ORIGINAL: mydartswinger
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.
According to the mcx manual, you can actually reverse the servos using the transmitter and holding the trim buttons for awhile, your mileage may very. Also the mcx is 4ch and I think the cx3 is 5ch, might be a problem, don't know.
Mike