We are attempting to design a solar car. The solar panel 4 1/2" x 13".
I like to break these problems into their simplest form, in order to eliminate the least amount of possibilities. So, the goal of the competition, as I understand it, is to transport the (provided) solar panel, and the (provided) electric motor down a 40 foot long track (the car is guided with fishing line as a guide wire).
The texture of the track is similar to the surface of a skateboard, although slightly rougher than that.
Of course there will be many other considerations besides the physical design of the car (gear ratios, lenses and/or mirrors for the panel, guide wire receiver), but right now I am focused on the car itself, and more specifically, the wheel orientation. I am wondering: What is the optimal wheel setup for this car on this track? Some ideas I have found/had are:
- Less rotational inertia in wheels will mean more energy being invested into the car itself. Additionally, the car, overall, should remain light weight. So, less wheels, and less massive wheels will be better.
- This terrain is relatively rough. As such, wider and larger diameter wheels should be used (the idea that a LEGO car rolls down the driveway extremely bumpily, whereas a bicycle does not). So perhaps large (but light weight) barrel shaped wheels would be most effective.
- The height of the fishing line guide wire can be chosen by us. So assuming we have a low friction guide wire receiver (like a lubricated, plastic drinking straw), it seems like we should set the guide wire in such a way to support a significant amount of the weight of the car. (Due to the fact that the car is solar powered, it is extremely unlikely that it would "peel out".) Should this supported weight be changing throughout the course of the track? Perhaps as the car moves along the track, the wire should support more and more weight, as the car will have less torque at those higher speeds, although, on the other hand, the sloped up rope could slow the car down.
What would the most efficient wheel orientation/setup for such a car be?