RE: Spektrum DX-7
My Mini Ultra Stick with an AR6100 also spiraled in uncontrollably without warning. I had lost all contact with the plane after flying for around 6 minutes on a fully charged 2100 lipo battery. When I got to the plane everything was working fine. The concensus at the field was that turbulance from a Euro Fighter jet taking off caused my problem. I was flying on the other side of the runway, the jet took off and I was coming around to land so I could watch and as I got to the runway, it spiraled in. I called Horizon to talk to them about this and they blamed my setup of the Mini Ultra Stick saying that plane called for a separate BEC or receiver battery. When I told the guy I was running only 4 servos, (no flaps), he said that he had heard the MUS needed a separate BEC regardless. When I challenged him on this, he got annoyed with me and said I could send the receiver in but chances are they will find nothing wrong. I've since fixed the MUS and have been flying it with the same 6100 receiver and so far so good. Not flying with jets either.