I am using a Futaba FASST 7ch module in my FF9c, in a Hanger 9 Funtana 90, with no problems at all, so far. I am only using a 4cell, 1100mah nicad for RX power with all digital servos, & have no issues with it. But I will need a lot more, trouble free, flights to convince me to committ it to jet power. Then I will consider the Futaba 12, on 2.4Ghz, rather than the add on module system. Ray.