In a glider or conventional airplane, moving the CG farther aft generally results in:

• A. Less stability at all speeds
• B. Increased stability at all speeds
• C. No change in stability
• D. Higher maximum lift coefficient

Answer: (A)

The main idea is longitudinal stability, which comes from the CG position relative to the neutral point. If the CG sits ahead of that point, a pitch disturbance creates a restoring moment that tends to bring the nose back toward the original attitude. When the CG moves farther aft, this restoring moment shrinks because the tail’s stabilizing force has less lever arm about the CG. That makes the airplane less able to return to its original pitch after a disturbance, so stability decreases.

This reduced restoring tendency generally applies across flight speeds, so moving the CG aft tends to make the aircraft less stable at all speeds. The maximum lift coefficient isn’t directly increased by shifting the CG; stability and lift are governed by different aspects of the aerodynamics, and a more aft CG doesn’t magically raise CLmax.