What effect does increased dihedral have on a sweptwing airplane with weak static directional stability?

Increased dihedral in a swept-wing airplane affects its stability characteristics, particularly with regard to lateral control and response to lateral movement. When dihedral angle increases, the wings are angled slightly upward from the horizontal plane, which enhances the aircraft's lateral stability.

In the context of an airplane with weak static directional stability, this increase in dihedral has the effect of increasing the aircraft's Dutch roll tendency. Dutch roll is a type of oscillation where the aircraft yaws (changes direction) and simultaneously rolls (tilts sideways). With weak static directional stability, the aircraft can become more susceptible to such yaw and roll oscillations. The added dihedral contributes to the rolling response when the aircraft experiences yaw motions.

By improving lateral stability—due to the dihedral—the aircraft might initially seem more stable; however, if the directional stability is already weak, the dihedral may enhance the coupling between yaw and roll. Hence, the airplane is more prone to experience pronounced oscillations known as Dutch roll.

The other effects mentioned, like increasing longitudinal stability, increasing stall resistance, or reducing Mach tuck tendency, do not specifically relate to the direct impact of increased dihedral in the same way. Thus, the assertion that increased dihedral increases Dutch roll tendency accurately captures