Science Forums 2

[GAHD]

Originally Posted by CraigD

Remember, you still want the bicycle to have good performance as a bicycle, so keeping wheel mass to a minimum, especially near the rim, is as important as ever, which to my thinking rules out permanent magnets on the wheel schemes.

Exactly my thoughts. Curses and praises to rare earths being so damn heavy.

Originally Posted by CraigD

Ultimately, I imagine you’ll want to epoxy and autoclave cure wires into/onto something like a 4-spoke carbon fiber wheel/rim, and use some sort of brush commutator near the hub to get the current to the battery.

Fairly accurate, though I was considering 2 seperate brushes one near hub one near rim, and Using a high-current low voltage idea akin to a faraday wheel. Being an ASS, I 'sume that if the wheel were sectored the counterflows of current would be almost negated, the mass of wheel not exposed to brush & magnets mounted to the forks not receiving a charge. Again being an ass and suming I understand the basics of lorence I was thinking having a mass of parralel wires running radially, ignoring the customary coiling structure of motors as this would essentially become a brushed linear motor.

First design:
The rim would be "spokeless" in that I expect it to have a smooth and unbroken outer surface, the sectored brush conacts being inlayed radially close to the rim and bearing hub. The wireing itself would be affixed below a .004-.016" Boeing prepreg carbonfiber/epoxy skin, and on top of another skinreinforcing an as-yet unspecified grade/type Boeing 'honeycomb' core. (the shop is supplied by Boeing stock).

I expect to have to make the final magnets for the forks myself, first blocking two Halbach arrays and then chopping out a grouve for fork mounting in the final model, though I'd love to hear some other ideas there.

any theory math you could throw at this? The devil's in the details but I'd like to see what others think the math should look like.

Originally Posted by CraigD

It would be really nifty if you could manage some way of doing it brushlessly, via inductance (the wheel will, after all, be moving most of the time), but that seems a lot more complicated to me.

Indeed! Another drawback to this inductance scheme is an inability for regenerative braking which would limit usefulness and range. The whole point of this wheel is to mitigate the stop-start of in-city movement.