- I needed a bit more room for these 4000 mAh cells, so I trimmed a bit from the front and back of the battery compartment.
- Other people have commented that crashes were crunching up the Zii nose, and that a plywood battery box helps prevent this by transferring the crash energy to the rear of the body where there's more foam to absorb the energy.
Here's the cut I made to the the front and back of the battery compartment. I made it flush with the leading indentation.
Here's the side view of the box. Be sure that the bottom and sides touch the flat surface of the front and back walls. this will transfer energy from the front of the plane to the back if you nose in.