How does center of gravity position affect stability and stall behavior?

• A. Forward CG increases stability and reduces stall speed; aft CG decreases stability and reduces stall margin.
• B. Forward CG increases stability and stall speed; aft CG decreases stability and reduces stall margin.
• C. Aft CG increases stability and reduces stall margin.
• D. CG position has no effect on stability.

Answer: (D)

Center of gravity location relative to the aircraft’s aerodynamic center sets how the plane responds to pitch disturbances and how easily it can be controlled near stall. When the CG is forward, the airplane has stronger static stability: if it’s nudged nose-up or nose-down, the forces and moments tend to return it toward the original attitude. The tail must push down more to balance, which also means you’ll feel higher elevator forces to maintain or change pitch. This stability helps keep the aircraft from wandering in pitch, and it often makes the stall behavior more predictable, with the elevator remaining effective longer as you approach the stall.

If the CG is moved aft, stability decreases. The airplane becomes more susceptible to pitch changes and can become harder to keep from wandering off from level flight. Near stall, reduced stability and reduced tail effectiveness can make control less predictable and the stall more abrupt or harder to recover from, especially if you’re near the limits of elevator authority.

Stall speed itself is mainly governed by weight, but CG position influences how the airplane behaves as it approaches the stall and how controllable it remains at low speeds.