sounds like the tail fork is cracked and slipping, this is a very common problem with the plastic version. my R60 has a JR extreme heading lock gyro G5000T with the 8700g servo and it breaks the plastics regularly, just snapped 2 of them this weekend, I've got the aluminum to replace it with this time. I've been pretty lucky, I've broke at least a dozen or so of them and every time I'm able to give hard right tail and it'll shove it back on the brass and auto in, last one didn't make it to the runway and had to put it down in the grass, which for those who know me is an insult and I'd rather be hung then sit my bird in the grass [:@]

kc

EDIT: Better Pic added