whats the auw of the mx2? with a hacker 9l? I dont know which Hk Motor adam has, but the one I`m using is comparable to a 2203/46, or slightly better. my 2 Gernot yaks one is about 5.2 the other is slightly heavier due to a crash (never let friends drink and fly and even some sober) around 5.6-6.0 and on a 2 cell 350 the motor still pulls it around with authority. 3 cells on it and its insane power. I also used this motor on a GP Yak and it flew fine.
Sorry to hijack the thread back to the MX2, speaking of which still waiting patiently!!!!