The one I owned a while back was a good solid heli, just set her down easy in the application you will be using her for it will be great. When autoing Iwould get the occasional boom strike with the flapping head was about it, but so did my Kalt Enforcers as well. The heli was fairly well upgraded..out of the box
Instead of the spindle shaft, a flapping plate connects with both side rotor blades...I really miss mine (Concept 60). I's like to find another or a 60 SR Champion.
The Concept line & their history..
http://www.geocities.com/CapeCanaver.../kyosh1-e.html