well it could be a number of things that causes this. Your Rx could be losing the signal which would be a sign of a bad Rx. However, you stated that this is an OrangeRx which is a cheap clone of the DXM2 Rx's from spektrum. There have been known compatibility issues with them that could be causing this. On my Rx that I had in the Bipe, If I moved a stick too fast it would not respond. However it could also be caused by low voltage. If you are running your pack until the low voltage cutoff kicks in, this could do it as well.
Just for clarification, I have the OrangeRx in my RCH Trainer, but I will be removing it once I have another Rx to put in there that is genuine Spektrum DSMX. It flew fine on the maiden flight, but I really dont' want to lose this plane.