It may be possible to use the mCX controller with the CX3. However, when pilots go from the CX2 to an mCX, they need to change some of the dip switches (reversing the servos). In that case, you may not be able to use the mCX Tx with the CX3 since the mCX radio does not have servo reversing capabilities. I could be wrong, HH may have included some special programming in the radio to allow the mCX radio to be compatible with another heli/airplane.