mehmet1846-
...If you looked ground looping effects ,you must check the both wing incidence first and C.G. second...
Sorry, but I completely disagree. Neither wing incidence nor CG have anything to do with ground looping. It is directly related to engine torque and a short fuselage. The rudder can only counteract this if you throttle into it very slowly. Most RC runways are not long enough to allow enough time for this.
Brian