Original sentence: (although not all foreplanes are used for this purpose).A static horizontal stabilizer may be placed either behind the center of mass, as a tailplane, or forward of it as a canard foreplane.In some cases the foreplane acts with the other horizontal surfaces to provide longitudinal (or "pitch") stability, in which case it acts as a stabilizer.Static vertical stabilizers are small wing surfaces placed behind the center of mass of an aircraft, either as part of the tail empennage or outboard on aft-swept wings.The tailplane is a small horizontal wing attached to an aircraft, which acts with the other horizontal surfaces to provide longitudinal (or "pitch") stability
Edited sentence: Following the first flight, the Wright Flyers added ballast to the nose.Pitch stability requires that the lift slope of the canard wing is lower than the lift slope of the main wing : to achieve stability, the change in lift coefficient with angle of attack should be less than that for the main plane.. The first powered airplane to fly, the Wright Flyer, a lifting-canard, was pitch unstable.Static vertical stabilizer is wing surface placed behind the center of mass of an aircraft, either as part of the tail empennage or outboard on aft-swept wings.The horizontal stabilizer or tailplane is a small horizontal wing attached to an aircraft, which acts with the other horizontal surfaces to provide longitudinal (or "pitch") stability