The rear cantilever section of the fus does not have any internal support its only supported by the glassfibre skin of the fus,
The smaller Chinese Bobcats are the same, my rear fuse was already cracked when I bought this one crashed.
Unbelievably the designers put a great lump of heavy wood in the rear 'shelf' area to bolt the engine to but it stops where the shelf stops, there is no overlap into the fuselage.
This was my solution, a bit agricultural but it works.
And it looks great from the top! - John.