Our field has 16 fellows with 50 size helis, most with more then one...and some are pretty hot 3D pilots. They all use the 401/9254 combo on one or more of their 50's and we are all very satisfied with them. They hold onto the tail almost as well as the top line gyros like the 611 etc.. The only area they are not as proficient, is in keeping the same piro rate upwind, as downwind, in any traveling piro maneuver...vertical or horizontal.