a buddy has a h9 540 with a os 1.6 and it wieghs 13 bls. It really doesnt feel that heavy in the air. The cg was at 4 inch when i flew it so not a hole lot of anything was tryed. It took about 3/4 down elevator to keep it from falling when inverted. Watching the video the 2.1 really pulls this plane around! The 1.6 does ok but its not tuned yet. This thing has a metal motor mount???? Gonna have to look in to it. Any way, the cg got moved to 4.5 and as soon as the weather breaks we will get some more flights on it.
Might be able to get it down to 12.5. will have to look in to it.

As far as i can tell from looking at other guys planes here and on the market the h9 540 is pretty lite for its size. Maybe im wrong.