Power and Propulsion 9/15/09

All three members were present. We discussed the pros and cons of axial fans vs. propellors. Although they may be more difficult to mount and install mesh around, propellors were successful on previous hovercrafts. They also produce more thrust. We are leaning towards propellors over axial fans at the moment. Axial fans have a high flowrate and are easier to mount but we realize that winning doesn't necissarily mean picking waht is easy.....nor does it mean making things more complicated than they have to be.

Another design aspect discussed was the way our hovercraft would steer. One option considered was dual fans mounted on the left and right for tank-style steering. This option may provide quicker steering, but at the same time may be hard to balance and keep in a straight line. Another option considered was a single fan which can be manipulated by a servo. This way makes for easier straight-line motion (only one fan/speed to worry about) but could also be heavier and harder to mount. The steering might also be slower, but we will decide later whether sharp or gradual steering is desireable. Either way is plausible as the NXT has 3 outputs, but we were assured by the sensor and controls team that the latter option would be significantly harder to code and that is something we msut consider.