hello, them story that the day of yesterday, next of almost fly a year my Zafiroe, that has a motor O.S 91fx, change prop to me, since when torque roll the model it is not layers to leave the vertical, thus installs one to him prop 15x6, with fear to that it lost traction and it did not have a limitless vertical, and that creates? The model change , flies but slow and now is 1/2 throtel layers to do torque roll and to leave the vertical