Hi mate Check your CG, On the early 1.9 the self level was set low as it was for the acro board or if an ACC was down on the board , Steveis did a lot of work on the set up and was asked to up the self level like Jackson said its been done, 1.9 is more aggressive This is why steveis says use 1.8 for normal KK2.1.5 and normal type flying default is good for 99% of the quads out there