When I flew the Ripper, and then the Avenger by Seaholm, I used duct tape to tape the rx to the fuse, with one end of it at the trailing edge. The battery on the Riper was about on the spar line, and for the Avenger, it was pull tied on opposite the fuel tank as per the instructions in order for the model to balance. I don't know if I was lucky or good, but I was never mid-aired underneath the wing of either airframe. Make an effort to keep the Ripper as light as possible as the semi-symetrical wing is not the best when it comes to lift.