I have checked the balance on it and it looks fine. Does not usually pitch up or roll/slide to one side (trims seem ok). It will be hovering smoothly but as I said, after about 30-40 seconds THEN ON ONLY THEN does it start to vibrate. I am thinking that your advice about the main rotor blade tightness may be the issue. I have seen that if the main blades are too loose, it will vibrate immediately, as soon as I start to spool up the blades.

The heli is a Dragonfly kit but not the one that I have seen with the white canopy. This one is a cheaper version I guess from hong kong. The canopy has a clear windshield which is different from the Dragonfly I have seen on the internet on other web sites. The ESC, RCV,Gyro are all housed inside a small black box. It came completely assembled and ready to fly.

I have a Fun Piccolo, and I do not have any of the problems with that one that I am having with this Dragonfly.

Thanks for your help. I'll check the main rotor blade screws again and see if maybe they are now too tight.