I can safely say that securing your rx in foam rubber is a good idea. In my electric planes, the rx is attached just via velcro.
I was doing that in my glow planes, just putting some velcro in the fuse and sticking on the rx. I had a Cessna Skylane w/.46 engine.
Plane looked really good in the air. However on its 4th flight, about 6 minutes into it, I was doing a slow left hand turn when the plane wouldn't respond to anything. It spiraled in from 150 feet. Upon checking, I found the crystal was fractured. I was using a Hitec 6 channel rx. I surmise that this may have been due to vibration and I had the Electron rx just velcro'd to the side of the fuse.

Dave...