just started flying mine. and on knife edge it rolls and pitches towards the belly bad. is useing the mixing in the radio the only way to fix this?

Make sure you have it trimmed and the incidence is right on the stab and engine thust line. An aft CG will also cause the plane to pitch to the belly on knife edge. Also, being overweight will increase this phenominon. Got like a Brison 3.2 in it?

no a moki 210.

What does an aft CG have to do with it?

I'm not an aeronautical engineer so I can't explain it , but there is a post in the 200 word range regarding this issue if you do a search on knife edge pitch coupling.

I looked it up for
you..http://www.rcuniverse.com/showthread...ght=knife+edge]

I also have a DP Edge. Running a DA-50 on it. Balanced @ 5" and all incidences are @ zero. I too had the same issues on knife edge. Either side knife edge tucked to the belly and rolled to upright. I ended up dialing it rudder to aileron, and rudder to elevator mixing. Works fine now, but spent a few flights one day setting the mixing up.

I have a DP Edge 540 with a Moki 2.10 CG at 4 3/4" and it also pitches to the belly. It will fly a knife edge circle if I let it.