Not enough power to stay airborne!
The amp dumping capability of NiMH is nearly the same as NiCds of the same physical size these days.
I run the "S2" drive (same ratio as your 2XC) on a Birdworks Tilde with a 7060 prop and 8 cells. 12-15 minute flights on 300mAh NiMH cells, and the amps are only about 2.25 static. On 6 cells, this plane would fall flat on its face.