I've been building an electromagnetic wheel (a bike wheel which rotates by electromagnetic interaction between electromagnets on the hub and permanent magnets on the rim) and I've come across an interesting problem. Currently, I've got the electromagnets mounted on the hub with the coils pointed towards the rim, where the permanent magnets are mounted with their poles perpendicular to the coils of the electromagnet. I decided to do this because I figured that the electromagnets would have an easier time reaching the next pole in their rotation if the permanent magnet poles were closer to each other, as my concern at the time was that electromagnets wouldn't be strong enough to interact fully with the permanent magnetic field. However, my physics teacher/adviser for this project informed me that I could achieve far greater rotational force if I mount the permanent magnets with the faces parallel to the electromagnet coils. I'm wondering if it makes a tremendous amount of difference; does anyone have any insights? I'll try to post pictures at a later date to help out. Thanks!