Rookie power
This is really a neat and compact design. We used the plastic drill motor mounts and mounted them to our steel frame. We then added a little L shape piece of aluminum on all four sides to serve two purposes:
1) Mount four small muffin fans to cool our motors down
and
2) Support the servo mounts
The airflow was superb, we didn't overheat once after they were installed, and being able to switch from high to low gear allowed us to have a quick/precise autonomous mode followed by a powerful low gear. It all worked out nicely =)
I would also like to point out that it was one of our wonderful students who designed that little gear-shift mechanism. Hope the picture helps
