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I have and idea i'm goin to try by putting my batterry packs in a sliding tray and using a retract servo with pulleys to have the battery packs slide to the rear when I switch to flight mode thre for 3D. Anyone have any input on this idea or ever tried anything like this I know alot of fliers add weight to the tail for there 3d freestyles . I think being able to change your CG with a flick of the switch to high rate would work with the right design????