 One consequence of this is that models in general require additional longitudinal and directional stability, resisting sudden changes in pitch and yaw.While it may be possible for a pilot to respond quickly enough to control an unstable aircraft (such as a Wright Flyer), a radio control scale model of the same aircraft would only be flyable with design adjustments such as increased tail surfaces and wing dihedral for stability, or with avionics providing artificial stability.Free flight models need to have both static and dynamic stability.