think you can determine the magnitude of the eddy currents from a video. The inertia ("flywheel effect") of the huge mass they are using in the video (compared to a few grams in a BSA wheel) is certainly an apples to oranges comparison. Plus consider the absolutely miniscule magnets that must be used to to maintain light weight wheels. At any rate, it is certain that eddy current would have a much more pronounced effects on an ultralight PWD wheel...the required magnets are probably going to weigh more than the wheels...even with Neodymium Iron Boron or Samarium Cobalt. I think a better comparison would be (2) ring magnets on an axle (plastic straw or similar). Even though one you can "levitate" the ring on the magnetic field, it does not rotate very freely around the axle...due to eddy currents. Anyway, I agree it is worth some real world testing...but I still think the application is trickier than you night think. A.T.
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