This is probably the simplest picture of the insides, taken a few years ago. The massive servo sits on its long end, with the horn connected directly to one of the lifting arms. I then bolted a piece of HDPE to the opposite side of the servo (effectively its bottom) with an M6 bolt protruding and I use this as a pivot point for the other lifting arm support.



As I said, the servo is rated at 20kg/cm, so over the full length of the arm, it's not actually got a huge amount of power on the end of the flipper but it's enough to tip other robots over if the angles are right.
The drive motors here were some of the MFA 15:1 motors, but I found them to be quite slow and underpowered so I changed to the 1000rpm motors that everyone uses and it was a big improvement. The battery in the picture is an old nicad pack from a drill, but I've since changed that to a lipo.

This is a more up-to-date picture of the insides, although still with the old motors:



The lipo is mounted underneath the radio receiver, just held down with a polycarb clamp. The bit right at the front is the BEC, as the ones on the drive ESCs weren't powerful enough. Incidentally the drive ESC are Botbitz 10A ones and they're located in the back corners, along with the wiring loom.