Could you post a photo of this adapter cable? If your G3 controller is working with the usb dongle, then the dongle should be fine. Best way is to confirm with a different Futaba radio

The adapter cable I'm using is the one in the first photo. I was able to borrow another one with a JR/Spektrum end that was working on his AeroFly. Unfortunately he did not bring his dongle along to try on my AeroFly. We tested his adapter and radio on my dongle and no work.

I'm still working on another Futaba radio to try.