Good call. I didn't even think of that. The weight of the battery will produce more stress on the tips of the hatch. How much more does light ply weigh vs balsa? With a lite ply hatch and the mounting rails I don't want to end up adding a lot of wood that will increase the weight to a point that I could just add lead to the tail and forget about a hatch. What do you think?

Or maybe there is a better way to mount the battery inside the fuse and then there would be no stress on the hatch.