diff --git a/ArduCopter/mode_acro.cpp b/ArduCopter/mode_acro.cpp
index 1620c78833..dcfa838839 100644
--- a/ArduCopter/mode_acro.cpp
+++ b/ArduCopter/mode_acro.cpp
@@ -124,15 +124,15 @@ void ModeAcro::get_pilot_desired_angle_rates(int16_t roll_in, int16_t pitch_in,
         if (g.acro_trainer == ACRO_TRAINER_LIMITED) {
             const float angle_max = copter.aparm.angle_max;
             if (roll_angle > angle_max){
-                rate_ef_level.x -=  g.acro_balance_roll*(roll_angle-angle_max);
+                rate_ef_level.x +=  AC_AttitudeControl::sqrt_controller(angle_max - roll_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_roll_max(), G_Dt);
             }else if (roll_angle < -angle_max) {
-                rate_ef_level.x -=  g.acro_balance_roll*(roll_angle+angle_max);
+                rate_ef_level.x +=  AC_AttitudeControl::sqrt_controller(-angle_max - roll_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_roll_max(), G_Dt);
             }
 
             if (pitch_angle > angle_max){
-                rate_ef_level.y -=  g.acro_balance_pitch*(pitch_angle-angle_max);
+                rate_ef_level.y +=  AC_AttitudeControl::sqrt_controller(angle_max - pitch_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_pitch_max(), G_Dt);
             }else if (pitch_angle < -angle_max) {
-                rate_ef_level.y -=  g.acro_balance_pitch*(pitch_angle+angle_max);
+                rate_ef_level.y +=  AC_AttitudeControl::sqrt_controller(-angle_max - pitch_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_pitch_max(), G_Dt);
             }
         }
 
diff --git a/ArduCopter/mode_sport.cpp b/ArduCopter/mode_sport.cpp
index 462402f004..588f8c50ad 100644
--- a/ArduCopter/mode_sport.cpp
+++ b/ArduCopter/mode_sport.cpp
@@ -54,15 +54,15 @@ void ModeSport::run()
 
     const float angle_max = copter.aparm.angle_max;
     if (roll_angle > angle_max){
-        target_roll_rate -=  g.acro_rp_p*(roll_angle-angle_max);
+        target_roll_rate +=  AC_AttitudeControl::sqrt_controller(angle_max - roll_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_roll_max(), G_Dt);
     }else if (roll_angle < -angle_max) {
-        target_roll_rate -=  g.acro_rp_p*(roll_angle+angle_max);
+        target_roll_rate +=  AC_AttitudeControl::sqrt_controller(-angle_max - roll_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_roll_max(), G_Dt);
     }
 
     if (pitch_angle > angle_max){
-        target_pitch_rate -=  g.acro_rp_p*(pitch_angle-angle_max);
+        target_pitch_rate +=  AC_AttitudeControl::sqrt_controller(angle_max - pitch_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_pitch_max(), G_Dt);
     }else if (pitch_angle < -angle_max) {
-        target_pitch_rate -=  g.acro_rp_p*(pitch_angle+angle_max);
+        target_pitch_rate +=  AC_AttitudeControl::sqrt_controller(-angle_max - pitch_angle, g.acro_rp_p * 4.5, attitude_control->get_accel_pitch_max(), G_Dt);
     }
 
     // get pilot's desired yaw rate