Center of pressure is used in sailboat design to represent the position on a sail where the aerodynamic force is concentrated.
A slight amount of weather helm is thought by some sailors to be a desirable situation, both from the standpoint of the "feel" of the helm, and the tendency of the boat to head slightly to windward in stronger gusts, to some extent self-feathering the sails.
[5][6][7] The aerodynamic center plays an important role in analysis of the longitudinal static stability of all flying machines.
For an aircraft to return towards its trimmed attitude, without input from a pilot or autopilot, it must have positive longitudinal static stability.
Since the center of pressure for symmetric airfoils is relatively constant for small angle of attack, missile engineers typically speak of the complete center of pressure of the entire vehicle for stability and control analysis.
In missiles at lower angles of attack, the contributions to the center of pressure are dominated by the nose, wings, and fins.
The center of pressure of the added flow field is behind the center of gravity and the additional force "points" in the direction of the added angle of attack; this produces a moment that pushes the vehicle back to the trim position.
For a symmetric airfoil, as angle of attack and lift coefficient change, the center of pressure does not move.
The role of center of pressure in the control characterization of aircraft takes a different form than in missiles.
[11] For a conventionally cambered airfoil, the center of pressure lies a little behind the quarter-chord point at maximum lift coefficient (large angle of attack), but as lift coefficient reduces (angle of attack reduces) the center of pressure moves toward the rear.
For a reflex-cambered airfoil, the center of pressure lies a little ahead of the quarter-chord point at maximum lift coefficient (large angle of attack), but as lift coefficient reduces (angle of attack reduces) the center of pressure moves forward.
The aerodynamic center occupies a fixed location on an airfoil, typically close to the quarter-chord point.