Which of the following reduces roll control during a stall when using swept wings?

Stalling from the root to the wing tips is indeed a critical factor in understanding roll control during a stall, particularly with swept-wing designs. When a swept-wing aircraft experiences a stall, it is typically the wing root that reaches the critical angle of attack first, leading to a stall that propagates outward toward the tips. This sequential stalling can cause a significant loss of aileron effectiveness as airflow over the control surfaces diminishes, resulting in a reduction of roll control.

In swept-wing aircraft, the design affects how and where the stall occurs. With the root stalling first, the wing’s center of lift shifts inboard, causing unpredictable roll behavior. This phenomenon can mean that while one wing may stall, the other may still retain enough lift, leading to an uncommanded roll.

The other options, while relevant to stall characteristics and aircraft handling, do not specifically address the relationship between the stall propagation and roll control in the context of swept wings. Increased dihedral stability, for example, impacts overall stability and can help counteract roll, but it does not directly contribute to the stall characteristics. The use of a stall fence is intended to delay stall onset and improve controllability, but again, it doesn't inherently reduce roll control during a stall